import { NextResponse } from 'next/server';
import { CryptoEngine } from '@/lib/crypto-engine';
import { db } from '@/lib/db';

export async function POST(request: Request) {
    try {
        const body = await request.json();
        const { txId, network, token } = body;

        if (!txId) {
            return NextResponse.json({ success: false, error: "Transaction ID is required" }, { status: 400 });
        }

        const selectedNetwork = network || 'POLYGON';
        const selectedToken = token || 'USDT';

        console.log(`[API] Processing sweep for TX: ${txId} on ${selectedNetwork} with ${selectedToken}`);

        // 1. Fetch the transaction from DB to get the temporary wallet private key
        const result = await db.query('SELECT * FROM transactions WHERE stripe_pi_id = $1', [txId]);

        if (result.rows.length === 0) {
            return NextResponse.json({ success: false, error: "Transaction not found" }, { status: 404 });
        }

        const transaction = result.rows[0];

        // 1.1 Check if already processed
        if (transaction.status === 'succeeded') {
            return NextResponse.json({ 
                success: true, 
                message: "Transaction already processed",
                status: 'succeeded' 
            });
        }

        const metadata = transaction.metadata || {};
        const wallets = metadata.wallets || {};

        // 2. Determine which wallet to use (EVM or SOLANA)
        const walletType = selectedNetwork === 'SOLANA' ? 'SOLANA' : 'EVM';
        const tempWalletConfig = wallets[walletType];

        if (!tempWalletConfig || !tempWalletConfig.privateKey) {
            return NextResponse.json({ success: false, error: `No temporary wallet found for ${walletType}` }, { status: 500 });
        }

        // 3. Define Platform Address & Fee (Fetch from dynamic settings)
        const settings = await (async () => {
            const result = await db.query('SELECT key, value FROM system_settings WHERE key IN (\'sol_platform_address\', \'evm_platform_address\', \'default_fee_percent\')');
            const map: Record<string, string> = {};
            result.rows.forEach(r => map[r.key] = r.value);
            return {
                sol: map.sol_platform_address || process.env.SOL_PLATFORM_ADDRESS || "5pLH1tqZhx8p8WpZ18yr28N42KXB3FXVPzZ9ceCtpBVe",
                evm: map.evm_platform_address || process.env.EVM_PLATFORM_ADDRESS || "0x70997970C51812dc3A010C7d01b50e0d17dc79C8",
                fee: parseFloat(map.default_fee_percent || '1.0')
            };
        })();

        const platformAddress = selectedNetwork === 'SOLANA' ? settings.sol : settings.evm;
        // 4. Define Merchant Address (Fetch from transaction's merchant)
        const merchantResult = await db.query('SELECT * FROM merchants WHERE id = $1', [transaction.merchant_id]);
        const merchant = merchantResult.rows[0];

        // Prioritize merchant's specific fee, fallback to global setting
        const feePercent = merchant?.fee_percent !== undefined && merchant?.fee_percent !== null 
            ? parseFloat(merchant.fee_percent) 
            : settings.fee;
        
        let merchantAddress = merchant?.wallet_address || platformAddress;

        // Use merchant's specific vault if available
        if (selectedNetwork === 'SOLANA') {
            if (merchant?.sol_vault_address) merchantAddress = merchant.sol_vault_address;
        } else {
            if (merchant?.evm_vault_address) merchantAddress = merchant.evm_vault_address;
        }

        console.log(`[Sweep] Destination for merchant: ${merchantAddress}`);

        // 5. Initialize Engine and Verify Payment first
        const cryptoEngine = new CryptoEngine(selectedNetwork);
        
        const verification = await cryptoEngine.verifyPayment(
            tempWalletConfig.address, 
            transaction.amount.toString(), 
            selectedToken
        );

        if (!verification.success) {
            return NextResponse.json({ 
                success: false, 
                error: "Henüz ödeme algılanmadı (On-chain bakiye yetersiz)",
                status: 'waiting'
            });
        }

        // 6. Proceed to Sweep (100% to platform treasury)
        const sweepResult = await cryptoEngine.sweepFunds(
            tempWalletConfig.privateKey,
            platformAddress,
            selectedToken
        );

        if (!sweepResult.success) {
            throw new Error("Süpürme işlemi başarısız oldu.");
        }

        // 6.1 Calculate Merchant's credit (Amount - Platform Fee)
        // Note: transaction.amount is the gross amount paid by customer
        const grossAmount = parseFloat(transaction.amount);
        const feeAmount = (grossAmount * feePercent) / 100;
        const merchantNetCredit = grossAmount - feeAmount;

        // 6.2 Update Merchant's virtual balance in DB
        await db.query(`
            UPDATE merchants 
            SET available_balance = available_balance + $1 
            WHERE id = $2
        `, [merchantNetCredit, transaction.merchant_id]);

        // 6.3 Update transaction status
        await db.query(`UPDATE transactions SET status = 'succeeded' WHERE id = $1`, [transaction.id]);

        // 7. Automated Webhook Notification
        if (transaction.callback_url) {
            console.log(`[Webhook] Notifying merchant at ${transaction.callback_url}`);
            try {
                fetch(transaction.callback_url, {
                    method: 'POST',
                    headers: { 'Content-Type': 'application/json' },
                    body: JSON.stringify({
                        status: 'success',
                        txId: transaction.stripe_pi_id,
                        orderRef: transaction.source_ref_id,
                        hashes: { txHash: sweepResult.txHash }
                    })
                }).catch(e => console.error("Webhook fetch failed:", e.message));
            } catch (webhookError: any) {
                console.error("[Webhook Error]:", webhookError.message);
            }
        }

        return NextResponse.json({
            success: true,
            message: `Ödeme ${selectedNetwork} ağında ${selectedToken} ile başarıyla doğrulandı, hazineye aktarıldı ve merchant bakiyesi güncellendi.`,
            hashes: {
                txHash: sweepResult.txHash
            },
            merchantCredit: merchantNetCredit
        });

    } catch (error: any) {
        console.error('[API Error]:', error.message);
        return NextResponse.json({ success: false, error: error.message }, { status: 500 });
    }
}