const express = require('express');
const http = require('http');
const { Server } = require('socket.io');
const cors = require('cors');
const axios = require('axios');
require('dotenv').config();

const app = express();
const server = http.createServer(app);
const io = new Server(server, {
    cors: {
        origin: '*',
        methods: ['GET', 'POST']
    }
});

const authRoutes = require('./routes/auth');
const channelRoutes = require('./routes/channels');
const uploadRoutes = require('./routes/upload');
const inviteRoutes = require('./routes/invites');
const rolesRoutes = require('./routes/roles');
const dmRoutes = require('./routes/dms');

app.use(cors());
app.use(express.json());

// Attach IO to request
app.use((req, res, next) => {
    req.io = io;
    next();
});

// Serve uploads folder based on relative path from server.js
const path = require('path');
app.use('/uploads', express.static(path.join(__dirname, 'uploads')));

app.use('/api/auth', authRoutes);
app.use('/api/channels', channelRoutes);
app.use('/api/upload', uploadRoutes);
app.use('/api/invites', inviteRoutes);
app.use('/api/invites', inviteRoutes);
app.use('/api/roles', rolesRoutes);
app.use('/api/dms', dmRoutes);
app.use('/api/voice', require('./routes/voice'));

app.get('/', (req, res) => {
    res.send('Secure Chat Backend Running');
});

// GIF Routes
const gifCategories = require('./data/gif_categories.json');

app.get('/api/gifs/categories', (req, res) => {
    res.json(gifCategories);
});

app.get('/api/gifs/search', async (req, res) => {
    const { q, limit = 8 } = req.query;
    const apiKey = process.env.TENOR_API_KEY;

    if (!apiKey) {
        // Return mock data or error if no key
        console.warn('TENOR_API_KEY missing in .env');
        // Return dummy response to prevent crash
        return res.json({ results: [] });
    }

    try {
        const response = await axios.get(`https://tenor.googleapis.com/v2/search`, {
            params: {
                q,
                key: apiKey,
                limit
            }
        });
        res.json(response.data);
    } catch (err) {
        console.error('Tenor API Error:', err.message);
        res.status(500).json({ error: 'Failed to fetch GIFs' });
    }
});

const redisClient = require('./redis');
const db = require('./db');

io.on('connection', (socket) => {
    console.log('User connected:', socket.id);

    socket.on('join_channel', async (data) => {
        // Handle both simple string (legacy) and object payload
        const channelId = typeof data === 'object' ? data.channelId : data;
        const userId = typeof data === 'object' ? data.userId : null;

        socket.join(channelId);
        console.log(`User ${socket.id} (ID: ${userId}) joined channel ${channelId}`);
        // Load recent messages with reactions
        try {
            const query = `
                SELECT m.*, u.username, u.public_signing_key,
                (
                    SELECT json_object_agg(res.emoji, res.data)
                    FROM (
                        SELECT r.emoji, json_build_object(
                            'count', COUNT(*)::int,
                            'me', BOOL_OR(r.user_id = $2)
                        ) as data
                        FROM message_reactions r
                        WHERE r.message_id = m.id
                        GROUP BY r.emoji
                    ) res
                ) as reactions
                FROM messages m 
                JOIN users u ON m.sender_id = u.id 
                WHERE m.channel_id = $1 
                ORDER BY m.created_at DESC LIMIT 50
            `;
            
            const result = await db.query(query, [channelId, userId]);
            socket.emit('recent_messages', result.rows.reverse());
        } catch (err) {
            console.error('Error fetching messages:', err);
        }
    });

    socket.on('send_message', async (data) => {
        // data: { channelId, senderId, ciphertext, nonce, signature, keyVersion }
        const { channelId, senderId, ciphertext, nonce, signature, keyVersion } = data;

        try {
            // Store in DB
            const result = await db.query(
                `INSERT INTO messages (channel_id, sender_id, ciphertext, nonce, signature, key_version)
                 VALUES ($1, $2, $3, $4, $5, $6) RETURNING id, created_at`,
                [channelId, senderId, ciphertext, nonce, signature, keyVersion]
            );

            const message = {
                id: result.rows[0].id,
                created_at: result.rows[0].created_at,
                ...data
            };

            // Get username and signing key for display/verification
            const userRes = await db.query('SELECT username, public_signing_key FROM users WHERE id = $1', [senderId]);
            if (userRes.rows.length > 0) {
                message.username = userRes.rows[0].username;
                message.public_signing_key = userRes.rows[0].public_signing_key;
            }

            // Broadcast to channel
            io.to(channelId).emit('new_message', message);
        } catch (err) {
            console.error('Error saving message:', err);
        }
    });

    socket.on('typing_start', (data) => {
        io.to(data.channelId).emit('typing_start', data);
    });

    socket.on('typing_stop', (data) => {
        io.to(data.channelId).emit('typing_stop', data);
    });

    // ... Message handling ...

