import { NextRequest, NextResponse } from 'next/server'
import { cookies } from 'next/headers'
import pool from '@/lib/db'
import { getNowPaymentsConfig } from '@/lib/nowpayments'

// POST /api/payments/create-invoice - Create a NOWPayments invoice
export async function POST(request: NextRequest) {
  try {
    // Get buyer_id from session cookie
    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 { drop_id, size } = body

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

    // Get drop details
    const [dropRows] = await pool.execute(
      'SELECT * FROM drops WHERE id = ?',
      [drop_id]
    )
    const drops = dropRows as any[]
    if (drops.length === 0) {
      return NextResponse.json(
        { error: 'Drop not found' },
        { status: 404 }
      )
    }

    const drop = drops[0]

    // Check inventory availability (but don't reserve yet - will reserve when payment confirmed)
    const [salesRows] = await pool.execute(
      'SELECT COALESCE(SUM(size), 0) as total_fill FROM sales WHERE drop_id = ?',
      [drop_id]
    )
    const salesData = salesRows as any[]
    const currentFill = salesData[0]?.total_fill || 0

    // Convert fill to the drop's unit for comparison
    let currentFillInDropUnit = currentFill
    let sizeInDropUnit = size
    if (drop.unit === 'kg') {
      currentFillInDropUnit = currentFill / 1000
      sizeInDropUnit = size / 1000
    }

    // Check if there's enough remaining inventory
    const remaining = drop.size - currentFillInDropUnit
    if (sizeInDropUnit > remaining) {
      return NextResponse.json(
        { error: 'Not enough inventory remaining' },
        { status: 400 }
      )
    }

    // Calculate price
    let priceAmount = 0
    if (drop.unit === 'kg') {
      priceAmount = (size / 1000) * drop.ppu
    } else {
      priceAmount = size * drop.ppu
    }

    // Round to 2 decimal places
    priceAmount = Math.round(priceAmount * 100) / 100

    // Generate order ID
    const orderId = `SALE-${Date.now()}-${drop_id}-${buyer_id}`

    // Get base URL for success/cancel redirects
    const baseUrl = process.env.NEXT_PUBLIC_BASE_URL || 
                   request.headers.get('origin') || 
                   'http://localhost:3420'

    // Get IPN callback URL from environment variable
    const ipnCallbackUrl = process.env.IPN_CALLBACK_URL
    if (!ipnCallbackUrl) {
      return NextResponse.json(
        { error: 'IPN_CALLBACK_URL environment variable is required' },
        { status: 500 }
      )
    }

    // Get NOWPayments config (testnet or production)
    const nowPaymentsConfig = getNowPaymentsConfig()

    // Create NOWPayments invoice
    const nowPaymentsResponse = await fetch(`${nowPaymentsConfig.baseUrl}/v1/invoice`, {
      method: 'POST',
      headers: {
        'x-api-key': nowPaymentsConfig.apiKey,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        price_amount: priceAmount,
        price_currency: nowPaymentsConfig.currency,
        order_id: orderId,
        order_description: `${drop.item} - ${size}g`,
        ipn_callback_url: ipnCallbackUrl,
        success_url: `${baseUrl}/?payment=success&order_id=${orderId}`,
        cancel_url: `${baseUrl}/?payment=cancelled&order_id=${orderId}`,
      }),
    })

    if (!nowPaymentsResponse.ok) {
      const error = await nowPaymentsResponse.json()
      console.error('NOWPayments error:', error)
      return NextResponse.json(
        { error: 'Failed to create payment invoice', details: error },
        { status: 500 }
      )
    }

    const invoice = await nowPaymentsResponse.json()

    // Store pending order (will create sale when payment is confirmed)
    const [result] = await pool.execute(
      'INSERT INTO pending_orders (payment_id, order_id, drop_id, buyer_id, size, price_amount, price_currency) VALUES (?, ?, ?, ?, ?, ?, ?)',
      [invoice.id, orderId, drop_id, buyer_id, size, priceAmount, nowPaymentsConfig.currency]
    )

    // Return invoice URL - sale will be created when payment is confirmed via IPN
    return NextResponse.json({
      invoice_url: invoice.invoice_url,
      payment_id: invoice.id,
      order_id: orderId,
    }, { status: 201 })
  } catch (error) {
    console.error('Error creating invoice:', error)
    return NextResponse.json(
      { error: 'Failed to create invoice' },
      { status: 500 }
    )
  }
}