Draft: Nextcloud sync

Please test and comment.

data

• json data types for sync
• store episode_actions in a table
• store subscription_actions in a table
• store last sync date in a table
• store ADD & REMOVE on Source::update_url
• optimize dbqueries and use joinable!
• reconsider the feed fetch / sync order. (now fetch feeds -> sync subs (fetches new ones) -> sync eps)

conflicts

• ignore remote plays that happened before local plays unless they are finished plays
• ignore remote unsubs that happened before local subs
• ignore remote subs that happened before local unsubs

login

• get existing password from goa (gnome online accounts)
• add a ui to input the server/user/password
• check if password is app password
• turn real password into app password, parse response xml
• browser login flow v2
• store app password with oo7?
• delete app password on logout

upload

• POST subscriptions
• POST Episode Actions
• do a first time sync
• filter out stuff that is already on the server from the initial post
• do delta posts (only post things that happened since last change)

download

• GET subscriptions
• GET Episode Actions
• do a first time sync
• do delta GETs (add ?since parameter)

podcasts-gtk

• do a sync when an update(feed refresh) happens in the ui
• do a sync when closing
• do sync when pausing / changing track (add options)
• make the preferences gui look good
• show an inapp notification when a sync fails?
• show an inapp notification when a login fails

test

• test browser login
• test password login
• unit test json parsing
• unit tests for db sync data types
• unit tests with mock nextcloud server
• test initial post
  • Create a new Nextcloud account and sync an existing podcasts-sqlite-db to the new nextcloud account
  • Clear the podcasts-sqlite-db and restore it by logging into nextcloud
• test play
• test finish ep
• test subscribe
• test unsubscribe
• test with AntennaPod
  • Did a sync with an existing long runnning AntennaPod DB.
  • played an episode for a few seconds and confimed it was synced (both ways)
  • played an episode to the end and confimed it was synced (both ways)
  • subscribed to a new podcast and confimed it was synced (both ways)
  • unsubscribed from a podcast and confimed it was synced (both ways)
• test with kasts
  • played an episode for a few seconds and confimed it was synced (both ways)
  • played an episode to the end and confimed it was synced (both ways)
  • subscribed to a new podcast and confimed it was synced (both ways)
  • unsubscribed from a podcast and confimed it was synced (both ways)
• test a11y
  • None of the new UI shows any Errors in the Inspector a11y overlay
  • All elements are reachable via keyboard
  • Loading update messages get focused, although I'm not sure how well this works when switching between browser and Podcasts for the Login

Would Close #268