import {
  uuidv1,
  Data,
  replayWithLatest,
  useGeneralDriver
} from './libs/mobius-utils'

export type uuidGenerator = (scene?: 'batch'|'update'|'record') => string
export interface UpdateManagerOptions {
  uuidGenerator?: uuidGenerator
}
export class UpdateManager {
  public generateUuid: uuidGenerator
  private _updateRequest: any[] | null | undefined

  constructor (options: UpdateManagerOptions) {
    const { uuidGenerator } = options
    this.generateUuid = (scene) => {
      let id
      try {
        id = uuidv1()
      } catch (e) {
        if (uuidGenerator == null) {
          throw (new Error('Please privide an uuidGenerator cause default generator is invalid in current environment!'))
        }
        id = uuidGenerator(scene)
      }
      return id
    }
    this.reset()
  }

  reset (): void {
    this._updateRequest = null
    this._batchId = ''
    this._updateDetail = null
    this._updateSummary = null
    this._collectRequest = null
    this._collectResult = null
    this._updateItems = null
    this._acceptResult = null
    this._parsedAcceptResult = null
  }

  // [{ type, detail: { ... } }]
  parseUpdateRequest (request) {
    this._updateRequest = request
    // TODO: 为 createRecord request 补充 id
    console.log('[UpdateManager] parsedUpdateRequest', request)
    return this._updateRequest
  }

  generateBatchId () {
    this._batchId = this.generateUuid()
    return this._batchId
  }

  /**
   * {
   *    batchId,
   *    payload: {
   *      [updateId]: { batchId, updateId, type, detail: { ... } }
   *    }
   * }
   */
  createUpdateDetail ({ batchId }) {
    const updateDetail = {
      batchId: batchId,
      batchTime: Date.now(),
      payload: this._updateRequest.reduce((updates, request) => {
        const updateId = this.generateUuid()
        updates[updateId] = { ...request, updateId }
        return updates
      }, {})
    }

    console.log('[UpdateManager] updateDetail', updateDetail)

    this._updateDetail = updateDetail
    return this._updateDetail
  }

  parseUpdateSummary (summary) {
    this._updateSummary = summary
    return this._updateSummary
  }

  /**
   * {
   *    batchId,
   *    payload: {
   *      batch: batchId,
   *      updates: {
   *        [updateId]: { updateId, recordId },
   *        ...
   *      }
   *    }
   * }
   */
  createCollectRequest ({ batchId }) {
    const collectRequest = {
      batchId: batchId,
      payload: {
        batch: batchId,
        updates: Object.entries(this._updateSummary.payload).reduce((acc, cur) => {
          const [updateId, { update: { detail: { recordId } } }] = cur
          acc[updateId] = { updateId, recordId }
          return acc
        }, {})
      }
    }

    console.log('[UpdateManager] collectRequest', collectRequest)

    this._collectRequest = collectRequest
    return this._collectRequest
  }

  createUpdateItems (collectResult) {
    this._collectResult = collectResult

    console.log('[UpdateManager] collectResult', collectResult)

    const { batchId, payload: { batch, updates } } = collectResult
    const updateSummary = this._updateSummary.payload
    const updateDetail = this._updateDetail

    const updateItems = {
      batchId: batchId,
      payload: Object.values(updateSummary).reduce((items, cur) => {
        const { update: { type, detail, updateId }, updateTime } = cur
        items[updateId] = {
          type: type,
          batchId: batchId,
          batchTime: updateDetail.batchTime,
          lastBatchId: batch.lastBatchId,
          updateId: updateId,
          updateTime: updateTime,
          lastUpdateId: updates[updateId].lastUpdateId,
          detail: detail
        }
        return items
      }, {})
    }

    console.log('[UpdateManager] updateItems', updateItems)

    this._updateItems = updateItems
    return this._updateItems
  }

  parseAcceptResult (acceptResult) {
    this._acceptResult = acceptResult
    const { batchId } = acceptResult

