use runner::config::Settings;
use runner::effects::run_effect_worker;
use runner::http;
use runner::observability::Observability;
use runner::outbox::OutboxRelay;
use runner::saga::{run_saga_worker, SagaPrograms, SagaRuntime};
use runner::schedule::Scheduler;
use runner::storage::KvClient;
use runner::stream::JetStreamClient;
use runner::tenant_placement::{start_tenant_filter, TenantGate};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;

#[tokio::main]
async fn main() {
    match std::env::args().nth(1).as_deref() {
        Some("-h") | Some("--help") => {
            print_help();
            return;
        }
        Some("serve") | None => serve().await,
        Some(other) => {
            eprintln!("Unknown command: {}", other);
            print_help();
        }
    }
}

async fn serve() {
    let settings = load_settings();
    if let Err(e) = settings.validate() {
        eprintln!("Invalid configuration: {}", e);
        std::process::exit(2);
    }

    let observability = Observability::default();
    observability.init();
    let metrics = observability.metrics();

    tracing::info!(settings = ?settings, "Runner starting");

    let shutdown = Arc::new(tokio::sync::Notify::new());
    let reload = Arc::new(tokio::sync::Notify::new());
    let draining = Arc::new(AtomicBool::new(false));

    let storage = match KvClient::open(settings.storage_path.clone()) {
        Ok(s) => s,
        Err(e) => {
            eprintln!("Failed to open storage: {}", e);
            std::process::exit(1);
        }
    };

    let tenant_filter = match start_tenant_filter(&settings).await {
        Ok(v) => v,
        Err(e) => {
            tracing::error!(error = %e, "Failed to initialize tenant filter");
            None
        }
    };

    let tenant_gate = Arc::new(TenantGate::new(tenant_filter.clone()));

    let state = Arc::new(http::AppState::new(
        settings.clone(),
        draining.clone(),
        tenant_gate.clone(),
        metrics.clone(),
        storage.clone(),
        reload.clone(),
    ));

    let http_listener = tokio::net::TcpListener::bind(settings.http_addr.as_str())
        .await
        .unwrap();

    let http_shutdown = shutdown.clone();
    let http_state = state.clone();
    let http_task = tokio::spawn(async move {
        http::serve(http_listener, http_state, async move {
            http_shutdown.notified().await
        })
        .await
    });

    let grpc_addr: std::net::SocketAddr = settings.grpc_addr.parse().unwrap();
    let grpc_shutdown = shutdown.clone();
    let grpc_state = state.clone();
    let grpc_task = tokio::spawn(async move {
        runner::grpc_admin::serve(grpc_addr, grpc_state, async move {
            grpc_shutdown.notified().await
        })
        .await
    });

    let signal_shutdown = shutdown.clone();
    let signal_draining = draining.clone();
    tokio::spawn(async move {
        #[cfg(unix)]
        {
            use tokio::signal::unix::{signal, SignalKind};
            let mut sigterm = signal(SignalKind::terminate()).ok();
            let mut sigint = signal(SignalKind::interrupt()).ok();
            tokio::select! {
                _ = tokio::signal::ctrl_c() => {},
                _ = async { if let Some(s) = &mut sigterm { let _ = s.recv().await; } } => {},
                _ = async { if let Some(s) = &mut sigint { let _ = s.recv().await; } } => {},
            }
        }

        #[cfg(not(unix))]
        {
            let _ = tokio::signal::ctrl_c().await;
        }

        signal_draining.store(true, Ordering::Relaxed);
        signal_shutdown.notify_waiters();
    });

    let mut tasks = Vec::new();

