import { forwardRef, Inject, Logger } from "@nestjs/common";
import { ConfigService } from "@nestjs/config";
import {
	ConnectedSocket,
	MessageBody,
	OnGatewayConnection,
	OnGatewayDisconnect,
	OnGatewayInit,
	SubscribeMessage,
	WebSocketGateway,
	WebSocketServer,
} from "@nestjs/websockets";
import { getIronSession } from "iron-session";
import { Server, Socket } from "socket.io";
import { getSessionOptions, SessionData } from "../auth/session.config";
import { JwtService } from "../crypto/services/jwt.service";
import { UsersService } from "../users/users.service";

@WebSocketGateway({
	transports: ["websocket"],
	cors: {
		origin: (
			origin: string,
			callback: (err: Error | null, allow?: boolean) => void,
		) => {
			// Autoriser si pas d'origine (ex: app mobile ou serveur à serveur)
			// ou si on est en développement local
			if (
				!origin ||
				origin.includes("localhost") ||
				origin.includes("127.0.0.1")
			) {
				callback(null, true);
				return;
			}

			// En production, on peut restreindre via une variable d'environnement
			const domainName = process.env.CORS_DOMAIN_NAME;
			if (!domainName || domainName === "*") {
				callback(null, true);
				return;
			}

			const allowedOrigins = domainName.split(",").map((o) => o.trim());
			if (allowedOrigins.includes(origin)) {
				callback(null, true);
			} else {
				callback(new Error("Not allowed by CORS"));
			}
		},
		credentials: true,
		methods: ["GET", "POST"],
	},
})
export class EventsGateway
	implements OnGatewayInit, OnGatewayConnection, OnGatewayDisconnect
{
	@WebSocketServer()
	server!: Server;

	private readonly logger = new Logger(EventsGateway.name);
	private readonly onlineUsers = new Map<string, Set<string>>(); // userId -> Set of socketIds

	constructor(
		private readonly jwtService: JwtService,
		private readonly configService: ConfigService,
		@Inject(forwardRef(() => UsersService))
		private readonly usersService: UsersService,
	) {}

	afterInit(_server: Server) {
		this.logger.log("WebSocket Gateway initialized");
	}

	async handleConnection(client: Socket) {
		try {
			// Simuler un objet Request/Response pour iron-session
			const req: any = {
				headers: client.handshake.headers,
			};
			const res: any = {
				setHeader: () => {},
				getHeader: () => {},
			};

			const session = await getIronSession<SessionData>(
				req,
				res,
				getSessionOptions(this.configService.get("SESSION_PASSWORD") as string),
			);

			if (!session.accessToken) {
				this.logger.warn(`Client ${client.id} unauthorized connection`);
				// Permettre les connexions anonymes pour voir les commentaires en temps réel ?
				// Pour l'instant on déconnecte car le système actuel semble exiger l'auth
				client.disconnect();
				return;
			}

			const payload = await this.jwtService.verifyJwt(session.accessToken);
			if (!payload.sub) {
				throw new Error("Invalid token payload: missing sub");
			}

			client.data.user = payload;

			// Rejoindre une room personnelle pour les notifications
			client.join(`user:${payload.sub}`);

			// Gérer le statut en ligne
			const userId = payload.sub as string;

			if (!this.onlineUsers.has(userId)) {
				this.onlineUsers.set(userId, new Set());

				// Vérifier les préférences de l'utilisateur
				const user = await this.usersService.findOne(userId);
				if (user?.showOnlineStatus) {
					this.broadcastStatus(userId, "online");
				}
			}
			this.onlineUsers.get(userId)?.add(client.id);

			this.logger.log(`Client connected: ${client.id} (User: ${payload.sub})`);
		} catch (error) {
			this.logger.error(`Connection error for client ${client.id}: ${error}`);
			client.disconnect();
		}
	}

	async handleDisconnect(client: Socket) {
		const userId = client.data.user?.sub;
		if (userId && this.onlineUsers.has(userId)) {
			const sockets = this.onlineUsers.get(userId);
			sockets?.delete(client.id);
			if (sockets?.size === 0) {
				this.onlineUsers.delete(userId);

				const user = await this.usersService.findOne(userId);
				if (user?.showOnlineStatus) {
					this.broadcastStatus(userId, "offline");
				}
			}
		}
		this.logger.log(`Client disconnected: ${client.id}`);
	}

	broadcastStatus(userId: string, status: "online" | "offline") {
		this.server.emit("user_status", { userId, status });
	}

	isUserOnline(userId: string): boolean {
		return this.onlineUsers.has(userId);
	}

	@SubscribeMessage("join_content")
	handleJoinContent(
		@ConnectedSocket() client: Socket,
		@MessageBody() contentId: string,
	) {
		client.join(`content:${contentId}`);
		this.logger.log(`Client ${client.id} joined content room: ${contentId}`);
	}

	@SubscribeMessage("leave_content")
	handleLeaveContent(
		@ConnectedSocket() client: Socket,
		@MessageBody() contentId: string,
	) {
		client.leave(`content:${contentId}`);
		this.logger.log(`Client ${client.id} left content room: ${contentId}`);
	}

	@SubscribeMessage("typing")
	async handleTyping(
		@ConnectedSocket() client: Socket,
		@MessageBody() data: { recipientId: string; isTyping: boolean },
	) {
		const userId = client.data.user?.sub;
		if (!userId) return;

		// Optionnel: vérifier si l'utilisateur autorise le statut en ligne avant d'émettre "typing"
		// ou si on considère que typing est une interaction directe qui outrepasse le statut.
		// Instagram affiche "Typing..." même si le statut en ligne est désactivé si on est dans le chat.
		// Mais par souci de cohérence avec "showOnlineStatus", on peut le vérifier.
		const user = await this.usersService.findOne(userId);
		if (!user?.showOnlineStatus) return;

		this.server.to(`user:${data.recipientId}`).emit("user_typing", {
			userId,
			isTyping: data.isTyping,
		});
	}

	@SubscribeMessage("check_status")
	async handleCheckStatus(
		@ConnectedSocket() _client: Socket,
		@MessageBody() userId: string,
	) {
		const isOnline = this.onlineUsers.has(userId);
		if (!isOnline) return { userId, status: "offline" };

		const user = await this.usersService.findOne(userId);
		if (!user?.showOnlineStatus) return { userId, status: "offline" };

		return {
			userId,
			status: "online",
		};
	}

	// Méthode utilitaire pour envoyer des messages à un utilisateur spécifique
	sendToUser(userId: string, event: string, data: any) {
		this.server.to(`user:${userId}`).emit(event, data);
	}

	sendToContent(contentId: string, event: string, data: any) {
		this.server.to(`content:${contentId}`).emit(event, data);
	}
}