const express = require('express');
const http = require('http');
const { Server } = require('socket.io');
const cors = require('cors');
const { db, con } = require('./db');

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

const server = http.createServer(app);
const io = new Server(server, {
    cors: {
        origin: "*", // Allow all for dev, restrict in prod
        methods: ["GET", "POST"]
    }
});

const CHANNELS = [
    { id: 'nebula', name: 'Nebula' },
    { id: 'solstice', name: 'Solstice' },
    { id: 'zenith', name: 'Zenith' },
    { id: 'aether', name: 'Aether' },
    { id: 'vortex', name: 'Vortex' },
    { id: 'borealis', name: 'Borealis' },
    { id: 'chronos', name: 'Chronos' },
    { id: 'elysium', name: 'Elysium' },
    { id: 'ignis', name: 'Ignis' },
    { id: 'nova', name: 'Nova' }
];

// Store connected users in memory for "Online" status
// Map<socketId, walletAddress>
const connectedSockets = new Map();

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

    socket.on('join', async ({ walletAddress, username }) => {
        console.log(`User joining: ${username} (${walletAddress})`);
        connectedSockets.set(socket.id, walletAddress);

        const now = new Date().toISOString();

        // First, check if this wallet already has a username
        con.prepare(`SELECT username FROM users WHERE wallet_address = ?`, (err, stmt) => {
            if (err) return console.error("Prepare error:", err);
            stmt.all(walletAddress, (err, rows) => {
                stmt.finalize();
                if (err) return console.error("Execute error:", err);

                if (rows.length > 0) {
                    // User exists, update last seen
                    const existingUsername = rows[0].username;
                    con.prepare(`UPDATE users SET last_seen = ? WHERE wallet_address = ?`, (err, uStmt) => {
                        if (err) return console.error("Prepare error:", err);
                        uStmt.run(now, walletAddress, (err) => {
                            uStmt.finalize();
                            if (err) console.error("Update error:", err);
                            socket.emit('usernameUpdated', { username: existingUsername });
                            broadcastUserList();
                        });
                    });
                } else {
                    // New user, check if username is taken
                    con.prepare(`SELECT wallet_address FROM users WHERE username = ?`, (err, nStmt) => {
                        if (err) return console.error("Prepare error:", err);
                        nStmt.all(username, (err, uRows) => {
                            nStmt.finalize();
                            if (err) return console.error("Check error:", err);

                            let finalUsername = username;
                            if (uRows.length > 0) {
                                finalUsername = `${username}_${walletAddress.slice(0, 4)}`;
                            }

                            con.prepare(`INSERT INTO users (wallet_address, username, last_seen) VALUES (?, ?, ?)`, (err, iStmt) => {
                                if (err) return console.error("Prepare error:", err);
                                iStmt.run(walletAddress, finalUsername, now, (err) => {
                                    iStmt.finalize();
                                    if (err) console.error("Insert error:", err);
                                    socket.emit('usernameUpdated', { username: finalUsername });
                                    broadcastUserList();
                                });
                            });
                        });
                    });
                }
            });
        });
    });

    socket.on('updateUsername', ({ walletAddress, newUsername, txId }) => {
        console.log(`User ${walletAddress} requesting username change to ${newUsername} (TX: ${txId})`);

        // Check if username is taken
        con.prepare(`SELECT wallet_address FROM users WHERE username = ?`, (err, stmt) => {
            if (err) return socket.emit('error', { message: 'Database error' });
            stmt.all(newUsername, (err, rows) => {
                stmt.finalize();
                if (err) return socket.emit('error', { message: 'Database error' });

                if (rows.length > 0) {
                    return socket.emit('error', { message: 'Username already taken' });
                }

                // Update username
                con.prepare(`UPDATE users SET username = ? WHERE wallet_address = ?`, (err, uStmt) => {
                    if (err) return socket.emit('error', { message: 'Failed to update username' });
                    uStmt.run(newUsername, walletAddress, (err) => {
                        uStmt.finalize();
                        if (err) return socket.emit('error', { message: 'Failed to update username' });

                        console.log(`Username updated for ${walletAddress} to ${newUsername}`);
                        socket.emit('usernameUpdated', { username: newUsername });
                        broadcastUserList();

