import { Injectable } from '@nestjs/common'

import { HttpService } from '../http'

import { YoutubePlaylist, YoutubeVideo } from './types'

type resources = 'videos' | 'playlists' | 'playlistItems'

@Injectable()
export class Youtube {
  constructor(private readonly httpService: HttpService) {}

  async getPlaylistById(id: string): Promise<YoutubePlaylist> {
    const response = await this.fetch('playlists', { field: 'id', value: id })
    const playlist = response.items.shift()

    return {
      id: playlist.id,
      snippet: { ...playlist.snippet, publishedAt: new Date(playlist.snippet.publishedAt) },
    }
  }

  async getVideoById(id: string): Promise<YoutubeVideo> {
    const response = await this.fetch('videos', { field: 'id', value: id })
    const video = response.items.shift()

    return {
      id: video.id,
      snippet: { ...video.snippet, publishedAt: new Date(video.snippet.publishedAt) },
    }
  }

  async findPlaylistsByChannelId(channelId: string): Promise<YoutubeVideo[]> {
    const response = await this.fetch('playlists', { field: 'channelId', value: channelId })
    const videos: any[] = response.items

    return videos.map(playlist => ({
      id: playlist.id,
      snippet: { ...playlist.snippet, publishedAt: new Date(playlist.snippet.publishedAt) },
    }))
  }

  async findVideosByPlaylistId(playlistId: string): Promise<YoutubeVideo[]> {
    const response = await this.fetch('playlistItems', { field: 'playlistId', value: playlistId })
    const videos: any[] = response.items

    return videos.map(video => ({
      id: video.snippet.resourceId.videoId,
      snippet: { ...video.snippet, publishedAt: new Date(video.snippet.publishedAt) },
    }))
  }

  private async fetch(resource: resources, filter: { field: string; value: string }): Promise<any> {
    return await this.httpService.get(this.getURL(resource, filter), {
      name: this.constructor.name,
    })
  }

  private getURL(resource: resources, filter: { field: string; value: string }, maxResults = 50): string {
    return `https://www.googleapis.com/youtube/v3/${resource}?maxResults=${maxResults}&key=${globalThis.secret.firebase_config.api_key}&part=snippet&${filter.field}=${filter.value}`
  }
}