mod analytics;
mod auth;
mod backup_rpc;
mod bitcoin;
mod container;
mod content;
mod credentials;
mod dispatcher;
mod dwn;
mod federation;
mod handshake;
mod identity;
mod interfaces;
mod marketplace;
mod middleware;
mod monitoring;
mod names;
mod lnd;
mod mesh;
mod network;
mod node;
mod nostr;
mod package;
mod peers;
mod response;
mod router;
mod security;
mod tor;
mod transport;
mod totp;
mod system;
mod update;
mod vpn;
mod wallet;
mod webhooks;

use crate::auth::AuthManager;
use crate::config::Config;
use crate::container::DevContainerOrchestrator;
use crate::monitoring::MetricsStore;
use crate::port_allocator::PortAllocator;
use crate::rate_limit::{EndpointRateLimiter, LoginRateLimiter};
use crate::session::{self, SessionStore, REMEMBER_TTL};
use crate::state::StateManager;
use anyhow::{Context, Result};
use hyper::{Request, Response, StatusCode};
use std::sync::Arc;
use tracing::{debug, error};

use middleware::{
    UNAUTHENTICATED_METHODS, CACHEABLE_METHODS,
    derive_csrf_token, extract_client_ip, extract_cookie, sanitize_error_message,
};
use response::{RpcRequest, RpcResponse, RpcError, ResponseCache, json_response, cookie_header};

/// Default dev password when no user is set up (matches mock-backend).
pub(crate) const DEV_DEFAULT_PASSWORD: &str = "password123";

pub struct RpcHandler {
    config: Config,
    auth_manager: AuthManager,
    orchestrator: Option<Arc<DevContainerOrchestrator>>,
    state_manager: Arc<StateManager>,
    pub(crate) metrics_store: Arc<MetricsStore>,
    port_allocator: Arc<tokio::sync::Mutex<PortAllocator>>,
    pub session_store: SessionStore,
    login_rate_limiter: LoginRateLimiter,
    endpoint_rate_limiter: EndpointRateLimiter,
    response_cache: ResponseCache,
    mesh_service: Arc<tokio::sync::RwLock<Option<crate::mesh::MeshService>>>,
    transport_router: Arc<tokio::sync::RwLock<Option<Arc<crate::transport::TransportRouter>>>>,
}

impl RpcHandler {
    pub async fn new(
        config: Config,
        state_manager: Arc<StateManager>,
        metrics_store: Arc<MetricsStore>,
        session_store: SessionStore,
    ) -> Result<Self> {
        let auth_manager = AuthManager::new(config.data_dir.clone());
        let orchestrator = if config.dev_mode {
            Some(Arc::new(
                DevContainerOrchestrator::new(config.clone()).await?,
            ))
        } else {
            None
        };
        let port_allocator = Arc::new(tokio::sync::Mutex::new(PortAllocator::new(&config.data_dir).await?));

        let login_rate_limiter = LoginRateLimiter::new();
        let endpoint_rate_limiter = EndpointRateLimiter::new();

        // Spawn periodic rate limiter cleanup (every 5 minutes)
        {
            let limiter = endpoint_rate_limiter.clone();
            tokio::spawn(async move {
                let mut interval = tokio::time::interval(std::time::Duration::from_secs(300));
                loop {
                    interval.tick().await;
                    limiter.cleanup().await;
                }
            });
        }
        {
            let limiter = login_rate_limiter.clone();
            tokio::spawn(async move {
                let mut interval = tokio::time::interval(std::time::Duration::from_secs(300));
                loop {
                    interval.tick().await;
                    limiter.cleanup().await;
                }
            });
        }

        Ok(Self {
            config,
            auth_manager,
            orchestrator,
            state_manager,
            metrics_store,
            port_allocator,
            session_store,
            login_rate_limiter,
            endpoint_rate_limiter,
            response_cache: ResponseCache::new(5),
            mesh_service: Arc::new(tokio::sync::RwLock::new(None)),
            transport_router: Arc::new(tokio::sync::RwLock::new(None)),
        })
    }

    /// Set the mesh service (called after identity is loaded).
    pub async fn set_mesh_service(&self, service: crate::mesh::MeshService) {
        *self.mesh_service.write().await = Some(service);
    }

    /// Set the transport router (called after all transports are initialized).
    pub async fn set_transport_router(&self, router: Arc<crate::transport::TransportRouter>) {
        *self.transport_router.write().await = Some(router);
    }

