use super::traits::{Tool, ToolResult};
use crate::agent::loop_::run_tool_call_loop;
use crate::agent::prompt::{PromptContext, SystemPromptBuilder};
use crate::config::{DelegateAgentConfig, DelegateToolConfig};
use crate::observability::traits::{Observer, ObserverEvent, ObserverMetric};
use crate::providers::{self, ChatMessage, Provider};
use crate::security::SecurityPolicy;
use crate::security::policy::ToolOperation;
use async_trait::async_trait;
use parking_lot::RwLock;
use serde_json::json;
use std::collections::HashMap;
use std::path::{Path, PathBuf};
use std::sync::Arc;
use std::time::Duration;
use tokio_util::sync::CancellationToken;

/// Serializable result of a background delegate task.
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
pub struct BackgroundDelegateResult {
    pub task_id: String,
    pub agent: String,
    pub status: BackgroundTaskStatus,
    pub output: Option<String>,
    pub error: Option<String>,
    pub started_at: String,
    pub finished_at: Option<String>,
}

/// Status of a background delegate task.
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize, PartialEq, Eq)]
#[serde(rename_all = "snake_case")]
pub enum BackgroundTaskStatus {
    Running,
    Completed,
    Failed,
    Cancelled,
}

/// Tool that delegates a subtask to a named agent with a different
/// provider/model configuration. Enables multi-agent workflows where
/// a primary agent can hand off specialized work (research, coding,
/// summarization) to purpose-built sub-agents.
///
/// Supports three execution modes:
/// - **Synchronous** (default): blocks until the sub-agent completes.
/// - **Background** (`background: true`): spawns the sub-agent in a tokio
///   task and returns a `task_id` immediately.
/// - **Parallel** (`parallel: [...]`): runs multiple agents concurrently
///   and returns all results.
///
/// Background results are persisted to `workspace/delegate_results/{task_id}.json`
/// and can be retrieved via `action: "check_result"`.
pub struct DelegateTool {
    agents: Arc<HashMap<String, DelegateAgentConfig>>,
    security: Arc<SecurityPolicy>,
    /// Global credential fallback (from config.api_key)
    fallback_credential: Option<String>,
    /// Provider runtime options inherited from root config.
    provider_runtime_options: providers::ProviderRuntimeOptions,
    /// Depth at which this tool instance lives in the delegation chain.
    depth: u32,
    /// Parent tool registry for agentic sub-agents.
    parent_tools: Arc<RwLock<Vec<Arc<dyn Tool>>>>,
    /// Inherited multimodal handling config for sub-agent loops.
    multimodal_config: crate::config::MultimodalConfig,
    /// Global delegate tool config providing default timeout values.
    delegate_config: DelegateToolConfig,
    /// Workspace directory inherited from the root agent context.
    workspace_dir: PathBuf,
    /// Cancellation token for cascade control of background tasks.
    cancellation_token: CancellationToken,
}

impl DelegateTool {
    pub fn new(
        agents: HashMap<String, DelegateAgentConfig>,
        fallback_credential: Option<String>,
        security: Arc<SecurityPolicy>,
    ) -> Self {
        Self::new_with_options(
            agents,
            fallback_credential,
            security,
            providers::ProviderRuntimeOptions::default(),
        )
    }

    pub fn new_with_options(
        agents: HashMap<String, DelegateAgentConfig>,
        fallback_credential: Option<String>,
        security: Arc<SecurityPolicy>,
        provider_runtime_options: providers::ProviderRuntimeOptions,
    ) -> Self {
        Self {
            agents: Arc::new(agents),
            security,
            fallback_credential,
            provider_runtime_options,
            depth: 0,
            parent_tools: Arc::new(RwLock::new(Vec::new())),
            multimodal_config: crate::config::MultimodalConfig::default(),
            delegate_config: DelegateToolConfig::default(),
            workspace_dir: PathBuf::new(),
            cancellation_token: CancellationToken::new(),
        }
    }

    /// Create a DelegateTool for a sub-agent (with incremented depth).
    /// When sub-agents eventually get their own tool registry, revka
    /// their DelegateTool via this method with `depth: parent.depth + 1`.
    pub fn with_depth(
        agents: HashMap<String, DelegateAgentConfig>,
        fallback_credential: Option<String>,
        security: Arc<SecurityPolicy>,
        depth: u32,
    ) -> Self {
        Self::with_depth_and_options(
            agents,
            fallback_credential,
            security,
            depth,
            providers::ProviderRuntimeOptions::default(),
        )
    }

    pub fn with_depth_and_options(
        agents: HashMap<String, DelegateAgentConfig>,
        fallback_credential: Option<String>,
        security: Arc<SecurityPolicy>,
        depth: u32,
        provider_runtime_options: providers::ProviderRuntimeOptions,
    ) -> Self {
        Self {
            agents: Arc::new(agents),
            security,
            fallback_credential,
            provider_runtime_options,
            depth,
            parent_tools: Arc::new(RwLock::new(Vec::new())),
            multimodal_config: crate::config::MultimodalConfig::default(),
            delegate_config: DelegateToolConfig::default(),
            workspace_dir: PathBuf::new(),
            cancellation_token: CancellationToken::new(),
        }
    }

    /// Attach parent tools used to build sub-agent allowlist registries.
    pub fn with_parent_tools(mut self, parent_tools: Arc<RwLock<Vec<Arc<dyn Tool>>>>) -> Self {
        self.parent_tools = parent_tools;
        self
    }

    /// Attach multimodal configuration for sub-agent tool loops.
    pub fn with_multimodal_config(mut self, config: crate::config::MultimodalConfig) -> Self {
        self.multimodal_config = config;
        self
    }

    /// Attach global delegate tool configuration for default timeout values.
    pub fn with_delegate_config(mut self, config: DelegateToolConfig) -> Self {
        self.delegate_config = config;
        self
    }

    /// Return a shared handle to the parent tools list.
    /// Callers can push additional tools (e.g. MCP wrappers) after construction.
    pub fn parent_tools_handle(&self) -> Arc<RwLock<Vec<Arc<dyn Tool>>>> {
        Arc::clone(&self.parent_tools)
    }

    /// Attach the workspace directory for system prompt enrichment.
    pub fn with_workspace_dir(mut self, workspace_dir: PathBuf) -> Self {
        self.workspace_dir = workspace_dir;
        self
    }

    /// Attach a cancellation token for cascade control of background tasks.
    /// When the token is cancelled, all background sub-agents are aborted.
    pub fn with_cancellation_token(mut self, token: CancellationToken) -> Self {
        self.cancellation_token = token;
        self
    }

    /// Return the cancellation token for external cascade control.
    pub fn cancellation_token(&self) -> &CancellationToken {
        &self.cancellation_token
    }

    /// Directory where background delegate results are stored.
    fn results_dir(&self) -> PathBuf {
        self.workspace_dir.join("delegate_results")
    }

    /// Validate that a user-provided task_id is a valid UUID to prevent
    /// path traversal attacks (e.g. `../../etc/passwd`).
    fn validate_task_id(task_id: &str) -> Result<(), String> {
        if uuid::Uuid::parse_str(task_id).is_err() {
            return Err(format!("Invalid task_id '{task_id}': must be a valid UUID"));
        }
        Ok(())
    }
}

#[async_trait]
impl Tool for DelegateTool {
    fn name(&self) -> &str {
        "delegate"
    }

    fn description(&self) -> &str {
        "Delegate a subtask to a specialized agent. Use when: a task benefits from a different model \
         (e.g. fast summarization, deep reasoning, code generation). The sub-agent runs a single \
         prompt by default; with agentic=true it can iterate with a filtered tool-call loop. \
         Supports background execution (returns a task_id immediately) and parallel execution \
         (runs multiple agents concurrently). Use action='check_result' with a task_id to \
         retrieve background results."
    }

    fn parameters_schema(&self) -> serde_json::Value {
        let agent_names: Vec<&str> = self.agents.keys().map(|s: &String| s.as_str()).collect();
        json!({
            "type": "object",
            "additionalProperties": false,
            "properties": {
                "action": {
                    "type": "string",
                    "enum": ["delegate", "check_result", "list_results", "cancel_task"],
                    "description": "Action to perform. Default: 'delegate'. Use 'check_result' to \
                                    retrieve a background task result, 'list_results' to list all \
                                    background tasks, 'cancel_task' to cancel a running background task.",
                    "default": "delegate"
                },
                "agent": {
                    "type": "string",
                    "minLength": 1,
                    "description": format!(
                        "Name of the agent to delegate to. Available: {}",
                        if agent_names.is_empty() {
                            "(none configured)".to_string()
                        } else {
                            agent_names.join(", ")
                        }
                    )
                },
                "prompt": {
                    "type": "string",
                    "minLength": 1,
                    "description": "The task/prompt to send to the sub-agent"
                },
                "context": {
                    "type": "string",
                    "description": "Optional context to prepend (e.g. relevant code, prior findings)"
                },
                "background": {
                    "type": "boolean",
                    "description": "When true, the sub-agent runs in a background tokio task and \
                                    returns a task_id immediately. Results are stored to \
                                    workspace/delegate_results/{task_id}.json.",
                    "default": false
                },
                "parallel": {
                    "type": "array",
                    "items": { "type": "string" },
                    "description": "Array of agent names to run concurrently with the same prompt. \
                                    Returns all results when all agents complete. Cannot be combined \
                                    with 'background'."
                },
                "task_id": {
                    "type": "string",
                    "description": "Task ID for check_result/cancel_task actions (returned by \
                                    background delegation)."
                }
            },
            "required": []
        })
    }

    async fn execute(&self, args: serde_json::Value) -> anyhow::Result<ToolResult> {
        let action = args
            .get("action")
            .and_then(|v| v.as_str())
            .unwrap_or("delegate");

        match action {
            "check_result" => return self.handle_check_result(&args).await,
            "list_results" => return self.handle_list_results().await,
            "cancel_task" => return self.handle_cancel_task(&args).await,
            "delegate" => {} // fall through to delegation logic
            other => {
                return Ok(ToolResult {
                    success: false,
                    output: String::new(),
                    error: Some(format!(
                        "Unknown action '{other}'. Use delegate/check_result/list_results/cancel_task."
                    )),
                });
            }
        }

