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

// POST /api/sales - Create a new sale
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. Please log in to make a purchase.' },
        { 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 }
      )
    }

    // Validate size is positive
    if (size <= 0) {
      return NextResponse.json(
        { error: 'Size must be greater than 0' },
        { status: 400 }
      )
    }

    // Check if drop exists and get its 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]

    // Calculate current fill from sales
    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') {
      // If drop unit is kg, convert sales (in grams) to 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 }
      )
    }

    // Insert new sale
    const [result] = await pool.execute(
      'INSERT INTO sales (drop_id, buyer_id, size) VALUES (?, ?, ?)',
      [drop_id, buyer_id, size]
    )

    const insertId = (result as any).insertId

    // Fetch the created sale
    const [rows] = await pool.execute('SELECT * FROM sales WHERE id = ?', [
      insertId,
    ])

    const sales = rows as any[]
    return NextResponse.json(sales[0], { status: 201 })
  } catch (error) {
    console.error('Error creating sale:', error)
    return NextResponse.json(
      { error: 'Failed to create sale' },
      { status: 500 }
    )
  }
}