import { Router } from 'express'
import path from 'node:path'
import multer, { MulterError } from 'multer'
import type { Request, Response, NextFunction } from 'express'
import { promises as fs } from 'node:fs'
import { requireAuth } from '../auth.js'
import {
  createFolder,
  deleteFolder,
  deleteVideo,
  folderPath,
  listFolders,
  listVideos,
  loadVideoMeta,
  moveUploadIntoVideo,
  newVideoId,
  readAccounts,
  renameFolder,
  sanitizeFolderName,
  saveVideoMeta,
  type VideoMeta
} from '../store.js'
import { tmpDir } from '../paths.js'
import {
  YtDlpUnavailableError,
  getJob,
  probeYoutube,
  startYoutubeDownload
} from '../youtube.js'
import { FfmpegUnavailableError, applyTrimToVideo } from '../editor.js'

export const opRouter = Router()

// 업로드 용량 상한. 기본 1 GiB. UPLOAD_MAX_BYTES 환경변수로 변경 가능.
// 명시적으로 무제한이 필요하면 UPLOAD_MAX_BYTES=0 (또는 Infinity).
const DEFAULT_UPLOAD_MAX_BYTES = 1024 * 1024 * 1024
const uploadMaxBytes = (() => {
  const raw = process.env.UPLOAD_MAX_BYTES
  if (raw === undefined || raw === '') return DEFAULT_UPLOAD_MAX_BYTES
  const n = Number(raw)
  if (!Number.isFinite(n) || n <= 0) return Infinity
  return Math.max(1, n)
})()
const upload = multer({
  dest: tmpDir,
  limits: { fileSize: uploadMaxBytes }
})

function pickStr(v: unknown): string {
  if (Array.isArray(v)) return typeof v[0] === 'string' ? v[0] : ''
  return typeof v === 'string' ? v : ''
}

opRouter.get('/op', (req, res) => {
  if (req.session?.userId) {
    res.redirect('/op/dashboard')
    return
  }
  res.render('op/login', { error: null })
})

opRouter.post('/op', async (req, res, next) => {
  try {
    const password = pickStr(req.body.password)
    const accounts = await readAccounts()
    const matched = accounts.find((a) => a.password === password)
    if (!matched) {
      res.status(401).render('op/login', { error: '비밀번호가 올바르지 않습니다.' })
      return
    }
    req.session.userId = matched.id
    res.redirect('/op/dashboard')
  } catch (err) {
    next(err)
  }
})

opRouter.post('/op/logout', (req, res) => {
  req.session.destroy(() => {
    res.redirect('/op')
  })
})

opRouter.get('/op/dashboard', requireAuth, async (req, res, next) => {
  try {
    const folders = await listFolders()
    res.render('op/dashboard', { userId: req.session.userId, folders })
  } catch (err) {
    next(err)
  }
})

opRouter.post('/op/folders', requireAuth, async (req, res, next) => {
  try {
    const name = pickStr(req.body.name)
    const safe = await createFolder(name)
    res.json({ ok: true, name: safe })
  } catch (err) {
    res.status(400).json({ ok: false, message: (err as Error).message })
  }
})

opRouter.post('/op/folders/rename', requireAuth, async (req, res) => {
  try {
    const oldName = pickStr(req.body.oldName)
    const newName = pickStr(req.body.newName)
    const result = await renameFolder(oldName, newName)
    res.json({ ok: true, name: result })
  } catch (err) {
    res.status(400).json({ ok: false, message: (err as Error).message })
  }
})

opRouter.post('/op/folders/delete', requireAuth, async (req, res) => {
  try {
    const name = pickStr(req.body.name)
    await deleteFolder(name)
    res.json({ ok: true })
  } catch (err) {
    res.status(400).json({ ok: false, message: (err as Error).message })
  }
})

