//! Plugin Security and Validation
//!
//! Implements security checks, validation, and sandboxing for plugins
//! to ensure safe execution within the cleanroom environment.

use crate::error::{CleanroomError, Result};
use crate::marketplace::metadata::PluginMetadata;
use std::collections::HashSet;

/// Security level for plugin execution
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum SecurityLevel {
    /// Trusted plugin - full system access
    Trusted,
    /// Verified plugin - limited system access
    Verified,
    /// Sandboxed plugin - minimal system access
    Sandboxed,
    /// Untrusted plugin - no system access
    Untrusted,
}

/// Security validation result
#[derive(Debug, Clone)]
pub struct SecurityValidation {
    /// Overall security level
    pub level: SecurityLevel,
    /// Validation passed
    pub passed: bool,
    /// Security warnings
    pub warnings: Vec<String>,
    /// Security errors
    pub errors: Vec<String>,
    /// Required permissions
    pub required_permissions: Vec<String>,
}

impl SecurityValidation {
    pub fn new(level: SecurityLevel) -> Self {
        Self {
            level,
            passed: true,
            warnings: Vec::new(),
            errors: Vec::new(),
            required_permissions: Vec::new(),
        }
    }

    pub fn add_warning(&mut self, warning: impl Into<String>) {
        self.warnings.push(warning.into());
    }

    pub fn add_error(&mut self, error: impl Into<String>) {
        self.errors.push(error.into());
        self.passed = false;
    }

    pub fn require_permission(&mut self, permission: impl Into<String>) {
        self.required_permissions.push(permission.into());
    }
}

/// Plugin security validator
pub struct SecurityValidator {
    /// Known malicious patterns
    malicious_patterns: HashSet<String>,
    /// Allowed system calls
    #[allow(dead_code)]
    allowed_syscalls: HashSet<String>,
}

impl SecurityValidator {
    /// Create new security validator
    pub fn new() -> Self {
        let mut malicious_patterns = HashSet::new();
        malicious_patterns.insert("eval(".to_string());
        malicious_patterns.insert("exec(".to_string());
        malicious_patterns.insert("system(".to_string());
        malicious_patterns.insert("__import__".to_string());

        let mut allowed_syscalls = HashSet::new();
        allowed_syscalls.insert("read".to_string());
        allowed_syscalls.insert("write".to_string());
        allowed_syscalls.insert("open".to_string());
        allowed_syscalls.insert("close".to_string());

        Self {
            malicious_patterns,
            allowed_syscalls,
        }
    }

    /// Validate plugin security
    pub async fn validate_plugin(&self, metadata: &PluginMetadata) -> Result<SecurityValidation> {
        let mut validation = SecurityValidation::new(SecurityLevel::Sandboxed);

        // Check metadata for security issues
        self.validate_metadata(metadata, &mut validation)?;

        // Check for suspicious patterns
        self.check_suspicious_patterns(metadata, &mut validation)?;

        // Verify signatures (if available)
        self.verify_signatures(metadata, &mut validation).await?;

        // Check permissions
        self.check_permissions(metadata, &mut validation)?;

        Ok(validation)
    }

    /// Validate plugin metadata
    fn validate_metadata(
        &self,
        metadata: &PluginMetadata,
        validation: &mut SecurityValidation,
    ) -> Result<()> {
        // Check for empty or suspicious fields
        if metadata.author.is_empty() {
            validation.add_error("Plugin author is empty");
        }

        if metadata.repository.is_none() {
            validation.add_warning("No repository URL provided");
        }

        if metadata.homepage.is_none() {
            validation.add_warning("No homepage URL provided");
        }

        // Check license
        if metadata.license.is_empty() {
            validation.add_warning("No license specified");
        }

        Ok(())
    }

    /// Check for suspicious patterns in plugin
    fn check_suspicious_patterns(
        &self,
        metadata: &PluginMetadata,
        validation: &mut SecurityValidation,
    ) -> Result<()> {
        // Check description for suspicious content
        for pattern in &self.malicious_patterns {
            if metadata.description.contains(pattern) {
                validation.add_warning(format!(
                    "Suspicious pattern found in description: {}",
                    pattern
                ));
            }
        }

        // Check custom fields
        for (key, value) in &metadata.custom_fields {
            for pattern in &self.malicious_patterns {
                if value.contains(pattern) {
                    validation.add_warning(format!(
                        "Suspicious pattern found in custom field '{}': {}",
                        key, pattern
                    ));
                }
            }
        }

