ferro-queue 0.2.3

//! Queue connection and operations.

use crate::{Error, JobPayload, QueueConfig};
use chrono::{DateTime, Utc};
use redis::aio::ConnectionManager;
use redis::AsyncCommands;
use serde::{Deserialize, Serialize};
use std::sync::Arc;
use tracing::debug;

/// Queue statistics for introspection
#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct QueueStats {
    /// Stats per queue
    pub queues: Vec<SingleQueueStats>,
    /// Total failed jobs count
    pub total_failed: usize,
}

/// Statistics for a single queue
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SingleQueueStats {
    /// Queue name
    pub name: String,
    /// Number of pending jobs
    pub pending: usize,
    /// Number of delayed jobs
    pub delayed: usize,
}

/// Job information for introspection (without full payload data)
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct JobInfo {
    /// Unique job ID
    pub id: String,
    /// Job type name
    pub job_type: String,
    /// Queue name
    pub queue: String,
    /// Number of attempts made
    pub attempts: u32,
    /// Maximum retry attempts
    pub max_retries: u32,
    /// When the job was created
    pub created_at: DateTime<Utc>,
    /// When the job should be available for processing
    pub available_at: DateTime<Utc>,
    /// Job state
    pub state: JobState,
}

/// Job state for introspection
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum JobState {
    Pending,
    Delayed,
    Failed,
}

/// Failed job information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FailedJobInfo {
    /// Job info
    pub job: JobInfo,
    /// Error message
    pub error: String,
    /// When the job failed
    pub failed_at: DateTime<Utc>,
}

/// Stored format for failed jobs
#[derive(Debug, Deserialize)]
struct StoredFailedJob {
    payload: JobPayload,
    error: String,
    failed_at: DateTime<Utc>,
}

/// A connection to the queue backend.
#[derive(Clone)]
pub struct QueueConnection {
    /// Redis connection manager.
    conn: ConnectionManager,
    /// Queue configuration.
    config: Arc<QueueConfig>,
}

impl QueueConnection {
    /// Create a new queue connection.
    pub async fn new(config: QueueConfig) -> Result<Self, Error> {
        let client = redis::Client::open(config.redis_url.as_str())
            .map_err(|e| Error::ConnectionFailed(e.to_string()))?;

        let conn = ConnectionManager::new(client)
            .await
            .map_err(|e| Error::ConnectionFailed(e.to_string()))?;

        Ok(Self {
            conn,
            config: Arc::new(config),
        })
    }

    /// Get the configuration.
    pub fn config(&self) -> &QueueConfig {
        &self.config
    }

    /// Push a job to a queue.
    pub async fn push(&self, payload: JobPayload) -> Result<(), Error> {
        let queue = &payload.queue;
        let json = payload.to_json()?;

        if payload.is_available() {
            // Push to the immediate queue
            let key = self.config.queue_key(queue);
            self.conn
                .clone()
                .lpush::<_, _, ()>(&key, &json)
                .await
                .map_err(Error::Redis)?;

            debug!(queue = queue, job_id = %payload.id, "Job pushed to queue");
        } else {
            // Push to the delayed queue (sorted set by available_at timestamp)
            let key = self.config.delayed_key(queue);
            let score = payload.available_at.timestamp() as f64;
            self.conn
                .clone()
                .zadd::<_, _, _, ()>(&key, &json, score)
                .await
                .map_err(Error::Redis)?;

            debug!(
                queue = queue,
                job_id = %payload.id,
                available_at = %payload.available_at,
                "Job pushed to delayed queue"
            );
        }

        Ok(())
    }

    /// Pop a job from a queue (blocking).
    pub async fn pop(&self, queue: &str) -> Result<Option<JobPayload>, Error> {
        let key = self.config.queue_key(queue);
        let timeout = self.config.block_timeout.as_secs() as f64;

        // BRPOP returns [key, value] or nil
        let result: Option<(String, String)> = self
            .conn
            .clone()
            .brpop(&key, timeout)
            .await
            .map_err(Error::Redis)?;

        match result {
            Some((_, json)) => {
                let mut payload = JobPayload::from_json(&json)?;
                payload.reserve();
                Ok(Some(payload))
            }
            None => Ok(None),
        }
    }

    /// Pop a job from a queue (non-blocking).
    pub async fn pop_nowait(&self, queue: &str) -> Result<Option<JobPayload>, Error> {
        let key = self.config.queue_key(queue);

        let result: Option<String> = self
            .conn
            .clone()
            .rpop(&key, None)
            .await
            .map_err(Error::Redis)?;

        match result {
            Some(json) => {
                let mut payload = JobPayload::from_json(&json)?;
                payload.reserve();
                Ok(Some(payload))
            }
            None => Ok(None),
        }
    }