    /// Get reference to the mesh service Arc (for MeshTransport wrapper).
    pub fn mesh_service_arc(&self) -> Arc<tokio::sync::RwLock<Option<crate::mesh::MeshService>>> {
        Arc::clone(&self.mesh_service)
    }

    fn cookie_suffix_for_request(&self, headers: &hyper::header::HeaderMap) -> &'static str {
        // Only set Secure flag when the original request was over HTTPS.
        // Nginx sends X-Forwarded-Proto: https for HTTPS connections.
        // On LAN HTTP, Secure flag prevents browsers from sending cookies back.
        if self.config.dev_mode {
            return "";
        }
        if let Some(proto) = headers.get("x-forwarded-proto") {
            if proto.as_bytes() == b"https" {
                tracing::debug!("[onboarding] cookie: Secure (X-Forwarded-Proto: https)");
                return "; Secure";
            }
        }
        tracing::debug!("[onboarding] cookie: no Secure flag (HTTP or no X-Forwarded-Proto)");
        ""
    }

    pub async fn handle(
        &self,
        req: Request<hyper::Body>,
    ) -> Result<Response<hyper::Body>> {
        // Extract session cookie before consuming the request
        let (parts, body) = req.into_parts();
        let session_token = session::extract_session_cookie(&parts.headers);
        let secure_suffix = self.cookie_suffix_for_request(&parts.headers);

        let body_bytes = hyper::body::to_bytes(body).await
            .context("Failed to read body")?;

        let rpc_req: RpcRequest = serde_json::from_slice(&body_bytes)
            .context("Invalid RPC request")?;

        debug!("RPC method: {}", rpc_req.method);

        // Enforce authentication for non-allowlisted methods
        let is_unauthenticated = UNAUTHENTICATED_METHODS.contains(&rpc_req.method.as_str());
        let mut new_session_cookies: Option<(String, String)> = None;
        if !is_unauthenticated {
            let mut authenticated = match &session_token {
                Some(token) => self.session_store.validate(token).await,
                None => false,
            };

            // If session invalid, try remember-me token to auto-restore session
            if !authenticated {
                if let Some(remember) = extract_cookie(&parts.headers, "remember") {
                    if crate::session::SessionStore::validate_remember_token(&remember).await {
                        let new_token = self.session_store.create().await;
                        let new_csrf = derive_csrf_token(&new_token).await;
                        tracing::info!("Auto-restored session from remember-me token");
                        new_session_cookies = Some((new_token, new_csrf));
                        authenticated = true;
                    }
                }
            }

            if !authenticated {
                let reason = if session_token.is_none() { "no session cookie" } else { "invalid/expired token" };
                tracing::warn!(method = %rpc_req.method, reason, "401 Unauthorized — rejecting RPC call");
                return Ok(self.error_response(401, "Unauthorized", StatusCode::UNAUTHORIZED));
            }
        }

        // RBAC: check if the user's role allows this method
        if !is_unauthenticated {
            if let Ok(Some(user)) = self.auth_manager.get_user().await {
                if !user.role.can_access(&rpc_req.method) {
                    return Ok(self.error_response(403, "Forbidden: insufficient permissions", StatusCode::FORBIDDEN));
                }
            }
        }

        // CSRF protection: validate X-CSRF-Token header via HMAC derivation from session token.
        // Skip CSRF check if session was just auto-restored from remember-me.
        if !is_unauthenticated && new_session_cookies.is_none() {
            let csrf_header = parts
                .headers
                .get("x-csrf-token")
                .and_then(|v| v.to_str().ok())
                .map(|s| s.to_string());

            let csrf_valid = match (&session_token, &csrf_header) {
                (Some(token), Some(header)) => {
                    use hmac::{Hmac, Mac};
                    use sha2::Sha256;
                    type HmacSha256 = Hmac<Sha256>;
                    let secret = SessionStore::load_or_create_remember_secret().await;
                    let mut mac = match HmacSha256::new_from_slice(&secret) {
                        Ok(m) => m,
                        Err(_) => { return Ok(json_response(StatusCode::INTERNAL_SERVER_ERROR, b"{}")); }
                    };
                    mac.update(format!("csrf:{}", token).as_bytes());
                    match hex::decode(header) {
                        Ok(header_bytes) => mac.verify_slice(&header_bytes).is_ok(),
                        Err(_) => false,
                    }
                }
                _ => false,
            };

            if !csrf_valid {
                tracing::warn!(
                    method = %rpc_req.method,
                    has_session = session_token.is_some(),
                    has_header = csrf_header.is_some(),
                    "403 CSRF validation failed — rejecting RPC call"
                );
                return Ok(self.error_response(403, "CSRF token missing or invalid", StatusCode::FORBIDDEN));
            }
        }