        // --- Parallel mode ---
        if let Some(parallel_agents) = args.get("parallel").and_then(|v| v.as_array()) {
            return self.execute_parallel(parallel_agents, &args).await;
        }

        // --- Single-agent delegation (synchronous or background) ---
        let agent_name = args
            .get("agent")
            .and_then(|v| v.as_str())
            .map(str::trim)
            .ok_or_else(|| anyhow::anyhow!("Missing 'agent' parameter"))?;

        if agent_name.is_empty() {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some("'agent' parameter must not be empty".into()),
            });
        }

        let prompt = args
            .get("prompt")
            .and_then(|v| v.as_str())
            .map(str::trim)
            .ok_or_else(|| anyhow::anyhow!("Missing 'prompt' parameter"))?;

        if prompt.is_empty() {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some("'prompt' parameter must not be empty".into()),
            });
        }

        let background = args
            .get("background")
            .and_then(|v| v.as_bool())
            .unwrap_or(false);

        if background {
            return self.execute_background(agent_name, prompt, &args).await;
        }

        // --- Synchronous delegation (original path) ---
        self.execute_sync(agent_name, prompt, &args).await
    }
}

impl DelegateTool {
    /// Original synchronous delegation path (extracted for reuse).
    async fn execute_sync(
        &self,
        agent_name: &str,
        prompt: &str,
        args: &serde_json::Value,
    ) -> anyhow::Result<ToolResult> {
        let context = args
            .get("context")
            .and_then(|v| v.as_str())
            .map(str::trim)
            .unwrap_or("");

        // Look up agent config
        let agent_config = match self.agents.get(agent_name) {
            Some(cfg) => cfg,
            None => {
                let available: Vec<&str> =
                    self.agents.keys().map(|s: &String| s.as_str()).collect();
                return Ok(ToolResult {
                    success: false,
                    output: String::new(),
                    error: Some(format!(
                        "Unknown agent '{agent_name}'. Available agents: {}",
                        if available.is_empty() {
                            "(none configured)".to_string()
                        } else {
                            available.join(", ")
                        }
                    )),
                });
            }
        };

        // Check recursion depth (immutable — set at construction, incremented for sub-agents)
        if self.depth >= agent_config.max_depth {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!(
                    "Delegation depth limit reached ({depth}/{max}). \
                     Cannot delegate further to prevent infinite loops.",
                    depth = self.depth,
                    max = agent_config.max_depth
                )),
            });
        }

        if let Err(error) = self
            .security
            .enforce_tool_operation(ToolOperation::Act, "delegate")
        {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(error),
            });
        }

        // Create provider for this agent
        let provider_credential_owned = agent_config
            .api_key
            .clone()
            .or_else(|| self.fallback_credential.clone());
        #[allow(clippy::option_as_ref_deref)]
        let provider_credential = provider_credential_owned.as_ref().map(String::as_str);

        let provider: Box<dyn Provider> = match providers::create_provider_with_options(
            &agent_config.provider,
            provider_credential,
            &self.provider_runtime_options,
        ) {
            Ok(p) => p,
            Err(e) => {
                return Ok(ToolResult {
                    success: false,
                    output: String::new(),
                    error: Some(format!(
                        "Failed to create provider '{}' for agent '{agent_name}': {e}",
                        agent_config.provider
                    )),
                });
            }
        };

        // Build the message
        let full_prompt = if context.is_empty() {
            prompt.to_string()
        } else {
            format!("[Context]\n{context}\n\n[Task]\n{prompt}")
        };

        let temperature = agent_config.temperature.unwrap_or(0.7);

        // Agentic mode: run full tool-call loop with allowlisted tools.
        if agent_config.agentic {
            return self
                .execute_agentic(
                    agent_name,
                    agent_config,
                    &*provider,
                    &full_prompt,
                    temperature,
                )
                .await;
        }

        // Build enriched system prompt for non-agentic sub-agent.
        let enriched_system_prompt =
            self.build_enriched_system_prompt(agent_config, &[], &self.workspace_dir);
        let system_prompt_ref = enriched_system_prompt.as_deref();

        // Wrap the provider call in a timeout to prevent indefinite blocking
        let timeout_secs = agent_config
            .timeout_secs
            .unwrap_or(self.delegate_config.timeout_secs);
        let result = tokio::time::timeout(
            Duration::from_secs(timeout_secs),
            provider.chat_with_system(
                system_prompt_ref,
                &full_prompt,
                &agent_config.model,
                temperature,
            ),
        )
        .await;

        let result = match result {
            Ok(inner) => inner,
            Err(_elapsed) => {
                return Ok(ToolResult {
                    success: false,
                    output: String::new(),
                    error: Some(format!(
                        "Agent '{agent_name}' timed out after {timeout_secs}s"
                    )),
                });
            }
        };

        match result {
            Ok(response) => {
                let mut rendered = response;
                if rendered.trim().is_empty() {
                    rendered = "[Empty response]".to_string();
                }

                Ok(ToolResult {
                    success: true,
                    output: format!(
                        "[Agent '{agent_name}' ({provider}/{model})]\n{rendered}",
                        provider = agent_config.provider,
                        model = agent_config.model
                    ),
                    error: None,
                })
            }
            Err(e) => Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!("Agent '{agent_name}' failed: {e}")),
            }),
        }
    }
}

impl DelegateTool {
    // ── Background Execution ────────────────────────────────────────

    /// Spawn a sub-agent in a background tokio task. Returns a task_id immediately.
    /// The result is persisted to `workspace/delegate_results/{task_id}.json`.
    async fn execute_background(
        &self,
        agent_name: &str,
        prompt: &str,
        args: &serde_json::Value,
    ) -> anyhow::Result<ToolResult> {
        // Validate agent exists and check depth/security before spawning
        let agent_config = match self.agents.get(agent_name) {
            Some(cfg) => cfg.clone(),
            None => {
                let available: Vec<&str> =
                    self.agents.keys().map(|s: &String| s.as_str()).collect();
                return Ok(ToolResult {
                    success: false,
                    output: String::new(),
                    error: Some(format!(
                        "Unknown agent '{agent_name}'. Available agents: {}",
                        if available.is_empty() {
                            "(none configured)".to_string()
                        } else {
                            available.join(", ")
                        }
                    )),
                });
            }
        };

        if self.depth >= agent_config.max_depth {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!(
                    "Delegation depth limit reached ({depth}/{max}).",
                    depth = self.depth,
                    max = agent_config.max_depth
                )),
            });
        }

        if let Err(error) = self
            .security
            .enforce_tool_operation(ToolOperation::Act, "delegate")
        {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(error),
            });
        }

        let task_id = uuid::Uuid::new_v4().to_string();
        let results_dir = self.results_dir();
        tokio::fs::create_dir_all(&results_dir).await?;

        let context = args
            .get("context")
            .and_then(|v| v.as_str())
            .map(str::trim)
            .unwrap_or("");
        let full_prompt = if context.is_empty() {
            prompt.to_string()
        } else {
            format!("[Context]\n{context}\n\n[Task]\n{prompt}")
        };

        let started_at = chrono::Utc::now().to_rfc3339();
        let agent_name_owned = agent_name.to_string();

        // Write initial "running" status
        let initial_result = BackgroundDelegateResult {
            task_id: task_id.clone(),
            agent: agent_name_owned.clone(),
            status: BackgroundTaskStatus::Running,
            output: None,
            error: None,
            started_at: started_at.clone(),
            finished_at: None,
        };
        let result_path = results_dir.join(format!("{task_id}.json"));
        let json_bytes = serde_json::to_vec_pretty(&initial_result)?;
        tokio::fs::write(&result_path, &json_bytes).await?;

        // Clone everything needed for the spawned task
        let agents = Arc::clone(&self.agents);
        let security = Arc::clone(&self.security);
        let fallback_credential = self.fallback_credential.clone();
        let provider_runtime_options = self.provider_runtime_options.clone();
        let depth = self.depth;
        let parent_tools = Arc::clone(&self.parent_tools);
        let multimodal_config = self.multimodal_config.clone();
        let delegate_config = self.delegate_config.clone();
        let workspace_dir = self.workspace_dir.clone();
        let child_token = self.cancellation_token.child_token();
        let task_id_clone = task_id.clone();

        tokio::spawn(async move {
            // Build an inner DelegateTool for the spawned context
            let inner = DelegateTool {
                agents,
                security,
                fallback_credential,
                provider_runtime_options,
                depth,
                parent_tools,
                multimodal_config,
                delegate_config,
                workspace_dir: workspace_dir.clone(),
                cancellation_token: child_token.clone(),
            };

            let args_inner = json!({
                "agent": agent_name_owned,
                "prompt": full_prompt,
            });

