bunch of design decisions related to the entire architecture of Stremio (notifications, calendar, library) about stremio-core HOT 1 CLOSED

How to re-implement Calendar/Notifications to be add-on based

And as a result, not requiring additional backend work and more importantly, extendable

• The add-on system would gain "multi" catalogs that return CatalogDetailResp { metasDetailed: Vec<MetaDetail> }; they take a required extra prop ids, which is in the format ["tt0944947", ...]
• cinemeta/channels and potentially others (#24) implement those, and implement "last-videos" catalog IDs which return a MetaDetail with videos being set to the last N videos; even if cinemeta is static, this can be done via a Cloudflare worker
• LibAddon would implement resource(s) that the Calendar and Notifications can use directly
  • for example, a new /videos/ resource, with extra prop whereIsNew which allows you to specify either new or non-new videos
  • alternatively, we can use the same CatalogDetailResp but without ids and instead with isNew - seems like the cleaner way to go
• the LibAddon would query all "last-videos" catalogs with ids set to the most watched series/channels of the user
• this will happen in an asynchronous tick (in action: UpdateLastVids, out action: LastVidsUpdated); this out action should trigger re-requests of the resources used for Calendar/Notifications
• if any of the addons errors or times out, we can fallback on our own cache (managed by the LibAddon)
• results of the resources for Calendar/Notifications can update even offline and without LastVidsUpdated happening: since every time we recalculate the results, some videos that were upcoming might have become available
• the way we mark notifications as seen is by keeping state.last_video_released for each LibItem; all of the videos where released is larger than state.last_video_released are considered new to the user
  • for new library items, this value won't be set, and we will use the libitem ctime instead
  • compat: we can update this property each time a datastorePut is done for a notif to maintain compatibility with older versions
  • caveat: compraed to the previous system, this obviously cannot keep state for each video individually; this shouldn't be a big issue, since users watch videos in succession and there's also watched (watchedBitfield)

from stremio-core.