use axum::{
    extract::{FromRequestParts, State},
    http::request::Parts,
    response::{IntoResponse, Response},
};

use super::IdentityToken;

use crate::{
    app::App,
    clock::RequestedAt,
    error::{Internal, Unauthorized},
    login::{app::ValidateError, Login},
    token,
};

#[derive(Clone, Debug)]
pub struct Identity {
    pub token: token::Id,
    pub login: Login,
}

#[async_trait::async_trait]
impl FromRequestParts<App> for Identity {
    type Rejection = LoginError<Internal>;

    async fn from_request_parts(parts: &mut Parts, state: &App) -> Result<Self, Self::Rejection> {
        // After Rust 1.82 (and #[feature(min_exhaustive_patterns)] lands on
        // stable), the following can be replaced:
        //
        // ```
        // let Ok(identity_token) = IdentityToken::from_request_parts(
        //     parts,
        //     state,
        // ).await;
        // ```
        let identity_token = IdentityToken::from_request_parts(parts, state).await?;
        let RequestedAt(used_at) = RequestedAt::from_request_parts(parts, state).await?;

        let secret = identity_token.secret().ok_or(LoginError::Unauthorized)?;

        let app = State::<App>::from_request_parts(parts, state).await?;
        match app.logins().validate(&secret, &used_at).await {
            Ok((token, login)) => Ok(Identity { token, login }),
            Err(ValidateError::InvalidToken) => Err(LoginError::Unauthorized),
            Err(other) => Err(other.into()),
        }
    }
}

pub enum LoginError<E> {
    Failure(E),
    Unauthorized,
}

impl<E> IntoResponse for LoginError<E>
where
    E: IntoResponse,
{
    fn into_response(self) -> Response {
        match self {
            Self::Unauthorized => Unauthorized.into_response(),
            Self::Failure(e) => e.into_response(),
        }
    }
}

impl<E> From<E> for LoginError<Internal>
where
    E: Into<Internal>,
{
    fn from(err: E) -> Self {
        Self::Failure(err.into())
    }
}