This pull request is a full overhaul of the chat-composer and contains various improvements to the thread panel. They have been grouped in the same PR as lots of improvements/fixes to the thread panel needed an improved composer. This is meant as a first step.
### New features included in this PR
- A resizable side panel
- A clear dropzone area for uploads
- A simplified design for image uploads, this is only a first step towards more redesign of this area in the future
### Notable fixes in this PR
- Correct placeholder in thread panel
- Allows to edit the last message of a thread with arrow up
- Correctly focus composer when replying to a message
- The reply indicator is added instantly in the channel when starting a thread
- Prevents a large variety of bug where the composer could bug and prevent sending message or would clear your input while it has content
### Technical notes
To achieve this PR, three important changes have been made:
- `<ChatComposer>` has been fully rewritten and is now a glimmer component
- The chat composer now takes a `ChatMessage` as input which can directly be used in other operations, it simplifies a lot of logic as we are always working a with a `ChatMessage`
- `TextareaInteractor` has been created to wrap the existing `TextareaTextManipulation` mixin, it will make future migrations easier and allow us to have a less polluted `<ChatComposer>`
Note ".chat-live-pane" has been renamed ".chat-channel"
Design for upload dropzone is from @chapoi
Note this is a very large PR, and some of it could have been splited, but keeping it one chunk made it to merge conflicts and to revert if necessary. Actual new code logic is also not that much, as most of the changes are removing js tests, adding system specs or moving things around.
To make it possible this commit is doing the following changes:
- converting (and adding new) existing js acceptances tests into system tests. This change was necessary to ensure as little regressions as possible while changing paradigm
- moving away from store. Using glimmer and tracked properties requires to have class objects everywhere and as a result works well with models. However store/adapters are suffering from many bugs and limitations. As a workaround the `chat-api` and `chat-channels-manager` are an answer to this problem by encapsulating backend calls and frontend storage logic; while still using js models.
- dropping `appEvents` as much as possible. Using tracked properties and a better local storage of channel models, allows to be much more reactive and doesn’t require arbitrary manual updates everywhere in the app.
- while working on replacing store, the existing work of a chat api (backend) has been continued to support more cases.
- removing code from the `chat` service to separate concerns, `chat-subscriptions-manager` and `chat-channels-manager`, being the largest examples of where the code has been rewritten/moved.
Future wok:
- improve behavior when closing/deleting a channel, it's already slightly buggy on live, it's rare enough that it's not a big issue, but should be improved
- improve page objects used in chat
- move more endpoints to the API
- finish temporarily skipped tests
- extract more code from the `chat` service
- use glimmer for `chat-messages`
- separate concerns in `chat-live-pane`
- eventually add js tests for `chat-api`, `chat-channels-manager` and `chat-subscriptions-manager`, they are indirectly heavy tested through system tests but it would be nice to at least test the public API
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