use mongodb::bson::doc;
use tokio_cron_scheduler::{Job, JobScheduler};

use compliance_core::models::ScanTrigger;

use crate::agent::ComplianceAgent;
use crate::error::AgentError;

pub async fn start_scheduler(agent: &ComplianceAgent) -> Result<(), AgentError> {
    let sched = JobScheduler::new()
        .await
        .map_err(|e| AgentError::Scheduler(format!("Failed to create scheduler: {e}")))?;

    // Periodic scan job
    let scan_agent = agent.clone();
    let scan_schedule = agent.config.scan_schedule.clone();
    let scan_job = Job::new_async(scan_schedule.as_str(), move |_uuid, _lock| {
        let agent = scan_agent.clone();
        Box::pin(async move {
            tracing::info!("Scheduled scan triggered");
            scan_all_repos(&agent).await;
        })
    })
    .map_err(|e| AgentError::Scheduler(format!("Failed to create scan job: {e}")))?;
    sched
        .add(scan_job)
        .await
        .map_err(|e| AgentError::Scheduler(format!("Failed to add scan job: {e}")))?;

    // CVE monitor job (daily)
    let cve_agent = agent.clone();
    let cve_schedule = agent.config.cve_monitor_schedule.clone();
    let cve_job = Job::new_async(cve_schedule.as_str(), move |_uuid, _lock| {
        let agent = cve_agent.clone();
        Box::pin(async move {
            tracing::info!("CVE monitor triggered");
            monitor_cves(&agent).await;
        })
    })
    .map_err(|e| AgentError::Scheduler(format!("Failed to create CVE monitor job: {e}")))?;
    sched
        .add(cve_job)
        .await
        .map_err(|e| AgentError::Scheduler(format!("Failed to add CVE monitor job: {e}")))?;

    sched
        .start()
        .await
        .map_err(|e| AgentError::Scheduler(format!("Failed to start scheduler: {e}")))?;

    tracing::info!(
        "Scheduler started: scans='{}', CVE monitor='{}'",
        agent.config.scan_schedule,
        agent.config.cve_monitor_schedule,
    );

    // Keep scheduler alive
    loop {
        tokio::time::sleep(tokio::time::Duration::from_secs(3600)).await;
    }
}

async fn scan_all_repos(agent: &ComplianceAgent) {
    use futures_util::StreamExt;

    let cursor = match agent.db.repositories().find(doc! {}).await {
        Ok(c) => c,
        Err(e) => {
            tracing::error!("Failed to list repos for scheduled scan: {e}");
            return;
        }
    };

    let repos: Vec<_> = cursor.filter_map(|r| async { r.ok() }).collect().await;

    for repo in repos {
        let repo_id = repo.id.map(|id| id.to_hex()).unwrap_or_default();
        if let Err(e) = agent.run_scan(&repo_id, ScanTrigger::Scheduled).await {
            tracing::error!("Scheduled scan failed for {}: {e}", repo.name);
        }
    }
}

async fn monitor_cves(agent: &ComplianceAgent) {
    use futures_util::StreamExt;

    // Re-scan all SBOM entries for new CVEs
    let cursor = match agent.db.sbom_entries().find(doc! {}).await {
        Ok(c) => c,
        Err(e) => {
            tracing::error!("Failed to list SBOM entries for CVE monitoring: {e}");
            return;
        }
    };

    let entries: Vec<_> = cursor.filter_map(|r| async { r.ok() }).collect().await;

    if entries.is_empty() {
        return;
    }

    tracing::info!("CVE monitor: checking {} dependencies", entries.len());
    // The actual CVE checking is handled by the CveScanner in the pipeline
    // This is a simplified version that just logs the activity
}