Show or create direct message room

[alfogrillo]

As a user I want to create a new 1:1 chat with an other user.

• The users can use the matrix-id of an other user to create a new chat
• A new timeline view is shown

Designs
Start a chat

Note

• The creation of the room on the first message has been moved here: Create a DM chat after the first message is sent #1160. @Florian14 is leading the conversation for the implementation here.

ACs

• The user can type a matrix identifier in the search field
• Exactly one user with the typed identifier will be shown under the search field
• The real search isn't part of this ticket we just want to navigate to a DM room with the matrix identifier the user is typing
• Tap on the user opens a timeline with the user's avatar and display name
• The search screen should be dismissed before the navigation to the timeline
• The room is created after the user taps on a person he found
  • A fullscreen loader should be shown during the creation
  • Show a fullscreen alert in case of errors
    - Title: "Server error"
    - Description: "An error occurred when trying to start a chat"
    - "Cancel" button: dismiss the alert
    - "Retry" button: retries the room creation
• ⚠️ When creating new chat the room preset should be: preset: trusted_private_chat
• If a user has already a pending chat with another user, the existing timeline should be shown instead
  • The account_data.m.direct must be used to check the pending DM chats with a given user (more details here)
  • Show the first room with the target user in the account_data.m.direct where the current user has the join membership (if any).

APIs

• Create room
• Users' profiles

Out of scope

• Creating a 1:1 with an email will add the email to the m.direct dictionary of the account data. This email is then replaced with the matrixId when the user creates an account. This is currently done client side. -> should we keep this behaviour and will this be done in the rust sdk?
• After creating a 1:1 with an email, when the user creates an account, there are then 3 members in the room (myUserId, the email address, the otherUserId) -> how to manage this?
• When creating a DM (1:1 or group) including an email, the DM is not encrypted because the second user will not be able to decrypt messages sent before joining the room with the account. This should be solved by setting the history visibility to shared (currently, this is not supported on mobile clients)
• Should we also support MSISDN invites?

Tasks

Preview Give feedback

1. Add "createRoom" Rust binding matrix-org/matrix-rust-sdk#1615
   Z-ElementX-Alpha enhancement good first issue +3
   
2. Expose get_dm_room to UniFFI matrix-org/matrix-rust-sdk#1673
   Z-ElementX-Alpha enhancement +2
   
3. Update m.direct account_data when creating a new DM room matrix-org/matrix-rust-sdk#1674
   Z-ElementX-Alpha enhancement +2
   
4. Make "name" optional when creating a room matrix-org/matrix-rust-sdk#1698
   Z-ElementX-Alpha enhancement good first issue +3
   
5. Show or create direct message room vector-im/element-x-android#96
   T-Enhancement Team: Element X Feature +2
   
6. Show or create direct message room vector-im/element-x-ios#595
   T-Enhancement Team: Element X Feature +2