hyaenidae/TODO.md

# Things That Need To Be Done

## Actix Web 4.0
It's not out yet, and not everything has a beta release yet, but we should continue tracking the
status of 4.0 and update our libraries as we can.

## Async
A lot of logic in the Profiles and Submissions modules synchronously accesses Sled, which is an
issue because Sled is potentially blocking. All of the Big Dangers (transactions) are safely on a
threadpool already, but a couple iterations are currently occuring directly on the Arbiters.

## Organization
A lot of modules in hyaenidae-server have circular dependencies, and a few are more than a thousand
lines long, each. These should be separated where possible into smaller modules which create a
dependency DAG

## Record Caching
Although Sled itself has in-memory caching for data, anything that requires
serialization/deserialization should be read at most once when in a route. This can be done in a
manner similar to the FederationView in the admin module. We build HashMaps mapping object IDs to
the Objects, and construct Vecs of Object IDs to denote ordering of objects. The view then produces
iterators over references to Objects by iterating over the IDs and fetching objects from the
HashMap.

#### Example
```rust
struct SubmissionView<'a> {
    author: &'a Profile,
    submission: &'a Submission,
}

impl<'a> SubmissionView<'a> {
    fn whatever_method(&self) -> String {
        ...
    }
}

struct ViewState {
    profiles: HashMap<Uuid, Profile>,
    submissions: HashMap<Uuid, Submission>,
    ordered: Vec<Uuid>,
}

impl ViewState {
    fn submissions<'a>(&'a self) -> impl Iterator<Item = SubmissionView<'a>> + 'a {
        self.ordered.iter().filter_map(move |id| {
            let submission = self.submissions.get(id)?;
            let author = self.profiles.get(&submission.profile_id())?;

            Some(SubmissionView { author, submission })
        })
    }
}
```

This pattern allows for each Object to be stored at most once during a route, and it also avoids
cloning when multiple submissions were posted by the same profile, for example.

## Tags
Tags are useful for searching Hyaenidae for content. There should be a tag system that makes it
simple to search for submissions.

Tasks:
- Design a Tag database optimized for multi-tag lookups (within reason)
- Design a UI for authors to add tags to a submission
- Design ActivityPub interop for tag federation

## Reports
Reports are implemented for on-server moderation, but cross-server moderation has not been tested.

Tasks:
- Add a "delete" mechanism for remote objects. This should not induce any federation, but should
    ensure the object is not accessible locally
- Enable forwarding reports to origin server. There is already code written to perform this
    forwarding, but it is not exposed in the UI.

## Reacts
Reacts are similar to "likes" on other platforms, but do not get added to a collection for a given
profile. Reacts only notify the author of the item being reacted to.

Tasks:
- Design a UI for reacting to submissions
- Design a UI for reacting to comments
- Design a UI for reacting to posts (see Posts)
- Decide which kinds of reacts are valid

## Posts
Posts are top-level content created by profiles that do not have associated images, and so cannot be
considered Submissions. Posts are stored and viewed separately from submissions, and are more
"ephemeral" in that they will not backfill (see Backfills).

Tasks:
- Design a Post database
- Design a UI for creating new posts
- Design a UI for viewing posts from followed accounts
- Hook Posts into Note federation code

## Direct Messages
Direct Messages are Posts that are shared directly between two profiles, and are not publically
visible to other profiles.

## Backfills
Bakfills for a given item should not be permitted to run concurrently. A single backfill task may be
permitted to have multiple requests in-flight, but no two tasks may backfill the same item. There
should also be a limit on concurrency for backfills from a given server

Tasks:
- Add Profile Backfill on federation
- Add Submission Backfill on follow

## Object Cleanup
When things get deleted or suspended, we need to ensure that the database does not hold onto any
lingering data. This includes cleaning text fields for deleted items, cleaning up dependent items on
deletion.

Tasks:
- Differentiate between Profile Deletion and Profile Suspsension
- Federate profile suspensions for local suspended profiles
- Delete profiles (and submissions and comments and reacts) for defederated servers

## Federation Fixes
Not all of federation has been tested yet

Things that have been tested:
- Federation:
    - Request
    - Accept
    - Reject
    - Defederate
- Profiles:
    - Create
    - Update
- Submissions:
    - Create
    - Update

Anything not in this list has not been tested and needs to be verified and possibly fixed.