                        // Also broadcast a system message about the change
                        const systemMsg = {
                            id: Date.now(),
                            channelId: 'nebula',
                            walletAddress: 'system',
                            username: 'System',
                            content: `${walletAddress.slice(0, 4)}... changed their name to ${newUsername}`,
                            timestamp: new Date().toISOString()
                        };
                        io.emit('newMessage', systemMsg);
                    });
                });
            });
        });
    });

    socket.on('sendMessage', ({ channelId, walletAddress, content, txId }) => {
        if (!content || content.trim() === '') return;
        console.log(`Message from ${walletAddress} in ${channelId} (TX: ${txId}): ${content}`);
        const timestamp = new Date().toISOString();

        con.prepare(`INSERT INTO messages (id, channel_id, wallet_address, content, timestamp, tx_id) 
                VALUES (nextval('seq_msg_id'), ?, ?, ?, ?, ?) RETURNING id`, (err, stmt) => {
            if (err) return console.error("Prepare error:", err);
            stmt.all(channelId, walletAddress, content, timestamp, txId, (err, rows) => {
                stmt.finalize();
                if (err) {
                    console.error("Error saving message:", err);
                    return;
                }
                const msgId = rows[0].id;

                con.prepare(`SELECT username FROM users WHERE wallet_address = ?`, (err, uStmt) => {
                    if (err) return console.error("Prepare error:", err);
                    uStmt.all(walletAddress, (err, uRows) => {
                        uStmt.finalize();
                        const username = uRows.length > 0 ? uRows[0].username : walletAddress.slice(0, 4) + '...';
                        const message = {
                            id: msgId,
                            channelId,
                            walletAddress,
                            username,
                            content,
                            timestamp,
                            txId
                        };
                        io.emit('newMessage', message);
                    });
                });
            });
        });
    });

    socket.on('getProfile', (walletAddress) => {
        console.log(`Fetching profile for ${walletAddress}`);
        con.prepare(`SELECT wallet_address, username, bio, banner_color, last_seen FROM users WHERE wallet_address = ?`, (err, stmt) => {
            if (err) return socket.emit('error', { message: 'Database error' });
            stmt.all(walletAddress, (err, rows) => {
                stmt.finalize();
                if (err || rows.length === 0) return socket.emit('error', { message: 'User not found' });

                const user = rows[0];
                // Fetch posts
                con.prepare(`SELECT * FROM posts WHERE wallet_address = ? ORDER BY timestamp DESC LIMIT 50`, (err, pStmt) => {
                    if (err) return socket.emit('profileData', { ...user, posts: [] });
                    pStmt.all(walletAddress, (err, posts) => {
                        pStmt.finalize();
                        socket.emit('profileData', { ...user, posts: posts || [] });
                    });
                });
            });
        });
    });

    socket.on('updateProfile', ({ walletAddress, bio, bannerColor }) => {
        console.log(`Updating profile for ${walletAddress}`);
        con.prepare(`UPDATE users SET bio = ?, banner_color = ? WHERE wallet_address = ?`, (err, stmt) => {
            if (err) return socket.emit('error', { message: 'Database error' });
            stmt.run(bio, bannerColor, walletAddress, (err) => {
                stmt.finalize();
                if (err) return socket.emit('error', { message: 'Failed to update profile' });
                socket.emit('profileUpdated', { bio, bannerColor });
                broadcastUserList();
            });
        });
    });

    socket.on('createPost', ({ walletAddress, content }) => {
        if (!content || content.trim() === '') return;
        console.log(`New post from ${walletAddress}: ${content}`);
        const timestamp = new Date().toISOString();

        con.prepare(`INSERT INTO posts (id, wallet_address, content, timestamp) VALUES (nextval('seq_post_id'), ?, ?, ?)`, (err, stmt) => {
            if (err) return socket.emit('error', { message: 'Database error' });
            stmt.run(walletAddress, content, timestamp, (err) => {
                stmt.finalize();
                if (err) return socket.emit('error', { message: 'Failed to create post' });

                // Fetch all posts to broadcast update or just emit the new one
                // For simplicity, we'll just tell the user it was created
                socket.emit('postCreated', { content, timestamp });

