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import { OnDestroy, OnInit } from '@angular/core'
import { ActivatedRoute, Router } from '@angular/router'
import { NotificationsService } from 'angular2-notifications'
import { Observable } from 'rxjs/Observable'
import { Subscription } from 'rxjs/Subscription'
import { SortField } from './sort-field.type'
import { VideoPagination } from './video-pagination.model'
import { Video } from './video.model'
export abstract class AbstractVideoList implements OnInit, OnDestroy {
pagination: VideoPagination = {
currentPage: 1,
itemsPerPage: 25,
totalItems: null
}
sort: SortField = '-createdAt'
videos: Video[] = []
protected notificationsService: NotificationsService
protected router: Router
protected route: ActivatedRoute
protected subActivatedRoute: Subscription
protected abstract currentRoute: string
abstract titlePage: string
private loadedPages: { [ id: number ]: boolean } = {}
abstract getVideosObservable (): Observable<{ videos: Video[], totalVideos: number}>
ngOnInit () {
// Subscribe to route changes
const routeParams = this.route.snapshot.params
this.loadRouteParams(routeParams)
this.loadMoreVideos('after')
}
ngOnDestroy () {
if (this.subActivatedRoute) {
this.subActivatedRoute.unsubscribe()
}
}
onNearOfTop () {
if (this.pagination.currentPage > 1) {
this.previousPage()
}
}
onNearOfBottom () {
if (this.hasMoreVideos()) {
this.nextPage()
}
}
loadMoreVideos (where: 'before' | 'after') {
if (this.loadedPages[this.pagination.currentPage] === true) return
const observable = this.getVideosObservable()
observable.subscribe(
({ videos, totalVideos }) => {
this.loadedPages[this.pagination.currentPage] = true
this.pagination.totalItems = totalVideos
if (where === 'before') {
this.videos = videos.concat(this.videos)
} else {
this.videos = this.videos.concat(videos)
}
},
error => this.notificationsService.error('Error', error.text)
)
}
protected hasMoreVideos () {
if (!this.pagination.totalItems) return true
const maxPage = this.pagination.totalItems / this.pagination.itemsPerPage
return maxPage > this.pagination.currentPage
}
protected previousPage () {
this.pagination.currentPage--
this.setNewRouteParams()
this.loadMoreVideos('before')
}
protected nextPage () {
this.pagination.currentPage++
this.setNewRouteParams()
this.loadMoreVideos('after')
}
protected buildRouteParams () {
// There is always a sort and a current page
const params = {
sort: this.sort,
page: this.pagination.currentPage
}
return params
}
protected loadRouteParams (routeParams: { [ key: string ]: any }) {
this.sort = routeParams['sort'] as SortField || '-createdAt'
if (routeParams['page'] !== undefined) {
this.pagination.currentPage = parseInt(routeParams['page'], 10)
} else {
this.pagination.currentPage = 1
}
}
protected setNewRouteParams () {
const routeParams = this.buildRouteParams()
this.router.navigate([ this.currentRoute, routeParams ])
}
}
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