import { NextRequest, NextResponse } from 'next/server';
import { db } from '@/lib/db';
import { PaymentProviderFactory } from '@/lib/payment-providers';
import { CryptoEngine } from '@/lib/crypto-engine';

export async function POST(req: NextRequest) {
    try {
        const { amount, currency, ref_id, callback_url, customer_name, customer_phone, merchant_id } = await req.json();

        if (!amount || !currency) {
            return NextResponse.json(
                { error: 'Tutar ve para birimi zorunludur.' },
                { status: 400 }
            );
        }

        let merchant;
        // 1. Fetch Merchant to check provider (Support both UUID and Short ID)
        if (merchant_id) {
            const isUUID = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(merchant_id);
            let result;
            if (isUUID) {
                result = await db.query('SELECT * FROM merchants WHERE id = $1', [merchant_id]);
            } else {
                result = await db.query('SELECT * FROM merchants WHERE short_id = $1', [merchant_id]);
            }

            if (result.rows.length === 0) {
                return NextResponse.json({ error: 'Firma bulunamadı.' }, { status: 404 });
            }
            merchant = result.rows[0];
        } else {
            // For demo purposes on the landing page, fetch any existing merchant
            const result = await db.query('SELECT * FROM merchants LIMIT 1');
            if (result.rows.length === 0) {
                return NextResponse.json({ error: 'Sistemde kayıtlı firma bulunamadı (Önce admin panelinden firma ekleyin).' }, { status: 404 });
            }
            merchant = result.rows[0];
        }

        // Use the actual UUID for DB operations
        const resolvedMerchantId = merchant.id;

        const provider = merchant.payment_provider || 'stripe';
        const useMock = process.env.NEXT_PUBLIC_USE_MOCK_PAYMENTS === 'true';

        let clientSecret = '';
        let providerTxId = '';
        let nextAction = 'none';
        let redirectUrl = '';

        if (useMock) {
            clientSecret = 'mock_secret_' + Math.random().toString(36).substring(7);
            providerTxId = clientSecret;
        } else {
            // 2. Use Factory to create intent based on provider
            const intent = await PaymentProviderFactory.createIntent(provider, {
                amount,
                currency,
                merchantId: resolvedMerchantId,
                refId: ref_id,
                customerName: customer_name,
                customerPhone: customer_phone,
                callbackUrl: callback_url,
                providerConfig: merchant.provider_config
            });

            clientSecret = intent.clientSecret;
            providerTxId = intent.providerTxId;
            nextAction = intent.nextAction || 'none';
            redirectUrl = intent.redirectUrl || '';
        }

        // 3. Generate Temporary Wallets for Crypto fallback
        const evmWallet = await CryptoEngine.createTemporaryWallet('POLYGON');
        const solWallet = await CryptoEngine.createTemporaryWallet('SOLANA');
        const tronWallet = await CryptoEngine.createTemporaryWallet('TRON');
        const btcWallet = await CryptoEngine.createTemporaryWallet('BITCOIN');

        const cryptoWallets = {
            EVM: { address: evmWallet.address, privateKey: evmWallet.privateKey },
            SOLANA: { address: solWallet.address, privateKey: solWallet.privateKey },
            TRON: { address: tronWallet.address, privateKey: tronWallet.privateKey },
            BITCOIN: { address: btcWallet.address, privateKey: btcWallet.privateKey }
        };

        // 4. Log transaction in Supabase
        try {
            await db.query(`
                INSERT INTO transactions (
                    amount, currency, status, stripe_pi_id, source_ref_id, 
                    customer_name, customer_phone, callback_url, merchant_id, 
                    provider, metadata
                ) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
            `, [
                amount, currency, 'pending', providerTxId, ref_id,
                customer_name, customer_phone, callback_url, resolvedMerchantId,
                provider, JSON.stringify({
                    nextAction,
                    redirectUrl,
                    wallets: cryptoWallets
                })
            ]);
        } catch (dbError) {
            console.error('Database log error:', dbError);
        }

        return NextResponse.json({
            clientSecret: clientSecret,
            nextAction,
            redirectUrl,
            provider,
            wallets: {
                EVM: evmWallet.address,
                SOLANA: solWallet.address,
                TRON: tronWallet.address,
                BITCOIN: btcWallet.address
            }
        });
    } catch (err: any) {
        console.error('Internal Error:', err);
        return NextResponse.json(
            { error: `Internal Server Error: ${err.message}` },
            { status: 500 }
        );
    }
}