    const parsedAcceptResult = {
      batchId: batchId,
      payload: {
        isSuccess: Object.values(acceptResult.payload).every(b => b)
      }
    }

    console.log('[UpdateContainer] parsedAcceptResult', parsedAcceptResult)

    this._parsedAcceptResult = parsedAcceptResult
    return this._parsedAcceptResult
  }
}

export interface updateManagerDriverOptions {
  uuidGenerator?: uuidGenerator
}
export interface updateManagerDriverInstance {
  inputs: Record<string, Data>
  outputs: Record<string, Data>
}
export const updateManagerDriver = (options: updateManagerDriverOptions): updateManagerDriverInstance => {
  const { uuidGenerator } = options
  const updateManager = new UpdateManager({ uuidGenerator })

  const processInD = Data.empty()
  const executeStatusRD = replayWithLatest(1, Data.empty())

  const updateRequestInD = Data.empty()
  const updateSummaryInD = Data.empty()
  const collectResultInD = Data.empty()
  const acceptResultInD = Data.empty()
  // const endUpdateD = Data.empty()

  const updateDetailD = Data.empty()
  const collectRequestD = Data.empty()
  const updateItemsD = Data.empty()

  // 接收到调度器的运行状态之后，进行相应的处理
  processInD.subscribeValue(processStatus => {
    const { status } = processStatus
    console.log('[UpdateManagerDriver] receive status', status)
    if (status === 'start') {
      executeStatusRD.mutate(() => ({ status: 'start' }))
    }
    if (status === 'update') {
      executeStatusRD.mutate(() => ({ status: 'update' }))
      const updateDetail = updateManager.createUpdateDetail({ batchId: updateManager._batchId })
      updateDetailD.mutate(() => updateDetail)
    }
    if (status === 'end') {
      updateManager.reset()
      console.log('[UpdateManagerDriver] reset updateManager instance')
      executeStatusRD.mutate(() => ({ status }))
    }
  })

  // 接收到 UpdateRequest 之后，进行更新前的准备工作
  //   -> 解析 UpdateRequest
  //   -> 生成 BatchId
  //   -> 广播 StartUpdateStatus
  updateRequestInD.subscribeValue(request => {
    updateManager.parseUpdateRequest(request)
    const batchId = updateManager.generateBatchId()
    executeStatusRD.mutate(() => ({ status: 'init' }))
  })

  // 接收到 UpdateSummary 之后，广播一条 CollectRequest
  updateSummaryInD.subscribeValue(updateSummary => {
    const { batchId } = updateManager.parseUpdateSummary(updateSummary)
    const collectRequest = updateManager.createCollectRequest({ batchId })
    collectRequestD.mutate(() => collectRequest)
  })

  // 接收到 CollectResult 之后，
  collectResultInD.subscribeValue(collectResult => {
    const updateItems = updateManager.createUpdateItems(collectResult)
    updateItemsD.mutate(() => updateItems)
  })

  // 接收到 AcceptResult 之后，解析 AcceptResult 并将本次更新结果上报
  acceptResultInD.subscribeValue(acceptResult => {
    const { batchId, payload: { isSuccess } } = updateManager.parseAcceptResult(acceptResult)
    if (isSuccess) {
      executeStatusRD.mutate(() => ({ status: 'update', result: 'success', batchId }))
    } else {
      executeStatusRD.mutate(() => ({ status: 'update', result: 'fail', batchId }))
    }
  })

  return {
    inputs: {
      process: processInD,

      updateRequest: updateRequestInD,
      updateSummary: updateSummaryInD,
      collectResult: collectResultInD,
      acceptResult: acceptResultInD
    },
    outputs: {
      executeStatus: executeStatusRD,

      updateDetail: updateDetailD,
      collectRequest: collectRequestD,
      updateItems: updateItemsD
    }
  }
}

export const useUpdateManagerDriver = useGeneralDriver(updateManagerDriver)