require('dotenv').config();
const express = require('express');
const cors = require('cors');
const crypto = require('crypto');
const path = require('path');
const bot = require('./bot');
const db = require('./db');
const { spin } = require('./games/slots');
const { rollDice } = require('./games/dice');

const app = express();
const PORT = process.env.PORT || 7860;
const BOT_TOKEN = process.env.TELEGRAM_BOT_TOKEN;
const ADMIN_IDS = (process.env.ADMIN_IDS || '').split(',').map(s => s.trim());

app.use(cors());
app.use(express.json());
app.use(express.static(path.join(__dirname, 'public')));

// ── Validate Telegram initData ───────────────────────────────────────────────
function validateInitData(initData) {
    try {
        const params = new URLSearchParams(initData);
        const hash = params.get('hash');
        params.delete('hash');
        const dataCheckString = [...params.entries()]
            .sort(([a], [b]) => a.localeCompare(b))
            .map(([k, v]) => `${k}=${v}`)
            .join('\n');
        const secret = crypto.createHmac('sha256', 'WebAppData').update(BOT_TOKEN).digest();
        const expectedHash = crypto.createHmac('sha256', secret).update(dataCheckString).digest('hex');
        return hash === expectedHash;
    } catch {
        return false;
    }
}

function parseInitData(initData) {
    const params = new URLSearchParams(initData);
    const userStr = params.get('user');
    if (!userStr) return null;
    return JSON.parse(userStr);
}

// ── Auth middleware ──────────────────────────────────────────────────────────
function authMiddleware(req, res, next) {
    const initData = req.headers['x-init-data'];
    if (!initData) return res.status(401).json({ error: 'Missing initData' });

    // Dev mode: skip validation if token not set
    if (BOT_TOKEN && !validateInitData(initData)) {
        return res.status(403).json({ error: 'Invalid initData' });
    }

    const tgUser = parseInitData(initData);
    if (!tgUser) return res.status(400).json({ error: 'No user in initData' });

    req.tgUser = tgUser;
    db.upsertUser(tgUser.id, tgUser.username, tgUser.first_name);
    next();
}

// ── Routes ───────────────────────────────────────────────────────────────────

// Auth check
app.post('/api/auth', (req, res) => {
    const { initData } = req.body;
    if (!initData) return res.status(400).json({ error: 'Missing initData' });
    const valid = !BOT_TOKEN || validateInitData(initData);
    if (!valid) return res.status(403).json({ error: 'Invalid' });
    const tgUser = parseInitData(initData);
    db.upsertUser(tgUser.id, tgUser.username, tgUser.first_name);
    res.json({ ok: true, user: tgUser });
});

// Get current user
app.get('/api/me', authMiddleware, (req, res) => {
    const user = db.getUser(req.tgUser.id);
    res.json(user);
});

// Spin slots
app.post('/api/spin', authMiddleware, (req, res) => {
    const { bet, isDemo } = req.body;
    const betAmount = parseInt(bet) || 10;

    if (!isDemo && betAmount < 5) return res.status(400).json({ error: 'Minimum bet is 5 credits' });

    const user = db.getUser(req.tgUser.id);

    // If not demo, check balance and if they have a pending prize
    if (!isDemo) {
        if (user.pending_prize_value) return res.status(400).json({ error: 'You have a pending gift! Claim or Retry first.' });
        if (!user || user.balance < betAmount) return res.status(400).json({ error: 'Insufficient balance' });

        db.deductBalance(req.tgUser.id, betAmount, 'Slot spin bet');
    }

    const result = spin(betAmount, !!isDemo);

    if (!isDemo) {
        db.recordBetWin(req.tgUser.id, result.isWin ? result.payout : 0, betAmount);
        if (result.isWin) {
            // Don't add balance yet, set pending prize
            db.setPendingPrize(req.tgUser.id, result.prizeName, result.payout);
        }
    }

    const updated = db.getUser(req.tgUser.id);
    res.json({
        ...result,
        newBalance: updated.balance,
        hasPending: !!updated.pending_prize_value,
        pendingPrize: updated.pending_prize_name
    });
});

// Claim pending prize
app.post('/api/claim', async (req, res) => {
    try {
        const user = db.getUser(req.tgUser.id);
        if (!user || (!user.pending_prize_value && !user.pending_gift_id)) {
            return res.status(400).json({ error: 'No prize to claim' });
        }

        const prize = db.claimPrize(user.tg_id);
        
        // Handle native gift fulfillment
        if (prize.gift_id) {
            try {
                // Call bot api directly
                const bot = require('./bot');
                await bot.api.sendGift(user.tg_id, prize.gift_id, "Congratulations from GiftBot! 🎆");
                db.logSentGift(user.tg_id, prize.gift_id, prize.name);
            } catch (e) {
                console.error('API claim sendGift error:', e.message);
                // Credit fallback on failure
                db.addBalance(user.tg_id, 100, "Refund: Gift delivery failed");
            }
        }

        const updated = db.getUser(user.tg_id);
        res.json({ success: true, prize, newBalance: updated.balance });
    } catch (e) {
        res.status(500).json({ error: e.message });
    }
});

