import { ChangeDetectorRef, Component, OnDestroy, OnInit } from '@angular/core'
import { ActivatedRoute, Router } from '@angular/router'
import { Subscription } from 'rxjs/Subscription'
import { BehaviorSubject } from 'rxjs/BehaviorSubject'

import { NotificationsService } from 'angular2-notifications'

import {
  SortField,
  Video,
  VideoService,
  VideoPagination
} from '../shared'
import { AuthService, AuthUser } from '../../core'
import { Search, SearchField, SearchService } from '../../shared'

@Component({
  selector: 'my-videos-list',
  styleUrls: [ './video-list.component.scss' ],
  templateUrl: './video-list.component.html'
})
export class VideoListComponent implements OnInit, OnDestroy {
  loading: BehaviorSubject<boolean> = new BehaviorSubject(false)
  pagination: VideoPagination = {
    currentPage: 1,
    itemsPerPage: 25,
    totalItems: null
  }
  sort: SortField
  user: AuthUser = null
  videos: Video[] = []

  private search: Search
  private subActivatedRoute: Subscription
  private subSearch: Subscription

  constructor (
    private notificationsService: NotificationsService,
    private authService: AuthService,
    private changeDetector: ChangeDetectorRef,
    private router: Router,
    private route: ActivatedRoute,
    private videoService: VideoService,
    private searchService: SearchService
  ) {}

  ngOnInit () {
    if (this.authService.isLoggedIn()) {
      this.user = AuthUser.load()
    }

    // Subscribe to route changes
    this.subActivatedRoute = this.route.params.subscribe(routeParams => {
      this.loadRouteParams(routeParams)

      // Update the search service component
      this.searchService.updateSearch.next(this.search)
      this.getVideos()
    })

    // Subscribe to search changes
    this.subSearch = this.searchService.searchUpdated.subscribe(search => {
      this.search = search
      // Reset pagination
      this.pagination.currentPage = 1

      this.navigateToNewParams()
    })
  }

  ngOnDestroy () {
    this.subActivatedRoute.unsubscribe()
    this.subSearch.unsubscribe()
  }

  getVideos () {
    this.loading.next(true)
    this.videos = []

    let observable = null
    if (this.search.value) {
      observable = this.videoService.searchVideos(this.search, this.pagination, this.sort)
    } else {
      observable = this.videoService.getVideos(this.pagination, this.sort)
    }

    observable.subscribe(
      ({ videos, totalVideos }) => {
        this.videos = videos
        this.pagination.totalItems = totalVideos

        this.loading.next(false)
      },
      error => this.notificationsService.error('Error', error.text)
    )
  }

  isThereNoVideo () {
    return !this.loading.getValue() && this.videos.length === 0
  }

  onPageChanged (event: { page: number }) {
    // Be sure the current page is set
    this.pagination.currentPage = event.page

    this.navigateToNewParams()
  }

  onSort (sort: SortField) {
    this.sort = sort

    this.navigateToNewParams()
  }

  private buildRouteParams () {
    // There is always a sort and a current page
    const params = {
      sort: this.sort,
      page: this.pagination.currentPage
    }

    // Maybe there is a search
    if (this.search.value) {
      params['field'] = this.search.field
      params['search'] = this.search.value
    }

    return params
  }

  private loadRouteParams (routeParams: { [ key: string ]: any }) {
    if (routeParams['search'] !== undefined) {
      this.search = {
        value: routeParams['search'],
        field: routeParams['field'] as SearchField
      }
    } else {
      this.search = {
        value: '',
        field: 'name'
      }
    }

    this.sort = routeParams['sort'] as SortField || '-createdAt'

    if (routeParams['page'] !== undefined) {
      this.pagination.currentPage = parseInt(routeParams['page'], 10)
    } else {
      this.pagination.currentPage = 1
    }
  }

  private navigateToNewParams () {
    const routeParams = this.buildRouteParams()
    this.router.navigate([ '/videos/list', routeParams ])
  }
}