import { createReadStream, statSync } from 'node:fs'
import { resolve, sep } from 'node:path'

const contentTypes: Record<string, string> = {
  jpg: 'image/jpeg',
  jpeg: 'image/jpeg',
  png: 'image/png',
  webp: 'image/webp',
}

export default defineEventHandler((event) => {
  const requested = getRouterParam(event, 'path') || ''
  const uploadsRoot = resolve(process.cwd(), 'data', 'uploads')
  const legacyRoot = resolve(process.cwd(), 'data', 'media')
  let mediaRoot = uploadsRoot
  let filePath = resolve(mediaRoot, requested)
  if (!filePath.startsWith(`${mediaRoot}${sep}`)) {
    throw createError({ statusCode: 400, statusMessage: '无效的文件路径' })
  }

  let fileStat
  try {
    fileStat = statSync(filePath)
  } catch {
    const legacyPath = resolve(legacyRoot, requested)
    if (!legacyPath.startsWith(`${legacyRoot}${sep}`)) throw createError({ statusCode: 400, statusMessage: '无效的文件路径' })
    try { fileStat = statSync(legacyPath); filePath = legacyPath; mediaRoot = legacyRoot }
    catch { throw createError({ statusCode: 404, statusMessage: '图片不存在' }) }
  }
  if (!fileStat.isFile()) {
    throw createError({ statusCode: 404, statusMessage: '图片不存在' })
  }

  const extension = filePath.split('.').pop()?.toLowerCase() || ''
  const contentType = contentTypes[extension]
  if (!contentType) {
    throw createError({ statusCode: 415, statusMessage: '不支持的文件类型' })
  }
  setHeader(event, 'Content-Type', contentType)
  setHeader(event, 'Content-Length', fileStat.size)
  setHeader(event, 'Cache-Control', 'public, max-age=31536000, immutable')
  return sendStream(event, createReadStream(filePath))
})