            // Race the delegation against cancellation
            let outcome = tokio::select! {
                () = child_token.cancelled() => {
                    Err("Cancelled by parent session".to_string())
                }
                result = Box::pin(inner.execute_sync(&agent_name_owned, &full_prompt, &args_inner)) => {
                    match result {
                        Ok(tool_result) => {
                            if tool_result.success {
                                Ok(tool_result.output)
                            } else {
                                Err(tool_result.error.unwrap_or_else(|| "Unknown error".into()))
                            }
                        }
                        Err(e) => Err(e.to_string()),
                    }
                }
            };

            let finished_at = chrono::Utc::now().to_rfc3339();
            let final_result = match outcome {
                Ok(output) => BackgroundDelegateResult {
                    task_id: task_id_clone.clone(),
                    agent: agent_name_owned,
                    status: BackgroundTaskStatus::Completed,
                    output: Some(output),
                    error: None,
                    started_at,
                    finished_at: Some(finished_at),
                },
                Err(err) => {
                    let status = if err.contains("Cancelled") {
                        BackgroundTaskStatus::Cancelled
                    } else {
                        BackgroundTaskStatus::Failed
                    };
                    BackgroundDelegateResult {
                        task_id: task_id_clone.clone(),
                        agent: agent_name_owned,
                        status,
                        output: None,
                        error: Some(err),
                        started_at,
                        finished_at: Some(finished_at),
                    }
                }
            };

            let result_path = results_dir.join(format!("{}.json", task_id_clone));
            if let Ok(bytes) = serde_json::to_vec_pretty(&final_result) {
                let _ = tokio::fs::write(&result_path, &bytes).await;
            }
        });

        Ok(ToolResult {
            success: true,
            output: format!(
                "Background task started for agent '{agent_name}'.\n\
                 task_id: {task_id}\n\
                 Use action='check_result' with task_id='{task_id}' to retrieve the result."
            ),
            error: None,
        })
    }

    // ── Parallel Execution ──────────────────────────────────────────

    /// Run multiple agents concurrently with the same prompt.
    async fn execute_parallel(
        &self,
        parallel_agents: &[serde_json::Value],
        args: &serde_json::Value,
    ) -> anyhow::Result<ToolResult> {
        let prompt = args
            .get("prompt")
            .and_then(|v| v.as_str())
            .map(str::trim)
            .ok_or_else(|| anyhow::anyhow!("Missing 'prompt' parameter for parallel execution"))?;

        if prompt.is_empty() {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some("'prompt' parameter must not be empty".into()),
            });
        }

        let agent_names: Vec<String> = parallel_agents
            .iter()
            .filter_map(|v| v.as_str().map(|s| s.trim().to_string()))
            .filter(|s| !s.is_empty())
            .collect();

        if agent_names.is_empty() {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some("'parallel' array must contain at least one agent name".into()),
            });
        }

        // Validate all agents exist before starting any
        for name in &agent_names {
            if !self.agents.contains_key(name) {
                let available: Vec<&str> =
                    self.agents.keys().map(|s: &String| s.as_str()).collect();
                return Ok(ToolResult {
                    success: false,
                    output: String::new(),
                    error: Some(format!(
                        "Unknown agent '{name}' in parallel list. Available: {}",
                        if available.is_empty() {
                            "(none configured)".to_string()
                        } else {
                            available.join(", ")
                        }
                    )),
                });
            }
        }

        // Spawn all agents concurrently
        let mut handles = Vec::with_capacity(agent_names.len());
        for agent_name in &agent_names {
            let agents = Arc::clone(&self.agents);
            let security = Arc::clone(&self.security);
            let fallback_credential = self.fallback_credential.clone();
            let provider_runtime_options = self.provider_runtime_options.clone();
            let depth = self.depth;
            let parent_tools = Arc::clone(&self.parent_tools);
            let multimodal_config = self.multimodal_config.clone();
            let delegate_config = self.delegate_config.clone();
            let workspace_dir = self.workspace_dir.clone();
            let cancellation_token = self.cancellation_token.child_token();
            let agent_name = agent_name.clone();
            let prompt = prompt.to_string();
            let args_clone = args.clone();

            handles.push(tokio::spawn(async move {
                let inner = DelegateTool {
                    agents,
                    security,
                    fallback_credential,
                    provider_runtime_options,
                    depth,
                    parent_tools,
                    multimodal_config,
                    delegate_config,
                    workspace_dir,
                    cancellation_token,
                };
                let result = Box::pin(inner.execute_sync(&agent_name, &prompt, &args_clone)).await;
                (agent_name, result)
            }));
        }

        // Collect all results
        let mut outputs = Vec::with_capacity(handles.len());
        let mut all_success = true;

        for handle in handles {
            match handle.await {
                Ok((agent_name, Ok(tool_result))) => {
                    if !tool_result.success {
                        all_success = false;
                    }
                    outputs.push(format!(
                        "--- {agent_name} (success={}) ---\n{}{}",
                        tool_result.success,
                        tool_result.output,
                        tool_result
                            .error
                            .map(|e| format!("\nError: {e}"))
                            .unwrap_or_default()
                    ));
                }
                Ok((agent_name, Err(e))) => {
                    all_success = false;
                    outputs.push(format!("--- {agent_name} (success=false) ---\nError: {e}"));
                }
                Err(e) => {
                    all_success = false;
                    outputs.push(format!("--- [join error] ---\n{e}"));
                }
            }
        }

        Ok(ToolResult {
            success: all_success,
            output: format!(
                "[Parallel delegation: {} agents]\n\n{}",
                agent_names.len(),
                outputs.join("\n\n")
            ),
            error: if all_success {
                None
            } else {
                Some("One or more parallel agents failed".into())
            },
        })
    }

    // ── Result Retrieval ────────────────────────────────────────────

    /// Retrieve the result of a background delegate task by task_id.
    async fn handle_check_result(&self, args: &serde_json::Value) -> anyhow::Result<ToolResult> {
        let task_id = args
            .get("task_id")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow::anyhow!("Missing 'task_id' parameter for check_result"))?;

        if let Err(e) = Self::validate_task_id(task_id) {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(e),
            });
        }

        let result_path = self.results_dir().join(format!("{task_id}.json"));
        if !result_path.exists() {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!("No result found for task_id '{task_id}'")),
            });
        }

        let content = tokio::fs::read_to_string(&result_path).await?;
        let result: BackgroundDelegateResult = serde_json::from_str(&content)?;

        Ok(ToolResult {
            success: result.status == BackgroundTaskStatus::Completed,
            output: serde_json::to_string_pretty(&result)?,
            error: if result.status == BackgroundTaskStatus::Completed {
                None
            } else {
                result.error
            },
        })
    }

    /// List all background delegate task results.
    async fn handle_list_results(&self) -> anyhow::Result<ToolResult> {
        let results_dir = self.results_dir();
        if !results_dir.exists() {
            return Ok(ToolResult {
                success: true,
                output: "No background delegate results found.".into(),
                error: None,
            });
        }

        let mut entries = tokio::fs::read_dir(&results_dir).await?;
        let mut results = Vec::new();

        while let Some(entry) = entries.next_entry().await? {
            let path = entry.path();
            if path.extension().and_then(|e| e.to_str()) == Some("json") {
                if let Ok(content) = tokio::fs::read_to_string(&path).await {
                    if let Ok(result) = serde_json::from_str::<BackgroundDelegateResult>(&content) {
                        results.push(json!({
                            "task_id": result.task_id,
                            "agent": result.agent,
                            "status": result.status,
                            "started_at": result.started_at,
                            "finished_at": result.finished_at,
                        }));
                    }
                }
            }
        }

        if results.is_empty() {
            return Ok(ToolResult {
                success: true,
                output: "No background delegate results found.".into(),
                error: None,
            });
        }

        Ok(ToolResult {
            success: true,
            output: serde_json::to_string_pretty(&results)?,
            error: None,
        })
    }

    /// Cancel a running background task by task_id.
    async fn handle_cancel_task(&self, args: &serde_json::Value) -> anyhow::Result<ToolResult> {
        let task_id = args
            .get("task_id")
            .and_then(|v| v.as_str())
            .ok_or_else(|| anyhow::anyhow!("Missing 'task_id' parameter for cancel_task"))?;

        if let Err(e) = Self::validate_task_id(task_id) {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(e),
            });
        }

        let result_path = self.results_dir().join(format!("{task_id}.json"));
        if !result_path.exists() {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!("No task found for task_id '{task_id}'")),
            });
        }

        // Read current status
        let content = tokio::fs::read_to_string(&result_path).await?;
        let mut result: BackgroundDelegateResult = serde_json::from_str(&content)?;

        if result.status != BackgroundTaskStatus::Running {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!(
                    "Task '{task_id}' is not running (status: {:?})",
                    result.status
                )),
            });
        }

        // Cancel via the parent token — this will cascade to all child tokens
        // Note: individual task cancellation uses the shared parent token, which
        // cancels all background tasks. For per-task cancellation, each background
        // task uses a child token, and the parent token cancels all.
        // We update the result file to reflect the cancellation request.
        result.status = BackgroundTaskStatus::Cancelled;
        result.error = Some("Cancelled by user request".into());
        result.finished_at = Some(chrono::Utc::now().to_rfc3339());
        let bytes = serde_json::to_vec_pretty(&result)?;
        tokio::fs::write(&result_path, &bytes).await?;

        Ok(ToolResult {
            success: true,
            output: format!("Task '{task_id}' cancellation requested."),
            error: None,
        })
    }

    /// Cancel all background tasks (cascade control).
    /// Call this when the parent session ends.
    pub fn cancel_all_background_tasks(&self) {
        self.cancellation_token.cancel();
    }

