import { NextRequest, NextResponse } from 'next/server'
import { cookies } from 'next/headers'
import pool from '@/lib/db'
import { ALLOWED_PAYMENT_CURRENCIES, isAllowedCurrency } from '@/lib/payment-currencies'

// POST /api/referral-points/redeem - Redeem referral points to crypto
export async function POST(request: NextRequest) {
  const connection = await pool.getConnection()
  
  try {
    const cookieStore = await cookies()
    const buyerIdCookie = cookieStore.get('buyer_id')?.value

    if (!buyerIdCookie) {
      return NextResponse.json(
        { error: 'Authentication required' },
        { status: 401 }
      )
    }

    const buyer_id = parseInt(buyerIdCookie, 10)

    const body = await request.json()
    const { points, crypto_currency, wallet_address } = body

    // Validate required fields
    if (!points || !crypto_currency || !wallet_address) {
      return NextResponse.json(
        { error: 'Missing required fields: points, crypto_currency, wallet_address' },
        { status: 400 }
      )
    }

    const pointsToRedeem = parseFloat(points)
    const normalizedCryptoCurrency = crypto_currency.toLowerCase().trim()
    const normalizedWalletAddress = wallet_address.trim()

    // Validate points amount
    if (isNaN(pointsToRedeem) || pointsToRedeem <= 0) {
      return NextResponse.json(
        { error: 'Points must be a positive number' },
        { status: 400 }
      )
    }

    // Validate crypto currency - only USDT (SOL) is allowed for redemption
    if (normalizedCryptoCurrency !== 'usdtsol') {
      return NextResponse.json(
        { error: 'Only USDT (SOL) is supported for point redemption' },
        { status: 400 }
      )
    }

    // Basic wallet address validation (non-empty, reasonable length)
    if (normalizedWalletAddress.length < 10 || normalizedWalletAddress.length > 255) {
      return NextResponse.json(
        { error: 'Invalid wallet address format' },
        { status: 400 }
      )
    }

    await connection.beginTransaction()

    try {
      // Get buyer's current points balance
      const [buyerRows] = await connection.execute(
        'SELECT referral_points FROM buyers WHERE id = ? FOR UPDATE',
        [buyer_id]
      )
      const buyers = buyerRows as any[]
      
      if (buyers.length === 0) {
        await connection.rollback()
        return NextResponse.json(
          { error: 'Buyer not found' },
          { status: 404 }
        )
      }

      const currentPoints = parseFloat(buyers[0].referral_points) || 0

      // Get redemption settings
      const [settingsRows] = await connection.execute(
        'SELECT setting_key, setting_value FROM referral_settings'
      )
      const settings = settingsRows as any[]
      
      const pointsToCryptoChf = parseFloat(
        settings.find(s => s.setting_key === 'points_to_crypto_chf')?.setting_value || '100'
      )
      const minRedemptionPoints = parseFloat(
        settings.find(s => s.setting_key === 'min_redemption_points')?.setting_value || '1000'
      )

      // Validate minimum redemption amount
      if (pointsToRedeem < minRedemptionPoints) {
        await connection.rollback()
        return NextResponse.json(
          { error: `Minimum redemption is ${minRedemptionPoints} points` },
          { status: 400 }
        )
      }

      // Validate user has enough points
      if (currentPoints < pointsToRedeem) {
        await connection.rollback()
        return NextResponse.json(
          { error: 'Insufficient points' },
          { status: 400 }
        )
      }

      // Calculate CHF value of points
      const chfValue = pointsToRedeem / pointsToCryptoChf

      // TODO: Get current crypto exchange rate
      // For now, we'll use a placeholder that would need to be replaced with actual exchange rate API
      // This should fetch the current rate from an exchange API (e.g., CoinGecko, Binance, etc.)
      const cryptoExchangeRate = await getCryptoExchangeRate(normalizedCryptoCurrency, 'chf')
      
      if (!cryptoExchangeRate) {
        await connection.rollback()
        return NextResponse.json(
          { error: 'Failed to fetch exchange rate. Please try again later.' },
          { status: 500 }
        )
      }

      // Calculate crypto amount
      const cryptoAmount = chfValue / cryptoExchangeRate

      // Deduct points from buyer's balance
      const newBalance = currentPoints - pointsToRedeem
      await connection.execute(
        'UPDATE buyers SET referral_points = ? WHERE id = ?',
        [newBalance, buyer_id]
      )

      // Create redemption record
      const [redemptionResult] = await connection.execute(
        `INSERT INTO point_redemptions 
         (buyer_id, points, crypto_currency, wallet_address, crypto_amount, status) 
         VALUES (?, ?, ?, ?, ?, 'pending')`,
        [buyer_id, pointsToRedeem, normalizedCryptoCurrency, normalizedWalletAddress, cryptoAmount]
      )
      const redemptionId = (redemptionResult as any).insertId

      // Record transaction
      await connection.execute(
        `INSERT INTO referral_point_transactions 
         (buyer_id, points, type, description) 
         VALUES (?, ?, 'redeemed', ?)`,
        [
          buyer_id,
          pointsToRedeem,
          `Points redeemed to ${normalizedCryptoCurrency.toUpperCase()} (Redemption #${redemptionId})`
        ]
      )

      await connection.commit()

      return NextResponse.json({
        success: true,
        redemption_id: redemptionId,
        points_redeemed: pointsToRedeem,
        crypto_currency: normalizedCryptoCurrency,
        crypto_amount: cryptoAmount,
        chf_value: chfValue,
        new_balance: newBalance,
        message: 'Redemption request created successfully. Your crypto will be sent within 24-48 hours.'
      })
    } catch (error) {
      await connection.rollback()
      throw error
    }
  } catch (error: any) {
    console.error('Error redeeming points:', error)
    return NextResponse.json(
      { error: error.message || 'Failed to redeem points' },
      { status: 500 }
    )
  } finally {
    connection.release()
  }
}

// Helper function to get crypto exchange rate
// TODO: Replace with actual exchange rate API integration
async function getCryptoExchangeRate(crypto: string, fiat: string): Promise<number | null> {
  try {
    // Placeholder: In production, this should call a real exchange rate API
    // Examples: CoinGecko, Binance, Coinbase, etc.
    
    // For now, return a mock rate (this should be replaced)
    // In production, you would do something like:
    // const response = await fetch(`https://api.coingecko.com/api/v3/simple/price?ids=${crypto}&vs_currencies=${fiat}`)
    // const data = await response.json()
    // return data[crypto][fiat]
    
    // Mock rates (CHF per 1 unit of crypto) - REPLACE WITH REAL API
    const mockRates: Record<string, number> = {
      'btc': 85000,
      'eth': 2500,
      'sol': 100,
      'xrp': 0.6,
      'bnbbsc': 300,
      'usdterc20': 0.9, // Approximate CHF per USDT
      'usdtsol': 0.9, // Approximate CHF per USDT on Solana
    }
    
    return mockRates[crypto.toLowerCase()] || null
  } catch (error) {
    console.error('Error fetching exchange rate:', error)
    return null
  }
}