pub mod get {
    use axum::{
        extract::{Path, State},
        response::{self, IntoResponse, Redirect},
    };

    use crate::{
        app::App,
        channel,
        error::Internal,
        token::extract::Identity,
        ui::{
            assets::{Asset, Assets},
            error::NotFound,
        },
    };

    pub async fn handler(
        State(app): State<App>,
        identity: Option<Identity>,
        Path(channel): Path<channel::Id>,
    ) -> Result<Asset, Error> {
        let _ = identity.ok_or(Error::NotLoggedIn)?;
        app.channels()
            .get(&channel)
            .await
            .map_err(Error::internal)?
            .ok_or(Error::NotFound)?;

        Assets::index().map_err(Error::Internal)
    }

    #[derive(Debug, thiserror::Error)]
    pub enum Error {
        #[error("requested channel not found")]
        NotFound,
        #[error("not logged in")]
        NotLoggedIn,
        #[error("{0}")]
        Internal(Internal),
    }

    impl Error {
        fn internal(err: impl Into<Internal>) -> Self {
            Self::Internal(err.into())
        }
    }

    impl IntoResponse for Error {
        fn into_response(self) -> response::Response {
            match self {
                Self::NotFound => match Assets::index() {
                    Ok(asset) => NotFound(asset).into_response(),
                    Err(internal) => internal.into_response(),
                },
                Self::NotLoggedIn => Redirect::temporary("/login").into_response(),
                Self::Internal(error) => error.into_response(),
            }
        }
    }
}