import { readFile, writeFile } from 'node:fs/promises'
import { sendNuggetsUploadNotification } from './email.js'
import {
  SEAFILE_URL,
  SEAFILE_TOKEN,
  SEAFILE_NUGGETS_REPO_ID,
  SEAFILE_EPISODE_UPLOAD_DIR,
  SEAFILE_EPISODE_INFO_DIR,
  SEAFILE_POLL_INTERVAL_MS,
  NUGGETS_SEAFILE_SEEN_FILE,
  NUGGETS_NOTIFY_EMAIL,
} from './config.js'

async function loadSeen() {
  try {
    return JSON.parse(await readFile(NUGGETS_SEAFILE_SEEN_FILE, 'utf8'))
  } catch {
    return { files: [] }
  }
}

async function saveSeen(data) {
  await writeFile(NUGGETS_SEAFILE_SEEN_FILE, JSON.stringify(data, null, 2), 'utf8')
}

// Called by the upload route after a successful portal upload so the poller
// doesn't also fire a notification for the same file.
export async function markSeafileFileSeen(filename) {
  const data = await loadSeen()
  if (!data.files.includes(filename)) {
    data.files.push(filename)
    await saveSeen(data)
  }
}

async function listSeafileDir(dir) {
  if (!SEAFILE_URL || !SEAFILE_TOKEN || !SEAFILE_NUGGETS_REPO_ID) return []
  try {
    const url = `${SEAFILE_URL}/api2/repos/${SEAFILE_NUGGETS_REPO_ID}/dir/?p=${encodeURIComponent(dir)}`
    const res = await fetch(url, {
      headers: { Authorization: `Token ${SEAFILE_TOKEN}` },
      signal: AbortSignal.timeout(10_000),
    })
    if (!res.ok) return []
    const data = await res.json()
    return (data.dirent ?? []).filter(e => e.type === 'file').map(e => e.name)
  } catch {
    return []
  }
}

async function poll() {
  if (!SEAFILE_URL || !SEAFILE_TOKEN || !SEAFILE_NUGGETS_REPO_ID) return

  const [uploadFiles, seen] = await Promise.all([
    listSeafileDir(SEAFILE_EPISODE_UPLOAD_DIR),
    loadSeen(),
  ])

  const seenSet = new Set(seen.files)
  const newFiles = uploadFiles.filter(f => !seenSet.has(f))

  if (newFiles.length === 0) return

  for (const filename of newFiles) {
    console.log(`[nuggets-watcher] new direct upload detected: ${filename}`)
    await sendNuggetsUploadNotification({
      to: NUGGETS_NOTIFY_EMAIL,
      source: 'direct',
      filename,
    })
    seenSet.add(filename)
  }

  seen.files = [...seenSet]
  await saveSeen(seen)
}

export function startNuggetsSeafileWatcher() {
  if (!SEAFILE_URL || !SEAFILE_TOKEN || !SEAFILE_NUGGETS_REPO_ID) {
    console.log('[nuggets-watcher] Seafile not configured — watcher disabled.')
    return
  }
  // Initial poll after 2 min (let the server settle), then every 15 min
  setTimeout(() => {
    poll().catch(err => console.error('[nuggets-watcher] poll error:', err))
    setInterval(() => {
      poll().catch(err => console.error('[nuggets-watcher] poll error:', err))
    }, SEAFILE_POLL_INTERVAL_MS)
  }, 2 * 60 * 1000)

  console.log(`[nuggets-watcher] started — polling every ${SEAFILE_POLL_INTERVAL_MS / 60000} min`)
}