// Retry (Gamble) pending prize
app.post('/api/retry', async (req, res) => {
    try {
        const user = db.getUser(req.tgUser.id);
        if (!user || (!user.pending_prize_value && !user.pending_gift_id)) {
            return res.status(400).json({ error: 'No prize to retry' });
        }

        const originalBet = user.pending_prize_value ? user.pending_prize_value / 10 : 10;
        db.clearPendingPrize(user.tg_id);

        const result = spin(originalBet, false);
        if (result.isWin) {
            // Find a real gift for the re-spin win
            const bot = require('./bot');
            const cachedGifts = await bot.api.getAvailableGifts().catch(() => []);
            const targetGift = cachedGifts.find(g => g.name === result.prizeName) || (cachedGifts.length ? cachedGifts[0] : null);
            
            db.setPendingPrize(user.tg_id, result.prizeName, result.payout, targetGift?.id);
        }

        const updated = db.getUser(user.tg_id);
        res.json({ ...result, newBalance: updated.balance });
    } catch (e) {
        res.status(500).json({ error: e.message });
    }
});

// Dice bet
app.post('/api/bet', authMiddleware, (req, res) => {
    const { bet, guess } = req.body;
    const betAmount = parseInt(bet) || 10;
    const guessNum = parseInt(guess);

    if (betAmount < 5) return res.status(400).json({ error: 'Minimum bet is 5 credits' });
    if (!guessNum || guessNum < 1 || guessNum > 6) return res.status(400).json({ error: 'Guess must be 1-6' });

    const user = db.getUser(req.tgUser.id);
    if (!user || user.balance < betAmount) return res.status(400).json({ error: 'Insufficient balance' });

    db.deductBalance(req.tgUser.id, betAmount, 'Dice bet');
    const result = rollDice(betAmount, guessNum);
    db.recordBetWin(req.tgUser.id, result.payout, betAmount);

    if (result.isWin) {
        db.addBalance(req.tgUser.id, result.payout, 'Dice win x5');
    }

    const updated = db.getUser(req.tgUser.id);
    res.json({ ...result, newBalance: updated.balance });
});

// Send gift
app.post('/api/gift', authMiddleware, (req, res) => {
    const { toUsername, amount } = req.body;
    const giftAmount = parseInt(amount);

    if (!toUsername || !giftAmount || giftAmount < 1) {
        return res.status(400).json({ error: 'Invalid gift parameters' });
    }

    const sender = db.getUser(req.tgUser.id);
    if (!sender || sender.balance < giftAmount) return res.status(400).json({ error: 'Insufficient balance' });

    const cleaned = toUsername.replace('@', '');
    const allUsers = db.getAllUsers();
    const target = allUsers.find(u => u.username === cleaned);
    if (!target) return res.status(404).json({ error: 'User not found. They must start the bot first.' });
    if (target.tg_id === req.tgUser.id) return res.status(400).json({ error: 'Cannot gift yourself' });

    db.deductBalance(req.tgUser.id, giftAmount, `Gift to @${cleaned}`);
    db.addBalance(target.tg_id, giftAmount, `Gift from @${req.tgUser.username || 'someone'}`);
    db.logGift(req.tgUser.id, target.tg_id, req.tgUser.username, cleaned, giftAmount);

    // Notify recipient via bot
    bot.api.sendMessage(target.tg_id,
        `🎁 *You received a gift!*\n\n@${req.tgUser.username || req.tgUser.first_name} sent you *${giftAmount} credits*!`,
        { parse_mode: 'Markdown' }
    ).catch(() => { });

    const updated = db.getUser(req.tgUser.id);
    res.json({ ok: true, newBalance: updated.balance });
});

// Transaction history
app.get('/api/history', authMiddleware, (req, res) => {
    const history = db.getHistory(req.tgUser.id, 30);
    res.json(history);
});

// Leaderboard
app.get('/api/leaderboard', (req, res) => {
    const board = db.getLeaderboard(10);
    res.json(board);
});

// Admin stats (protected by tg_id)
app.get('/api/admin/stats', authMiddleware, (req, res) => {
    if (!ADMIN_IDS.includes(String(req.tgUser.id))) {
        return res.status(403).json({ error: 'Forbidden' });
    }
    res.json(db.getStats());
});

// Admin: all users
app.get('/api/admin/users', authMiddleware, (req, res) => {
    if (!ADMIN_IDS.includes(String(req.tgUser.id))) {
        return res.status(403).json({ error: 'Forbidden' });
    }
    res.json(db.getAllUsers());
});

// ── Start bot polling + HTTP server ─────────────────────────────────────────
app.listen(PORT, () => {
    console.log(`🌐 Server running on port ${PORT}`);
    console.log(`🎮 Mini App: http://localhost:${PORT}`);
});

bot.start({
    onStart: (info) => console.log(`🤖 Bot @${info.username} started`)
});