/*
Copyright (C) 2017  Cloudbase Solutions SRL
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

// @flow

import { observable, runInAction, computed, action } from 'mobx'

import type { Instance } from '../types/Instance'
import type { Endpoint } from '../types/Endpoint'
import InstanceSource from '../sources/InstanceSource'
import ApiCaller from '../utils/ApiCaller'
import configLoader from '../utils/Config'


class InstanceStore {
  @observable instancesLoading = false
  @observable instancesPerPage = 6
  @observable currentPage = 1
  @observable searchChunksLoading = false
  @observable searchedInstances: Instance[] = []
  @observable backgroundInstances: Instance[] = []
  @observable backgroundChunksLoading = false
  @observable searching = false
  @observable searchNotFound = false
  @observable reloading = false
  @observable instancesDetails: Instance[] = []
  @observable loadingInstancesDetails = true
  @observable instancesDetailsCount = 0
  @observable instancesDetailsRemaining = 0
  @observable searchText = ''

  @computed get instances(): Instance[] {
    if (this.searchText && this.searchedInstances.length > 0) {
      return this.searchedInstances
    }
    return this.backgroundInstances
  }

  @computed get chunksLoading(): boolean {
    if (this.searchText) {
      return this.searchChunksLoading
    }
    return this.backgroundChunksLoading
  }

  lastEndpointId: string
  reqId: number

  @action async loadInstancesInChunks(options: {
    endpoint: Endpoint,
    vmsPerPage?: number,
    reload?: boolean,
    env?: any,
    useCache?: boolean,
  }) {
    let { endpoint, vmsPerPage, reload, env, useCache } = options
    vmsPerPage = vmsPerPage || 6

    ApiCaller.cancelRequests(`${endpoint.id}-chunk`)

    this.backgroundInstances = []
    if (reload) {
      this.reloading = true
    } else {
      this.instancesLoading = true
    }
    this.backgroundChunksLoading = true
    this.lastEndpointId = endpoint.id
    let chunkSize = configLoader.config.instancesListBackgroundLoading
    let chunkCount = Math.max(chunkSize[endpoint.type] || chunkSize.default, vmsPerPage)

    let loadNextChunk = async (lastEndpointId?: string) => {
      let currentEndpointId = endpoint.id
      let instances = await InstanceSource.loadInstancesChunk(currentEndpointId, chunkCount, lastEndpointId, `${endpoint.id}-chunk`, undefined, env, useCache)
      if (currentEndpointId !== this.lastEndpointId) {
        return
      }
      let shouldContinue = this.loadInstancesInChunksSuccess(instances, chunkCount, reload)
      if (shouldContinue) {
        loadNextChunk(instances[instances.length - 1].id)
      }
    }
    loadNextChunk()
  }

  @action loadInstancesInChunksSuccess(instances: Instance[], chunkCount: number, reload?: boolean): boolean {
    this.backgroundInstances = [...this.backgroundInstances, ...instances]
    if (reload) {
      this.reloading = false
    }
    this.instancesLoading = false

    if (instances.length < chunkCount) {
      this.backgroundChunksLoading = false
      return false
    }
    return true
  }

  @action async loadInstances(endpointId: string): Promise<void> {
    this.instancesLoading = true
    this.lastEndpointId = endpointId

    try {
      let instances = await InstanceSource.loadInstances(endpointId, true)
      if (endpointId !== this.lastEndpointId) {
        return
      }
      this.loadInstancesSuccess(instances)
    } catch (ex) {
      if (endpointId !== this.lastEndpointId) {
        return
      }
      runInAction(() => { this.instancesLoading = false })
      throw ex
    }
  }

  @action loadInstancesSuccess(instances: Instance[]) {
    this.backgroundInstances = instances
    this.instancesLoading = false
  }

  @action async searchInstances(endpoint: Endpoint, searchText: string) {
    ApiCaller.cancelRequests(`${endpoint.id}-chunk-search`)

    this.searchText = searchText
    this.searchNotFound = false

    if (!searchText) {
      this.currentPage = 1
      this.searchedInstances = []
      return
    }

    if (!this.backgroundChunksLoading) {
      this.searchedInstances = this.backgroundInstances
        .filter(i => (i.instance_name || i.name).toLowerCase().indexOf(searchText.toLowerCase()) > -1)
      this.searchNotFound = Boolean(this.searchedInstances.length === 0)
      this.currentPage = 1
      return
    }

    this.searching = true
    this.searchChunksLoading = true

    let chunkSize = configLoader.config.instancesListBackgroundLoading
    let chunkCount = Math.max(chunkSize[endpoint.type] || chunkSize.default, this.instancesPerPage)

    let loadNextChunk = async (lastEndpointId?: string) => {
      let instances = await InstanceSource.loadInstancesChunk(
        endpoint.id,
        chunkCount,
        lastEndpointId,
        `${endpoint.id}-chunk-search`,
        searchText
      )
      if (this.searching) {
        runInAction(() => {
          this.currentPage = 1
          this.searchedInstances = []
        })
      }
      let shouldContinue = this.searchInstancesSuccess(instances, chunkCount)
      if (shouldContinue) {
        loadNextChunk(instances[instances.length - 1].id)
      }
    }
    loadNextChunk()
  }