        // Rate limit login attempts
        if rpc_req.method == "auth.login" {
            let client_ip = extract_client_ip(&parts.headers);
            if !self.login_rate_limiter.check(client_ip).await {
                return Ok(self.rate_limit_response());
            }
        }

        // Rate limit sensitive endpoints
        {
            let client_ip = extract_client_ip(&parts.headers);
            if !self.endpoint_rate_limiter.check(&rpc_req.method, client_ip).await {
                return Ok(self.rate_limit_response());
            }
            self.endpoint_rate_limiter.record(&rpc_req.method, client_ip).await;
        }

        // Extract params; clone for post-routing use (login 2FA check needs password)
        let params = rpc_req.params;
        let login_params: Option<serde_json::Value> = if rpc_req.method == "auth.login" {
            params.clone()
        } else {
            None
        };

        // Check cache for cacheable methods
        let is_cacheable = CACHEABLE_METHODS.contains(&rpc_req.method.as_str());
        if is_cacheable {
            if let Some(cached) = self.response_cache.get(&rpc_req.method).await {
                let rpc_resp = RpcResponse {
                    result: Some(cached),
                    error: None,
                };
                let body = serde_json::to_vec(&rpc_resp)?;
                return Ok(json_response(StatusCode::OK, &body));
            }
        }

        // Route to handler (track latency for metrics)
        let rpc_start = std::time::Instant::now();
        let result = self.dispatch(&rpc_req.method, params, &session_token).await;

        // Record RPC latency for monitoring
        let elapsed_ms = rpc_start.elapsed().as_secs_f64() * 1000.0;
        self.metrics_store.record_rpc_latency(elapsed_ms).await;

        // Build response (cache successful results for cacheable methods)
        let mut rpc_resp = match result {
            Ok(data) => {
                if is_cacheable {
                    self.response_cache.set(rpc_req.method.clone(), data.clone()).await;
                }
                RpcResponse {
                    result: Some(data),
                    error: None,
                }
            }
            Err(e) => {
                error!("RPC error on {}: {}", rpc_req.method, e);
                let user_message = sanitize_error_message(&e.to_string());
                RpcResponse {
                    result: None,
                    error: Some(RpcError {
                        code: -1,
                        message: user_message,
                        data: None,
                    }),
                }
            }
        };

        let resp_body = serde_json::to_vec(&rpc_resp)
            .context("Failed to serialize response")?;

        let mut response = json_response(StatusCode::OK, &resp_body);

        // Post-dispatch: set cookies for auth-related methods
        let client_ip = extract_client_ip(&parts.headers);
        self.apply_auth_cookies(
            &rpc_req.method,
            &mut rpc_resp,
            &mut response,
            &session_token,
            &login_params,
            &new_session_cookies,
            client_ip,
            secure_suffix,
        ).await;

        Ok(response)
    }

    /// Build a JSON error response with the given RPC error code and HTTP status.
    fn error_response(&self, code: i32, message: &str, status: StatusCode) -> Response<hyper::Body> {
        let rpc_resp = RpcResponse {
            result: None,
            error: Some(RpcError {
                code,
                message: message.to_string(),
                data: None,
            }),
        };
        let resp_body = serde_json::to_vec(&rpc_resp).unwrap_or_default();
        json_response(status, &resp_body)
    }

    /// Build a 429 Too Many Requests response.
    fn rate_limit_response(&self) -> Response<hyper::Body> {
        let rpc_resp = RpcResponse {
            result: None,
            error: Some(RpcError {
                code: 429,
                message: "Rate limit exceeded. Try again later.".to_string(),
                data: None,
            }),
        };
        let resp_body = serde_json::to_vec(&rpc_resp).unwrap_or_default();
        let mut resp = json_response(StatusCode::TOO_MANY_REQUESTS, &resp_body);
        resp.headers_mut().insert("Retry-After", cookie_header("60"));
        resp
    }

    /// Apply session/CSRF/remember-me cookies after dispatch for auth-related methods.
    async fn apply_auth_cookies(
        &self,
        method: &str,
        rpc_resp: &mut RpcResponse,
        response: &mut Response<hyper::Body>,
        session_token: &Option<String>,
        login_params: &Option<serde_json::Value>,
        new_session_cookies: &Option<(String, String)>,
        client_ip: std::net::IpAddr,
        secure_suffix: &str,
    ) {
        // Track failed login attempts for rate limiting
        if method == "auth.login" && rpc_resp.error.is_some() {
            self.login_rate_limiter.record_failure(client_ip).await;
        }