    // Voice State Handling
    // Stores: channelId -> Set(serializedUser: {userId, username})
    // For simplicity: channelId -> [{userId, username}]
    
    // We need a global variable outside the connection loop, but for this file structure 'socket.on' is inside io.on
    // So we need to define it outside.
    // See defining it at top of file logic.
    

    // Reactions
    socket.on('add_reaction', async ({ channelId, messageId, userId, emoji }) => {
        try {
             if (!messageId || !userId || !emoji) return;

             const result = await db.query(
                `INSERT INTO message_reactions (message_id, user_id, emoji)
                 VALUES ($1, $2, $3)
                 ON CONFLICT (message_id, user_id, emoji) DO NOTHING`,
                [messageId, userId, emoji]
             );
            
             if (result.rowCount > 0) {
                io.to(channelId).emit('reaction_added', { messageId, userId, emoji });
             }
        } catch (err) {
            console.error('Error adding reaction:', err);
        }
    });

    socket.on('remove_reaction', async ({ channelId, messageId, userId, emoji }) => {
        try {
             if (!messageId || !userId || !emoji) return;

             const result = await db.query(
                `DELETE FROM message_reactions 
                 WHERE message_id = $1 AND user_id = $2 AND emoji = $3`,
                [messageId, userId, emoji]
             );
            
             if (result.rowCount > 0) {
                io.to(channelId).emit('reaction_removed', { messageId, userId, emoji });
             }
        } catch (err) {
            console.error('Error removing reaction:', err);
        }
    });

    socket.on('join_voice', (channelId) => { }); // Deprecated/Unused placeholder

    socket.on('voice_state_change', (data) => {
        // data: { channelId, userId, username, action: 'joined' | 'left' | 'state_update', isMuted, isDeafened }
        console.log(`Voice State Update: ${data.username} (${data.userId}) ${data.action} ${data.channelId}`);
        
        // Update Server State
        if (!global.voiceStates) global.voiceStates = {};
        
        const currentUsers = global.voiceStates[data.channelId] || [];

        if (data.action === 'joined') {
            const existingUser = currentUsers.find(u => u.userId === data.userId);
            if (!existingUser) {
                currentUsers.push({ 
                    userId: data.userId, 
                    username: data.username,
                    isMuted: data.isMuted || false,
                    isDeafened: data.isDeafened || false
                });
            } else {
                // Update existing on re-join (or just state sync)
                existingUser.isMuted = data.isMuted || false;
                existingUser.isDeafened = data.isDeafened || false;
            }
            global.voiceStates[data.channelId] = currentUsers;
        } else if (data.action === 'left') {
            const index = currentUsers.findIndex(u => u.userId === data.userId);
            if (index !== -1) {
                currentUsers.splice(index, 1);
                global.voiceStates[data.channelId] = currentUsers;
            }
        } else if (data.action === 'state_update') {
            const user = currentUsers.find(u => u.userId === data.userId);
            if (user) {
                if (data.isMuted !== undefined) user.isMuted = data.isMuted;
                if (data.isDeafened !== undefined) user.isDeafened = data.isDeafened;
                global.voiceStates[data.channelId] = currentUsers;
            }
        }

        io.emit('voice_state_update', data);
    });

    socket.on('request_voice_state', () => {
        socket.emit('full_voice_state', global.voiceStates || {});
    });

    socket.on('disconnect', () => {
        console.log('User disconnected:', socket.id);
        // TODO: Auto-leave logic would require mapping socketId -> userId/channelId
    });
});

const PORT = process.env.PORT || 3000;
server.listen(PORT, () => {
    console.log(`Server running on port ${PORT}`);
});