import express from 'express';
import path from 'path';
import http from 'http';
import { WebSocketServer, WebSocket } from 'ws';
import { v4 as uuidv4 } from 'uuid';
import { defaultState } from '../src/defaultState.js';
import { getPersistedSession, persistSession } from './db.js';

import { fileURLToPath } from 'url';
import { dirname } from 'path';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

const app = express();
const port = process.env.PORT || 3001;
const subfolder = '/ag-beats';
const distPath = path.join(__dirname, '../dist');

const COLORS = ['#F94144', '#F3722C', '#F8961E', '#F9C74F', '#90BE6D', '#43AA8B', '#4D908E', '#577590', '#277DA1'];
const getRandomColor = () => COLORS[Math.floor(Math.random() * COLORS.length)];

app.use(subfolder, express.static(distPath));
app.get(subfolder + '/*', (req, res) => res.sendFile(path.join(distPath, 'index.html')));
app.get('/', (req, res) => res.redirect(subfolder));

const httpServer = http.createServer(app);
const wss = new WebSocketServer({ path: '/ag-beats', server: httpServer });

interface ClientInfo {
    ws: WebSocket;
    color: string;
}

interface Session {
    clients: Map<string, ClientInfo>;
    state: any;
}

const sessions = new Map<string, Session>();

wss.on('connection', (ws: WebSocket, req) => {
    const url = new URL(req.url || '', `http://${req.headers.host}`);
    const sessionId = url.searchParams.get('sessionId');
    const clientId = uuidv4();
    const clientColor = getRandomColor();

    if (!sessionId) return ws.close(1008, 'Session ID required');

    if (!sessions.has(sessionId)) {
        const persisted = getPersistedSession(sessionId);
        const initialState = persisted || JSON.parse(JSON.stringify(defaultState));
        sessions.set(sessionId, { clients: new Map(), state: initialState });
    }

    const session = sessions.get(sessionId)!;
    session.clients.set(clientId, { ws, color: clientColor });

    console.log(`Client ${clientId} connected to session ${sessionId}`);

    ws.send(JSON.stringify({ type: 'welcome', payload: { clientId } }));

    const broadcastUserUpdate = () => {
        const userList = Array.from(session.clients.entries()).map(([id, { color }]) => ({ id, color }));
        const msg = JSON.stringify({ type: 'user-update', payload: { users: userList } });
        session.clients.forEach(({ ws: c }) => c.readyState === WebSocket.OPEN && c.send(msg));
    };

    broadcastUserUpdate();

    ws.on('message', (messageBuffer) => {
        const message = JSON.parse(messageBuffer.toString());

        if (message.type === 'get_state') {
            ws.send(JSON.stringify({ type: 'session_state', payload: session.state }));
            return;
        }

        const messageToSend = JSON.stringify({ ...message, senderId: clientId });

        if (message.type !== 'cursor-move') {
            session.state = { ...session.state, ...message.payload };
            persistSession(sessionId, session.state);
        }

        session.clients.forEach(({ ws: c }) => {
            if (c.readyState === WebSocket.OPEN) c.send(messageToSend);
        });
    });

    ws.on('close', () => {
        console.log(`Client ${clientId} disconnected from session ${sessionId}`);
        session.clients.delete(clientId);
        if (session.clients.size === 0) {
            // keep session in DB but remove from memory
            sessions.delete(sessionId);
        } else {
            broadcastUserUpdate();
        }
    });
});

httpServer.listen(port, () => console.log(`AG Beats (TS) started on port ${port}`));