use anyhow::Result;
use serde::{Deserialize, Serialize};
use tokio::io::{AsyncBufReadExt, BufReader};
use tracing::{info, error};

use crate::RustProxy;
use rustproxy_config::RustProxyOptions;

/// A management request from the TypeScript wrapper.
#[derive(Debug, Deserialize)]
pub struct ManagementRequest {
    pub id: String,
    pub method: String,
    #[serde(default)]
    pub params: serde_json::Value,
}

/// A management response back to the TypeScript wrapper.
#[derive(Debug, Serialize)]
pub struct ManagementResponse {
    pub id: String,
    pub success: bool,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub result: Option<serde_json::Value>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub error: Option<String>,
}

/// An unsolicited event from the proxy to the TypeScript wrapper.
#[derive(Debug, Serialize)]
pub struct ManagementEvent {
    pub event: String,
    pub data: serde_json::Value,
}

impl ManagementResponse {
    fn ok(id: String, result: serde_json::Value) -> Self {
        Self {
            id,
            success: true,
            result: Some(result),
            error: None,
        }
    }

    fn err(id: String, message: String) -> Self {
        Self {
            id,
            success: false,
            result: None,
            error: Some(message),
        }
    }
}

fn send_line(line: &str) {
    // Use blocking stdout write - we're writing short JSON lines
    use std::io::Write;
    let stdout = std::io::stdout();
    let mut handle = stdout.lock();
    let _ = handle.write_all(line.as_bytes());
    let _ = handle.write_all(b"\n");
    let _ = handle.flush();
}

fn send_response(response: &ManagementResponse) {
    match serde_json::to_string(response) {
        Ok(json) => send_line(&json),
        Err(e) => error!("Failed to serialize management response: {}", e),
    }
}

fn send_event(event: &str, data: serde_json::Value) {
    let evt = ManagementEvent {
        event: event.to_string(),
        data,
    };
    match serde_json::to_string(&evt) {
        Ok(json) => send_line(&json),
        Err(e) => error!("Failed to serialize management event: {}", e),
    }
}

/// Run the management loop, reading JSON commands from stdin and writing responses to stdout.
pub async fn management_loop() -> Result<()> {
    let stdin = BufReader::new(tokio::io::stdin());
    let mut lines = stdin.lines();
    let mut proxy: Option<RustProxy> = None;

    send_event("ready", serde_json::json!({}));

    loop {
        let line = match lines.next_line().await {
            Ok(Some(line)) => line,
            Ok(None) => {
                // stdin closed - parent process exited
                info!("Management stdin closed, shutting down");
                if let Some(ref mut p) = proxy {
                    let _ = p.stop().await;
                }
                break;
            }
            Err(e) => {
                error!("Error reading management stdin: {}", e);
                break;
            }
        };

        let line = line.trim().to_string();
        if line.is_empty() {
            continue;
        }

        let request: ManagementRequest = match serde_json::from_str(&line) {
            Ok(r) => r,
            Err(e) => {
                error!("Failed to parse management request: {}", e);
                // Send error response without an ID
                send_response(&ManagementResponse::err(
                    "unknown".to_string(),
                    format!("Failed to parse request: {}", e),
                ));
                continue;
            }
        };

        let response = handle_request(&request, &mut proxy).await;
        send_response(&response);
    }

    Ok(())
}

async fn handle_request(
    request: &ManagementRequest,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    let id = request.id.clone();

    match request.method.as_str() {
        "start" => handle_start(&id, &request.params, proxy).await,
        "stop" => handle_stop(&id, proxy).await,
        "updateRoutes" => handle_update_routes(&id, &request.params, proxy).await,
        "getMetrics" => handle_get_metrics(&id, proxy),
        "getStatistics" => handle_get_statistics(&id, proxy),
        "provisionCertificate" => handle_provision_certificate(&id, &request.params, proxy).await,
        "renewCertificate" => handle_renew_certificate(&id, &request.params, proxy).await,
        "getCertificateStatus" => handle_get_certificate_status(&id, &request.params, proxy).await,
        "getListeningPorts" => handle_get_listening_ports(&id, proxy),
        "getNftablesStatus" => handle_get_nftables_status(&id, proxy).await,
        "setSocketHandlerRelay" => handle_set_socket_handler_relay(&id, &request.params, proxy).await,
        "addListeningPort" => handle_add_listening_port(&id, &request.params, proxy).await,
        "removeListeningPort" => handle_remove_listening_port(&id, &request.params, proxy).await,
        "loadCertificate" => handle_load_certificate(&id, &request.params, proxy).await,
        _ => ManagementResponse::err(id, format!("Unknown method: {}", request.method)),
    }
}