    /// Build an enriched system prompt for a sub-agent by composing structured
    /// operational sections (tools, skills, workspace, datetime, shell policy)
    /// with the operator-configured `system_prompt` string.
    fn build_enriched_system_prompt(
        &self,
        agent_config: &DelegateAgentConfig,
        sub_tools: &[Box<dyn Tool>],
        workspace_dir: &Path,
    ) -> Option<String> {
        // Resolve skills directory: scoped if configured, otherwise workspace default.
        let skills_dir = agent_config
            .skills_directory
            .as_ref()
            .filter(|s| !s.trim().is_empty())
            .map(|dir| workspace_dir.join(dir))
            .unwrap_or_else(|| crate::skills::skills_dir(workspace_dir));
        let skills = crate::skills::load_skills_from_directory(&skills_dir, false);

        // Determine shell policy instructions when the `shell` tool is in the
        // effective tool list.
        let has_shell = sub_tools.iter().any(|t| t.name() == "shell");
        let shell_policy = if has_shell {
            "## Shell Policy\n\n\
             - Prefer non-destructive commands. Use `trash` over `rm` where possible.\n\
             - Do not run commands that exfiltrate data or modify system-critical paths.\n\
             - Avoid interactive commands that block on stdin.\n\
             - Quote paths that may contain spaces."
                .to_string()
        } else {
            String::new()
        };

        // Build structured operational context using SystemPromptBuilder sections.
        let ctx = PromptContext {
            workspace_dir,
            model_name: &agent_config.model,
            tools: crate::agent::prompt::PromptTools::Full(sub_tools),
            skills: &skills,
            skills_prompt_mode: crate::config::SkillsPromptInjectionMode::Full,
            skill_effectiveness: None,
            identity_config: None,
            dispatcher_instructions: "",
            tool_descriptions: None,
            security_summary: None,
            autonomy_level: crate::security::AutonomyLevel::default(),
            operator_enabled: false,
            kumiho_enabled: false,
            kumiho_memory_advanced_available: false,
            compact_tool_docs: false,
            mode: crate::agent::prompt::BuilderMode::Daemon,
        };

        let builder = SystemPromptBuilder::default()
            .add_section(Box::new(crate::agent::prompt::ToolsSection))
            .add_section(Box::new(crate::agent::prompt::SafetySection))
            .add_section(Box::new(crate::agent::prompt::SkillsSection))
            .add_section(Box::new(crate::agent::prompt::WorkspaceSection))
            .add_section(Box::new(crate::agent::prompt::DateTimeSection));

        let mut enriched = builder.build(&ctx).unwrap_or_default();

        if !shell_policy.is_empty() {
            enriched.push_str(&shell_policy);
            enriched.push_str("\n\n");
        }

        // Append the operator-configured system_prompt as the identity/role block.
        if let Some(operator_prompt) = agent_config.system_prompt.as_ref() {
            enriched.push_str(operator_prompt);
            enriched.push('\n');
        }

        let trimmed = enriched.trim().to_string();
        if trimmed.is_empty() {
            None
        } else {
            Some(trimmed)
        }
    }

    async fn execute_agentic(
        &self,
        agent_name: &str,
        agent_config: &DelegateAgentConfig,
        provider: &dyn Provider,
        full_prompt: &str,
        temperature: f64,
    ) -> anyhow::Result<ToolResult> {
        if agent_config.allowed_tools.is_empty() {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!(
                    "Agent '{agent_name}' has agentic=true but allowed_tools is empty"
                )),
            });
        }

        let allowed = agent_config
            .allowed_tools
            .iter()
            .map(|name| name.trim())
            .filter(|name| !name.is_empty())
            .collect::<std::collections::HashSet<_>>();

        let sub_tools: Vec<Box<dyn Tool>> = {
            let parent_tools = self.parent_tools.read();
            parent_tools
                .iter()
                .filter(|tool| allowed.contains(tool.name()))
                .filter(|tool| tool.name() != "delegate")
                .map(|tool| Box::new(ToolArcRef::new(tool.clone())) as Box<dyn Tool>)
                .collect()
        };

        if sub_tools.is_empty() {
            return Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!(
                    "Agent '{agent_name}' has no executable tools after filtering allowlist ({})",
                    agent_config.allowed_tools.join(", ")
                )),
            });
        }

        // Build enriched system prompt with tools, skills, workspace, datetime context.
        let enriched_system_prompt =
            self.build_enriched_system_prompt(agent_config, &sub_tools, &self.workspace_dir);

        let mut history = Vec::new();
        if let Some(system_prompt) = enriched_system_prompt.as_ref() {
            history.push(ChatMessage::system(system_prompt.clone()));
        }
        history.push(ChatMessage::user(full_prompt.to_string()));

        let noop_observer = NoopObserver;

        let agentic_timeout_secs = agent_config
            .agentic_timeout_secs
            .unwrap_or(self.delegate_config.agentic_timeout_secs);
        let result = tokio::time::timeout(
            Duration::from_secs(agentic_timeout_secs),
            run_tool_call_loop(
                provider,
                &mut history,
                &sub_tools,
                &noop_observer,
                &agent_config.provider,
                &agent_config.model,
                temperature,
                true,
                None,
                "delegate",
                None,
                &self.multimodal_config,
                agent_config.max_iterations,
                None,
                None,
                None,
                &[],
                &[],
                None,
                None,
                &crate::config::PacingConfig::default(),
                0,    // max_tool_result_chars: inherit from parent config in future
                0,    // context_token_budget: 0 = disabled for subagents
                None, // shared_budget: TODO thread from parent in future
            ),
        )
        .await;

        match result {
            Ok(Ok(response)) => {
                let rendered = if response.trim().is_empty() {
                    "[Empty response]".to_string()
                } else {
                    response
                };

                Ok(ToolResult {
                    success: true,
                    output: format!(
                        "[Agent '{agent_name}' ({provider}/{model}, agentic)]\n{rendered}",
                        provider = agent_config.provider,
                        model = agent_config.model
                    ),
                    error: None,
                })
            }
            Ok(Err(e)) => Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!("Agent '{agent_name}' failed: {e}")),
            }),
            Err(_) => Ok(ToolResult {
                success: false,
                output: String::new(),
                error: Some(format!(
                    "Agent '{agent_name}' timed out after {agentic_timeout_secs}s"
                )),
            }),
        }
    }
}

struct ToolArcRef {
    inner: Arc<dyn Tool>,
}

impl ToolArcRef {
    fn new(inner: Arc<dyn Tool>) -> Self {
        Self { inner }
    }
}

#[async_trait]
impl Tool for ToolArcRef {
    fn name(&self) -> &str {
        self.inner.name()
    }

    fn description(&self) -> &str {
        self.inner.description()
    }

    fn parameters_schema(&self) -> serde_json::Value {
        self.inner.parameters_schema()
    }

    async fn execute(&self, args: serde_json::Value) -> anyhow::Result<ToolResult> {
        self.inner.execute(args).await
    }
}

struct NoopObserver;

impl Observer for NoopObserver {
    fn record_event(&self, _event: &ObserverEvent) {}

    fn record_metric(&self, _metric: &ObserverMetric) {}

    fn name(&self) -> &str {
        "noop"
    }

    fn as_any(&self) -> &dyn std::any::Any {
        self
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::config::schema::{
        DEFAULT_DELEGATE_AGENTIC_TIMEOUT_SECS, DEFAULT_DELEGATE_TIMEOUT_SECS,
    };
    use crate::providers::{ChatRequest, ChatResponse, ToolCall};
    use crate::security::{AutonomyLevel, SecurityPolicy};
    use anyhow::anyhow;

    fn test_security() -> Arc<SecurityPolicy> {
        Arc::new(SecurityPolicy::default())
    }

    fn sample_agents() -> HashMap<String, DelegateAgentConfig> {
        let mut agents = HashMap::new();
        agents.insert(
            "researcher".to_string(),
            DelegateAgentConfig {
                provider: "ollama".to_string(),
                model: "llama3".to_string(),
                system_prompt: Some("You are a research assistant.".to_string()),
                api_key: None,
                temperature: Some(0.3),
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: None,
                agentic_timeout_secs: None,
                skills_directory: None,
            },
        );
        agents.insert(
            "coder".to_string(),
            DelegateAgentConfig {
                provider: "openrouter".to_string(),
                model: "anthropic/claude-sonnet-4-20250514".to_string(),
                system_prompt: None,
                api_key: Some("delegate-test-credential".to_string()),
                temperature: None,
                max_depth: 2,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: None,
                agentic_timeout_secs: None,
                skills_directory: None,
            },
        );
        agents
    }

    fn fast_failing_background_agents() -> HashMap<String, DelegateAgentConfig> {
        let mut agents = sample_agents();
        if let Some(researcher) = agents.get_mut("researcher") {
            researcher.provider = "invalid-for-test".to_string();
        }
        agents
    }

    #[derive(Default)]
    struct EchoTool;

    #[async_trait]
    impl Tool for EchoTool {
        fn name(&self) -> &str {
            "echo_tool"
        }

        fn description(&self) -> &str {
            "Echoes the `value` argument."
        }

        fn parameters_schema(&self) -> serde_json::Value {
            serde_json::json!({
                "type": "object",
                "properties": {
                    "value": {"type": "string"}
                },
                "required": ["value"]
            })
        }

        async fn execute(&self, args: serde_json::Value) -> anyhow::Result<ToolResult> {
            let value = args
                .get("value")
                .and_then(serde_json::Value::as_str)
                .unwrap_or_default()
                .to_string();
            Ok(ToolResult {
                success: true,
                output: format!("echo:{value}"),
                error: None,
            })
        }
    }

    struct OneToolThenFinalProvider;

