/**
* Prepares the channel and playlist entities for the subscription to the
* specified channel.
*
* @param entityManager The current entity manager in a transaction used to
* update the subscriptions.
* @param channel The entity representing the channel for which the
* subscription is being prepared.
* @return The channel entity representing the provided channel within this
* extension's database.
*/
async [PRIVATE.prepareSubscription](entityManager: EntityManager,
channel: Channel): {knownChannel: Channel, playlist: Playlist} {
let knownChannel = await entityManager.find(Channel, channel.id)
if (!knownChannel) {
knownChannel = await entityManager.persist(channel)
}
let playlist = await entityManager.find(
Playlist,
knownChannel.uploadsPlaylistId
)
if (!playlist) {
playlist = await this[PRIVATE.fetchUploadsPlaylist](channel)
playlist = await entityManager.persist(playlist)
}
return {
knownChannel,
playlist
}
}
/**
* Processes the provided subscription, adding it to the subscriptions in the
* database if not already present, and checking, updating and saving the
* related channel and uploads playlist.
*
* @param entityManager The current entity manager in a transaction used to
* update the subscriptions.
* @param knownSubscriptions A map of channel IDs to subscriptions to the
* channels.
* @param subscription The subscription to the channel.
* @param channel The channel to which the user is subscribed.
*/
async [PRIVATE.processSubscription](entityManager: EntityManager,
knownSubscriptions: Map<string, Subscription>,
subscription: Subscription, channel: Channel): void {
// save new subscriptions
if (!knownSubscriptions.has(channel.id)) {
await entityManager.persist(subscription)
}
let {knownChannel, playlist} = await this[PRIVATE.prepareSubscription](
entityManager,
channel
)
// update existing subscriptions
this[PRIVATE.updateKnownSubscription](
entityManager,
account,
knownChannel,
playlist
)
}