async fn handle_start(
    id: &str,
    params: &serde_json::Value,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    if proxy.is_some() {
        return ManagementResponse::err(id.to_string(), "Proxy is already running".to_string());
    }

    let config = match params.get("config") {
        Some(config) => config,
        None => return ManagementResponse::err(id.to_string(), "Missing 'config' parameter".to_string()),
    };

    let options: RustProxyOptions = match serde_json::from_value(config.clone()) {
        Ok(o) => o,
        Err(e) => return ManagementResponse::err(id.to_string(), format!("Invalid config: {}", e)),
    };

    match RustProxy::new(options) {
        Ok(mut p) => {
            match p.start().await {
                Ok(()) => {
                    send_event("started", serde_json::json!({}));
                    *proxy = Some(p);
                    ManagementResponse::ok(id.to_string(), serde_json::json!({}))
                }
                Err(e) => {
                    send_event("error", serde_json::json!({"message": format!("{}", e)}));
                    ManagementResponse::err(id.to_string(), format!("Failed to start: {}", e))
                }
            }
        }
        Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to create proxy: {}", e)),
    }
}

async fn handle_stop(
    id: &str,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    match proxy.as_mut() {
        Some(p) => {
            match p.stop().await {
                Ok(()) => {
                    *proxy = None;
                    send_event("stopped", serde_json::json!({}));
                    ManagementResponse::ok(id.to_string(), serde_json::json!({}))
                }
                Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to stop: {}", e)),
            }
        }
        None => ManagementResponse::ok(id.to_string(), serde_json::json!({})),
    }
}

async fn handle_update_routes(
    id: &str,
    params: &serde_json::Value,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    let p = match proxy.as_mut() {
        Some(p) => p,
        None => return ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    };

    let routes = match params.get("routes") {
        Some(routes) => routes,
        None => return ManagementResponse::err(id.to_string(), "Missing 'routes' parameter".to_string()),
    };

    let routes: Vec<rustproxy_config::RouteConfig> = match serde_json::from_value(routes.clone()) {
        Ok(r) => r,
        Err(e) => return ManagementResponse::err(id.to_string(), format!("Invalid routes: {}", e)),
    };

    match p.update_routes(routes).await {
        Ok(()) => ManagementResponse::ok(id.to_string(), serde_json::json!({})),
        Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to update routes: {}", e)),
    }
}

fn handle_get_metrics(
    id: &str,
    proxy: &Option<RustProxy>,
) -> ManagementResponse {
    match proxy.as_ref() {
        Some(p) => {
            let metrics = p.get_metrics();
            match serde_json::to_value(&metrics) {
                Ok(v) => ManagementResponse::ok(id.to_string(), v),
                Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to serialize metrics: {}", e)),
            }
        }
        None => ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    }
}

fn handle_get_statistics(
    id: &str,
    proxy: &Option<RustProxy>,
) -> ManagementResponse {
    match proxy.as_ref() {
        Some(p) => {
            let stats = p.get_statistics();
            match serde_json::to_value(&stats) {
                Ok(v) => ManagementResponse::ok(id.to_string(), v),
                Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to serialize statistics: {}", e)),
            }
        }
        None => ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    }
}

async fn handle_provision_certificate(
    id: &str,
    params: &serde_json::Value,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    let p = match proxy.as_mut() {
        Some(p) => p,
        None => return ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    };

    let route_name = match params.get("routeName").and_then(|v| v.as_str()) {
        Some(name) => name.to_string(),
        None => return ManagementResponse::err(id.to_string(), "Missing 'routeName' parameter".to_string()),
    };

    match p.provision_certificate(&route_name).await {
        Ok(()) => ManagementResponse::ok(id.to_string(), serde_json::json!({})),
        Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to provision certificate: {}", e)),
    }
}

async fn handle_renew_certificate(
    id: &str,
    params: &serde_json::Value,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    let p = match proxy.as_mut() {
        Some(p) => p,
        None => return ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    };

    let route_name = match params.get("routeName").and_then(|v| v.as_str()) {
        Some(name) => name.to_string(),
        None => return ManagementResponse::err(id.to_string(), "Missing 'routeName' parameter".to_string()),
    };

    match p.renew_certificate(&route_name).await {
        Ok(()) => ManagementResponse::ok(id.to_string(), serde_json::json!({})),
        Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to renew certificate: {}", e)),
    }
}

async fn handle_get_certificate_status(
    id: &str,
    params: &serde_json::Value,
    proxy: &Option<RustProxy>,
) -> ManagementResponse {
    let p = match proxy.as_ref() {
        Some(p) => p,
        None => return ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    };

