import { join } from 'node:path'
import { readFileSync, existsSync } from 'node:fs'

export default defineEventHandler(async () => {
  const config = await readYaml('bookplayer.config.yml')
  const pdfFile = config?.book?.pdfFile || '/pdf/une-economie-du-don.pdf'

  // En dev : public/, en prod : .output/public/
  const cwd = process.cwd()
  const candidates = [
    join(cwd, 'public', pdfFile),
    join(cwd, '.output', 'public', pdfFile),
  ]
  const pdfPath = candidates.find(p => existsSync(p))
  if (!pdfPath) return []

  let data: Uint8Array
  try {
    data = new Uint8Array(readFileSync(pdfPath))
  } catch {
    return []
  }

  const pdfjsLib = await import('pdfjs-dist/legacy/build/pdf.mjs')
  const doc = await pdfjsLib.getDocument({ data, useSystemFonts: true }).promise
  const outline = await doc.getOutline()

  if (!outline || outline.length === 0) {
    doc.destroy()
    return []
  }

  const entries: Array<{ title: string; page: number; level: number }> = []

  async function extract(items: any[], level: number) {
    for (const item of items) {
      let page: number | null = null
      try {
        let dest = item.dest
        if (typeof dest === 'string') dest = await doc.getDestination(dest)
        if (dest) page = (await doc.getPageIndex(dest[0])) + 1
      } catch {}
      if (page !== null) entries.push({ title: item.title, page, level })
      if (item.items?.length) await extract(item.items, level + 1)
    }
  }

  await extract(outline, 0)
  doc.destroy()
  return entries
})