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

use futures::StreamExt;
use tracing::{error, info, warn};

use application::processing::ProcessNextJobCommand;
use domain::events::DomainEvent;
use domain::ports::EventConsumer;

mod config;
mod factories;
mod plugin_registry;
mod plugins;

use factories::{Repos, build_plugin_registry, build_process_next_handler};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    tracing_subscriber::fmt()
        .with_env_filter(
            tracing_subscriber::EnvFilter::from_default_env().add_directive("worker=info".parse()?),
        )
        .init();

    let config = config::WorkerConfig::from_env();
    info!("Worker starting");

    let pool = adapters_postgres::connect(&config.database_url).await?;
    adapters_postgres::run_migrations(&pool).await?;

    let nats_client = async_nats::connect(&config.nats_url).await?;
    adapters_nats::ensure_stream(&nats_client).await?;
    info!(nats_url = %config.nats_url, "NATS connected");

    let event_store: Arc<dyn domain::ports::EventStore> =
        Arc::new(adapters_postgres::PostgresEventStore::new(pool.clone()));
    let repos = Repos::new(pool);
    let file_storage = Arc::new(adapters_storage::LocalFileStorage::new(
        &config.storage_path,
    ));
    let sidecar_writer: Arc<dyn domain::ports::SidecarWriterPort> = Arc::new(LogSidecarWriter);

    // Publisher transport consumes a client clone; the consumer gets another.
    let pub_transport = adapters_nats::NatsTransport::new(nats_client.clone());
    let nats_publisher: Arc<dyn domain::ports::EventPublisher> =
        Arc::new(event_transport::EventPublisherAdapter::new(pub_transport));
    let event_pub: Arc<dyn domain::ports::EventPublisher> =
        Arc::new(event_transport::CompositeEventPublisher::new(nats_publisher, event_store));

    let registry = Arc::new(build_plugin_registry(&repos, file_storage, sidecar_writer));
    let process_next = Arc::new(build_process_next_handler(&repos, registry, event_pub));

    // ── Fallback sweep task ────────────────────────────────────────────
    let sweep_interval = Duration::from_secs(config.fallback_sweep_secs);
    let sweep_handler = Arc::clone(&process_next);
    tokio::spawn(async move {
        info!(every_secs = config.fallback_sweep_secs, "fallback sweep task started");
        loop {
            tokio::time::sleep(sweep_interval).await;
            info!("fallback sweep: draining queued jobs");
            loop {
                match sweep_handler.execute(ProcessNextJobCommand).await {
                    Ok(Some(job)) => {
                        info!(job_id = %job.job_id, status = ?job.status, "sweep: processed job");
                    }
                    Ok(None) => break,
                    Err(e) => {
                        error!(error = %e, "sweep: error processing job");
                        break;
                    }
                }
            }
        }
    });

    // ── Event-driven loop via NATS ─────────────────────────────────────
    let consumer_source = adapters_nats::NatsMessageSource::new(nats_client);
    let event_consumer = event_transport::EventConsumerAdapter::new(consumer_source);

    info!("event loop: listening for NATS events");
    let mut stream = event_consumer.consume();

    while let Some(result) = stream.next().await {
        let envelope = match result {
            Ok(env) => env,
            Err(e) => {
                error!(error = %e, "event loop: consumer error");
                continue;
            }
        };

        match &envelope.event {
            DomainEvent::JobEnqueued {
                job_id, job_type, ..
            } => {
                info!(job_id = %job_id, job_type = %job_type, "event loop: JobEnqueued received");
                (envelope.ack)();
                match process_next.execute(ProcessNextJobCommand).await {
                    Ok(Some(job)) => {
                        info!(job_id = %job.job_id, status = ?job.status, "event loop: processed job");
                    }
                    Ok(None) => {
                        warn!("event loop: JobEnqueued event but no queued job found");
                    }
                    Err(e) => {
                        error!(error = %e, "event loop: error processing job");
                    }
                }
            }
            other => {
                info!(event = ?other, "event loop: non-job event, acking");
                (envelope.ack)();
            }
        }
    }

    error!("event loop: NATS stream ended unexpectedly");
    Ok(())
}

struct LogSidecarWriter;

#[async_trait::async_trait]
impl domain::ports::SidecarWriterPort for LogSidecarWriter {
    fn format_name(&self) -> &str {
        "log_noop"
    }

    async fn write_sidecar(
        &self,
        _data: &domain::value_objects::StructuredData,
        path: &str,
    ) -> Result<(), domain::errors::DomainError> {
        info!(path, "sidecar write (no-op)");
        Ok(())
    }

    async fn read_sidecar(
        &self,
        path: &str,
    ) -> Result<domain::value_objects::StructuredData, domain::errors::DomainError> {
        info!(path, "sidecar read (no-op)");
        Ok(domain::value_objects::StructuredData::new())
    }
}