opRouter.get('/op/folder/:name', requireAuth, async (req, res, next) => {
  try {
    const safe = sanitizeFolderName(req.params.name)
    if (!safe) {
      res.status(404).send('폴더를 찾을 수 없습니다.')
      return
    }
    try {
      await fs.access(folderPath(safe))
    } catch {
      res.status(404).send('폴더를 찾을 수 없습니다.')
      return
    }
    const videos = await listVideos(safe)
    res.render('op/folder', { userId: req.session.userId, folder: safe, videos })
  } catch (err) {
    next(err)
  }
})

opRouter.get('/op/folder/:name/video/editor', requireAuth, async (req, res, next) => {
  try {
    const safe = sanitizeFolderName(req.params.name)
    if (!safe) {
      res.status(404).send('폴더를 찾을 수 없습니다.')
      return
    }
    const videoId = typeof req.query.id === 'string' ? req.query.id : null
    let video: VideoMeta | null = null
    if (videoId) {
      video = await loadVideoMeta(safe, videoId)
    }
    res.render('op/editor', {
      userId: req.session.userId,
      folder: safe,
      video
    })
  } catch (err) {
    next(err)
  }
})

opRouter.post('/op/folder/:name/video/rename', requireAuth, async (req, res) => {
  try {
    const safe = sanitizeFolderName(req.params.name)
    if (!safe) throw new Error('폴더 이름이 올바르지 않습니다.')
    const id = pickStr(req.body.id)
    const title = pickStr(req.body.title).trim()
    if (!title) throw new Error('제목을 입력해 주세요.')
    const meta = await loadVideoMeta(safe, id)
    if (!meta) throw new Error('영상을 찾을 수 없습니다.')
    meta.title = title
    await saveVideoMeta(safe, meta)
    res.json({ ok: true })
  } catch (err) {
    res.status(400).json({ ok: false, message: (err as Error).message })
  }
})

opRouter.post('/op/folder/:name/video/delete', requireAuth, async (req, res) => {
  try {
    const safe = sanitizeFolderName(req.params.name)
    if (!safe) throw new Error('폴더 이름이 올바르지 않습니다.')
    const id = pickStr(req.body.id)
    await deleteVideo(safe, id)
    res.json({ ok: true })
  } catch (err) {
    res.status(400).json({ ok: false, message: (err as Error).message })
  }
})

// multer 가 던지는 LIMIT_FILE_SIZE 같은 에러를 라우트 핸들러가 잡지 못해
// 글로벌 에러 핸들러로 새서 stack trace 가 그대로 노출되던 문제를 막는다.
function uploadSingle(fieldName: string) {
  const mw = upload.single(fieldName)
  return (req: Request, res: Response, next: NextFunction) => {
    mw(req, res, (err: unknown) => {
      if (!err) return next()
      if (err instanceof MulterError) {
        const message =
          err.code === 'LIMIT_FILE_SIZE'
            ? `파일이 너무 큽니다. (한도: ${uploadMaxBytes === Infinity ? '무제한' : uploadMaxBytes + ' bytes'}; UPLOAD_MAX_BYTES 환경변수로 조정)`
            : `업로드 실패: ${err.message}`
        res.status(413).json({ ok: false, code: err.code, message })
        return
      }
      res.status(400).json({ ok: false, message: (err as Error).message || '업로드 실패' })
    })
  }
}

// 업로드: 단일 파일. multipart/form-data, fields: title, file
opRouter.post(
  '/op/folder/:name/video/upload',
  requireAuth,
  uploadSingle('file'),
  async (req, res) => {
    try {
      const safe = sanitizeFolderName(req.params.name)
      if (!safe) throw new Error('폴더 이름이 올바르지 않습니다.')
      const file = req.file
      if (!file) throw new Error('파일이 없습니다.')
      const title = pickStr(req.body?.title).trim() || file.originalname
      const ext = (path.extname(file.originalname) || '.mp4').toLowerCase()
      const videoId = newVideoId()
      const destName = `original${ext}`
      await moveUploadIntoVideo(safe, videoId, file.path, destName)
      const now = new Date().toISOString()
      const meta = {
        id: videoId,
        title,
        originalFile: destName,
        editedFile: null,
        durationSec: null,
        sourceType: 'upload' as const,
        sourceUrl: null,
        trim: null,
        createdAt: now,
        updatedAt: now
      }
      await saveVideoMeta(safe, meta)
      res.json({ ok: true, videoId, folder: safe })
    } catch (err) {
      res.status(400).json({ ok: false, message: (err as Error).message })
    }
  }
)

