intent-engine 0.11.1

//! Intent-Engine Logging System
//!
//! Provides structured logging with configurable levels and output formats.
//! Uses tracing crate for structured logging with spans and events.

use std::io::{self, IsTerminal};
use tracing::Level;
use tracing_subscriber::{
    fmt::{self, format::FmtSpan},
    layer::SubscriberExt,
    util::SubscriberInitExt,
    EnvFilter, Layer, Registry,
};

/// Logging configuration options
#[derive(Debug, Clone)]
pub struct LoggingConfig {
    /// Minimum log level to output
    pub level: Level,
    /// Enable colored output
    pub color: bool,
    /// Show timestamps
    pub show_timestamps: bool,
    /// Show target/module name
    pub show_target: bool,
    /// Enable JSON format for machine parsing
    pub json_format: bool,
    /// Enable span events for tracing
    pub enable_spans: bool,
    /// Output to file instead of stdout (for daemon mode)
    pub file_output: Option<std::path::PathBuf>,
}

impl Default for LoggingConfig {
    fn default() -> Self {
        Self {
            level: Level::INFO,
            color: true,
            show_timestamps: false,
            show_target: false,
            json_format: false,
            enable_spans: false,
            file_output: None,
        }
    }
}

impl LoggingConfig {
    /// Create config for different application modes
    pub fn for_mode(mode: ApplicationMode) -> Self {
        match mode {
            ApplicationMode::McpServer => Self {
                level: Level::DEBUG,
                color: false, // MCP output should be clean
                show_timestamps: true,
                show_target: true,
                json_format: true,   // Machine-readable for MCP
                enable_spans: false, // Avoid noise in JSON-RPC
                file_output: None,
            },
            ApplicationMode::Dashboard => Self {
                level: Level::INFO,
                color: false, // Background service
                show_timestamps: true,
                show_target: true,
                json_format: false,
                enable_spans: true, // Good for debugging dashboard
                file_output: None,
            },
            ApplicationMode::Cli => Self {
                level: Level::INFO,
                color: true,
                show_timestamps: false,
                show_target: false,
                json_format: false,
                enable_spans: false,
                file_output: None,
            },
            ApplicationMode::Test => Self {
                level: Level::DEBUG,
                color: false,
                show_timestamps: true,
                show_target: true,
                json_format: false,
                enable_spans: true,
                file_output: None,
            },
        }
    }

    /// Create config from CLI arguments
    pub fn from_args(quiet: bool, verbose: bool, json: bool) -> Self {
        let level = if verbose {
            Level::DEBUG
        } else if quiet {
            Level::ERROR
        } else {
            Level::INFO
        };

        Self {
            level,
            color: !quiet && !json && std::io::stdout().is_terminal(),
            show_timestamps: verbose || json,
            show_target: verbose,
            json_format: json,
            enable_spans: verbose,
            file_output: None,
        }
    }
}

/// Application modes with different logging requirements
#[derive(Debug, Clone, Copy)]
pub enum ApplicationMode {
    /// MCP server mode - clean, structured output
    McpServer,
    /// Dashboard server mode - detailed for debugging
    Dashboard,
    /// CLI mode - user-friendly output
    Cli,
    /// Test mode - maximum detail for testing
    Test,
}

/// Initialize the logging system
///
/// Note: For production use on Linux/Unix, consider using `logrotate` for log rotation.
/// See `docs/deployment/logrotate.conf` for configuration example.
/// The built-in daily rotation is provided as a fallback for Windows or simple deployments.
pub fn init_logging(config: LoggingConfig) -> io::Result<()> {
    let env_filter = EnvFilter::try_from_default_env()
        .unwrap_or_else(|_| EnvFilter::new(format!("intent_engine={}", config.level)));

    let registry = Registry::default().with(env_filter);

    if let Some(log_file) = config.file_output {
        let log_dir = log_file
            .parent()
            .ok_or_else(|| io::Error::new(io::ErrorKind::InvalidInput, "Invalid log file path"))?;

        let file_name = log_file
            .file_name()
            .ok_or_else(|| io::Error::new(io::ErrorKind::InvalidInput, "Invalid log file name"))?;

        // Create log directory if it doesn't exist
        std::fs::create_dir_all(log_dir)?;