    /// Move delayed jobs that are ready to the main queue.
    pub async fn migrate_delayed(&self, queue: &str) -> Result<usize, Error> {
        let delayed_key = self.config.delayed_key(queue);
        let queue_key = self.config.queue_key(queue);
        let now = chrono::Utc::now().timestamp() as f64;

        // Get jobs that are ready (score <= now)
        let ready_jobs: Vec<String> = self
            .conn
            .clone()
            .zrangebyscore(&delayed_key, "-inf", now)
            .await
            .map_err(Error::Redis)?;

        let count = ready_jobs.len();

        for job in ready_jobs {
            // Remove from delayed set
            self.conn
                .clone()
                .zrem::<_, _, ()>(&delayed_key, &job)
                .await
                .map_err(Error::Redis)?;

            // Push to main queue
            self.conn
                .clone()
                .lpush::<_, _, ()>(&queue_key, &job)
                .await
                .map_err(Error::Redis)?;
        }

        if count > 0 {
            debug!(queue = queue, count = count, "Migrated delayed jobs");
        }

        Ok(count)
    }

    /// Release a job back to the queue (for retry).
    pub async fn release(
        &self,
        mut payload: JobPayload,
        delay: std::time::Duration,
    ) -> Result<(), Error> {
        payload.increment_attempts();
        payload.reserved_at = None;

        if delay.is_zero() {
            payload.available_at = chrono::Utc::now();
        } else {
            payload.available_at =
                chrono::Utc::now() + chrono::Duration::from_std(delay).unwrap_or_default();
        }

        self.push(payload).await
    }

    /// Mark a job as failed.
    pub async fn fail(&self, payload: JobPayload, error: &Error) -> Result<(), Error> {
        let failed_key = self.config.failed_key();

        #[derive(serde::Serialize)]
        struct FailedJob {
            payload: JobPayload,
            error: String,
            failed_at: chrono::DateTime<chrono::Utc>,
        }

        let failed = FailedJob {
            payload,
            error: error.to_string(),
            failed_at: chrono::Utc::now(),
        };

        let json = serde_json::to_string(&failed)
            .map_err(|e| Error::SerializationFailed(e.to_string()))?;

        self.conn
            .clone()
            .lpush::<_, _, ()>(&failed_key, &json)
            .await
            .map_err(Error::Redis)?;

        Ok(())
    }

    /// Get the number of jobs in a queue.
    pub async fn size(&self, queue: &str) -> Result<usize, Error> {
        let key = self.config.queue_key(queue);
        let len: usize = self.conn.clone().llen(&key).await.map_err(Error::Redis)?;
        Ok(len)
    }

    /// Get the number of delayed jobs in a queue.
    pub async fn delayed_size(&self, queue: &str) -> Result<usize, Error> {
        let key = self.config.delayed_key(queue);
        let len: usize = self.conn.clone().zcard(&key).await.map_err(Error::Redis)?;
        Ok(len)
    }

    /// Clear all jobs from a queue.
    pub async fn clear(&self, queue: &str) -> Result<(), Error> {
        let queue_key = self.config.queue_key(queue);
        let delayed_key = self.config.delayed_key(queue);

        self.conn
            .clone()
            .del::<_, ()>(&queue_key)
            .await
            .map_err(Error::Redis)?;
        self.conn
            .clone()
            .del::<_, ()>(&delayed_key)
            .await
            .map_err(Error::Redis)?;

        Ok(())
    }

    /// Get pending jobs from a queue (without removing them).
    pub async fn get_pending_jobs(&self, queue: &str, limit: usize) -> Result<Vec<JobInfo>, Error> {
        let key = self.config.queue_key(queue);
        let jobs: Vec<String> = self
            .conn
            .clone()
            .lrange(&key, 0, limit as isize - 1)
            .await
            .map_err(Error::Redis)?;

        let mut result = Vec::with_capacity(jobs.len());
        for json in jobs {
            if let Ok(payload) = JobPayload::from_json(&json) {
                result.push(JobInfo {
                    id: payload.id.to_string(),
                    job_type: payload.job_type,
                    queue: payload.queue,
                    attempts: payload.attempts,
                    max_retries: payload.max_retries,
                    created_at: payload.created_at,
                    available_at: payload.available_at,
                    state: JobState::Pending,
                });
            }
        }
        Ok(result)
    }

