Implement multi-user experience

[invisibleroads]

Among the topics discussed this morning was how to properly implement the multi-user experience.
https://docs.google.com/document/d/1enWIQKUBlPj7DxWjFTuv0d3eZ38eHv7xgUL4uZ9gs6s/edit#

• Work through how to implement live update when other users update an asset

  • Using Websockets
    • Channel ID = Utility ID
      • On Sign In, each user subscribes to a /utilities/UTILITY-ID
      • When server updates, it finds which utilities it should update
      • Sends message on each channel asking clients to refresh
      • Client listens to channel and refreshes on receiving update signal

• Decide how to update (PROBLEM: When multiple people are updating, one person's changes might overwrite another person's changes and this will happen if you send the whole JSON)

  • Option 1: Someone enters sketch mode, everyone else is locked out of editing that set of assets
    • PHASE 1: Lock everything that the user can edit on entering sketch mode
      • Each asset has a property isLocked = true/false
      • When user tries to sketch on locked assets, there is a error snackbar or dialog indicating that the assets are locked
    • [Postponed] PHASE 2:
      • If nothing is selected when they enter sketch mode, then they can only add assets.
      • Select what user wants to edit before entering sketch mode and only lock those assets.
  • Option 2: Update JSON as people are sketching (might complicate undo)