        // Use daily rotation (recommended to configure logrotate on Linux)
        let file_appender = tracing_appender::rolling::daily(log_dir, file_name);

        if config.json_format {
            let json_layer = tracing_subscriber::fmt::layer()
                .json()
                .with_current_span(config.enable_spans)
                .with_span_events(FmtSpan::CLOSE)
                .with_writer(file_appender);
            json_layer.with_subscriber(registry).init();
        } else {
            let fmt_layer = fmt::layer()
                .with_target(config.show_target)
                .with_level(true)
                .with_ansi(false)
                .with_writer(file_appender);

            if config.show_timestamps {
                fmt_layer
                    .with_timer(fmt::time::ChronoUtc::rfc_3339())
                    .with_subscriber(registry)
                    .init();
            } else {
                fmt_layer.with_subscriber(registry).init();
            }
        }
    } else if config.json_format {
        let json_layer = tracing_subscriber::fmt::layer()
            .json()
            .with_current_span(config.enable_spans)
            .with_span_events(FmtSpan::CLOSE)
            .with_writer(io::stdout);
        json_layer.with_subscriber(registry).init();
    } else {
        let fmt_layer = fmt::layer()
            .with_target(config.show_target)
            .with_level(true)
            .with_ansi(config.color)
            .with_writer(io::stdout);

        if config.show_timestamps {
            fmt_layer
                .with_timer(fmt::time::ChronoUtc::rfc_3339())
                .with_subscriber(registry)
                .init();
        } else {
            fmt_layer.with_subscriber(registry).init();
        }
    }

    Ok(())
}

/// Clean up old log files based on retention policy
///
/// Scans the log directory and removes files older than the specified retention period.
/// Only removes files matching the pattern `.log.YYYY-MM-DD` (rotated log files).
///
/// # Arguments
/// * `log_dir` - Directory containing log files
/// * `retention_days` - Number of days to retain logs (default: 7)
///
/// # Example
/// ```no_run
/// use std::path::Path;
/// use intent_engine::logging::cleanup_old_logs;
///
/// let log_dir = Path::new("/home/user/.intent-engine/logs");
/// cleanup_old_logs(log_dir, 7).ok();
/// ```
pub fn cleanup_old_logs(log_dir: &std::path::Path, retention_days: u32) -> io::Result<()> {
    use std::fs;
    use std::time::SystemTime;

    if !log_dir.exists() {
        return Ok(()); // Nothing to clean if directory doesn't exist
    }

    let now = SystemTime::now();
    let retention_duration = std::time::Duration::from_secs(retention_days as u64 * 24 * 60 * 60);

    let mut cleaned_count = 0;
    let mut cleaned_size: u64 = 0;

    for entry in fs::read_dir(log_dir)? {
        let entry = entry?;
        let path = entry.path();

        // Only process rotated log files (containing .log. followed by a date)
        // Examples: dashboard.log.2025-11-22, mcp-server.log.2025-11-21
        let path_str = path.to_string_lossy();
        if !path_str.contains(".log.") || !path.is_file() {
            continue;
        }

        let metadata = entry.metadata()?;
        let modified = metadata.modified()?;

        if let Ok(age) = now.duration_since(modified) {
            if age > retention_duration {
                let size = metadata.len();
                match fs::remove_file(&path) {
                    Ok(_) => {
                        cleaned_count += 1;
                        cleaned_size += size;
                        tracing::info!(
                            "Cleaned up old log file: {} (age: {} days, size: {} bytes)",
                            path.display(),
                            age.as_secs() / 86400,
                            size
                        );
                    },
                    Err(e) => {
                        tracing::warn!(path = %path.display(), error = %e, "Failed to remove old log file");
                    },
                }
            }
        }
    }

    if cleaned_count > 0 {
        tracing::info!(
            "Log cleanup completed: removed {} files, freed {} bytes",
            cleaned_count,
            cleaned_size
        );
    }

    Ok(())
}

/// Get log file path for a given application mode
pub fn log_file_path(mode: ApplicationMode) -> std::path::PathBuf {
    let home = dirs::home_dir().expect("Failed to get home directory");
    let log_dir = home.join(".intent-engine").join("logs");