    /// Get delayed jobs from a queue (without removing them).
    pub async fn get_delayed_jobs(&self, queue: &str, limit: usize) -> Result<Vec<JobInfo>, Error> {
        let key = self.config.delayed_key(queue);
        let jobs: Vec<String> = self
            .conn
            .clone()
            .zrange(&key, 0, limit as isize - 1)
            .await
            .map_err(Error::Redis)?;

        let mut result = Vec::with_capacity(jobs.len());
        for json in jobs {
            if let Ok(payload) = JobPayload::from_json(&json) {
                result.push(JobInfo {
                    id: payload.id.to_string(),
                    job_type: payload.job_type,
                    queue: payload.queue,
                    attempts: payload.attempts,
                    max_retries: payload.max_retries,
                    created_at: payload.created_at,
                    available_at: payload.available_at,
                    state: JobState::Delayed,
                });
            }
        }
        Ok(result)
    }

    /// Get failed jobs (without removing them).
    pub async fn get_failed_jobs(&self, limit: usize) -> Result<Vec<FailedJobInfo>, Error> {
        let key = self.config.failed_key();
        let jobs: Vec<String> = self
            .conn
            .clone()
            .lrange(&key, 0, limit as isize - 1)
            .await
            .map_err(Error::Redis)?;

        let mut result = Vec::with_capacity(jobs.len());
        for json in jobs {
            if let Ok(failed) = serde_json::from_str::<StoredFailedJob>(&json) {
                result.push(FailedJobInfo {
                    job: JobInfo {
                        id: failed.payload.id.to_string(),
                        job_type: failed.payload.job_type,
                        queue: failed.payload.queue,
                        attempts: failed.payload.attempts,
                        max_retries: failed.payload.max_retries,
                        created_at: failed.payload.created_at,
                        available_at: failed.payload.available_at,
                        state: JobState::Failed,
                    },
                    error: failed.error,
                    failed_at: failed.failed_at,
                });
            }
        }
        Ok(result)
    }

    /// Get the count of failed jobs.
    pub async fn failed_count(&self) -> Result<usize, Error> {
        let key = self.config.failed_key();
        let len: usize = self.conn.clone().llen(&key).await.map_err(Error::Redis)?;
        Ok(len)
    }

    /// Get queue statistics for specified queues.
    pub async fn get_stats(&self, queues: &[&str]) -> Result<QueueStats, Error> {
        let mut stats = QueueStats::default();

        for queue in queues {
            let pending = self.size(queue).await?;
            let delayed = self.delayed_size(queue).await?;
            stats.queues.push(SingleQueueStats {
                name: queue.to_string(),
                pending,
                delayed,
            });
        }

        stats.total_failed = self.failed_count().await?;
        Ok(stats)
    }
}

/// Queue facade for static access.
pub struct Queue;

impl Queue {
    /// Get the global queue connection.
    pub fn connection() -> &'static QueueConnection {
        GLOBAL_CONNECTION
            .get()
            .expect("Queue not initialized. Call Queue::init() first.")
    }

    /// Initialize the global queue connection.
    pub async fn init(config: QueueConfig) -> Result<(), Error> {
        let conn = QueueConnection::new(config).await?;
        GLOBAL_CONNECTION
            .set(conn)
            .map_err(|_| Error::custom("Queue already initialized"))?;
        Ok(())
    }

    /// Check if the queue is initialized.
    pub fn is_initialized() -> bool {
        GLOBAL_CONNECTION.get().is_some()
    }
}

static GLOBAL_CONNECTION: std::sync::OnceLock<QueueConnection> = std::sync::OnceLock::new();

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

    #[test]
    fn test_queue_stats_default() {
        let stats = QueueStats::default();
        assert!(stats.queues.is_empty());
        assert_eq!(stats.total_failed, 0);
    }

    #[test]
    fn test_queue_stats_serialization() {
        let stats = QueueStats {
            queues: vec![
                SingleQueueStats {
                    name: "default".to_string(),
                    pending: 5,
                    delayed: 2,
                },
                SingleQueueStats {
                    name: "emails".to_string(),
                    pending: 10,
                    delayed: 0,
                },
            ],
            total_failed: 3,
        };

        let json = serde_json::to_string(&stats).unwrap();
        let restored: QueueStats = serde_json::from_str(&json).unwrap();

        assert_eq!(restored.queues.len(), 2);
        assert_eq!(restored.queues[0].name, "default");
        assert_eq!(restored.queues[0].pending, 5);
        assert_eq!(restored.queues[1].name, "emails");
        assert_eq!(restored.total_failed, 3);
    }

