/// Central configuration for Sofos. The actual file-size and bash-output
/// caps live next to the code that enforces them — `MAX_FILE_SIZE` in
/// `src/tools/filesystem.rs` (50 MB) and `MAX_BASH_OUTPUT_BYTES` in
/// `src/tools/bashexec.rs` (10 MB) — not here, so this struct only
/// carries config values that the rest of the crate actually reads.
///
/// Per-model knowledge (context window, auto-compact trigger,
/// pricing, adaptive-thinking flag) lives in
/// [`crate::api::model_info::lookup`] instead of in this struct.
/// `set_max_context_tokens` and `set_auto_compact_token_limit` on
/// [`crate::repl::conversation::ConversationHistory`] populate the
/// runtime values from the model lookup at REPL startup.
#[derive(Debug, Clone)]
pub struct SofosConfig {
    pub max_messages: usize,
    /// Hard drop-trim floor in tokens. Above this, older messages are
    /// dropped without summary as a last resort. Populated from
    /// `ModelInfo::effective_window()` at startup.
    pub max_context_tokens: usize,
    pub max_tool_iterations: u32,
    /// Auto-compaction trigger in tokens. Compaction runs an LLM
    /// summary step that preserves context, so this fires well below
    /// `max_context_tokens`. Populated from `ModelInfo::auto_compact_at()`
    /// at startup.
    pub auto_compact_token_limit: usize,
    /// Number of recent messages to preserve during compaction
    pub compaction_preserve_recent: usize,
    /// Truncate tool results longer than this (chars) during compaction
    pub tool_result_truncate_threshold: usize,
}

impl Default for SofosConfig {
    fn default() -> Self {
        // Defaults match `ModelInfo::default()`: a Sonnet-class
        // fallback with 200K context window, 95% effective window,
        // and 125K auto-compact override. These get overwritten by
        // model-specific values at REPL startup.
        let info = crate::api::ModelInfo::default();
        Self {
            max_messages: 500,
            max_context_tokens: info.effective_window() as usize,
            max_tool_iterations: 200,
            auto_compact_token_limit: info.auto_compact_at() as usize,
            compaction_preserve_recent: 20,
            tool_result_truncate_threshold: 2000,
        }
    }
}

/// Configuration for the language model
#[derive(Clone)]
pub struct ModelConfig {
    pub model: String,
    pub max_tokens: u32,
    pub reasoning_effort: crate::api::ReasoningEffort,
}

impl ModelConfig {
    pub fn new(
        model: String,
        max_tokens: u32,
        reasoning_effort: crate::api::ReasoningEffort,
    ) -> Self {
        Self {
            model,
            max_tokens,
            reasoning_effort,
        }
    }

    pub fn set_reasoning_effort(&mut self, effort: crate::api::ReasoningEffort) {
        self.reasoning_effort = effort;
    }
}

/// Per-model trim-safety floor. Above this value the conversation
/// trim drops older messages without summary as a last resort —
/// auto-compaction (which preserves context) runs much earlier at
/// [`crate::api::ModelInfo::auto_compact_at`]. Both numbers come
/// from the same per-model lookup so a single
/// [`crate::api::model_info::lookup`] call is the source of truth.
pub fn max_context_tokens_for(model: &str) -> usize {
    crate::api::model_info::lookup(model).effective_window() as usize
}

/// Auto-compaction trigger for `model`. Mirrors the codex pattern of
/// keeping the cost-shaping cap and the API ceiling as separate
/// concepts: this is where the LLM-summary phase fires, while
/// [`max_context_tokens_for`] is where the hard drop-trim kicks in.
pub fn auto_compact_token_limit_for(model: &str) -> usize {
    crate::api::model_info::lookup(model).auto_compact_at() as usize
}

/// Safe mode message shown to user and AI. Must stay in sync with the
/// tool set returned by `tools::get_read_only_tools()` (+ the optional
/// `search_code` tool wired in when ripgrep is on PATH).
pub const SAFE_MODE_MESSAGE: &str = "[SYSTEM: Safe (read-only) mode has been enabled. \
                                     No file modifications or bash commands are allowed. \
                                     Available tools: list_directory, read_file, glob_files, \
                                     search_code (when ripgrep is installed), web_fetch, web_search.]";

/// Normal mode message shown when switching from safe mode
pub const NORMAL_MODE_MESSAGE: &str = "[SYSTEM: Normal (unrestricted) mode has been enabled. \
                                       File modifications and bash commands are now allowed.\
                                       All tools are available]";

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_default_config_matches_fallback_model_info() {
        let config = SofosConfig::default();
        let info = crate::api::ModelInfo::default();
        assert_eq!(config.max_messages, 500);
        assert_eq!(config.max_context_tokens, info.effective_window() as usize);
        assert_eq!(config.max_tool_iterations, 200);
        assert_eq!(
            config.auto_compact_token_limit,
            info.auto_compact_at() as usize
        );
        assert_eq!(config.compaction_preserve_recent, 20);
        assert_eq!(config.tool_result_truncate_threshold, 2000);
    }
}
