import generateId from '@/utils/generateId'
import useMiaoFetchApi from '@/hooks/useMiaoFetchApi'
import VirtualDirectory from './VirtualDirectory'

const miaoFetchApi = useMiaoFetchApi()

export class UploadQueueItem {
   constructor(
      file: File,
      targetDirectory: VirtualDirectory,
      config?: {
         onSuccess?: () => void
         onFailed?: () => void
      }
   ) {
      this.file = file
      this.targetDirectory = targetDirectory
      this.uid = generateId()
      this.status = 'waiting'
      this.process = 0
      this.onSuccess = config && config.onSuccess
      this.onFailed = config && config.onFailed
   }
   uid: number
   file: File
   targetDirectory: VirtualDirectory
   status: 'waiting' | 'uploading' | 'success' | 'failed'
   process: number
   failedReason: unknown | undefined

   onSuccess?: () => void
   onFailed?: () => void

   _abort: (() => void | undefined) | undefined
   _status: Promise<any> | undefined

   /**
    * 开始上传文件
    */
   startUpload() {
      if (this.status === 'uploading') {
         return
      }
      const { abort, response } = miaoFetchApi.upload(
         this.file,
         this.targetDirectory,
         {
            onProcess: (percent) => {
               this.process = percent
            }
         }
      )
      this._abort = abort
      this._status = response
      this.status = 'uploading'
      response
         .then(() => {
            this.status = 'success'
            this.onSuccess && this.onSuccess()
            this._abort = undefined
            this._status = undefined
         })
         .catch((e) => {
            this.status = 'failed'
            this.failedReason = e
            this.onFailed && this.onFailed()
         })
   }

   /**
    * 终止上传文件
    */
   abortUpload() {
      this._abort && this._abort()
      this.status = 'failed'
      this.failedReason = 'abort'
   }
}

export default class UploadQueue {
   constructor() {
      this.uid = generateId()
      this.queue = []
      this.mode = 'serial'
   }
   uid: number
   queue: UploadQueueItem[]
   current: UploadQueueItem | undefined

   // 未来再去实现，目前就是串行的
   // 好像也不用去实现
   mode: 'serial' | 'parallel'
   get status() {
      for (let item of this.queue) {
         if (item.status === 'uploading') {
            return 'busy'
         }
      }
      return 'free'
   }

   /**
    * 获取下一个需要被上传的item
    */
   get nextUplpadItem() {
      for (let item of this.queue) {
         if (item.status === 'waiting') {
            return item
         }
      }
   }

   /**
    * 开始串行的上传循环
    */
   loop() {
      if (this.status === 'busy') {
         return
      }
      if (this.nextUplpadItem) {
         this.nextUplpadItem.startUpload()
      }
   }

   /**
    * 向上传文件队列输送一批新的文件
    * @param {any} files 需要上传的文件
    * @param {any} targetDirectory 目标文件夹
    * @param {any} option 每个文件上传完成以后都会触发一遍的回调函数
    * @returns {any}
    */
   push(
      files: File[],
      targetDirectory: VirtualDirectory,
      option?: {
         /**
          * 每个文件上传完成以后都会触发一遍的回调函数
          */
         onFinish?: () => void
         /**
          * 是否立即开始上传，若否则按队列顺序一个一个上传
          */
         immediately?: boolean
      }
   ) {
      const onFinish = option?.onFinish
      const immediately = option?.immediately ?? false
      const uploadQueue = files.map((file) => {
         return new UploadQueueItem(file, targetDirectory, {
            onSuccess: () => {
               this.loop()
               onFinish && onFinish()
            },
            onFailed: () => {
               this.loop()
            }
         })
      })
      this.queue.push(...uploadQueue)
      if (!immediately) {
         this.loop()
      } else {
         uploadQueue.forEach((item) => {
            item.startUpload()
         })
      }
      return uploadQueue
   }
}