ToolsPCastApi-TS/src/apis/Channels.ts

import {HttpMethod} from '../net/http/HttpMethod';
import type {PCastHttpRequests} from './PCastRequests';
import type {ChannelResponse, ChannelsResponse, MembersResponse} from './IResponse';

export type ChannelId = string;
export type Channel = {
  options: string[];
  alias: string;
  name: string;
  description: string;
  type: string;
  streamKey: string;
  created: string;
  lastUpdated: string;
  channelId: string;
};
export type ChannelAlias = string;
export type Member = {
  sessionId: string;
  screenName: string;
  role: string;
  streams: [
    {
      type: string;
      uri: string;
      audioState: string;
      videoState: string;
    }
  ];
  state: string;
  lastUpdate: number;
};

type GetChannelParams = {
  alias?: string;
  channelId?: string;
};

export class ChannelError extends Error {
  constructor(
    message: string,
    public readonly code: string
  ) {
    super(message);
    this.name = 'ChannelError';
  }
}

export class Channels {
  private readonly _httpRequests: PCastHttpRequests;
  private readonly _channelsByAlias: Map<ChannelAlias, Channel> = new Map();

  constructor(pcastHttpRequests: PCastHttpRequests, skipInitialization = false) {
    this._httpRequests = pcastHttpRequests;
    if (!skipInitialization) {
      this.initialize();
    }
  }

  public async create(name: string, description: string, channelOptions: string[] = []): Promise<Channel> {
    if (!name || name.trim().length === 0) {
      throw new ChannelError('Channel name cannot be empty', 'INVALID_NAME');
    }

    if (!description || description.trim().length === 0) {
      throw new ChannelError('Channel description cannot be empty', 'INVALID_DESCRIPTION');
    }

    if (!Array.isArray(channelOptions)) {
      throw new ChannelError('Channel options must be an array', 'INVALID_OPTIONS');
    }

    const createChannel = {
      channel: {
        name: name.trim(),
        alias: name.trim(),
        description: description.trim(),
        options: channelOptions
      }
    };

    const route = '/channel';
    const requestOptions = {body: JSON.stringify(createChannel)};
    const response = await this._httpRequests.request<ChannelResponse>(HttpMethod.PUT, route, requestOptions);

    if (!response.channel) {
      throw new ChannelError('Invalid response format - missing channel data', 'INVALID_RESPONSE');
    }

    this._channelsByAlias.set(response.channel.alias, response.channel);

    return response.channel;
  }

  public async list(): Promise<Channel[]> {
    const response = await this._httpRequests.request<ChannelsResponse>(HttpMethod.GET, '/channels');

    if (!response.channels) {
      throw new ChannelError('Invalid response format - missing channels data', 'INVALID_RESPONSE');
    }

    this._channelsByAlias.clear();

    for (const channel of response.channels) {
      this._channelsByAlias.set(channel.alias, channel);
    }

    return response.channels;
  }

  public async refreshCache(): Promise<void> {
    // eslint-disable-next-line @typescript-eslint/no-unused-vars
    const ignored = await this.list();
  }

  public async getChannelInfoByAlias(alias: string): Promise<Channel | undefined> {
    return this.get({alias});
  }

  public async get({alias, channelId}: GetChannelParams): Promise<Channel | undefined> {
    if (!alias && !channelId) {
      throw new ChannelError('Either alias or channelId must be provided', 'MISSING_PARAMETER');
    }

    if (alias && this._channelsByAlias.has(alias)) {
      return this._channelsByAlias.get(alias);
    }

    const channelList = await this.list();

    return alias ? channelList.find(channel => channel.alias === alias) : channelList.find(channel => channel.channelId === channelId);
  }

  public async getPublisherCount(channelId: string): Promise<number> {
    const response = await this._httpRequests.request<string>(HttpMethod.GET, `/channel/${encodeURIComponent(channelId)}/publishers/count`);

    return parseInt(response, 10);
  }

  public async getMembers(channelId: string): Promise<Member[]> {
    if (!channelId || channelId.trim().length === 0) {
      throw new ChannelError('Channel ID cannot be empty', 'INVALID_CHANNEL_ID');
    }

    const response = await this._httpRequests.request<MembersResponse>(HttpMethod.GET, `/channel/${encodeURIComponent(channelId)}/members`);

    if (!response.members) {
      throw new ChannelError(`Invalid response format for channel members: ${channelId}`, 'INVALID_RESPONSE');
    }

    return response.members;
  }

  public async getMembersByChannelAlias(alias: string): Promise<Member[]> {
    const channel = await this.get({alias});

    if (!channel) {
      throw new ChannelError(`Channel not found: ${alias}`, 'CHANNEL_NOT_FOUND');
    }

    return this.getMembers(channel.channelId);
  }

  public async delete({channelId, alias}: {channelId?: string; alias?: string}): Promise<Channel> {
    if (!channelId && !alias) {
      throw new ChannelError('Deleting a channel requires either a channelId or alias', 'INVALID_ARGUMENTS');
    }

    const channelIdToDelete = alias ? (await this.get({alias}))?.channelId : channelId;

    if (!channelIdToDelete) {
      throw new ChannelError('Unable to find room to delete', 'NOT_FOUND');
    }

    const route = `/channel/${encodeURIComponent(channelIdToDelete)}`;
    const response = await this._httpRequests.request<ChannelResponse>(HttpMethod.DELETE, route);

    if (!response.channel) {
      throw new ChannelError(`Invalid response format for deleted channel [${channelId}]`, 'INVALID_RESPONSE');
    }

    const deletedChannel = response.channel;

    if (this._channelsByAlias.has(deletedChannel.alias)) {
      this._channelsByAlias.delete(deletedChannel.alias);
    }

    return deletedChannel;
  }

  async getPublishSourceStreamId(channelId: string, retryCount: number = 3): Promise<string | null> {
    const retryCountRemaining = retryCount || 3;
    const channelMembers = await this.getMembers(channelId);

    if (channelMembers.length === 0) {
      if (retryCountRemaining > 0) {
        return this.getPublishSourceStreamId(channelId, retryCountRemaining - 1);
      }

      return null;
    }

    const presenter = channelMembers.find(member => member.role === 'Presenter');

    if (!presenter) {
      if (retryCountRemaining > 0) {
        return this.getPublishSourceStreamId(channelId, retryCountRemaining - 1);
      }

      return null;
    }

    const publishSourceStreamIdRegExp = /pcast:\/\/.*\/([^?]*)/;

    return presenter.streams[0].uri.match(publishSourceStreamIdRegExp)?.[1] ?? null;
  }

  // TODO(AZ): Implement this
  // public async fork(channelId: string): Promise<Channel>

  // TODO(AZ): Implement this
  // public async killChannel(channelId: string): Promise<Channel>

  // TODO(AZ): Implement this
  // public async publishViaUrl(mediaUriToPublish: string, token: string): Promise<Channel>

  private async initialize(): Promise<void> {
    try {
      const channelsList = await this.list();
      if (!channelsList) {
        console.warn('[Channels] Failed to initialize cache - no channels returned');
        return;
      }

      for (const channel of channelsList) {
        this._channelsByAlias.set(channel.alias, channel);
      }
    } catch (error) {
      console.error('[Channels] Failed to initialize cache:', error);
    }
  }
}