use crate::api::ApiHandler;
use crate::config::{Config, ContainerRuntime};
use crate::container::{docker_packages, DockerPackageScanner};
use crate::identity::{self, NodeIdentity};
use crate::monitoring::MetricsStore;
use crate::node_message;
use crate::nostr_discovery;
use crate::nostr_handshake;
use crate::peers;
use crate::state::StateManager;
use anyhow::Result;
use hyper::server::conn::Http;
use hyper::service::service_fn;
use std::net::SocketAddr;
use std::sync::Arc;
use std::time::Duration;
use tokio::net::TcpListener;
use tracing::{debug, error, info, warn};

pub struct Server {
    _config: Config,
    _identity: Arc<NodeIdentity>,
    api_handler: Arc<ApiHandler>,
    _state_manager: Arc<StateManager>,
}

impl Server {
    pub async fn new(config: Config) -> Result<Self> {
        let state_manager = Arc::new(StateManager::new());

        // Load node identity and set stable server_info
        let identity_dir = config.data_dir.join("identity");
        let identity = NodeIdentity::load_or_create(&identity_dir).await?;
        let (mut data, _) = state_manager.get_snapshot().await;
        data.server_info.id = identity.node_id();
        data.server_info.pubkey = identity.pubkey_hex();
        data.server_info.tor_address = docker_packages::read_tor_address("archipelago");
        if let Some(ref tor) = data.server_info.tor_address {
            data.server_info.node_address = Some(identity.node_address(tor));
        }
        state_manager.update_data(data.clone()).await;

        // Revoke any previously published Nostr data (runs before publish so revocation is not overwritten)
        let identity_dir = config.data_dir.join("identity");
        let tor_proxy_revoke = config.nostr_tor_proxy.clone();
        if let Err(e) = nostr_discovery::revoke_if_needed(&identity_dir, tor_proxy_revoke.as_deref()).await {
            tracing::debug!("Nostr revoke (non-fatal): {}", e);
        }

        // Publish presence-only to Nostr (DID + Nostr pubkey, NO onion address).
        // Onion addresses are exchanged privately via NIP-44 encrypted DMs.
        if config.nostr_discovery_enabled
            && !config.nostr_relays.is_empty()
        {
            let identity_dir = config.data_dir.join("identity");
            let did = identity::did_key_from_pubkey_hex(&data.server_info.pubkey).unwrap_or_default();
            let version = data.server_info.version.clone();
            let relays = config.nostr_relays.clone();
            let tor_proxy = config.nostr_tor_proxy.clone();
            tokio::spawn(async move {
                if let Err(e) = nostr_handshake::publish_presence(
                    &identity_dir,
                    &did,
                    &version,
                    &relays,
                    tor_proxy.as_deref(),
                )
                .await
                {
                    tracing::debug!("Nostr presence publish (non-fatal): {}", e);
                }
            });
        }
        info!("🔑 Node identity: {} (pubkey: {}...)", identity.node_id(), &identity.pubkey_hex()[..16.min(identity.pubkey_hex().len())]);

        let identity = Arc::new(identity);

        // Create metrics store and spawn background collector
        let metrics_store = Arc::new(MetricsStore::with_data_dir(config.data_dir.clone()));
        crate::monitoring::spawn_metrics_collector(metrics_store.clone(), Some(state_manager.clone()), Some(config.data_dir.clone()));

        let api_handler = Arc::new(
            ApiHandler::new(config.clone(), state_manager.clone(), metrics_store).await?,
        );

        // Periodic Tor address refresh (runs regardless of dev_mode)
        // Picks up hostname when Tor creates it after startup/rotation (30-60s delay)
        {
            let state = state_manager.clone();
            let identity_clone = identity.clone();
            tokio::spawn(async move {
                let mut interval = tokio::time::interval(Duration::from_secs(30));
                loop {
                    interval.tick().await;
                    if let Err(e) = refresh_tor_address(&state, identity_clone.as_ref()).await {
                        debug!("Tor address refresh (non-fatal): {}", e);
                    }
                }
            });
        }

        // Initialize container scanner — discovers installed apps from Podman/Docker
        {
            let scanner = create_docker_scanner(&config).await?;
            let state = state_manager.clone();
            let identity_clone = identity.clone();

            // Initial scan
            tokio::spawn(async move {
                info!("🐳 Scanning containers...");
                if let Err(e) = scan_and_update_packages(&scanner, &state, identity_clone.as_ref()).await {
                    error!("Failed to scan containers: {}", e);
                }

                // Periodic scan every 10 seconds (only broadcasts if state changed)
                let mut interval = tokio::time::interval(Duration::from_secs(10));
                loop {
                    interval.tick().await;
                    if let Err(e) = scan_and_update_packages(&scanner, &state, identity_clone.as_ref()).await {
                        error!("Failed to update containers: {}", e);
                    }
                }
            });
        }

        // Peer health monitoring — check every 5 minutes
        {
            let state = state_manager.clone();
            let data_dir = config.data_dir.clone();
            tokio::spawn(async move {
                let mut interval = tokio::time::interval(Duration::from_secs(300));
                loop {
                    interval.tick().await;
                    if let Err(e) = check_peer_health(&state, &data_dir).await {
                        debug!("Peer health check (non-fatal): {}", e);
                    }
                }
            });
        }

        // Container health monitoring — auto-restart unhealthy containers
        // Respects webhook config: skips when disabled or ContainerCrash not subscribed
        crate::health_monitor::spawn_health_monitor(state_manager.clone(), config.data_dir.clone());

