import { mkdir, writeFile, unlink } from 'fs/promises'
import path from 'path'

const UPLOAD_DIR = path.join(process.cwd(), 'public', 'uploads')

export async function saveImage(
  productId: string,
  buffer: Buffer,
  originalFilename: string
): Promise<string> {
  const dir = path.join(UPLOAD_DIR, productId)
  await mkdir(dir, { recursive: true })
  const safeName = originalFilename.replace(/[^a-z0-9._-]/gi, '_').toLowerCase()
  const filename = `${Date.now()}-${safeName}`
  await writeFile(path.join(dir, filename), buffer)
  return `/uploads/${productId}/${filename}`
}

const IMAGE_MAGIC_BYTES: Record<string, (buf: Buffer) => boolean> = {
  'image/jpeg': (b) => b[0] === 0xff && b[1] === 0xd8 && b[2] === 0xff,
  'image/png': (b) => b[0] === 0x89 && b[1] === 0x50 && b[2] === 0x4e && b[3] === 0x47,
  'image/webp': (b) =>
    b[0] === 0x52 && b[1] === 0x49 && b[2] === 0x46 && b[3] === 0x46 &&
    b[8] === 0x57 && b[9] === 0x45 && b[10] === 0x42 && b[11] === 0x50,
  'image/x-icon': (b) => b[0] === 0x00 && b[1] === 0x00 && b[2] === 0x01 && b[3] === 0x00,
}

export async function validateImageMagicBytes(file: File, declaredType: string): Promise<boolean> {
  const checker = IMAGE_MAGIC_BYTES[declaredType]
  if (!checker) return false
  const arrayBuffer = await file.slice(0, 12).arrayBuffer()
  const buf = Buffer.from(arrayBuffer)
  return checker(buf)
}

export async function deleteImageFile(url: string): Promise<void> {
  const filePath = path.join(process.cwd(), 'public', url)
  await unlink(filePath)
}