3 files changed, 52 insertions, 15 deletions

diff --git a/src/channel/app.rs b/src/channel/app.rs
index cb7ad32..7c0b107 100644
--- a/src/channel/app.rs
+++ b/src/channel/app.rs
@@ -2,7 +2,7 @@ use chrono::TimeDelta;
 use itertools::Itertools;
 use sqlx::sqlite::SqlitePool;
 
-use super::{repo::Provider as _, Channel, Id};
+use super::{repo::Provider as _, Channel, History, Id};
 use crate::{
     clock::DateTime,
     db::NotFound,
@@ -36,6 +36,16 @@ impl<'a> Channels<'a> {
         Ok(channel.as_created())
     }
 
+    // This function is careless with respect to time, and gets you the channel as
+    // it exists in the specific moment when you call it.
+    pub async fn get(&self, channel: &Id) -> Result<Option<Channel>, sqlx::Error> {
+        let mut tx = self.db.begin().await?;
+        let channel = tx.channels().by_id(channel).await.optional()?;
+        tx.commit().await?;
+
+        Ok(channel.iter().flat_map(History::events).collect())
+    }
+
     pub async fn delete(&self, channel: &Id, deleted_at: &DateTime) -> Result<(), Error> {
         let mut tx = self.db.begin().await?;
 
diff --git a/src/db/mod.rs b/src/db/mod.rs
index b9c59ef..36d888f 100644
--- a/src/db/mod.rs
+++ b/src/db/mod.rs
@@ -97,24 +97,33 @@ pub enum Error {
 
 pub trait NotFound {
     type Ok;
+    type Error;
+
     fn not_found<E, F>(self, map: F) -> Result<Self::Ok, E>
     where
-        E: From<sqlx::Error>,
+        E: From<Self::Error>,
         F: FnOnce() -> E;
+
+    fn optional(self) -> Result<Option<Self::Ok>, Self::Error>;
 }
 
 impl<T> NotFound for Result<T, sqlx::Error> {
     type Ok = T;
+    type Error = sqlx::Error;
+
+    fn optional(self) -> Result<Option<T>, sqlx::Error> {
+        match self {
+            Ok(value) => Ok(Some(value)),
+            Err(sqlx::Error::RowNotFound) => Ok(None),
+            Err(other) => Err(other),
+        }
+    }
 
     fn not_found<E, F>(self, map: F) -> Result<T, E>
     where
         E: From<sqlx::Error>,
         F: FnOnce() -> E,
     {
-        match self {
-            Err(sqlx::Error::RowNotFound) => Err(map()),
-            Err(other) => Err(other.into()),
-            Ok(value) => Ok(value),
-        }
+        self.optional()?.ok_or_else(map)
     }
 }
diff --git a/src/ui.rs b/src/ui.rs
index 18dd049..9654195 100644
--- a/src/ui.rs
+++ b/src/ui.rs
@@ -1,24 +1,24 @@
 use axum::{
-    extract::Path,
+    extract::{Path, State},
     http::{header, StatusCode},
-    response::{IntoResponse, Response},
+    response::{IntoResponse, Redirect, Response},
     routing::get,
     Router,
 };
 use mime_guess::Mime;
 use rust_embed::EmbeddedFile;
 
+use crate::{app::App, channel, error::Internal, login::Login};
+
 #[derive(rust_embed::Embed)]
 #[folder = "hi-ui/build"]
 struct Assets;
 
-pub fn router<S>() -> Router<S>
-where
-    S: Clone + Send + Sync + 'static,
-{
+pub fn router() -> Router<App> {
     Router::new()
         .route("/*path", get(asset))
         .route("/", get(root))
+        .route("/ch/:channel", get(channel))
 }
 
 async fn asset(Path(path): Path<String>) -> Result<Asset, NotFound<String>> {
@@ -29,8 +29,24 @@ async fn asset(Path(path): Path<String>) -> Result<Asset, NotFound<String>> {
         .ok_or(NotFound(format!("not found: {path}")))
 }
 
-async fn root() -> impl IntoResponse {
-    asset(Path(String::from("index.html"))).await
+async fn root() -> Result<Asset, Internal> {
+    // "not found" in this case really is an internal error, as it should
+    // never happen. `index.html` is a known-valid path.
+    Ok(asset(Path(String::from("index.html"))).await?)
+}
+
+async fn channel(
+    State(app): State<App>,
+    login: Option<Login>,
+    Path(channel): Path<channel::Id>,
+) -> Result<impl IntoResponse, Internal> {
+    Ok(if login.is_none() {
+        Redirect::temporary("/").into_response()
+    } else if app.channels().get(&channel).await?.is_none() {
+        NotFound(root().await?).into_response()
+    } else {
+        root().await?.into_response()
+    })
 }
 
 struct Asset(Mime, EmbeddedFile);
@@ -47,6 +63,8 @@ impl IntoResponse for Asset {
     }
 }
 
+#[derive(Debug, thiserror::Error)]
+#[error("{0}")]
 struct NotFound<E>(pub E);
 
 impl<E> IntoResponse for NotFound<E>