import { mkdir, writeFile } from 'node:fs/promises'
import { join } from 'node:path'
import { createError, readMultipartFormData } from 'h3'
import sharp from 'sharp'
import { requireAdminSession } from '../../../../utils/admin-auth'
import { upsertMediaMetadataCategory } from '../../../../utils/media-library'

const allowedImageTypes = new Set(['image/jpeg', 'image/png', 'image/webp'])

const homeCoverWidth = 720

/**
 * 시스템 자산 파일명 접미사
 * @returns {string}
 */
const createSystemAssetSuffix = () => {
  const now = new Date()
  const year = now.getFullYear()
  const month = String(now.getMonth() + 1).padStart(2, '0')

  return `${year}${month}-${Math.random().toString(36).slice(2, 8)}`
}

/**
 * 메인 화면 커버 이미지 업로드 API
 * @param {import('h3').H3Event} event - 요청 이벤트
 * @returns {Promise<Object>} 수정된 사이트 설정
 */
export default defineEventHandler(async (event) => {
  requireAdminSession(event)

  const config = useRuntimeConfig()
  const maxFileSize = Number(config.maxFileSize || 10485760)
  const formData = await readMultipartFormData(event)
  const file = (formData || []).find((part) => part.name === 'file' && part.filename)

  if (!file) {
    throw createError({
      statusCode: 400,
      message: '업로드할 커버 이미지가 없습니다.'
    })
  }

  if (!allowedImageTypes.has(file.type)) {
    throw createError({
      statusCode: 400,
      message: 'JPG, PNG, WebP 이미지만 커버로 사용할 수 있습니다.'
    })
  }

  if (file.data.length > maxFileSize) {
    throw createError({
      statusCode: 413,
      message: '업로드 가능한 파일 크기를 초과했습니다.'
    })
  }

  const metadata = await sharp(file.data).metadata()
  if (!metadata.width || !metadata.height) {
    throw createError({
      statusCode: 400,
      message: '이미지 메타데이터를 읽을 수 없습니다.'
    })
  }

  const uploadBaseUrl = String(config.uploadDir || '/uploads').replace(/\/+$/g, '') || '/uploads'
  const publicBasePath = uploadBaseUrl.replace(/^\/+/, '')
  const directoryPath = join(process.cwd(), 'public', publicBasePath, 'system')
  const assetSuffix = createSystemAssetSuffix()
  const coverFileName = `home-cover-${assetSuffix}.webp`
  const coverPath = join(directoryPath, coverFileName)
  const homeCoverImageUrl = `${uploadBaseUrl}/system/${coverFileName}`

  await mkdir(directoryPath, { recursive: true })

  const coverBuffer = await sharp(file.data)
    .rotate()
    .resize({
      width: homeCoverWidth,
      withoutEnlargement: true
    })
    .webp({ quality: 88 })
    .toBuffer()

  await writeFile(coverPath, coverBuffer)
  await upsertMediaMetadataCategory(homeCoverImageUrl, '시스템')

  return { homeCoverImageUrl }
})