    let route_name = match params.get("routeName").and_then(|v| v.as_str()) {
        Some(name) => name,
        None => return ManagementResponse::err(id.to_string(), "Missing 'routeName' parameter".to_string()),
    };

    match p.get_certificate_status(route_name).await {
        Some(status) => ManagementResponse::ok(id.to_string(), serde_json::json!({
            "domain": status.domain,
            "source": status.source,
            "expiresAt": status.expires_at,
            "isValid": status.is_valid,
        })),
        None => ManagementResponse::ok(id.to_string(), serde_json::Value::Null),
    }
}

fn handle_get_listening_ports(
    id: &str,
    proxy: &Option<RustProxy>,
) -> ManagementResponse {
    match proxy.as_ref() {
        Some(p) => {
            let ports = p.get_listening_ports();
            ManagementResponse::ok(id.to_string(), serde_json::json!({ "ports": ports }))
        }
        None => ManagementResponse::ok(id.to_string(), serde_json::json!({ "ports": [] })),
    }
}

async fn handle_get_nftables_status(
    id: &str,
    proxy: &Option<RustProxy>,
) -> ManagementResponse {
    match proxy.as_ref() {
        Some(p) => {
            match p.get_nftables_status().await {
                Ok(status) => {
                    match serde_json::to_value(&status) {
                        Ok(v) => ManagementResponse::ok(id.to_string(), v),
                        Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to serialize: {}", e)),
                    }
                }
                Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to get status: {}", e)),
            }
        }
        None => ManagementResponse::ok(id.to_string(), serde_json::json!({})),
    }
}

async fn handle_set_socket_handler_relay(
    id: &str,
    params: &serde_json::Value,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    let p = match proxy.as_mut() {
        Some(p) => p,
        None => return ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    };

    let socket_path = params.get("socketPath")
        .and_then(|v| v.as_str())
        .map(|s| s.to_string());

    info!("setSocketHandlerRelay: socket_path={:?}", socket_path);
    p.set_socket_handler_relay_path(socket_path);

    ManagementResponse::ok(id.to_string(), serde_json::json!({}))
}

async fn handle_add_listening_port(
    id: &str,
    params: &serde_json::Value,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    let p = match proxy.as_mut() {
        Some(p) => p,
        None => return ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    };

    let port = match params.get("port").and_then(|v| v.as_u64()) {
        Some(port) => port as u16,
        None => return ManagementResponse::err(id.to_string(), "Missing 'port' parameter".to_string()),
    };

    match p.add_listening_port(port).await {
        Ok(()) => ManagementResponse::ok(id.to_string(), serde_json::json!({})),
        Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to add port {}: {}", port, e)),
    }
}

async fn handle_remove_listening_port(
    id: &str,
    params: &serde_json::Value,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    let p = match proxy.as_mut() {
        Some(p) => p,
        None => return ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    };

    let port = match params.get("port").and_then(|v| v.as_u64()) {
        Some(port) => port as u16,
        None => return ManagementResponse::err(id.to_string(), "Missing 'port' parameter".to_string()),
    };

    match p.remove_listening_port(port).await {
        Ok(()) => ManagementResponse::ok(id.to_string(), serde_json::json!({})),
        Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to remove port {}: {}", port, e)),
    }
}

async fn handle_load_certificate(
    id: &str,
    params: &serde_json::Value,
    proxy: &mut Option<RustProxy>,
) -> ManagementResponse {
    let p = match proxy.as_mut() {
        Some(p) => p,
        None => return ManagementResponse::err(id.to_string(), "Proxy is not running".to_string()),
    };

    let domain = match params.get("domain").and_then(|v| v.as_str()) {
        Some(d) => d.to_string(),
        None => return ManagementResponse::err(id.to_string(), "Missing 'domain' parameter".to_string()),
    };

    let cert = match params.get("cert").and_then(|v| v.as_str()) {
        Some(c) => c.to_string(),
        None => return ManagementResponse::err(id.to_string(), "Missing 'cert' parameter".to_string()),
    };

    let key = match params.get("key").and_then(|v| v.as_str()) {
        Some(k) => k.to_string(),
        None => return ManagementResponse::err(id.to_string(), "Missing 'key' parameter".to_string()),
    };

    let ca = params.get("ca").and_then(|v| v.as_str()).map(|s| s.to_string());

    info!("loadCertificate: domain={}", domain);

    // Load cert into cert manager and hot-swap TLS config
    match p.load_certificate(&domain, cert, key, ca).await {
        Ok(()) => ManagementResponse::ok(id.to_string(), serde_json::json!({})),
        Err(e) => ManagementResponse::err(id.to_string(), format!("Failed to load certificate for {}: {}", domain, e)),
    }
}