    #[async_trait]
    impl Provider for OneToolThenFinalProvider {
        async fn chat_with_system(
            &self,
            _system_prompt: Option<&str>,
            _message: &str,
            _model: &str,
            _temperature: f64,
        ) -> anyhow::Result<String> {
            Ok("unused".to_string())
        }

        async fn chat(
            &self,
            request: ChatRequest<'_>,
            _model: &str,
            _temperature: f64,
        ) -> anyhow::Result<ChatResponse> {
            let has_tool_message = request.messages.iter().any(|m| m.role == "tool");
            if has_tool_message {
                Ok(ChatResponse {
                    text: Some("done".to_string()),
                    tool_calls: Vec::new(),
                    usage: None,
                    reasoning_content: None,
                })
            } else {
                Ok(ChatResponse {
                    text: None,
                    tool_calls: vec![ToolCall {
                        id: "call_1".to_string(),
                        name: "echo_tool".to_string(),
                        arguments: "{\"value\":\"ping\"}".to_string(),
                    }],
                    usage: None,
                    reasoning_content: None,
                })
            }
        }
    }

    struct InfiniteToolCallProvider;

    #[async_trait]
    impl Provider for InfiniteToolCallProvider {
        async fn chat_with_system(
            &self,
            _system_prompt: Option<&str>,
            _message: &str,
            _model: &str,
            _temperature: f64,
        ) -> anyhow::Result<String> {
            Ok("unused".to_string())
        }

        async fn chat(
            &self,
            _request: ChatRequest<'_>,
            _model: &str,
            _temperature: f64,
        ) -> anyhow::Result<ChatResponse> {
            Ok(ChatResponse {
                text: None,
                tool_calls: vec![ToolCall {
                    id: "loop".to_string(),
                    name: "echo_tool".to_string(),
                    arguments: "{\"value\":\"x\"}".to_string(),
                }],
                usage: None,
                reasoning_content: None,
            })
        }
    }

    struct FailingProvider;

    #[async_trait]
    impl Provider for FailingProvider {
        async fn chat_with_system(
            &self,
            _system_prompt: Option<&str>,
            _message: &str,
            _model: &str,
            _temperature: f64,
        ) -> anyhow::Result<String> {
            Ok("unused".to_string())
        }

        async fn chat(
            &self,
            _request: ChatRequest<'_>,
            _model: &str,
            _temperature: f64,
        ) -> anyhow::Result<ChatResponse> {
            Err(anyhow!("provider boom"))
        }
    }

    fn agentic_config(allowed_tools: Vec<String>, max_iterations: usize) -> DelegateAgentConfig {
        DelegateAgentConfig {
            provider: "openrouter".to_string(),
            model: "model-test".to_string(),
            system_prompt: Some("You are agentic.".to_string()),
            api_key: Some("delegate-test-credential".to_string()),
            temperature: Some(0.2),
            max_depth: 3,
            agentic: true,
            allowed_tools,
            max_iterations,
            timeout_secs: None,
            agentic_timeout_secs: None,
            skills_directory: None,
        }
    }

    #[test]
    fn name_and_schema() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        assert_eq!(tool.name(), "delegate");
        let schema = tool.parameters_schema();
        assert!(schema["properties"]["agent"].is_object());
        assert!(schema["properties"]["prompt"].is_object());
        assert!(schema["properties"]["context"].is_object());
        assert!(schema["properties"]["background"].is_object());
        assert!(schema["properties"]["parallel"].is_object());
        assert!(schema["properties"]["action"].is_object());
        assert!(schema["properties"]["task_id"].is_object());
        // required is empty because different actions need different params
        let required = schema["required"].as_array().unwrap();
        assert!(required.is_empty());
        assert_eq!(schema["additionalProperties"], json!(false));
        assert_eq!(schema["properties"]["agent"]["minLength"], json!(1));
        assert_eq!(schema["properties"]["prompt"]["minLength"], json!(1));
    }

    #[test]
    fn description_not_empty() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        assert!(!tool.description().is_empty());
    }

    #[test]
    fn schema_lists_agent_names() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let schema = tool.parameters_schema();
        let desc = schema["properties"]["agent"]["description"]
            .as_str()
            .unwrap();
        assert!(desc.contains("researcher") || desc.contains("coder"));
    }

    #[tokio::test]
    async fn missing_agent_param() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool.execute(json!({"prompt": "test"})).await;
        assert!(result.is_err());
    }

    #[tokio::test]
    async fn missing_prompt_param() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool.execute(json!({"agent": "researcher"})).await;
        assert!(result.is_err());
    }

    #[tokio::test]
    async fn unknown_agent_returns_error() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool
            .execute(json!({"agent": "nonexistent", "prompt": "test"}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(result.error.unwrap().contains("Unknown agent"));
    }

    #[tokio::test]
    async fn depth_limit_enforced() {
        let tool = DelegateTool::with_depth(sample_agents(), None, test_security(), 3);
        let result = tool
            .execute(json!({"agent": "researcher", "prompt": "test"}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(result.error.unwrap().contains("depth limit"));
    }

    #[tokio::test]
    async fn depth_limit_per_agent() {
        // coder has max_depth=2, so depth=2 should be blocked
        let tool = DelegateTool::with_depth(sample_agents(), None, test_security(), 2);
        let result = tool
            .execute(json!({"agent": "coder", "prompt": "test"}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(result.error.unwrap().contains("depth limit"));
    }

    #[test]
    fn empty_agents_schema() {
        let tool = DelegateTool::new(HashMap::new(), None, test_security());
        let schema = tool.parameters_schema();
        let desc = schema["properties"]["agent"]["description"]
            .as_str()
            .unwrap();
        assert!(desc.contains("none configured"));
    }

    #[tokio::test]
    async fn invalid_provider_returns_error() {
        let mut agents = HashMap::new();
        agents.insert(
            "broken".to_string(),
            DelegateAgentConfig {
                provider: "totally-invalid-provider".to_string(),
                model: "model".to_string(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: None,
                agentic_timeout_secs: None,
                skills_directory: None,
            },
        );
        let tool = DelegateTool::new(agents, None, test_security());
        let result = tool
            .execute(json!({"agent": "broken", "prompt": "test"}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(result.error.unwrap().contains("Failed to create provider"));
    }

    #[tokio::test]
    async fn blank_agent_rejected() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool
            .execute(json!({"agent": "  ", "prompt": "test"}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(result.error.unwrap().contains("must not be empty"));
    }

    #[tokio::test]
    async fn blank_prompt_rejected() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool
            .execute(json!({"agent": "researcher", "prompt": "  \t  "}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(result.error.unwrap().contains("must not be empty"));
    }

    #[tokio::test]
    async fn whitespace_agent_name_trimmed_and_found() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        // " researcher " with surrounding whitespace — after trim becomes "researcher"
        let result = tool
            .execute(json!({"agent": " researcher ", "prompt": "test"}))
            .await
            .unwrap();
        // Should find "researcher" after trim — will fail at provider level
        // since ollama isn't running, but must NOT get "Unknown agent".
        assert!(
            result.error.is_none()
                || !result
                    .error
                    .as_deref()
                    .unwrap_or("")
                    .contains("Unknown agent")
        );
    }

    #[tokio::test]
    async fn delegation_blocked_in_readonly_mode() {
        let readonly = Arc::new(SecurityPolicy {
            autonomy: AutonomyLevel::ReadOnly,
            ..SecurityPolicy::default()
        });
        let tool = DelegateTool::new(sample_agents(), None, readonly);
        let result = tool
            .execute(json!({"agent": "researcher", "prompt": "test"}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("read-only mode")
        );
    }

    #[tokio::test]
    async fn delegation_blocked_when_rate_limited() {
        let limited = Arc::new(SecurityPolicy {
            max_actions_per_hour: 0,
            ..SecurityPolicy::default()
        });
        let tool = DelegateTool::new(sample_agents(), None, limited);
        let result = tool
            .execute(json!({"agent": "researcher", "prompt": "test"}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("Rate limit exceeded")
        );
    }

    #[tokio::test]
    async fn delegate_context_is_prepended_to_prompt() {
        let mut agents = HashMap::new();
        agents.insert(
            "tester".to_string(),
            DelegateAgentConfig {
                provider: "invalid-for-test".to_string(),
                model: "test-model".to_string(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: None,
                agentic_timeout_secs: None,
                skills_directory: None,
            },
        );
        let tool = DelegateTool::new(agents, None, test_security());
        let result = tool
            .execute(json!({
                "agent": "tester",
                "prompt": "do something",
                "context": "some context data"
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("Failed to create provider")
        );
    }

    #[tokio::test]
    async fn delegate_empty_context_omits_prefix() {
        let mut agents = HashMap::new();
        agents.insert(
            "tester".to_string(),
            DelegateAgentConfig {
                provider: "invalid-for-test".to_string(),
                model: "test-model".to_string(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: None,
                agentic_timeout_secs: None,
                skills_directory: None,
            },
        );
        let tool = DelegateTool::new(agents, None, test_security());
        let result = tool
            .execute(json!({
                "agent": "tester",
                "prompt": "do something",
                "context": ""
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("Failed to create provider")
        );
    }

    #[test]
    fn delegate_depth_construction() {
        let tool = DelegateTool::with_depth(sample_agents(), None, test_security(), 5);
        assert_eq!(tool.depth, 5);
    }

    #[tokio::test]
    async fn delegate_no_agents_configured() {
        let tool = DelegateTool::new(HashMap::new(), None, test_security());
        let result = tool
            .execute(json!({"agent": "any", "prompt": "test"}))
            .await
            .unwrap();
        assert!(!result.success);
        assert!(result.error.unwrap().contains("none configured"));
    }

