import {
  completeUploadApi,
  getUploadProgressApi,
  initUploadApi,
  uploadChunkApi
} from '@/api/admin/media'
import type { MediaAsset } from '@/api/admin/types'

export interface UploadFileOptions {
  /** DRAMA_COVER / EPISODE / AVATAR */
  bizType?: string
  /** 并发分片数，默认 3 */
  concurrency?: number
  /** 视频时长（秒），由调用方探测后传入 */
  durationSec?: number
  onProgress?: (percent: number) => void
  /** init 建好会话就回调一次：调用方可以把它记下来，失败/刷新后走 resumeUpload 续传 */
  onSession?: (uploadId: string) => void
}

/**
 * 分片上传：init 建会话 → 并发传分片 → complete 合并。
 * 服务端返回合并后的媒资（含可访问 URL）。
 */
export async function uploadFile(file: File, options: UploadFileOptions = {}): Promise<MediaAsset> {
  const { bizType = 'EPISODE', concurrency = 3, onProgress } = options
  const initRes = await initUploadApi({
    fileName: file.name,
    fileSize: file.size,
    bizType
  })
  const info = initRes.data
  options.onSession?.(info.uploadId)
  const total = Math.max(info.totalChunks, 1)
  const pending: number[] = Array.from({ length: total }, (_, index) => index)
  let finished = 0

  const worker = async () => {
    for (;;) {
      const index = pending.shift()
      if (index === undefined) return
      const start = index * info.chunkSize
      const chunk = file.slice(start, Math.min(start + info.chunkSize, file.size))
      await uploadChunkApi(info.uploadId, index, chunk, file.name)
      finished += 1
      onProgress?.(Math.min(95, Math.round((finished / total) * 95)))
    }
  }

  await Promise.all(Array.from({ length: Math.min(concurrency, total) }, worker))
  const doneRes = await completeUploadApi(info.uploadId, options.durationSec)
  onProgress?.(100)
  return doneRes.data
}

/**
 * 断点续传：先问服务端传到第几片，从断点接着传，再合并。
 *
 * 服务端只记账"已收到多少片"，不回传具体是哪几片，所以这里按"已收片数之后的分片全部重传"处理 ——
 * 重传同一片是幂等覆盖，不会产生脏数据；片数落后于实际时最多多传几片。
 */
export async function resumeUpload(
  file: File,
  uploadId: string,
  options: UploadFileOptions = {}
): Promise<MediaAsset> {
  const { concurrency = 3, onProgress } = options
  const progress = (await getUploadProgressApi(uploadId)).data
  const total = Math.max(progress.totalChunks, 1)
  const received = Math.min(progress.receivedChunks || 0, total)
  const pending: number[] = []
  for (let index = received; index < total; index += 1) {
    pending.push(index)
  }
  let finished = received
  onProgress?.(Math.min(95, Math.round((finished / total) * 95)))

  const worker = async () => {
    for (;;) {
      const index = pending.shift()
      if (index === undefined) return
      const start = index * progress.chunkSize
      const chunk = file.slice(start, Math.min(start + progress.chunkSize, file.size))
      await uploadChunkApi(uploadId, index, chunk, file.name)
      finished += 1
      onProgress?.(Math.min(95, Math.round((finished / total) * 95)))
    }
  }

  await Promise.all(
    Array.from({ length: Math.min(concurrency, Math.max(pending.length, 1)) }, worker)
  )
  const doneRes = await completeUploadApi(uploadId, options.durationSec)
  onProgress?.(100)
  return doneRes.data
}

/** 读取本地视频时长，取不到时返回 0。 */
export function probeVideoDuration(file: File): Promise<number> {
  return new Promise((resolve) => {
    const url = URL.createObjectURL(file)
    const video = document.createElement('video')
    video.preload = 'metadata'
    const cleanup = (value: number) => {
      URL.revokeObjectURL(url)
      resolve(value)
    }
    video.onloadedmetadata = () => {
      cleanup(Number.isFinite(video.duration) ? Math.round(video.duration) : 0)
    }
    video.onerror = () => cleanup(0)
    video.src = url
  })
}