// 유튜브 프로브: 다운받기 전에 길이/사이즈/예상시간/5분초과경고
opRouter.post('/op/folder/:name/video/youtube/probe', requireAuth, async (req, res) => {
  try {
    const url = pickStr(req.body.url).trim()
    if (!url) throw new Error('URL 을 입력해 주세요.')
    const probe = await probeYoutube(url)
    res.json({ ok: true, probe })
  } catch (err) {
    if (err instanceof YtDlpUnavailableError) {
      res.status(503).json({ ok: false, message: err.message, code: 'NO_YTDLP' })
      return
    }
    res.status(400).json({ ok: false, message: (err as Error).message })
  }
})

opRouter.post('/op/folder/:name/video/youtube/start', requireAuth, async (req, res) => {
  try {
    const safe = sanitizeFolderName(req.params.name)
    if (!safe) throw new Error('폴더 이름이 올바르지 않습니다.')
    const url = pickStr(req.body.url).trim()
    const title = pickStr(req.body.title).trim() || undefined
    if (!url) throw new Error('URL 을 입력해 주세요.')
    const job = await startYoutubeDownload({ folder: safe, url, title })
    res.json({ ok: true, jobId: job.id, videoId: job.videoId })
  } catch (err) {
    if (err instanceof YtDlpUnavailableError) {
      res.status(503).json({ ok: false, message: err.message, code: 'NO_YTDLP' })
      return
    }
    res.status(400).json({ ok: false, message: (err as Error).message })
  }
})

opRouter.get('/op/job/:id', requireAuth, (req, res) => {
  const job = getJob(req.params.id)
  if (!job) {
    res.status(404).json({ ok: false, message: '작업을 찾을 수 없습니다.' })
    return
  }
  res.json({ ok: true, job })
})

// 편집 저장: trim 정보를 받아 ffmpeg 로 edited.<ext> 생성. 원본은 그대로 보존.
opRouter.post('/op/folder/:name/video/save', requireAuth, async (req, res) => {
  try {
    const safe = sanitizeFolderName(req.params.name)
    if (!safe) throw new Error('폴더 이름이 올바르지 않습니다.')
    const id = pickStr(req.body.id)
    const title = pickStr(req.body.title).trim()
    const startSec = Number(req.body.startSec ?? 0) || 0
    const endRaw = req.body.endSec
    const endSec =
      endRaw === null || endRaw === undefined || endRaw === ''
        ? null
        : Number(endRaw)
    const meta = await loadVideoMeta(safe, id)
    if (!meta) throw new Error('영상을 찾을 수 없습니다.')
    if (title) meta.title = title
    meta.trim = { startSec, endSec: endSec == null || Number.isNaN(endSec) ? null : endSec }
    await saveVideoMeta(safe, meta)
    // ffmpeg 가 없으면 trim 정보만 저장하고 안내.
    try {
      const outName = await applyTrimToVideo(safe, id, meta.trim)
      res.json({ ok: true, editedFile: outName, note: '편집본 저장 완료' })
    } catch (err) {
      if (err instanceof FfmpegUnavailableError) {
        res.json({
          ok: true,
          editedFile: null,
          note: 'ffmpeg 가 설치되지 않아 편집본을 만들지 못했습니다. trim 설정만 저장됐습니다.'
        })
        return
      }
      throw err
    }
  } catch (err) {
    res.status(400).json({ ok: false, message: (err as Error).message })
  }
})