    match settings.mode {
        runner::config::RunnerMode::Saga => {
            let programs = Arc::new(match SagaPrograms::load(&settings) {
                Ok(p) => p,
                Err(e) => {
                    tracing::error!(error = %e, "Failed to load saga manifest/programs");
                    std::process::exit(1);
                }
            });
            let saga_runtime = SagaRuntime::default();
            tasks.push(tokio::spawn(run_saga_worker(
                settings.clone(),
                storage.clone(),
                programs.clone(),
                saga_runtime.clone(),
                metrics.clone(),
                tenant_gate.clone(),
                tenant_filter.clone(),
                shutdown.clone(),
                draining.clone(),
            )));
            let outbox_settings = settings.clone();
            let outbox_storage = storage.clone();
            let outbox_shutdown = shutdown.clone();
            let outbox_draining = draining.clone();
            let outbox_metrics = metrics.clone();
            let outbox_tenant_gate = tenant_gate.clone();
            tasks.push(tokio::spawn(async move {
                let js = JetStreamClient::connect(&outbox_settings)
                    .await
                    .map_err(|e| runner::types::RunnerError::StreamError(e.to_string()))?;
                OutboxRelay
                    .run(
                        outbox_settings,
                        outbox_storage,
                        js,
                        outbox_metrics,
                        outbox_tenant_gate,
                        outbox_shutdown,
                        outbox_draining,
                    )
                    .await
            }));
            let scheduler_settings = settings.clone();
            let scheduler_storage = storage.clone();
            let scheduler_shutdown = shutdown.clone();
            let scheduler_draining = draining.clone();
            let scheduler_metrics = metrics.clone();
            let scheduler_tenant_gate = tenant_gate.clone();
            tasks.push(tokio::spawn(async move {
                Scheduler
                    .run(
                        scheduler_settings,
                        scheduler_storage,
                        programs,
                        saga_runtime,
                        scheduler_metrics,
                        scheduler_tenant_gate,
                        scheduler_shutdown,
                        scheduler_draining,
                    )
                    .await
            }));
        }
        runner::config::RunnerMode::Effect => {
            tasks.push(tokio::spawn(run_effect_worker(
                settings.clone(),
                storage.clone(),
                metrics.clone(),
                tenant_gate.clone(),
                tenant_filter.clone(),
                reload.clone(),
                shutdown.clone(),
                draining.clone(),
            )));
        }
        runner::config::RunnerMode::Combined => {
            let programs = Arc::new(match SagaPrograms::load(&settings) {
                Ok(p) => p,
                Err(e) => {
                    tracing::error!(error = %e, "Failed to load saga manifest/programs");
                    std::process::exit(1);
                }
            });
            let saga_runtime = SagaRuntime::default();
            tasks.push(tokio::spawn(run_saga_worker(
                settings.clone(),
                storage.clone(),
                programs.clone(),
                saga_runtime.clone(),
                metrics.clone(),
                tenant_gate.clone(),
                tenant_filter.clone(),
                shutdown.clone(),
                draining.clone(),
            )));
            tasks.push(tokio::spawn(run_effect_worker(
                settings.clone(),
                storage.clone(),
                metrics.clone(),
                tenant_gate.clone(),
                tenant_filter.clone(),
                reload.clone(),
                shutdown.clone(),
                draining.clone(),
            )));
            let outbox_settings = settings.clone();
            let outbox_storage = storage.clone();
            let outbox_shutdown = shutdown.clone();
            let outbox_draining = draining.clone();
            let outbox_metrics = metrics.clone();
            let outbox_tenant_gate = tenant_gate.clone();
            tasks.push(tokio::spawn(async move {
                let js = JetStreamClient::connect(&outbox_settings)
                    .await
                    .map_err(|e| runner::types::RunnerError::StreamError(e.to_string()))?;
                OutboxRelay
                    .run(
                        outbox_settings,
                        outbox_storage,
                        js,
                        outbox_metrics,
                        outbox_tenant_gate,
                        outbox_shutdown,
                        outbox_draining,
                    )
                    .await
            }));
            let scheduler_settings = settings.clone();
            let scheduler_storage = storage.clone();
            let scheduler_shutdown = shutdown.clone();
            let scheduler_draining = draining.clone();
            let scheduler_metrics = metrics.clone();
            let scheduler_tenant_gate = tenant_gate.clone();
            tasks.push(tokio::spawn(async move {
                Scheduler
                    .run(
                        scheduler_settings,
                        scheduler_storage,
                        programs,
                        saga_runtime,
                        scheduler_metrics,
                        scheduler_tenant_gate,
                        scheduler_shutdown,
                        scheduler_draining,
                    )
                    .await
            }));
        }
    }

    let mut failed = None;
    for task in tasks {
        match task.await {
            Ok(Ok(())) => {}
            Ok(Err(e)) => {
                failed = Some(e);
                break;
            }
            Err(e) => {
                failed = Some(runner::types::RunnerError::RuntimeError(e.to_string()));
                break;
            }
        }
    }

    draining.store(true, Ordering::Relaxed);
    shutdown.notify_waiters();
    let _ = http_task.await;
    let _ = grpc_task.await;

    if let Some(e) = failed {
        tracing::error!(error = %e, "Runner terminated with error");
        std::process::exit(1);
    }
}

fn print_help() {
    println!(
        "runner\n\nUSAGE:\n    runner [COMMAND]\n\nCOMMANDS:\n    serve    Start the HTTP server (default)\n\nOPTIONS:\n    -h, --help    Print help\n"
    );
}

fn load_settings() -> Settings {
    if let Ok(path) = std::env::var("RUNNER_CONFIG_PATH") {
        if let Ok(settings) = Settings::load_from_file_with_env_overrides(path) {
            return settings;
        }
    }

    Settings::from_env().unwrap_or_default()
}

#[cfg(test)]
mod tests {
    #[test]
    fn test_harness_runs() {
        let settings = runner::Settings::default();
        assert_eq!(settings.aggregate_events_stream, "AGGREGATE_EVENTS");
        assert!(settings
            .saga_trigger_subject_filters
            .iter()
            .any(|s| s == "tenant.*.aggregate.*.*"));
    }
}