    #[tokio::test]
    async fn agentic_mode_rejects_empty_allowed_tools() {
        let mut agents = HashMap::new();
        agents.insert("agentic".to_string(), agentic_config(Vec::new(), 10));

        let tool = DelegateTool::new(agents, None, test_security());
        let result = tool
            .execute(json!({"agent": "agentic", "prompt": "test"}))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("allowed_tools is empty")
        );
    }

    #[tokio::test]
    async fn agentic_mode_rejects_unmatched_allowed_tools() {
        let mut agents = HashMap::new();
        agents.insert(
            "agentic".to_string(),
            agentic_config(vec!["missing_tool".to_string()], 10),
        );

        let tool = DelegateTool::new(agents, None, test_security())
            .with_parent_tools(Arc::new(RwLock::new(vec![Arc::new(EchoTool)])));
        let result = tool
            .execute(json!({"agent": "agentic", "prompt": "test"}))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("no executable tools")
        );
    }

    #[tokio::test]
    async fn execute_agentic_runs_tool_call_loop_with_filtered_tools() {
        let config = agentic_config(vec!["echo_tool".to_string()], 10);
        let tool = DelegateTool::new(HashMap::new(), None, test_security()).with_parent_tools(
            Arc::new(RwLock::new(vec![
                Arc::new(EchoTool),
                Arc::new(DelegateTool::new(HashMap::new(), None, test_security())),
            ])),
        );

        let provider = OneToolThenFinalProvider;
        let result = tool
            .execute_agentic("agentic", &config, &provider, "run", 0.2)
            .await
            .unwrap();

        assert!(result.success);
        assert!(result.output.contains("(openrouter/model-test, agentic)"));
        assert!(result.output.contains("done"));
    }

    #[tokio::test]
    async fn execute_agentic_excludes_delegate_even_if_allowlisted() {
        let config = agentic_config(vec!["delegate".to_string()], 10);
        let tool = DelegateTool::new(HashMap::new(), None, test_security()).with_parent_tools(
            Arc::new(RwLock::new(vec![Arc::new(DelegateTool::new(
                HashMap::new(),
                None,
                test_security(),
            ))])),
        );

        let provider = OneToolThenFinalProvider;
        let result = tool
            .execute_agentic("agentic", &config, &provider, "run", 0.2)
            .await
            .unwrap();

        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("no executable tools")
        );
    }

    #[tokio::test]
    async fn execute_agentic_respects_max_iterations() {
        let config = agentic_config(vec!["echo_tool".to_string()], 2);
        let tool = DelegateTool::new(HashMap::new(), None, test_security())
            .with_parent_tools(Arc::new(RwLock::new(vec![Arc::new(EchoTool)])));

        let provider = InfiniteToolCallProvider;
        let result = tool
            .execute_agentic("agentic", &config, &provider, "run", 0.2)
            .await
            .unwrap();

        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("maximum tool iterations (2)")
        );
    }

    #[tokio::test]
    async fn execute_agentic_propagates_provider_errors() {
        let config = agentic_config(vec!["echo_tool".to_string()], 10);
        let tool = DelegateTool::new(HashMap::new(), None, test_security())
            .with_parent_tools(Arc::new(RwLock::new(vec![Arc::new(EchoTool)])));

        let provider = FailingProvider;
        let result = tool
            .execute_agentic("agentic", &config, &provider, "run", 0.2)
            .await
            .unwrap();

        assert!(!result.success);
        assert!(
            result
                .error
                .as_deref()
                .unwrap_or("")
                .contains("provider boom")
        );
    }

    /// MCP tools pushed into the shared parent_tools handle after DelegateTool
    /// construction must be visible to the sub-agent tool list.
    #[derive(Default)]
    struct FakeMcpTool;

    #[async_trait]
    impl Tool for FakeMcpTool {
        fn name(&self) -> &str {
            "mcp_fake"
        }

        fn description(&self) -> &str {
            "Fake MCP tool for testing."
        }

        fn parameters_schema(&self) -> serde_json::Value {
            serde_json::json!({"type": "object", "properties": {}})
        }

        async fn execute(&self, _args: serde_json::Value) -> anyhow::Result<ToolResult> {
            Ok(ToolResult {
                success: true,
                output: "mcp_fake_output".into(),
                error: None,
            })
        }
    }

    struct McpToolThenFinalProvider;

    #[async_trait]
    impl Provider for McpToolThenFinalProvider {
        async fn chat_with_system(
            &self,
            _system_prompt: Option<&str>,
            _message: &str,
            _model: &str,
            _temperature: f64,
        ) -> anyhow::Result<String> {
            Ok("unused".to_string())
        }

        async fn chat(
            &self,
            request: ChatRequest<'_>,
            _model: &str,
            _temperature: f64,
        ) -> anyhow::Result<ChatResponse> {
            let has_tool_message = request.messages.iter().any(|m| m.role == "tool");
            if has_tool_message {
                Ok(ChatResponse {
                    text: Some("mcp done".to_string()),
                    tool_calls: Vec::new(),
                    usage: None,
                    reasoning_content: None,
                })
            } else {
                Ok(ChatResponse {
                    text: None,
                    tool_calls: vec![ToolCall {
                        id: "call_mcp".to_string(),
                        name: "mcp_fake".to_string(),
                        arguments: "{}".to_string(),
                    }],
                    usage: None,
                    reasoning_content: None,
                })
            }
        }
    }

    #[tokio::test]
    async fn mcp_tools_included_in_subagent_tool_list() {
        // Build DelegateTool with NO parent tools initially
        let config = agentic_config(vec!["mcp_fake".to_string()], 10);
        let tool = DelegateTool::new(HashMap::new(), None, test_security())
            .with_parent_tools(Arc::new(RwLock::new(Vec::new())));

        // Simulate late MCP tool injection via the shared handle
        let handle = tool.parent_tools_handle();
        handle.write().push(Arc::new(FakeMcpTool));

        let provider = McpToolThenFinalProvider;
        let result = tool
            .execute_agentic("agentic", &config, &provider, "run mcp", 0.2)
            .await
            .unwrap();

        assert!(result.success, "Expected success, got: {:?}", result.error);
        assert!(
            result.output.contains("mcp done"),
            "Expected output containing 'mcp done', got: {}",
            result.output
        );
    }

    #[test]
    fn enriched_prompt_includes_tools_workspace_datetime() {
        let config = DelegateAgentConfig {
            provider: "openrouter".to_string(),
            model: "test-model".to_string(),
            system_prompt: Some("You are a code reviewer.".to_string()),
            api_key: None,
            temperature: None,
            max_depth: 3,
            agentic: true,
            allowed_tools: vec!["echo_tool".to_string()],
            max_iterations: 10,
            timeout_secs: None,
            agentic_timeout_secs: None,
            skills_directory: None,
        };

        let tools: Vec<Box<dyn Tool>> = vec![Box::new(EchoTool)];
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_enrich_test_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(HashMap::new(), None, test_security())
            .with_workspace_dir(workspace.clone());

        let prompt = tool
            .build_enriched_system_prompt(&config, &tools, &workspace)
            .unwrap();

        assert!(prompt.contains("## Tools"), "should contain tools section");
        assert!(prompt.contains("echo_tool"), "should list allowed tools");
        assert!(
            prompt.contains("## Workspace"),
            "should contain workspace section"
        );
        assert!(
            prompt.contains(&workspace.display().to_string()),
            "should contain workspace path"
        );
        assert!(
            prompt.contains("## CRITICAL CONTEXT: CURRENT DATE & TIME"),
            "should contain datetime section"
        );
        assert!(
            prompt.contains("You are a code reviewer."),
            "should append operator system_prompt"
        );

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[test]
    fn enriched_prompt_includes_shell_policy_when_shell_present() {
        let config = DelegateAgentConfig {
            provider: "openrouter".to_string(),
            model: "test-model".to_string(),
            system_prompt: None,
            api_key: None,
            temperature: None,
            max_depth: 3,
            agentic: true,
            allowed_tools: vec!["shell".to_string()],
            max_iterations: 10,
            timeout_secs: None,
            agentic_timeout_secs: None,
            skills_directory: None,
        };

        struct MockShellTool;
        #[async_trait]
        impl Tool for MockShellTool {
            fn name(&self) -> &str {
                "shell"
            }
            fn description(&self) -> &str {
                "Execute shell commands"
            }
            fn parameters_schema(&self) -> serde_json::Value {
                json!({"type": "object"})
            }
            async fn execute(&self, _args: serde_json::Value) -> anyhow::Result<ToolResult> {
                Ok(ToolResult {
                    success: true,
                    output: String::new(),
                    error: None,
                })
            }
        }

        let tools: Vec<Box<dyn Tool>> = vec![Box::new(MockShellTool)];
        let workspace = std::env::temp_dir();

        let tool = DelegateTool::new(HashMap::new(), None, test_security())
            .with_workspace_dir(workspace.to_path_buf());

        let prompt = tool
            .build_enriched_system_prompt(&config, &tools, &workspace)
            .unwrap();

        assert!(
            prompt.contains("## Shell Policy"),
            "should contain shell policy when shell tool is present"
        );
    }

    #[test]
    fn parent_tools_handle_returns_shared_reference() {
        let tool = DelegateTool::new(HashMap::new(), None, test_security()).with_parent_tools(
            Arc::new(RwLock::new(vec![Arc::new(EchoTool) as Arc<dyn Tool>])),
        );

        let handle = tool.parent_tools_handle();
        assert_eq!(handle.read().len(), 1);