    // Create log directory if it doesn't exist
    std::fs::create_dir_all(&log_dir).ok();

    match mode {
        ApplicationMode::Dashboard => log_dir.join("dashboard.log"),
        ApplicationMode::McpServer => log_dir.join("mcp-server.log"),
        ApplicationMode::Cli => log_dir.join("cli.log"),
        ApplicationMode::Test => log_dir.join("test.log"),
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;
    use std::time::SystemTime;
    use tempfile::TempDir;

    // ========== LoggingConfig tests ==========

    #[test]
    fn test_logging_config_default() {
        let config = LoggingConfig::default();

        assert_eq!(config.level, Level::INFO);
        assert!(config.color);
        assert!(!config.show_timestamps);
        assert!(!config.show_target);
        assert!(!config.json_format);
        assert!(!config.enable_spans);
        assert!(config.file_output.is_none());
    }

    #[test]
    fn test_logging_config_for_mode_mcp_server() {
        let config = LoggingConfig::for_mode(ApplicationMode::McpServer);

        assert_eq!(config.level, Level::DEBUG);
        assert!(!config.color); // MCP should be clean
        assert!(config.show_timestamps);
        assert!(config.show_target);
        assert!(config.json_format); // Machine-readable
        assert!(!config.enable_spans); // Avoid noise
        assert!(config.file_output.is_none());
    }

    #[test]
    fn test_logging_config_for_mode_dashboard() {
        let config = LoggingConfig::for_mode(ApplicationMode::Dashboard);

        assert_eq!(config.level, Level::INFO);
        assert!(!config.color); // Background service
        assert!(config.show_timestamps);
        assert!(config.show_target);
        assert!(!config.json_format);
        assert!(config.enable_spans); // Good for debugging
        assert!(config.file_output.is_none());
    }

    #[test]
    fn test_logging_config_for_mode_cli() {
        let config = LoggingConfig::for_mode(ApplicationMode::Cli);

        assert_eq!(config.level, Level::INFO);
        assert!(config.color); // User-friendly
        assert!(!config.show_timestamps);
        assert!(!config.show_target);
        assert!(!config.json_format);
        assert!(!config.enable_spans);
        assert!(config.file_output.is_none());
    }

    #[test]
    fn test_logging_config_for_mode_test() {
        let config = LoggingConfig::for_mode(ApplicationMode::Test);

        assert_eq!(config.level, Level::DEBUG);
        assert!(!config.color);
        assert!(config.show_timestamps);
        assert!(config.show_target);
        assert!(!config.json_format);
        assert!(config.enable_spans); // Maximum detail
        assert!(config.file_output.is_none());
    }

    #[test]
    fn test_logging_config_from_args_verbose() {
        let config = LoggingConfig::from_args(false, true, false);

        assert_eq!(config.level, Level::DEBUG);
        assert!(config.show_timestamps);
        assert!(config.show_target);
        assert!(!config.json_format);
        assert!(config.enable_spans);
    }

    #[test]
    fn test_logging_config_from_args_quiet() {
        let config = LoggingConfig::from_args(true, false, false);

        assert_eq!(config.level, Level::ERROR);
        assert!(!config.color); // Quiet mode disables color
        assert!(!config.show_timestamps); // Quiet mode, no verbose
        assert!(!config.show_target);
    }

    #[test]
    fn test_logging_config_from_args_json() {
        let config = LoggingConfig::from_args(false, false, true);

        assert_eq!(config.level, Level::INFO);
        assert!(!config.color); // JSON disables color
        assert!(config.show_timestamps); // JSON enables timestamps
        assert!(config.json_format);
    }

    #[test]
    fn test_logging_config_from_args_normal() {
        let config = LoggingConfig::from_args(false, false, false);

        assert_eq!(config.level, Level::INFO);
        assert!(!config.show_timestamps);
        assert!(!config.show_target);
        assert!(!config.json_format);
        assert!(!config.enable_spans);
    }

    // ========== log_file_path tests ==========

    #[test]
    fn test_log_file_path_dashboard() {
        let path = log_file_path(ApplicationMode::Dashboard);
        assert!(path.to_string_lossy().ends_with("dashboard.log"));
        assert!(path.to_string_lossy().contains(".intent-engine"));
        assert!(path.to_string_lossy().contains("logs"));
    }