                // If we want a live feed, we could broadcast to a "profile room"
                // For now, the user can just refresh or we emit to them
            });
        });
    });

    socket.on('toggleReaction', ({ messageId, walletAddress, emoji }) => {
        console.log(`Toggling reaction: ${emoji} on message ${messageId} by ${walletAddress}`);
        con.prepare(`SELECT * FROM reactions WHERE message_id = ? AND wallet_address = ? AND emoji = ?`, (err, stmt) => {
            if (err) return console.error("Prepare error:", err);
            stmt.all(messageId, walletAddress, emoji, (err, rows) => {
                stmt.finalize();
                if (err) return console.error("Error checking reaction:", err);

                if (rows.length > 0) {
                    con.prepare(`DELETE FROM reactions WHERE message_id = ? AND wallet_address = ? AND emoji = ?`, (err, dStmt) => {
                        if (err) return console.error("Prepare error:", err);
                        dStmt.run(messageId, walletAddress, emoji, (err) => {
                            dStmt.finalize();
                            if (err) return console.error("Error removing reaction:", err);
                            broadcastReactions(messageId);
                        });
                    });
                } else {
                    con.prepare(`INSERT INTO reactions (message_id, wallet_address, emoji) VALUES (?, ?, ?)`, (err, iStmt) => {
                        if (err) return console.error("Prepare error:", err);
                        iStmt.run(messageId, walletAddress, emoji, (err) => {
                            iStmt.finalize();
                            if (err) return console.error("Error adding reaction:", err);
                            broadcastReactions(messageId);
                        });
                    });
                }
            });
        });
    });

    function broadcastReactions(messageId) {
        console.log("Broadcasting reactions for message:", messageId);
        con.prepare(`SELECT emoji, wallet_address FROM reactions WHERE message_id = ?`, (err, stmt) => {
            if (err) return console.error("Prepare error:", err);
            stmt.all(messageId, (err, rows) => {
                stmt.finalize();
                if (err) {
                    console.error("Error fetching reactions for broadcast:", err);
                    return;
                }
                console.log(`Found ${rows.length} reactions, emitting updateReactions`);
                io.emit('updateReactions', { messageId, reactions: rows });
            });
        });
    }

    socket.on('disconnect', () => {
        const walletAddress = connectedSockets.get(socket.id);
        connectedSockets.delete(socket.id);
        if (walletAddress) {
            // Update last seen?
            broadcastUserList();
        }
        console.log('User disconnected:', socket.id);
    });

    function broadcastUserList() {
        // Get all users from DB to show offline ones too
        con.prepare(`SELECT wallet_address, username, last_seen FROM users`, (err, stmt) => {
            if (err) return console.error("Prepare error:", err);
            stmt.all((err, rows) => {
                stmt.finalize();
                if (err) return;

                const onlineWallets = new Set(connectedSockets.values());

                const users = rows.map(u => ({
                    ...u,
                    online: onlineWallets.has(u.wallet_address)
                }));

                io.emit('userList', users);
            });
        });
    }
});

app.get('/api/channels', (req, res) => {
    res.json(CHANNELS);
});

app.get('/api/messages/:channelId', (req, res) => {
    const { channelId } = req.params;
    con.prepare(`
        SELECT m.*, u.username 
        FROM messages m 
        LEFT JOIN users u ON m.wallet_address = u.wallet_address 
        WHERE m.channel_id = ? 
        ORDER BY m.timestamp ASC 
        LIMIT 100
    `, (err, stmt) => {
        if (err) return res.status(500).json({ error: err.message });
        stmt.all(channelId, (err, messages) => {
            stmt.finalize();
            if (err) return res.status(500).json({ error: err.message });

            // Fetch reactions for all these messages
            con.prepare(`SELECT * FROM reactions WHERE message_id IN (SELECT id FROM messages WHERE channel_id = ?)`, (err, rStmt) => {
                if (err) return res.json(messages.map(m => ({ ...m, reactions: [] })));
                rStmt.all(channelId, (err, reactions) => {
                    rStmt.finalize();
                    if (err) return res.json(messages.map(m => ({ ...m, reactions: [] })));

                    const messagesWithReactions = messages.map(m => ({
                        ...m,
                        reactions: reactions.filter(r => r.message_id === m.id)
                    }));
                    res.json(messagesWithReactions);
                });
            });
        });
    });
});

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