Rename "channel" to "conversation" within the server.

I've split this from the schema and API changes because, frankly, it's huge. Annoyingly so. There are no semantic changes in this, it's all symbol changes, but there are a _lot_ of them because the term "channel" leaks all over everything in a service whose primary role is managing messages sent to channels (now, conversations).

I found a buggy test while working on this! It's not fixed in this commit, because it felt mean to hide a real change in the middle of this much chaff.

2 files changed, 193 insertions, 0 deletions

diff --git a/src/conversation/handlers/send/mod.rs b/src/conversation/handlers/send/mod.rs
new file mode 100644
index 0000000..9ec020a
--- /dev/null
+++ b/src/conversation/handlers/send/mod.rs
@@ -0,0 +1,63 @@
+use axum::{
+    extract::{Json, Path, State},
+    http::StatusCode,
+    response::{self, IntoResponse},
+};
+
+use crate::conversation::handlers::PathInfo;
+use crate::{
+    app::App,
+    clock::RequestedAt,
+    error::{Internal, NotFound},
+    message::{Body, Message, app::SendError},
+    token::extract::Identity,
+};
+
+#[cfg(test)]
+mod test;
+
+pub async fn handler(
+    State(app): State<App>,
+    Path(conversation): Path<PathInfo>,
+    RequestedAt(sent_at): RequestedAt,
+    identity: Identity,
+    Json(request): Json<Request>,
+) -> Result<Response, Error> {
+    let message = app
+        .messages()
+        .send(&conversation, &identity.user, &sent_at, &request.body)
+        .await?;
+
+    Ok(Response(message))
+}
+
+#[derive(serde::Deserialize)]
+pub struct Request {
+    pub body: Body,
+}
+
+#[derive(Debug)]
+pub struct Response(pub Message);
+
+impl IntoResponse for Response {
+    fn into_response(self) -> response::Response {
+        let Self(message) = self;
+        (StatusCode::ACCEPTED, Json(message)).into_response()
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+#[error(transparent)]
+pub struct Error(#[from] pub SendError);
+
+impl IntoResponse for Error {
+    fn into_response(self) -> response::Response {
+        let Self(error) = self;
+        match error {
+            SendError::ConversationNotFound(_) | SendError::ConversationDeleted(_) => {
+                NotFound(error).into_response()
+            }
+            SendError::Name(_) | SendError::Database(_) => Internal::from(error).into_response(),
+        }
+    }
+}
diff --git a/src/conversation/handlers/send/test.rs b/src/conversation/handlers/send/test.rs
new file mode 100644
index 0000000..bd32510
--- /dev/null
+++ b/src/conversation/handlers/send/test.rs
@@ -0,0 +1,130 @@
+use axum::extract::{Json, Path, State};
+use futures::stream::{self, StreamExt as _};
+
+use crate::{
+    conversation,
+    event::Sequenced,
+    message::app::SendError,
+    test::fixtures::{self, future::Expect as _},
+};
+
+#[tokio::test]
+async fn messages_in_order() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+    let sender = fixtures::identity::create(&app, &fixtures::now()).await;
+    let conversation = fixtures::conversation::create(&app, &fixtures::now()).await;
+    let resume_point = fixtures::boot::resume_point(&app).await;
+
+    // Call the endpoint (twice)
+
+    let requests = vec![
+        (fixtures::now(), fixtures::message::propose()),
+        (fixtures::now(), fixtures::message::propose()),
+    ];
+
+    for (sent_at, body) in &requests {
+        let request = super::Request { body: body.clone() };
+
+        let _ = super::handler(
+            State(app.clone()),
+            Path(conversation.id.clone()),
+            sent_at.clone(),
+            sender.clone(),
+            Json(request),
+        )
+        .await
+        .expect("sending to a valid conversation succeeds");
+    }
+
+    // Verify the semantics
+
+    let mut events = app
+        .events()
+        .subscribe(resume_point)
+        .await
+        .expect("subscribing always succeeds")
+        .filter_map(fixtures::event::stream::message)
+        .filter_map(fixtures::event::stream::message::sent)
+        .zip(stream::iter(requests));
+
+    while let Some((event, (sent_at, body))) = events
+        .next()
+        .expect_ready("an event should be ready for each message")
+        .await
+    {
+        assert_eq!(*sent_at, event.at());
+        assert_eq!(sender.user.id, event.message.sender);
+        assert_eq!(body, event.message.body);
+    }
+}
+
+#[tokio::test]
+async fn nonexistent_conversation() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+    let sender = fixtures::identity::create(&app, &fixtures::now()).await;
+
+    // Call the endpoint
+
+    let sent_at = fixtures::now();
+    let conversation = conversation::Id::generate();
+    let request = super::Request {
+        body: fixtures::message::propose(),
+    };
+    let super::Error(error) = super::handler(
+        State(app),
+        Path(conversation.clone()),
+        sent_at,
+        sender,
+        Json(request),
+    )
+    .await
+    .expect_err("sending to a nonexistent conversation fails");
+
+    // Verify the structure of the response
+
+    assert!(matches!(
+        error,
+        SendError::ConversationNotFound(error_conversation) if conversation == error_conversation
+    ));
+}
+
+#[tokio::test]
+async fn deleted_conversation() {
+    // Set up the environment
+
+    let app = fixtures::scratch_app().await;
+    let sender = fixtures::identity::create(&app, &fixtures::now()).await;
+    let conversation = fixtures::conversation::create(&app, &fixtures::now()).await;
+
+    app.conversations()
+        .delete(&conversation.id, &fixtures::now())
+        .await
+        .expect("deleting a new conversation succeeds");
+
+    // Call the endpoint
+
+    let sent_at = fixtures::now();
+    let request = super::Request {
+        body: fixtures::message::propose(),
+    };
+    let super::Error(error) = super::handler(
+        State(app),
+        Path(conversation.id.clone()),
+        sent_at,
+        sender,
+        Json(request),
+    )
+    .await
+    .expect_err("sending to a deleted conversation fails");
+
+    // Verify the structure of the response
+
+    assert!(matches!(
+        error,
+        SendError::ConversationDeleted(error_conversation) if conversation.id == error_conversation
+    ));
+}