        // Push a new tool via the handle
        handle.write().push(Arc::new(FakeMcpTool));
        assert_eq!(handle.read().len(), 2);
    }

    // ── Configurable timeout tests ──────────────────────────────────

    #[test]
    fn default_timeout_values_used_when_config_unset() {
        let config = DelegateAgentConfig {
            provider: "ollama".to_string(),
            model: "llama3".to_string(),
            system_prompt: None,
            api_key: None,
            temperature: None,
            max_depth: 3,
            agentic: false,
            allowed_tools: Vec::new(),
            max_iterations: 10,
            timeout_secs: None,
            agentic_timeout_secs: None,
            skills_directory: None,
        };
        assert_eq!(
            config.timeout_secs.unwrap_or(DEFAULT_DELEGATE_TIMEOUT_SECS),
            120
        );
        assert_eq!(
            config
                .agentic_timeout_secs
                .unwrap_or(DEFAULT_DELEGATE_AGENTIC_TIMEOUT_SECS),
            300
        );
    }

    #[test]
    fn enriched_prompt_omits_shell_policy_without_shell_tool() {
        let config = DelegateAgentConfig {
            provider: "openrouter".to_string(),
            model: "test-model".to_string(),
            system_prompt: None,
            api_key: None,
            temperature: None,
            max_depth: 3,
            agentic: true,
            allowed_tools: vec!["echo_tool".to_string()],
            max_iterations: 10,
            timeout_secs: None,
            agentic_timeout_secs: None,
            skills_directory: None,
        };

        let tools: Vec<Box<dyn Tool>> = vec![Box::new(EchoTool)];
        let workspace = std::env::temp_dir();

        let tool = DelegateTool::new(HashMap::new(), None, test_security())
            .with_workspace_dir(workspace.to_path_buf());

        let prompt = tool
            .build_enriched_system_prompt(&config, &tools, &workspace)
            .unwrap();

        assert!(
            !prompt.contains("## Shell Policy"),
            "should not contain shell policy when shell tool is absent"
        );
    }

    #[test]
    fn custom_timeout_values_are_respected() {
        let config = DelegateAgentConfig {
            provider: "ollama".to_string(),
            model: "llama3".to_string(),
            system_prompt: None,
            api_key: None,
            temperature: None,
            max_depth: 3,
            agentic: false,
            allowed_tools: Vec::new(),
            max_iterations: 10,
            timeout_secs: Some(60),
            agentic_timeout_secs: Some(600),
            skills_directory: None,
        };
        assert_eq!(
            config.timeout_secs.unwrap_or(DEFAULT_DELEGATE_TIMEOUT_SECS),
            60
        );
        assert_eq!(
            config
                .agentic_timeout_secs
                .unwrap_or(DEFAULT_DELEGATE_AGENTIC_TIMEOUT_SECS),
            600
        );
    }

    #[test]
    fn timeout_deserialization_defaults_to_none() {
        let toml_str = r#"
            provider = "ollama"
            model = "llama3"
        "#;
        let config: DelegateAgentConfig = toml::from_str(toml_str).unwrap();
        assert!(config.timeout_secs.is_none());
        assert!(config.agentic_timeout_secs.is_none());
    }

    #[test]
    fn timeout_deserialization_with_custom_values() {
        let toml_str = r#"
            provider = "ollama"
            model = "llama3"
            timeout_secs = 45
            agentic_timeout_secs = 900
        "#;
        let config: DelegateAgentConfig = toml::from_str(toml_str).unwrap();
        assert_eq!(config.timeout_secs, Some(45));
        assert_eq!(config.agentic_timeout_secs, Some(900));
    }

    #[test]
    fn config_validation_rejects_zero_timeout() {
        let mut config = crate::config::Config::default();
        config.agents.insert(
            "bad".into(),
            DelegateAgentConfig {
                provider: "ollama".into(),
                model: "llama3".into(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: Some(0),
                agentic_timeout_secs: None,
                skills_directory: None,
            },
        );
        let err = config.validate().unwrap_err();
        assert!(
            format!("{err}").contains("timeout_secs must be greater than 0"),
            "unexpected error: {err}"
        );
    }

    #[test]
    fn config_validation_rejects_zero_agentic_timeout() {
        let mut config = crate::config::Config::default();
        config.agents.insert(
            "bad".into(),
            DelegateAgentConfig {
                provider: "ollama".into(),
                model: "llama3".into(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: None,
                agentic_timeout_secs: Some(0),
                skills_directory: None,
            },
        );
        let err = config.validate().unwrap_err();
        assert!(
            format!("{err}").contains("agentic_timeout_secs must be greater than 0"),
            "unexpected error: {err}"
        );
    }

    #[test]
    fn config_validation_rejects_excessive_timeout() {
        let mut config = crate::config::Config::default();
        config.agents.insert(
            "bad".into(),
            DelegateAgentConfig {
                provider: "ollama".into(),
                model: "llama3".into(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: Some(7200),
                agentic_timeout_secs: None,
                skills_directory: None,
            },
        );
        let err = config.validate().unwrap_err();
        assert!(
            format!("{err}").contains("exceeds max 3600"),
            "unexpected error: {err}"
        );
    }

    #[test]
    fn config_validation_rejects_excessive_agentic_timeout() {
        let mut config = crate::config::Config::default();
        config.agents.insert(
            "bad".into(),
            DelegateAgentConfig {
                provider: "ollama".into(),
                model: "llama3".into(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: None,
                agentic_timeout_secs: Some(5000),
                skills_directory: None,
            },
        );
        let err = config.validate().unwrap_err();
        assert!(
            format!("{err}").contains("exceeds max 3600"),
            "unexpected error: {err}"
        );
    }

    #[test]
    fn config_validation_accepts_max_boundary_timeout() {
        let mut config = crate::config::Config::default();
        config.agents.insert(
            "ok".into(),
            DelegateAgentConfig {
                provider: "ollama".into(),
                model: "llama3".into(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: Some(3600),
                agentic_timeout_secs: Some(3600),
                skills_directory: None,
            },
        );
        assert!(config.validate().is_ok());
    }

    #[test]
    fn config_validation_accepts_none_timeouts() {
        let mut config = crate::config::Config::default();
        config.agents.insert(
            "ok".into(),
            DelegateAgentConfig {
                provider: "ollama".into(),
                model: "llama3".into(),
                system_prompt: None,
                api_key: None,
                temperature: None,
                max_depth: 3,
                agentic: false,
                allowed_tools: Vec::new(),
                max_iterations: 10,
                timeout_secs: None,
                agentic_timeout_secs: None,
                skills_directory: None,
            },
        );
        assert!(config.validate().is_ok());
    }

    #[test]
    fn enriched_prompt_loads_skills_from_scoped_directory() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_skills_test_{}",
            uuid::Uuid::new_v4()
        ));
        let scoped_skills_dir = workspace.join("skills/code-review");
        std::fs::create_dir_all(scoped_skills_dir.join("lint-check")).unwrap();
        std::fs::write(
            scoped_skills_dir.join("lint-check/SKILL.toml"),
            "[skill]\nname = \"lint-check\"\ndescription = \"Run lint checks\"\nversion = \"1.0.0\"\n",
        )
        .unwrap();

        let config = DelegateAgentConfig {
            provider: "openrouter".to_string(),
            model: "test-model".to_string(),
            system_prompt: None,
            api_key: None,
            temperature: None,
            max_depth: 3,
            agentic: true,
            allowed_tools: vec!["echo_tool".to_string()],
            max_iterations: 10,
            timeout_secs: None,
            agentic_timeout_secs: None,
            skills_directory: Some("skills/code-review".to_string()),
        };

        let tools: Vec<Box<dyn Tool>> = vec![Box::new(EchoTool)];

        let tool = DelegateTool::new(HashMap::new(), None, test_security())
            .with_workspace_dir(workspace.clone());

        let prompt = tool
            .build_enriched_system_prompt(&config, &tools, &workspace)
            .unwrap();

        assert!(
            prompt.contains("lint-check"),
            "should contain skills from scoped directory"
        );

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[test]
    fn enriched_prompt_falls_back_to_default_skills_dir() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_fallback_test_{}",
            uuid::Uuid::new_v4()
        ));
        let default_skills_dir = workspace.join("skills");
        std::fs::create_dir_all(default_skills_dir.join("deploy")).unwrap();
        std::fs::write(
            default_skills_dir.join("deploy/SKILL.toml"),
            "[skill]\nname = \"deploy\"\ndescription = \"Deploy safely\"\nversion = \"1.0.0\"\n",
        )
        .unwrap();

        let config = DelegateAgentConfig {
            provider: "openrouter".to_string(),
            model: "test-model".to_string(),
            system_prompt: None,
            api_key: None,
            temperature: None,
            max_depth: 3,
            agentic: true,
            allowed_tools: vec!["echo_tool".to_string()],
            max_iterations: 10,
            timeout_secs: None,
            agentic_timeout_secs: None,
            skills_directory: None,
        };

        let tools: Vec<Box<dyn Tool>> = vec![Box::new(EchoTool)];

        let tool = DelegateTool::new(HashMap::new(), None, test_security())
            .with_workspace_dir(workspace.clone());

        let prompt = tool
            .build_enriched_system_prompt(&config, &tools, &workspace)
            .unwrap();

        assert!(
            prompt.contains("deploy"),
            "should contain skills from default workspace skills/ directory"
        );

        let _ = std::fs::remove_dir_all(workspace);
    }

    // ── Background and Parallel execution tests ─────────────────────

    #[tokio::test]
    async fn background_delegation_returns_task_id() {
        let workspace =
            std::env::temp_dir().join(format!("revka_delegate_bg_test_{}", uuid::Uuid::new_v4()));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(fast_failing_background_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());
        let result = tool
            .execute(json!({
                "agent": "researcher",
                "prompt": "test background",
                "background": true
            }))
            .await
            .unwrap();

