import { EventHandler } from './definitions'

interface PlayerEventRegistrar {
  registrations: Function[]
}

interface PlayerEventRegistrationMap {
  [ name: string ]: PlayerEventRegistrar
}

export class EventRegistrar {

  private eventRegistrations: PlayerEventRegistrationMap = {}

  public bindToChannel (channel: Channel.MessagingChannel) {
    for (let name of Object.keys(this.eventRegistrations)) {
      channel.bind(name, (txn, params) => this.fire(name, params))
    }
  }

  public registerTypes (names: string[]) {
    for (let name of names) {
      this.eventRegistrations[ name ] = { registrations: [] }
    }
  }

  public fire<T> (name: string, event: T) {
    this.eventRegistrations[ name ].registrations.forEach(x => x(event))
  }

  public addListener<T> (name: string, handler: EventHandler<T>) {
    if (!this.eventRegistrations[ name ]) {
      console.warn(`PeerTube: addEventListener(): The event '${name}' is not supported`)
      return false
    }

    this.eventRegistrations[ name ].registrations.push(handler)
    return true
  }

  public removeListener<T> (name: string, handler: EventHandler<T>) {
    if (!this.eventRegistrations[ name ]) return false

    this.eventRegistrations[ name ].registrations = this.eventRegistrations[ name ].registrations.filter(x => x === handler)

    return true
  }
}