        Ok(())
    }

    /// Verify plugin signatures
    async fn verify_signatures(
        &self,
        _metadata: &PluginMetadata,
        _validation: &mut SecurityValidation,
    ) -> Result<()> {
        unimplemented!("Signature verification: needs cryptographic signature validation using public keys")
        tracing::debug!("Signature verification would occur here");
        Ok(())
    }

    /// Check required permissions
    fn check_permissions(
        &self,
        metadata: &PluginMetadata,
        validation: &mut SecurityValidation,
    ) -> Result<()> {
        // Determine required permissions based on capabilities
        for capability in &metadata.capabilities {
            match capability.name.as_str() {
                "database" => {
                    validation.require_permission("network:connect");
                    validation.require_permission("storage:read");
                    validation.require_permission("storage:write");
                }
                "cache" => {
                    validation.require_permission("network:connect");
                    validation.require_permission("memory:read");
                    validation.require_permission("memory:write");
                }
                "message_queue" => {
                    validation.require_permission("network:connect");
                    validation.require_permission("network:listen");
                }
                "ai_ml" => {
                    validation.require_permission("network:connect");
                    validation.require_permission("compute:gpu");
                }
                _ => {
                    validation.require_permission("basic:execute");
                }
            }
        }

        Ok(())
    }

    /// Calculate security score (0-100)
    pub fn calculate_security_score(&self, validation: &SecurityValidation) -> f64 {
        let mut score = 100.0;

        // Deduct points for errors
        score -= validation.errors.len() as f64 * 20.0;

        // Deduct points for warnings
        score -= validation.warnings.len() as f64 * 5.0;

        // Adjust based on security level
        score += match validation.level {
            SecurityLevel::Trusted => 0.0,
            SecurityLevel::Verified => -10.0,
            SecurityLevel::Sandboxed => -20.0,
            SecurityLevel::Untrusted => -40.0,
        };

        score.clamp(0.0, 100.0)
    }

    /// Check if plugin can be trusted
    pub fn can_trust(&self, validation: &SecurityValidation) -> bool {
        validation.passed && validation.errors.is_empty()
    }
}

impl Default for SecurityValidator {
    fn default() -> Self {
        Self::new()
    }
}

/// Plugin sandbox configuration
#[derive(Debug, Clone)]
pub struct SandboxConfig {
    /// Allow network access
    pub allow_network: bool,
    /// Allow filesystem access
    pub allow_filesystem: bool,
    /// Allow system calls
    pub allow_syscalls: bool,
    /// Maximum memory usage (MB)
    pub max_memory_mb: usize,
    /// Maximum CPU usage (percentage)
    pub max_cpu_percent: usize,
    /// Execution timeout (seconds)
    pub timeout_seconds: u64,
}

impl Default for SandboxConfig {
    fn default() -> Self {
        Self {
            allow_network: true,
            allow_filesystem: true,
            allow_syscalls: false,
            max_memory_mb: 512,
            max_cpu_percent: 80,
            timeout_seconds: 300,
        }
    }
}

/// Plugin sandbox manager
pub struct PluginSandbox {
    #[allow(dead_code)]
    config: SandboxConfig,
}

impl PluginSandbox {
    pub fn new(config: SandboxConfig) -> Self {
        Self { config }
    }

    /// Execute plugin in sandbox
    pub async fn execute_sandboxed<F, T>(&self, _plugin_name: &str, _f: F) -> Result<T>
    where
        F: FnOnce() -> Result<T> + Send + 'static,
        T: Send + 'static,
    {
        unimplemented!("Sandboxing: needs container or process isolation for secure plugin execution")

        tokio::task::spawn_blocking(_f).await.map_err(|e| {
            CleanroomError::internal_error(format!("Sandbox execution failed: {}", e))
        })?
    }

    /// Check sandbox resource usage
    pub async fn check_resource_usage(&self, _plugin_name: &str) -> Result<ResourceUsage> {
        unimplemented!("Resource monitoring: needs CPU, memory, and network usage tracking for plugin execution")
    }
}

/// Resource usage information
#[derive(Debug, Clone, Default)]
pub struct ResourceUsage {
    pub memory_mb: f64,
    pub cpu_percent: f64,
    pub execution_time_ms: u64,
}