        Ok(Self {
            _config: config,
            _identity: identity,
            api_handler,
            _state_manager: state_manager,
        })
    }

    pub async fn serve(&self, addr: SocketAddr) -> Result<()> {
        self.serve_with_shutdown(addr, std::future::pending()).await
    }

    /// Serve with a graceful shutdown signal.
    /// When the shutdown future completes, stop accepting new connections and drain in-flight requests.
    pub async fn serve_with_shutdown(
        &self,
        addr: SocketAddr,
        shutdown: impl std::future::Future<Output = ()>,
    ) -> Result<()> {
        let listener = TcpListener::bind(addr).await?;
        let active_connections = Arc::new(tokio::sync::Semaphore::new(1024));

        tokio::pin!(shutdown);

        loop {
            tokio::select! {
                result = listener.accept() => {
                    let (stream, peer_addr) = match result {
                        Ok(conn) => conn,
                        Err(e) => {
                            error!("Failed to accept connection: {}", e);
                            continue;
                        }
                    };

                    let handler = self.api_handler.clone();
                    let permit = active_connections.clone().acquire_owned().await;

                    tokio::spawn(async move {
                        let _permit = permit;
                        let service = service_fn(move |req| {
                            let handler = handler.clone();
                            async move {
                                handler.handle_request(req).await
                                    .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, format!("{}", e)))
                            }
                        });

                        if let Err(e) = Http::new()
                            .http1_keep_alive(false)
                            .serve_connection(stream, service)
                            .with_upgrades()
                            .await
                        {
                            error!("Error serving connection from {}: {}", peer_addr, e);
                        }
                    });
                }
                _ = &mut shutdown => {
                    info!("Shutdown signal received, draining connections...");
                    // Wait up to 5 seconds for in-flight requests to complete
                    let drain_start = std::time::Instant::now();
                    let drain_timeout = std::time::Duration::from_secs(5);
                    while active_connections.available_permits() < 1024 {
                        if drain_start.elapsed() > drain_timeout {
                            warn!("Drain timeout reached, forcing shutdown");
                            break;
                        }
                        tokio::time::sleep(std::time::Duration::from_millis(100)).await;
                    }
                    info!("Shutdown complete");
                    return Ok(());
                }
            }
        }
    }
}

async fn create_docker_scanner(config: &Config) -> Result<DockerPackageScanner> {
    let user = std::env::var("USER").unwrap_or_else(|_| "archipelago".to_string());
    
    let runtime: Arc<dyn archipelago_container::ContainerRuntime> = match &config.container_runtime {
        ContainerRuntime::Podman => {
            Arc::new(archipelago_container::PodmanRuntime::new(user.clone()))
        }
        ContainerRuntime::Docker => {
            Arc::new(archipelago_container::DockerRuntime::new(user.clone()))
        }
        ContainerRuntime::Auto => {
            Arc::new(
                archipelago_container::AutoRuntime::new(user.clone())
                    .await?
            )
        }
    };
    
    Ok(DockerPackageScanner::new(runtime))
}

async fn refresh_tor_address(state: &StateManager, identity: &NodeIdentity) -> Result<()> {
    let tor_addr = docker_packages::read_tor_address("archipelago");
    let (current_data, _) = state.get_snapshot().await;
    if tor_addr != current_data.server_info.tor_address {
        let mut data = current_data;
        data.server_info.tor_address = tor_addr.clone();
        data.server_info.node_address = tor_addr.as_ref().map(|t| identity.node_address(t));
        state.update_data(data).await;
        if let Some(ref addr) = tor_addr {
            info!("🔒 Tor address updated: {}", addr);
        }
    }
    Ok(())
}

async fn scan_and_update_packages(
    scanner: &DockerPackageScanner,
    state: &StateManager,
    identity: &NodeIdentity,
) -> Result<()> {
    let packages = scanner.scan_containers().await?;
    
    let (current_data, _) = state.get_snapshot().await;
    let packages_changed = !packages.is_empty() && current_data.package_data != packages;
    let tor_addr = docker_packages::read_tor_address("archipelago");
    let tor_changed = tor_addr != current_data.server_info.tor_address;

    if packages_changed || tor_changed {
        let mut data = current_data;
        if !packages.is_empty() {
            data.package_data = packages;
        }
        data.server_info.tor_address = tor_addr.clone();
        data.server_info.node_address = tor_addr.as_ref().map(|t| identity.node_address(t));
        state.update_data(data).await;
        debug!("📦 State changed (packages={}, tor={}), broadcasting update", packages_changed, tor_changed);
    }

    Ok(())
}

/// Periodically check peer reachability and broadcast status changes.
async fn check_peer_health(state: &StateManager, data_dir: &std::path::Path) -> Result<()> {
    let known_peers = peers::load_peers(data_dir).await.unwrap_or_default();
    if known_peers.is_empty() {
        return Ok(());
    }

    let mut new_health = std::collections::HashMap::new();
    for peer in &known_peers {
        let reachable = node_message::check_peer_reachable(&peer.onion)
            .await
            .unwrap_or(false);
        new_health.insert(peer.onion.clone(), reachable);
    }

    let (current_data, _) = state.get_snapshot().await;
    if current_data.peer_health != new_health {
        let mut data = current_data;
        data.peer_health = new_health;
        state.update_data(data).await;
        debug!("🔗 Peer health updated, broadcasting changes");
    }

    Ok(())
}