    #[test]
    fn test_log_file_path_mcp_server() {
        let path = log_file_path(ApplicationMode::McpServer);
        assert!(path.to_string_lossy().ends_with("mcp-server.log"));
    }

    #[test]
    fn test_log_file_path_cli() {
        let path = log_file_path(ApplicationMode::Cli);
        assert!(path.to_string_lossy().ends_with("cli.log"));
    }

    #[test]
    fn test_log_file_path_test() {
        let path = log_file_path(ApplicationMode::Test);
        assert!(path.to_string_lossy().ends_with("test.log"));
    }

    // ========== cleanup_old_logs tests ==========

    #[test]
    fn test_cleanup_old_logs_nonexistent_dir() {
        let temp = TempDir::new().unwrap();
        let nonexistent = temp.path().join("nonexistent");

        // Should not error on non-existent directory
        let result = cleanup_old_logs(&nonexistent, 7);
        assert!(result.is_ok());
    }

    #[test]
    fn test_cleanup_old_logs_empty_dir() {
        let temp = TempDir::new().unwrap();

        let result = cleanup_old_logs(temp.path(), 7);
        assert!(result.is_ok());
    }

    #[test]
    fn test_cleanup_old_logs_keeps_current_logs() {
        let temp = TempDir::new().unwrap();

        // Create a current log file (not rotated)
        let current_log = temp.path().join("dashboard.log");
        fs::write(&current_log, "current log data").unwrap();

        // Should not remove current log file (no .log.DATE pattern)
        cleanup_old_logs(temp.path(), 0).unwrap();

        assert!(current_log.exists());
    }

    #[test]
    fn test_cleanup_old_logs_removes_old_rotated_files() {
        let temp = TempDir::new().unwrap();

        // Create an old rotated log file
        let old_log = temp.path().join("dashboard.log.2020-01-01");
        fs::write(&old_log, "old log data").unwrap();

        // Set modification time to 10 days ago
        let ten_days_ago = SystemTime::now()
            .checked_sub(std::time::Duration::from_secs(10 * 24 * 60 * 60))
            .unwrap();
        filetime::set_file_mtime(&old_log, filetime::FileTime::from_system_time(ten_days_ago))
            .unwrap();

        // Clean up logs older than 7 days
        cleanup_old_logs(temp.path(), 7).unwrap();

        // Old file should be removed
        assert!(!old_log.exists());
    }

    #[test]
    fn test_cleanup_old_logs_keeps_recent_rotated_files() {
        let temp = TempDir::new().unwrap();

        // Create a recent rotated log file
        let recent_log = temp.path().join("mcp-server.log.2025-11-25");
        fs::write(&recent_log, "recent log data").unwrap();

        // Set modification time to 3 days ago
        let three_days_ago = SystemTime::now()
            .checked_sub(std::time::Duration::from_secs(3 * 24 * 60 * 60))
            .unwrap();
        filetime::set_file_mtime(
            &recent_log,
            filetime::FileTime::from_system_time(three_days_ago),
        )
        .unwrap();

        // Clean up logs older than 7 days
        cleanup_old_logs(temp.path(), 7).unwrap();

        // Recent file should be kept
        assert!(recent_log.exists());
    }

    #[test]
    fn test_cleanup_old_logs_ignores_non_log_files() {
        let temp = TempDir::new().unwrap();

        // Create a non-log file that's old
        let old_file = temp.path().join("config.json");
        fs::write(&old_file, "{}").unwrap();

        let ten_days_ago = SystemTime::now()
            .checked_sub(std::time::Duration::from_secs(10 * 24 * 60 * 60))
            .unwrap();
        filetime::set_file_mtime(
            &old_file,
            filetime::FileTime::from_system_time(ten_days_ago),
        )
        .unwrap();

        // Should not remove non-log files
        cleanup_old_logs(temp.path(), 7).unwrap();

        assert!(old_file.exists());
    }

    #[test]
    fn test_cleanup_old_logs_ignores_subdirectories() {
        let temp = TempDir::new().unwrap();

        // Create a subdirectory with log-like name
        let subdir = temp.path().join("archive.log.2020-01-01");
        fs::create_dir(&subdir).unwrap();

        // Should not try to remove directories
        let result = cleanup_old_logs(temp.path(), 7);
        assert!(result.is_ok());
        assert!(subdir.exists());
    }
}