import { NextRequest, NextResponse } from 'next/server'
import jwt from 'jsonwebtoken'
import crypto from 'crypto'

interface AddBalanceRequest {
  amount: number
  currency: 'INR' | 'USD'
}

interface UserTokenPayload {
  siliconId: string
  email: string
  type: string
}

/**
 * Add Balance API
 * Initiates "Add Balance" transaction for user accounts
 */
export async function POST(request: NextRequest) {
  try {
    // Verify user authentication
    const token = request.cookies.get('accessToken')?.value
    if (!token) {
      return NextResponse.json(
        { success: false, message: 'Authentication required' },
        { status: 401 }
      )
    }

    const secret = process.env.JWT_SECRET || 'your-secret-key'
    const user = jwt.verify(token, secret) as UserTokenPayload

    // Parse request body
    const body: AddBalanceRequest = await request.json()
    const { amount, currency } = body

    // Validate input
    if (!amount || amount <= 0 || !['INR', 'USD'].includes(currency)) {
      return NextResponse.json(
        { success: false, message: 'Invalid amount or currency' },
        { status: 400 }
      )
    }

    // Validate amount limits
    const minAmount = currency === 'INR' ? 100 : 2 // Minimum ₹100 or $2
    const maxAmount = currency === 'INR' ? 100000 : 1500 // Maximum ₹1,00,000 or $1500

    if (amount < minAmount || amount > maxAmount) {
      return NextResponse.json(
        {
          success: false,
          message: `Amount must be between ${currency === 'INR' ? '₹' : '$'}${minAmount} and ${currency === 'INR' ? '₹' : '$'}${maxAmount}`,
        },
        { status: 400 }
      )
    }

    try {
      // Generate unique transaction ID
      const transactionId = generateTransactionId()

      // TODO: Save transaction to database
      // In real implementation:
      // await saveAddBalanceTransaction({
      //   siliconId: user.siliconId,
      //   amount,
      //   currency,
      //   transaction_id: transactionId,
      //   status: 'pending'
      // })

      // Mock database save for demo
      await mockSaveAddBalanceTransaction(user.siliconId, amount, currency, transactionId)

      // PayU configuration
      const merchantKey = process.env.PAYU_MERCHANT_KEY || 'test-key'
      const merchantSalt = process.env.PAYU_MERCHANT_SALT || 'test-salt'
      const payuUrl = process.env.PAYU_URL || 'https://test.payu.in/_payment'

      // Prepare payment data
      const productinfo = 'add_balance'
      const firstname = 'Customer'
      const email = user.email
      const phone = '9876543210' // Default phone or fetch from user profile

      // Success and failure URLs for balance transactions
      const baseUrl = process.env.NEXT_PUBLIC_BASE_URL || 'http://localhost:4024'
      const surl = `${baseUrl}/api/balance/success`
      const furl = `${baseUrl}/api/balance/failure`

      // Generate PayU hash
      const hashString = `${merchantKey}|${transactionId}|${amount}|${productinfo}|${firstname}|${email}|||||||||||${merchantSalt}`
      const hash = crypto.createHash('sha512').update(hashString).digest('hex')

      // Return payment form data for frontend submission
      const paymentData = {
        success: true,
        transaction_id: transactionId,
        currency,
        payment_url: payuUrl,
        form_data: {
          key: merchantKey,
          txnid: transactionId,
          amount: amount.toFixed(2),
          productinfo,
          firstname,
          email,
          phone,
          surl,
          furl,
          hash,
          service_provider: 'payu_paisa',
        },
      }

      return NextResponse.json(paymentData)
    } catch (dbError) {
      console.error('Database error during add balance:', dbError)
      return NextResponse.json(
        { success: false, message: 'Failed to initiate balance transaction' },
        { status: 500 }
      )
    }
  } catch (error) {
    console.error('Add balance error:', error)
    return NextResponse.json(
      { success: false, message: 'Add balance initiation failed' },
      { status: 500 }
    )
  }
}

/**
 * Get Add Balance History
 */
export async function GET(request: NextRequest) {
  try {
    // Verify user authentication
    const token = request.cookies.get('accessToken')?.value
    if (!token) {
      return NextResponse.json(
        { success: false, message: 'Authentication required' },
        { status: 401 }
      )
    }

    const secret = process.env.JWT_SECRET || 'your-secret-key'
    const user = jwt.verify(token, secret) as UserTokenPayload

    // TODO: Fetch balance history from database
    // In real implementation:
    // const history = await getBalanceHistory(user.siliconId)

    // Mock balance history for demo
    const mockHistory = await getMockBalanceHistory(user.siliconId)

    return NextResponse.json({
      success: true,
      balance_history: mockHistory,
    })
  } catch (error) {
    console.error('Get balance history error:', error)
    return NextResponse.json(
      { success: false, message: 'Failed to fetch balance history' },
      { status: 500 }
    )
  }
}

// Utility functions
function generateTransactionId(): string {
  const timestamp = Date.now().toString(36)
  const random = Math.random().toString(36).substr(2, 5)
  return `bal_${timestamp}${random}`.toUpperCase()
}

// Mock functions for demonstration
async function mockSaveAddBalanceTransaction(
  siliconId: string,
  amount: number,
  currency: string,
  transactionId: string
) {
  console.log(`Mock DB Save: Add Balance Transaction`)
  console.log(`SiliconID: ${siliconId}, Amount: ${amount} ${currency}, TxnID: ${transactionId}`)

  // Mock database record
  const transaction = {
    id: Date.now(),
    silicon_id: siliconId,
    transaction_id: transactionId,
    amount,
    currency,
    status: 'pending',
    created_at: new Date(),
    updated_at: new Date(),
  }

  // Mock delay
  await new Promise((resolve) => setTimeout(resolve, 100))
  return transaction
}

async function getMockBalanceHistory(siliconId: string) {
  // Mock balance transaction history
  return [
    {
      id: 1,
      transaction_id: 'BAL_123ABC',
      amount: 1000,
      currency: 'INR',
      status: 'success',
      created_at: '2025-01-15T10:30:00Z',
      updated_at: '2025-01-15T10:31:00Z',
    },
    {
      id: 2,
      transaction_id: 'BAL_456DEF',
      amount: 500,
      currency: 'INR',
      status: 'failed',
      created_at: '2025-01-10T14:20:00Z',
      updated_at: '2025-01-10T14:21:00Z',
    },
    {
      id: 3,
      transaction_id: 'BAL_789GHI',
      amount: 2000,
      currency: 'INR',
      status: 'success',
      created_at: '2025-01-05T09:15:00Z',
      updated_at: '2025-01-05T09:16:00Z',
    },
  ]
}