//! Rotation Job Scheduler - Phase 5
//!
//! Background job scheduler that periodically checks for secrets due for
//! rotation and executes rotation operations automatically.

use std::sync::Arc;
use std::time::Duration;

use chrono::Utc;
use tokio::task::JoinHandle;
use tokio::time::interval;
use tracing::{error, info, warn};

use super::{RotationSchedule, RotationScheduler};
use crate::error::Result;

/// Rotation job scheduler configuration
#[derive(Debug, Clone)]
pub struct RotationJobConfig {
    /// Check interval in seconds (default: 3600 = 1 hour)
    pub check_interval_secs: u64,

    /// Maximum concurrent rotations
    pub max_concurrent: usize,

    /// Enable automatic rotation on startup
    pub auto_start: bool,
}

impl Default for RotationJobConfig {
    fn default() -> Self {
        Self {
            check_interval_secs: 3600,
            max_concurrent: 5,
            auto_start: true,
        }
    }
}

/// Rotation job scheduler
pub struct RotationJobScheduler {
    /// Rotation scheduler service
    rotation_scheduler: Arc<RotationScheduler>,

    /// Configuration
    config: RotationJobConfig,

    /// Job handle (for stopping the job)
    job_handle: Arc<tokio::sync::Mutex<Option<JoinHandle<()>>>>,
}

impl RotationJobScheduler {
    /// Create new rotation job scheduler
    pub fn new(rotation_scheduler: Arc<RotationScheduler>, config: RotationJobConfig) -> Self {
        Self {
            rotation_scheduler,
            config,
            job_handle: Arc::new(tokio::sync::Mutex::new(None)),
        }
    }

    /// Start the rotation job scheduler
    pub async fn start(&self) -> Result<()> {
        if self.config.auto_start {
            let rotation_scheduler = self.rotation_scheduler.clone();
            let interval_secs = self.config.check_interval_secs;
            let max_concurrent = self.config.max_concurrent;

            let handle = tokio::spawn(async move {
                Self::rotation_loop(rotation_scheduler, interval_secs, max_concurrent).await;
            });

            let mut job = self.job_handle.lock().await;
            *job = Some(handle);

            info!(
                "Rotation job scheduler started (check interval: {}s)",
                interval_secs
            );
        }

        Ok(())
    }

    /// Stop the rotation job scheduler
    pub async fn stop(&self) -> Result<()> {
        let mut job = self.job_handle.lock().await;
        if let Some(handle) = job.take() {
            handle.abort();
            info!("Rotation job scheduler stopped");
        }

        Ok(())
    }

    /// Main rotation loop
    async fn rotation_loop(
        rotation_scheduler: Arc<RotationScheduler>,
        interval_secs: u64,
        max_concurrent: usize,
    ) {
        let mut ticker = interval(Duration::from_secs(interval_secs));

        loop {
            ticker.tick().await;

            match rotation_scheduler.get_due_schedules().await {
                Ok(due_schedules) => {
                    if due_schedules.is_empty() {
                        continue;
                    }

                    info!(count = %due_schedules.len(), "Found secrets due for rotation");
                    Self::process_rotations(&rotation_scheduler, &due_schedules, max_concurrent)
                        .await;
                }
                Err(e) => {
                    error!(error = %e, "Failed to get due rotation schedules");
                }
            }
        }
    }

    /// Process rotations with concurrency limit
    async fn process_rotations(
        rotation_scheduler: &Arc<RotationScheduler>,
        schedules: &[RotationSchedule],
        max_concurrent: usize,
    ) {
        let mut handles = Vec::new();

        for schedule in schedules {
            while handles.len() >= max_concurrent {
                if let Some(handle) = handles.pop() {
                    let _ = handle.await;
                }
            }

            let scheduler = rotation_scheduler.clone();
            let secret_path = schedule.secret_path.clone();

            let handle = tokio::spawn(async move {
                Self::rotate_secret(&scheduler, &secret_path).await;
            });

            handles.push(handle);
        }

        for handle in handles {
            let _ = handle.await;
        }
    }

    /// Rotate a single secret
    async fn rotate_secret(rotation_scheduler: &Arc<RotationScheduler>, secret_path: &str) {
        info!(secret = %secret_path, "Starting secret rotation");

        // Mark as in-progress
        if let Err(e) = rotation_scheduler.mark_in_progress(secret_path).await {
            error!(error = %e, secret = %secret_path, "Failed to mark rotation as in-progress");
            return;
        }

        // Simulate rotation (in production, this would call the actual rotation logic)
        match Self::execute_rotation(secret_path).await {
            Ok(_) => {
                info!(secret = %secret_path, "Secret rotated successfully");

                // Mark as completed
                if let Err(e) = rotation_scheduler.mark_completed(secret_path).await {
                    error!(error = %e, secret = %secret_path, "Failed to mark rotation as completed");
                }
            }
            Err(e) => {
                warn!(error = %e, secret = %secret_path, "Secret rotation failed");

                // Mark as failed
                let error_msg = format!("Rotation failed: {}", e);
                if let Err(mark_err) = rotation_scheduler
                    .mark_failed(secret_path, &error_msg)
                    .await
                {
                    error!(error = %mark_err, secret = %secret_path, "Failed to mark rotation as failed");
                }
            }
        }
    }

    /// Execute the actual rotation (placeholder)
    async fn execute_rotation(secret_path: &str) -> Result<()> {
        info!(secret = %secret_path, "Executing rotation logic");

        // TODO: Phase 5.1 - Implement actual rotation logic
        // This would involve:
        // 1. Calling the KMS service to generate a new secret
        // 2. Validating the new secret works (test connection for DB creds, etc.)
        // 3. Updating the SurrealDB with the new secret value
        // 4. Logging the rotation to the audit trail
        // 5. Notifying users/teams of the rotation

        // For now, just simulate a successful rotation
        tokio::time::sleep(Duration::from_millis(100)).await;
        Ok(())
    }

    /// Get rotation job status
    pub async fn get_status(&self) -> RotationJobStatus {
        let job = self.job_handle.lock().await;

        RotationJobStatus {
            running: job.is_some(),
            check_interval_secs: self.config.check_interval_secs,
            max_concurrent: self.config.max_concurrent,
            last_check: Utc::now().to_rfc3339(),
        }
    }
}

/// Rotation job status
#[derive(Debug, Clone)]
pub struct RotationJobStatus {
    /// Whether the job is currently running
    pub running: bool,

    /// Check interval in seconds
    pub check_interval_secs: u64,

    /// Maximum concurrent rotations
    pub max_concurrent: usize,

    /// Last check timestamp
    pub last_check: String,
}

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

    #[tokio::test]
    async fn test_rotation_job_config_default() {
        let config = RotationJobConfig::default();
        assert_eq!(config.check_interval_secs, 3600);
        assert_eq!(config.max_concurrent, 5);
        assert!(config.auto_start);
    }

    #[tokio::test]
    async fn test_rotation_job_status() {
        let rotation_scheduler = Arc::new(RotationScheduler::new());
        let config = RotationJobConfig {
            auto_start: false,
            ..Default::default()
        };

        let scheduler = RotationJobScheduler::new(rotation_scheduler, config);
        let status = scheduler.get_status().await;

        assert!(!status.running);
        assert_eq!(status.check_interval_secs, 3600);
        assert_eq!(status.max_concurrent, 5);
    }
}
