use dotenvy::dotenv;
use rtix::application::services::oauth::OAuthConfig;
use rtix::application::{reconciliation, services};
use rtix::core::session;
use rtix::infrastructure::{db, repositories, storage::assets};
use rtix::interfaces::http::api;
use std::env;
use std::sync::Arc;

use tracing_core::Subscriber;
use tracing_subscriber::layer::Context;
use tracing_subscriber::Layer;

struct TelemetryLayer {
    pool: sqlx::PgPool,
}

impl<S: Subscriber> Layer<S> for TelemetryLayer {
    fn on_event(&self, event: &tracing_core::Event<'_>, _ctx: Context<'_, S>) {
        if *event.metadata().level() == tracing_core::Level::ERROR {
            let mut visitor = ErrorVisitor {
                message: String::new(),
            };
            event.record(&mut visitor);

            let message = visitor.message.clone();
            if !message.is_empty() {
                let pool = self.pool.clone();
                if let Ok(handle) = tokio::runtime::Handle::try_current() {
                    handle.spawn(async move {
                        let _ = sqlx::query(
                            "INSERT INTO error_telemetry (source, error_level, message) VALUES ($1, $2, $3)"
                        )
                        .bind("BACKEND")
                        .bind("ERROR")
                        .bind(&message)
                        .execute(&pool)
                        .await;
                    });
                }
            }
        }
    }
}

struct ErrorVisitor {
    message: String,
}

impl tracing_core::field::Visit for ErrorVisitor {
    fn record_debug(&mut self, field: &tracing_core::Field, value: &dyn std::fmt::Debug) {
        if field.name() == "message" {
            self.message = format!("{:?}", value);
        }
    }
}

#[global_allocator]
static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;

#[cfg(test)]
mod mock_tests;

// Rebuild trigger
#[tokio::main]
async fn main() {
    dotenv().ok();

    // Critical Environment Verification
    let required_vars = [
        "DATABASE_URL",
        "JWT_SECRET",
        "RTIX_UPI_ID",
        "RTIX_MASTER_KEY",
    ];
    let mut missing_vars = Vec::new();
    for var in required_vars {
        if env::var(var).is_err() {
            missing_vars.push(var);
        }
    }

    if !missing_vars.is_empty() {
        eprintln!(
            "FATAL: Missing required environment variables: {:?}",
            missing_vars
        );
        eprintln!("Please add these to your Render Dashboard (Environment tab).");
        std::process::exit(1);
    }

    use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};

    // Initialize OpenTelemetry Tracer
    let tracer =
        rtix::core::telemetry::init_tracer().expect("Failed to initialize OpenTelemetry tracer");
    let telemetry_layer = tracing_opentelemetry::layer().with_tracer(tracer);

    // Database Connection & Schema Initialization
    let db_router = Arc::new(db::init_db_router().await);
    let pool = db_router.primary().clone();

    // Initialize Observability Registry
    tracing_subscriber::registry()
        .with(
            tracing_subscriber::EnvFilter::try_from_default_env()
                .unwrap_or_else(|_| "rtix=info,tower_http=info,axum::rejection=warn".into()),
        )
        .with(tracing_subscriber::fmt::layer())
        .with(telemetry_layer)
        .with(TelemetryLayer { pool: pool.clone() })
        .init();

    let env_type = if env::var("RENDER").is_ok() {
        "RENDER_CLOUD"
    } else {
        "LOCAL_DEVELOPMENT"
    };
    tracing::info!("🚀 Starting Rtix Secure Backend (Env: {})", env_type);

    // Initialize Prometheus Metrics
    let metrics_handle = metrics_exporter_prometheus::PrometheusBuilder::new()
        .install_recorder()
        .expect("Failed to install Prometheus recorder");

    // Initialize global broadcast channel for real-time events (4096 message buffer for headroom)
    let (tx, _rx) = tokio::sync::broadcast::channel(4096);

    // Start background IP block cache refresher (eliminates per-request DB queries)
    rtix::interfaces::http::middleware::spawn_blocked_ip_cache_refresher(pool.clone());

    // Asset Provider
    let upload_dir = env::var("UPLOAD_DIR").unwrap_or_else(|_| "uploads".to_string());
    let asset_provider: Arc<dyn assets::AssetProvider> =
        if let (Ok(bucket), Ok(access_key), Ok(secret_key)) = (
            env::var("S3_BUCKET"),
            env::var("S3_ACCESS_KEY_ID"),
            env::var("S3_SECRET_ACCESS_KEY"),
        ) {
            let region = env::var("S3_REGION").unwrap_or_else(|_| "us-east-1".to_string());
            let endpoint = env::var("S3_ENDPOINT").ok();
            let cdn_url = env::var("S3_CDN_URL").ok();

            tracing::info!(
                "Initializing S3 Cloud Asset Provider for bucket: {}",
                bucket
            );
            Arc::new(assets::S3AssetProvider::new(
                bucket, region, access_key, secret_key, endpoint, cdn_url,
            ))
        } else {
            tracing::info!("Initializing Local File Asset Provider at: {}", upload_dir);
            Arc::new(assets::LocalAssetProvider::new(&upload_dir))
        };