        // On successful login, check if 2FA is required
        if method == "auth.login" && rpc_resp.error.is_none() {
            let totp_enabled = self.auth_manager.is_totp_enabled().await.unwrap_or(false);
            if totp_enabled {
                let password = login_params
                    .as_ref()
                    .and_then(|p| p.get("password"))
                    .and_then(|v| v.as_str())
                    .unwrap_or("");
                if let Ok(Some(totp_data)) = self.auth_manager.get_totp_data().await {
                    if let Ok(secret) = crate::totp::decrypt_secret(&totp_data, password) {
                        let token = self.session_store.create_pending(secret).await;
                        let csrf_token = derive_csrf_token(&token).await;
                        self.set_session_cookie(response, &token, secure_suffix);
                        self.set_csrf_cookie(response, &csrf_token, secure_suffix);
                        let totp_body = serde_json::json!({
                            "result": { "requires_totp": true },
                            "error": null
                        });
                        *response.body_mut() = hyper::Body::from(
                            serde_json::to_vec(&totp_body).unwrap_or_default(),
                        );
                    }
                }
            } else {
                let token = self.session_store.create().await;
                let csrf_token = derive_csrf_token(&token).await;
                let remember_token = self.session_store.create_remember_token().await;
                self.set_session_cookie(response, &token, secure_suffix);
                self.set_csrf_cookie(response, &csrf_token, secure_suffix);
                self.set_remember_cookie(response, &remember_token, secure_suffix);
            }
        }

        // On successful TOTP verification, set the rotated session cookie
        if (method == "auth.login.totp" || method == "auth.login.backup")
            && rpc_resp.error.is_none()
        {
            let new_token_opt = rpc_resp
                .result
                .as_ref()
                .and_then(|r| r.get("new_session_token"))
                .and_then(|v| v.as_str())
                .map(|s| s.to_string());

            if let Some(new_token) = new_token_opt {
                let csrf_token = derive_csrf_token(&new_token).await;
                let remember_token = self.session_store.create_remember_token().await;
                self.set_session_cookie(response, &new_token, secure_suffix);
                self.set_csrf_cookie(response, &csrf_token, secure_suffix);
                self.set_remember_cookie(response, &remember_token, secure_suffix);
                // Strip the token from the response body
                if let Some(result) = rpc_resp.result.as_mut() {
                    if let Some(obj) = result.as_object_mut() {
                        obj.remove("new_session_token");
                    }
                }
                let body_bytes = serde_json::to_vec(&rpc_resp).unwrap_or_default();
                *response.body_mut() = hyper::Body::from(body_bytes);
            }
        }

        // On password change, rotate the session token for the caller
        if method == "auth.changePassword" && rpc_resp.error.is_none() {
            if let Some(token) = session_token {
                let new_token = self.session_store.rotate(token).await;
                let csrf_token = derive_csrf_token(&new_token).await;
                self.set_session_cookie(response, &new_token, secure_suffix);
                self.set_csrf_cookie(response, &csrf_token, secure_suffix);
            }
        }

        // On logout, invalidate session and expire cookies
        if method == "auth.logout" {
            if let Some(token) = session_token {
                self.session_store.remove(token).await;
            }
            response.headers_mut().append(
                "Set-Cookie",
                cookie_header(&format!("session=; HttpOnly; SameSite=Lax; Path=/; Max-Age=0{}", secure_suffix)),
            );
            response.headers_mut().append(
                "Set-Cookie",
                cookie_header(&format!("csrf_token=; SameSite=Lax; Path=/; Max-Age=0{}", secure_suffix)),
            );
        }

        // If session was auto-restored from remember-me, set new cookies
        if let Some((new_session, new_csrf)) = new_session_cookies {
            self.set_session_cookie(response, new_session, secure_suffix);
            self.set_csrf_cookie(response, new_csrf, secure_suffix);
        }
    }

    fn set_session_cookie(&self, response: &mut Response<hyper::Body>, token: &str, secure_suffix: &str) {
        response.headers_mut().append(
            "Set-Cookie",
            cookie_header(&format!("session={}; HttpOnly; SameSite=Lax; Path=/{}", token, secure_suffix)),
        );
    }

    fn set_csrf_cookie(&self, response: &mut Response<hyper::Body>, csrf_token: &str, secure_suffix: &str) {
        response.headers_mut().append(
            "Set-Cookie",
            cookie_header(&format!("csrf_token={}; SameSite=Lax; Path=/{}", csrf_token, secure_suffix)),
        );
    }

    fn set_remember_cookie(&self, response: &mut Response<hyper::Body>, remember_token: &str, secure_suffix: &str) {
        response.headers_mut().append(
            "Set-Cookie",
            cookie_header(&format!("remember={}; HttpOnly; SameSite=Lax; Path=/; Max-Age={}{}", remember_token, REMEMBER_TTL, secure_suffix)),
        );
    }
}