use std::time::Duration;

use once_cell::sync::OnceCell;
use sqlx::{Pool, Postgres};
use tokio::sync::mpsc;
use uuid::Uuid;
use windmill_common::{error, jobs::{JobKind, QueuedJob}, METRICS_ENABLED};
use windmill_worker::{
    create_token_for_owner, handle_job_error, AuthedClient, SESSION_TOKEN_EXPIRY,
};

lazy_static::lazy_static! {
    static ref ZOMBIE_JOB_TIMEOUT: String = std::env::var("ZOMBIE_JOB_TIMEOUT")
    .ok()
    .and_then(|x| x.parse::<String>().ok())
    .unwrap_or_else(|| "30".to_string());


    pub static ref RESTART_ZOMBIE_JOBS: bool = std::env::var("RESTART_ZOMBIE_JOBS")
    .ok()
    .and_then(|x| x.parse::<bool>().ok())
    .unwrap_or(true);

    static ref QUEUE_ZOMBIE_RESTART_COUNT: prometheus::IntCounter = prometheus::register_int_counter!(
        "queue_zombie_restart_count",
        "Total number of jobs restarted due to ping timeout."
    )
    .unwrap();
    static ref QUEUE_ZOMBIE_DELETE_COUNT: prometheus::IntCounter = prometheus::register_int_counter!(
        "queue_zombie_delete_count",
        "Total number of jobs deleted due to their ping timing out in an unrecoverable state."
    )
    .unwrap();
}

pub async fn handle_zombie_jobs_periodically<
    R: rsmq_async::RsmqConnection + Send + Sync + Clone,
>(
    db: &Pool<Postgres>,
    mut rx: tokio::sync::broadcast::Receiver<()>,
    base_internal_url: &str,
    rsmq: Option<R>,
) {
    loop {
        handle_zombie_jobs(db, base_internal_url, rsmq.clone()).await;

        tokio::select! {
            _ = tokio::time::sleep(Duration::from_secs(30))    => (),
            _ = rx.recv() => {
                    println!("received killpill for monitor job");
                    break;
            }
        }
    }
}

async fn handle_zombie_jobs<R: rsmq_async::RsmqConnection + Send + Sync + Clone>(
    db: &Pool<Postgres>,
    base_internal_url: &str,
    rsmq: Option<R>,
) {
    if *RESTART_ZOMBIE_JOBS {
        let restarted = sqlx::query!(
                "UPDATE queue SET running = false, started_at = null, logs = logs || '\nRestarted job after not receiving job''s ping for too long the ' || now() || '\n\n' WHERE last_ping < now() - ($1 || ' seconds')::interval AND running = true AND job_kind != $2 AND job_kind != $3 AND same_worker = false RETURNING id, workspace_id, last_ping",
                *ZOMBIE_JOB_TIMEOUT,
                JobKind::Flow: JobKind,
                JobKind::FlowPreview: JobKind,
            )
            .fetch_all(db)
            .await
            .ok()
            .unwrap_or_else(|| vec![]);

        if *METRICS_ENABLED {
            QUEUE_ZOMBIE_RESTART_COUNT.inc_by(restarted.len() as _);
        }
        for r in restarted {
            tracing::info!(
                "restarted zombie job {} {} {}",
                r.id,
                r.workspace_id,
                r.last_ping
            );
        }
    }

    let mut timeout_query = "SELECT * FROM queue WHERE last_ping < now() - ($1 || ' seconds')::interval AND running = true AND job_kind != $2".to_string();
    if *RESTART_ZOMBIE_JOBS {
        timeout_query.push_str(" AND same_worker = true");
    };
    let timeouts = sqlx::query_as::<_, QueuedJob>(&timeout_query)
        .bind(ZOMBIE_JOB_TIMEOUT.as_str())
        .bind(JobKind::Flow)
        .fetch_all(db)
        .await
        .ok()
        .unwrap_or_else(|| vec![]);

    if *METRICS_ENABLED {
        QUEUE_ZOMBIE_DELETE_COUNT.inc_by(timeouts.len() as _);
    }

    for job in timeouts {
        tracing::info!("timedout zombie job {} {}", job.id, job.workspace_id,);

        // since the job is unrecoverable, the same worker queue should never be sent anything
        let (same_worker_tx_never_used, _same_worker_rx_never_used) = mpsc::channel::<Uuid>(1);

        let token = create_token_for_owner(
            &db,
            &job.workspace_id,
            &job.permissioned_as,
            "ephemeral-zombie-jobs",
            *SESSION_TOKEN_EXPIRY,
            &job.email,
        )
        .await
        .expect("could not create job token");

        let client = AuthedClient {
            base_internal_url: base_internal_url.to_string(),
            token,
            workspace: job.workspace_id.to_string(),
            client: OnceCell::new(),
        };

        let last_ping = job.last_ping.clone();
        let _ = handle_job_error(
            db,
            &client,
            job,
            error::Error::ExecutionErr(format!(
                "Job timed out after no ping from job since {} (ZOMBIE_JOB_TIMEOUT: {})",
                last_ping
                    .map(|x| x.to_string())
                    .unwrap_or_else(|| "no ping".to_string()),
                *ZOMBIE_JOB_TIMEOUT
            )),
            None,
            true,
            same_worker_tx_never_used,
            "",
            base_internal_url,
            rsmq.clone(),
        )
        .await;
    }
}