    #[test]
    fn test_single_queue_stats_clone() {
        let stats = SingleQueueStats {
            name: "test".to_string(),
            pending: 10,
            delayed: 5,
        };

        let cloned = stats.clone();
        assert_eq!(cloned.name, stats.name);
        assert_eq!(cloned.pending, stats.pending);
        assert_eq!(cloned.delayed, stats.delayed);
    }

    #[test]
    fn test_job_state_serialization() {
        assert_eq!(
            serde_json::to_string(&JobState::Pending).unwrap(),
            "\"pending\""
        );
        assert_eq!(
            serde_json::to_string(&JobState::Delayed).unwrap(),
            "\"delayed\""
        );
        assert_eq!(
            serde_json::to_string(&JobState::Failed).unwrap(),
            "\"failed\""
        );
    }

    #[test]
    fn test_job_state_deserialization() {
        let pending: JobState = serde_json::from_str("\"pending\"").unwrap();
        let delayed: JobState = serde_json::from_str("\"delayed\"").unwrap();
        let failed: JobState = serde_json::from_str("\"failed\"").unwrap();

        assert!(matches!(pending, JobState::Pending));
        assert!(matches!(delayed, JobState::Delayed));
        assert!(matches!(failed, JobState::Failed));
    }

    #[test]
    fn test_job_info_serialization() {
        let now = Utc::now();
        let job_info = JobInfo {
            id: "job-123".to_string(),
            job_type: "SendEmailJob".to_string(),
            queue: "emails".to_string(),
            attempts: 2,
            max_retries: 3,
            created_at: now,
            available_at: now,
            state: JobState::Pending,
        };

        let json = serde_json::to_string(&job_info).unwrap();
        let restored: JobInfo = serde_json::from_str(&json).unwrap();

        assert_eq!(restored.id, "job-123");
        assert_eq!(restored.job_type, "SendEmailJob");
        assert_eq!(restored.queue, "emails");
        assert_eq!(restored.attempts, 2);
        assert_eq!(restored.max_retries, 3);
        assert!(matches!(restored.state, JobState::Pending));
    }

    #[test]
    fn test_job_info_clone() {
        let now = Utc::now();
        let job_info = JobInfo {
            id: "job-456".to_string(),
            job_type: "ProcessOrder".to_string(),
            queue: "orders".to_string(),
            attempts: 0,
            max_retries: 5,
            created_at: now,
            available_at: now,
            state: JobState::Delayed,
        };

        let cloned = job_info.clone();
        assert_eq!(cloned.id, job_info.id);
        assert_eq!(cloned.job_type, job_info.job_type);
    }

    #[test]
    fn test_failed_job_info_serialization() {
        let now = Utc::now();
        let failed_job = FailedJobInfo {
            job: JobInfo {
                id: "job-789".to_string(),
                job_type: "FailingJob".to_string(),
                queue: "default".to_string(),
                attempts: 3,
                max_retries: 3,
                created_at: now,
                available_at: now,
                state: JobState::Failed,
            },
            error: "Connection refused".to_string(),
            failed_at: now,
        };

        let json = serde_json::to_string(&failed_job).unwrap();
        let restored: FailedJobInfo = serde_json::from_str(&json).unwrap();

        assert_eq!(restored.job.id, "job-789");
        assert_eq!(restored.error, "Connection refused");
        assert!(matches!(restored.job.state, JobState::Failed));
    }

    #[test]
    fn test_failed_job_info_clone() {
        let now = Utc::now();
        let failed_job = FailedJobInfo {
            job: JobInfo {
                id: "job-999".to_string(),
                job_type: "TestJob".to_string(),
                queue: "test".to_string(),
                attempts: 1,
                max_retries: 3,
                created_at: now,
                available_at: now,
                state: JobState::Failed,
            },
            error: "Test error".to_string(),
            failed_at: now,
        };

        let cloned = failed_job.clone();
        assert_eq!(cloned.job.id, failed_job.job.id);
        assert_eq!(cloned.error, failed_job.error);
    }

    #[test]
    fn test_job_state_debug() {
        assert!(format!("{:?}", JobState::Pending).contains("Pending"));
        assert!(format!("{:?}", JobState::Delayed).contains("Delayed"));
        assert!(format!("{:?}", JobState::Failed).contains("Failed"));
    }

    // Note: Tests for actual queue operations (get_pending_jobs, get_delayed_jobs, etc.)
    // require integration tests with a running Redis instance.
}