        // The agent will fail at provider creation, but the background task
        // should still be spawned and return a task_id.
        assert!(result.success);
        assert!(result.output.contains("task_id:"));
        assert!(result.output.contains("Background task started"));

        let task_id = result
            .output
            .lines()
            .find(|l| l.starts_with("task_id:"))
            .unwrap()
            .trim_start_matches("task_id: ")
            .trim();
        await_bg_task_terminal(&workspace, task_id).await;

        // The results directory should exist
        assert!(workspace.join("delegate_results").exists());

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn background_unknown_agent_rejected() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_bg_unknown_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(sample_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());
        let result = tool
            .execute(json!({
                "agent": "nonexistent",
                "prompt": "test",
                "background": true
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(result.error.unwrap().contains("Unknown agent"));

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn check_result_missing_task_id() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_check_noid_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(sample_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());
        let result = tool.execute(json!({"action": "check_result"})).await;

        assert!(result.is_err());

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn check_result_nonexistent_task() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_check_miss_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(sample_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());
        // Use a valid UUID format that doesn't correspond to any real task
        let fake_uuid = uuid::Uuid::new_v4().to_string();
        let result = tool
            .execute(json!({
                "action": "check_result",
                "task_id": fake_uuid
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(result.error.unwrap().contains("No result found"));

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn list_results_empty() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_list_empty_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(sample_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());
        let result = tool
            .execute(json!({"action": "list_results"}))
            .await
            .unwrap();

        assert!(result.success);
        assert!(result.output.contains("No background delegate results"));

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn parallel_empty_list_rejected() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool
            .execute(json!({
                "parallel": [],
                "prompt": "test"
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(result.error.unwrap().contains("at least one agent"));
    }

    #[tokio::test]
    async fn parallel_unknown_agent_rejected() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool
            .execute(json!({
                "parallel": ["researcher", "nonexistent"],
                "prompt": "test"
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(result.error.unwrap().contains("Unknown agent"));
    }

    #[tokio::test]
    async fn parallel_missing_prompt_rejected() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool
            .execute(json!({
                "parallel": ["researcher"]
            }))
            .await;

        assert!(result.is_err());
    }

    #[tokio::test]
    async fn unknown_action_rejected() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool
            .execute(json!({"action": "invalid_action"}))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(result.error.unwrap().contains("Unknown action"));
    }

    #[tokio::test]
    async fn cancel_task_nonexistent() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_cancel_miss_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(sample_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());
        // Use a valid UUID format that doesn't correspond to any real task
        let fake_uuid = uuid::Uuid::new_v4().to_string();
        let result = tool
            .execute(json!({
                "action": "cancel_task",
                "task_id": fake_uuid
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(result.error.unwrap().contains("No task found"));

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[test]
    fn cancellation_token_accessor() {
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let token = tool.cancellation_token();
        assert!(!token.is_cancelled());

        tool.cancel_all_background_tasks();
        assert!(token.is_cancelled());
    }

    #[test]
    fn with_cancellation_token_replaces_default() {
        let custom_token = CancellationToken::new();
        let tool = DelegateTool::new(sample_agents(), None, test_security())
            .with_cancellation_token(custom_token.clone());

        assert!(!tool.cancellation_token().is_cancelled());
        custom_token.cancel();
        assert!(tool.cancellation_token().is_cancelled());
    }

    /// Poll the result file until the background task reaches a terminal
    /// status (`Completed` / `Failed` / `Cancelled`), up to ~10 s. Returns
    /// the final result. Hard-coded `tokio::time::sleep` here is flaky —
    /// the 500ms originally used wasn't enough on slow runners (real
    /// failure observed during release CI of v2026.5.9), and bumping the
    /// sleep just hides the timing dependency. Poll-with-deadline is the
    /// honest fix.
    async fn await_bg_task_terminal(
        workspace: &std::path::Path,
        task_id: &str,
    ) -> BackgroundDelegateResult {
        let path = workspace
            .join("delegate_results")
            .join(format!("{task_id}.json"));
        let deadline = std::time::Instant::now() + Duration::from_secs(10);
        while std::time::Instant::now() < deadline {
            if path.exists() {
                if let Ok(content) = std::fs::read_to_string(&path)
                    && let Ok(bg) = serde_json::from_str::<BackgroundDelegateResult>(&content)
                    && matches!(
                        bg.status,
                        BackgroundTaskStatus::Completed
                            | BackgroundTaskStatus::Failed
                            | BackgroundTaskStatus::Cancelled
                    )
                {
                    return bg;
                }
            }
            tokio::time::sleep(Duration::from_millis(50)).await;
        }
        panic!(
            "background task {task_id} did not reach a terminal status \
             within 10s (last path: {path:?}); test is genuinely broken \
             or the result writer hung"
        );
    }

    #[tokio::test]
    async fn background_task_result_persisted_to_disk() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_bg_persist_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(fast_failing_background_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());

        let result = tool
            .execute(json!({
                "agent": "researcher",
                "prompt": "persistence test",
                "background": true
            }))
            .await
            .unwrap();

        assert!(result.success);

        // Extract task_id from output
        let task_id = result
            .output
            .lines()
            .find(|l| l.starts_with("task_id:"))
            .unwrap()
            .trim_start_matches("task_id: ")
            .trim();

        // Wait for the background task to reach a terminal status.
        await_bg_task_terminal(&workspace, task_id).await;

        // Check that the result file exists
        let result_path = workspace
            .join("delegate_results")
            .join(format!("{task_id}.json"));
        assert!(
            result_path.exists(),
            "Result file should exist at {result_path:?}"
        );

        // Read and parse the result
        let content = std::fs::read_to_string(&result_path).unwrap();
        let bg_result: BackgroundDelegateResult = serde_json::from_str(&content).unwrap();
        assert_eq!(bg_result.task_id, task_id);
        assert_eq!(bg_result.agent, "researcher");
        // The task uses an invalid provider so it fails quickly, but it should be persisted.
        assert!(
            bg_result.status == BackgroundTaskStatus::Completed
                || bg_result.status == BackgroundTaskStatus::Failed
        );
        assert!(bg_result.finished_at.is_some());

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn check_result_retrieves_persisted_background_result() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_check_retrieve_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(fast_failing_background_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());

        // Start background task
        let result = tool
            .execute(json!({
                "agent": "researcher",
                "prompt": "retrieval test",
                "background": true
            }))
            .await
            .unwrap();

        let task_id = result
            .output
            .lines()
            .find(|l| l.starts_with("task_id:"))
            .unwrap()
            .trim_start_matches("task_id: ")
            .trim()
            .to_string();

        // Wait for the background task to reach a terminal status before
        // calling check_result — otherwise we race the writer and the
        // assertion below can see a "running" placeholder.
        await_bg_task_terminal(&workspace, &task_id).await;

        // Check result
        let check = tool
            .execute(json!({
                "action": "check_result",
                "task_id": task_id
            }))
            .await
            .unwrap();

        // The output should contain the serialized result
        assert!(check.output.contains(&task_id));
        assert!(check.output.contains("researcher"));

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn list_results_includes_background_tasks() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_list_tasks_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(fast_failing_background_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());

        // Start a background task
        let result = tool
            .execute(json!({
                "agent": "researcher",
                "prompt": "list test",
                "background": true
            }))
            .await
            .unwrap();
        assert!(result.success);

        // Extract task_id so we can poll for completion deterministically.
        let task_id = result
            .output
            .lines()
            .find(|l| l.starts_with("task_id:"))
            .unwrap()
            .trim_start_matches("task_id: ")
            .trim();
        await_bg_task_terminal(&workspace, task_id).await;

        // List results
        let list = tool
            .execute(json!({"action": "list_results"}))
            .await
            .unwrap();

        assert!(list.success);
        assert!(list.output.contains("researcher"));

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn default_action_is_delegate() {
        // Calling without action should behave like "delegate"
        let tool = DelegateTool::new(sample_agents(), None, test_security());
        let result = tool
            .execute(json!({"agent": "researcher", "prompt": "test"}))
            .await
            .unwrap();
        // Should proceed to delegation (will fail at provider since ollama isn't running)
        // but should NOT fail with "Unknown action" error
        assert!(
            result.error.is_none()
                || !result
                    .error
                    .as_deref()
                    .unwrap_or("")
                    .contains("Unknown action")
        );
    }

    #[tokio::test]
    async fn check_result_rejects_path_traversal() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_traversal_check_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(sample_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());
        let result = tool
            .execute(json!({
                "action": "check_result",
                "task_id": "../../etc/passwd"
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(result.error.unwrap().contains("Invalid task_id"));

        let _ = std::fs::remove_dir_all(workspace);
    }

    #[tokio::test]
    async fn cancel_task_rejects_path_traversal() {
        let workspace = std::env::temp_dir().join(format!(
            "revka_delegate_traversal_cancel_{}",
            uuid::Uuid::new_v4()
        ));
        std::fs::create_dir_all(&workspace).unwrap();

        let tool = DelegateTool::new(sample_agents(), None, test_security())
            .with_workspace_dir(workspace.clone());
        let result = tool
            .execute(json!({
                "action": "cancel_task",
                "task_id": "../../../etc/shadow"
            }))
            .await
            .unwrap();

        assert!(!result.success);
        assert!(result.error.unwrap().contains("Invalid task_id"));

        let _ = std::fs::remove_dir_all(workspace);
    }
}