  @action searchInstancesSuccess(instances: Instance[], chunkCount: number): boolean {
    this.searchedInstances = [...this.searchedInstances, ...instances]
    this.searching = false
    this.searchNotFound = Boolean(this.searchedInstances.length === 0)
    if (instances.length < chunkCount) {
      this.searchChunksLoading = false
      return false
    }
    return true
  }

  @action reloadInstances(endpoint: Endpoint, chunkSize?: number, env?: any) {
    this.searchNotFound = false
    this.searchText = ''
    this.currentPage = 1
    this.loadInstancesInChunks({ endpoint, vmsPerPage: chunkSize, reload: true, env })
  }

  @action cancelIntancesChunksLoading() {
    ApiCaller.cancelRequests(`${this.lastEndpointId}-chunk`)
    this.lastEndpointId = ''
    this.searchNotFound = false
    this.searchText = ''
    this.currentPage = 1
  }

  @action setPage(page: number) {
    this.currentPage = page
  }

  @action updateInstancesPerPage(instancesPerPage: number) {
    this.currentPage = 1
    this.instancesPerPage = instancesPerPage
  }

  @action async loadInstancesDetailsBulk(
    instanceInfos: {
      endpointId: string,
      instanceNames: string[],
      env?: ?any,
    }[]
  ) {
    this.reqId = !this.reqId ? 1 : this.reqId + 1
    this.instancesDetails = []
    this.loadingInstancesDetails = true
    InstanceSource.cancelInstancesDetailsRequests(this.reqId - 1)
    try {
      await Promise.all(instanceInfos.map(async i => {
        await Promise.all(i.instanceNames.map(async name => {
          let instanceDetails = await InstanceSource.loadInstanceDetails({
            endpointId: i.endpointId,
            instanceName: name,
            reqId: this.reqId,
            quietError: false,
            env: i.env,
            cache: true,
          })
          runInAction(() => {
            this.instancesDetails = this.instancesDetails.filter(i => (i.name || i.instance_name || '') !== name)
            this.instancesDetails.push(instanceDetails.instance)
            this.instancesDetails.sort(n => (n.name || n.instance_name || '')
              .localeCompare(n.name || n.instance_name || ''))
          })
        }))
      }))
    } finally {
      this.loadingInstancesDetails = false
    }
  }

  @action async loadInstancesDetails(opts: {
    endpointId: string,
    instancesInfo: Instance[],
    cache?: boolean,
    quietError?: boolean,
    env?: any,
    targetProvider: string,
  }): Promise<void> {
    let { endpointId, instancesInfo, cache, quietError, env, targetProvider } = opts
    // Use reqId to be able to uniquely identify the request so all but the latest request can be igonred and canceled
    this.reqId = !this.reqId ? 1 : this.reqId + 1
    InstanceSource.cancelInstancesDetailsRequests(this.reqId - 1)

    instancesInfo.sort((a, b) => (a.instance_name || a.name).localeCompare(b.instance_name || b.name))

    let count = instancesInfo.length
    this.loadingInstancesDetails = true
    this.instancesDetails = []
    this.loadingInstancesDetails = true
    this.instancesDetailsCount = count
    this.instancesDetailsRemaining = count

    await new Promise(resolve => {
      Promise.all(instancesInfo.map(async instanceInfo => {
        try {
          let resp: { instance: Instance, reqId: number } =
            await InstanceSource.loadInstanceDetails({
              endpointId,
              instanceName: instanceInfo.instance_name || instanceInfo.name,
              targetProvider,
              reqId: this.reqId,
              quietError,
              env,
              cache,
            })
          if (resp.reqId !== this.reqId) {
            return
          }

          runInAction(() => {
            this.instancesDetailsRemaining -= 1
            this.loadingInstancesDetails = this.instancesDetailsRemaining > 0

            if (this.instancesDetails.find(i => i.id === resp.instance.id)) {
              this.instancesDetails = this.instancesDetails.filter(i => i.id !== resp.instance.id)
            }
          })

          runInAction(() => {
            this.instancesDetails = [
              ...this.instancesDetails,
              resp.instance,
            ]
            this.instancesDetails.sort((a, b) => (a.instance_name || a.name).localeCompare((b.instance_name || b.name)))
          })
          if (this.instancesDetailsRemaining === 0) {
            resolve()
          }
        } catch (err) {
          runInAction(() => {
            this.instancesDetailsRemaining -= 1
            this.loadingInstancesDetails = this.instancesDetailsRemaining > 0
          })
          if (!err || err.reqId !== this.reqId) {
            return
          }
          if (count === 0) {
            resolve()
          }
        }
      }))
    })
  }

  @action clearInstancesDetails() {
    this.instancesDetails = []
    this.loadingInstancesDetails = false
    this.instancesDetailsCount = 0
    this.instancesDetailsRemaining = 0
  }
}

export default new InstanceStore()