import express from 'express';
import { createServer } from 'http';
import { Server } from 'socket.io';
import { PrismaClient } from '@prisma/client';
import { handler } from './build/handler.js';

const app = express();
const server = createServer(app);

const io = new Server(server, {
	cors: {
		origin: process.env.ORIGIN || 'http://localhost:3000',
		credentials: true
	}
});

// ─── Prisma client for session validation ───────────────────
const prisma = new PrismaClient();

// ─── Presence tracking ──────────────────────────────────────
// Map<boardId, Map<socketId, { id, name }>>
const presence = new Map();

function getPresenceList(boardId) {
	const room = presence.get(boardId);
	if (!room) return [];
	return Array.from(room.values());
}

// ─── Cookie parser ──────────────────────────────────────────
function parseCookies(cookieHeader) {
	const cookies = {};
	if (!cookieHeader) return cookies;
	cookieHeader.split(';').forEach((cookie) => {
		const [name, ...rest] = cookie.trim().split('=');
		cookies[name] = decodeURIComponent(rest.join('='));
	});
	return cookies;
}

// ─── Socket.IO auth middleware ───────────────────────────────
io.use(async (socket, next) => {
	try {
		const cookies = parseCookies(socket.handshake.headers.cookie);
		const sessionId = cookies['session'];
		if (!sessionId) {
			socket.data.user = null;
			return next();
		}

		const session = await prisma.session.findUnique({
			where: { id: sessionId },
			include: {
				user: {
					select: { id: true, name: true, avatarUrl: true, tenantId: true }
				}
			}
		});

		if (session && session.expiresAt > new Date()) {
			socket.data.user = session.user;
		} else {
			socket.data.user = null;
		}
		next();
	} catch (err) {
		console.error('Socket auth error:', err);
		socket.data.user = null;
		next();
	}
});

// ─── Socket.IO connection handler ────────────────────────────
io.on('connection', (socket) => {
	const user = socket.data.user;
	console.log(`Socket connected: ${socket.id} (user: ${user?.name ?? 'anon'})`);

	// Track which boards this socket has joined (for cleanup on disconnect)
	const joinedBoards = new Set();

	socket.on('join-board', (boardId) => {
		socket.join(`board:${boardId}`);
		joinedBoards.add(boardId);

		if (user) {
			if (!presence.has(boardId)) presence.set(boardId, new Map());
			presence.get(boardId).set(socket.id, { id: user.id, name: user.name, avatarUrl: user.avatarUrl });
		}

		// Notify others
		socket.to(`board:${boardId}`).emit('user-joined', {
			user: user ? { id: user.id, name: user.name, avatarUrl: user.avatarUrl } : null,
			socketId: socket.id
		});

		// Send full presence list to everyone in the room (including the joiner)
		io.to(`board:${boardId}`).emit('presence:update', getPresenceList(boardId));
	});

	socket.on('leave-board', (boardId) => {
		socket.leave(`board:${boardId}`);
		joinedBoards.delete(boardId);

		if (presence.has(boardId)) {
			presence.get(boardId).delete(socket.id);
			if (presence.get(boardId).size === 0) presence.delete(boardId);
		}

		socket.to(`board:${boardId}`).emit('user-left', {
			user: user ? { id: user.id, name: user.name } : null,
			socketId: socket.id
		});

		// Update presence for remaining
		const room = presence.get(boardId);
		io.to(`board:${boardId}`).emit('presence:update', room ? Array.from(room.values()) : []);
	});

	socket.on('disconnect', () => {
		console.log(`Socket disconnected: ${socket.id}`);
		for (const boardId of joinedBoards) {
			if (presence.has(boardId)) {
				presence.get(boardId).delete(socket.id);
				if (presence.get(boardId).size === 0) {
					presence.delete(boardId);
				}
			}

			socket.to(`board:${boardId}`).emit('user-left', {
				user: user ? { id: user.id, name: user.name } : null,
				socketId: socket.id
			});

			const room = presence.get(boardId);
			io.to(`board:${boardId}`).emit('presence:update', room ? Array.from(room.values()) : []);
		}
	});
});

// Store io globally so SvelteKit API routes can broadcast via realtime.ts
globalThis.__socketIO = io;

// SvelteKit handler
app.use(handler);

const port = process.env.PORT || 3000;
const host = process.env.HOST || '0.0.0.0';

server.listen(port, host, () => {
	console.log(`Server running on http://${host}:${port}`);
});