    // Repositories
    let merchant_repo = Arc::new(repositories::merchant::PostgresMerchantRepository::new(
        pool.clone(),
    ));
    let order_repo = Arc::new(repositories::order::PostgresOrderRepository::new(
        pool.clone(),
    ));
    let product_repo = Arc::new(repositories::product::PostgresProductRepository::new(
        pool.clone(),
    ));
    let idempotency_repo =
        Arc::new(repositories::idempotency::PostgresIdempotencyRepository::new(pool.clone()));
    let coupon_repo = Arc::new(repositories::coupon::PostgresCouponRepository::new(
        pool.clone(),
    ));

    // Services
    let auth_service = Arc::new(services::auth::RtixAuthService::new(
        merchant_repo.clone(),
        session::jwt_secret(),
    ));
    let merchant_service = Arc::new(services::merchant::RtixMerchantService::new(
        merchant_repo.clone(),
        product_repo.clone(),
        order_repo.clone(),
        coupon_repo.clone(),
        pool.clone(),
        tx.clone(),
    ));
    let checkout_service = Arc::new(services::checkout::RtixCheckoutService::new(
        product_repo.clone(),
        merchant_repo.clone(),
        order_repo.clone(),
        asset_provider.clone(),
        tx.clone(),
        pool.clone(),
    ));
    let payment_service = Arc::new(services::payment::RtixPaymentService::new(
        order_repo.clone(),
        merchant_repo.clone(),
        tx.clone(),
    ));
    let customer_service = Arc::new(services::customer::RtixCustomerService::new(
        pool.clone(),
        session::jwt_secret(),
    ));
    let idempotency_service = Arc::new(services::idempotency::RtixIdempotencyService::new(
        idempotency_repo,
    ));
    let intelligence_service = Arc::new(services::intelligence::IntelligenceService::new(
        pool.clone(),
    ));

    // Spawn AI Engineer background telemetry processor
    let bg_intelligence_service = intelligence_service.clone();
    tokio::spawn(async move {
        let mut interval = tokio::time::interval(std::time::Duration::from_secs(60));
        loop {
            interval.tick().await;
            if let Err(e) = bg_intelligence_service.process_unanalyzed_telemetry().await {
                tracing::error!("Background AI telemetry analysis failed: {:?}", e);
            }
        }
    });

    let state = api::AppState {
        pool,
        db: db_router,
        tx,
        assets: asset_provider,
        auth_service,
        merchant_service,
        checkout_service,
        payment_service,
        customer_service,
        idempotency_service,
        intelligence_service,
        order_repo: order_repo.clone(),
        metrics_handle: Arc::new(metrics_handle),
        oauth_config: OAuthConfig::from_env(),
        jwt_secret: std::env::var("JWT_SECRET").unwrap_or_default(),
    };

    let app = api::create_router(state.clone());

    // Spawn Autonomous Reconciliation Engine (Background Task)
    let recon_state = state.clone();
    tokio::spawn(async move {
        reconciliation::spawn_reconciliation_worker(recon_state).await;
    });

    // Spawn Protocol Sentinel (Operational Guard & Recovery)
    let protocol_sentinel =
        services::ProtocolSentinel::new(state.merchant_service.clone(), state.pool.clone());
    tokio::spawn(async move {
        protocol_sentinel.run().await;
    });

    // Spawn Webhook Service (Background Task)
    let webhook_service = services::webhook::WebhookService::new(state.pool.clone());
    let webhook_rx = state.tx.subscribe();
    tokio::spawn(async move {
        webhook_service.run(webhook_rx).await;
    });

    // Spawn SRE AI Log and Database Monitor (Continuous Background Worker)
    rtix::interfaces::http::routes::developer::start_ai_log_monitor(state.pool.clone());

    let port = env::var("PORT")
        .unwrap_or_else(|_| "3000".to_string())
        .parse::<u16>()
        .unwrap_or(3000);

    let listener = tokio::net::TcpListener::bind(format!("0.0.0.0:{}", port))
        .await
        .expect("Failed to bind port");

    tracing::info!(
        "🛡️  Rtix Core Engine ONLINE on {}",
        listener.local_addr().unwrap()
    );
    tracing::info!("💎  Security Guard Active. Payment Systems Stabilized.");

    // Graceful Shutdown Logic
    let shutdown = async {
        let ctrl_c = tokio::signal::ctrl_c();
        let terminate = async {
            tokio::signal::unix::signal(tokio::signal::unix::SignalKind::terminate())
                .expect("failed to install signal handler")
                .recv()
                .await;
        };

        tokio::select! {
            _ = ctrl_c => tracing::info!("Shutdown signal received (Ctrl-C)"),
            _ = terminate => tracing::info!("Shutdown signal received (SIGTERM)"),
        }

        tracing::info!("Commencing graceful shutdown of settlement engines...");
    };

    axum::serve(listener, app)
        .with_graceful_shutdown(shutdown)
        .await
        .expect("Server runtime error");

    rtix::core::telemetry::shutdown_tracer();
    tracing::info!("Rtix Secure Protocol OFFLINE. All assets protected.");
}