/** 导出整本小说：format=txt|md，scope=approved|all */
export default defineEventHandler(async (event) => {
  const project = getProject(param(event))
  const q = getQuery(event)
  const format = q.format === 'md' ? 'md' : 'txt'
  const scope = q.scope === 'approved' ? 'approved' : 'all'
  const chapters = listChapters(project.id).filter(c => c.activeVersionId && (scope === 'all' || c.status === 'approved'))

  const parts: string[] = []
  parts.push(format === 'md' ? `# ${project.title}` : project.title)
  if (project.description) parts.push(project.description)
  for (const c of chapters) {
    const v = getVersion(c.activeVersionId)
    if (!v) continue
    const body = stripHeading(await readChapterFile(v.filePath)).trim()
    const heading = `第${c.index}章 ${c.title}`
    parts.push(format === 'md' ? `## ${heading}\n\n${body}` : `${heading}\n\n${body}`)
  }
  const filename = encodeURIComponent(`${project.title}.${format}`)
  setHeader(event, 'Content-Type', format === 'md' ? 'text/markdown; charset=utf-8' : 'text/plain; charset=utf-8')
  setHeader(event, 'Content-Disposition', `attachment; filename*=UTF-8''${filename}`)
  return parts.join('\n\n\n')
})