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

use super::IdentityCookie;

use crate::{
    app::App,
    clock::RequestedAt,
    error::{Internal, Unauthorized},
    token::{self, app::ValidateError},
    user::User,
};

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

impl FromRequestParts<App> for Identity {
    type Rejection = LoginError<Internal>;

    async fn from_request_parts(parts: &mut Parts, state: &App) -> Result<Self, Self::Rejection> {
        let Ok(cookie) = IdentityCookie::from_request_parts(parts, state).await;
        let RequestedAt(used_at) = RequestedAt::from_request_parts(parts, state).await?;

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

        let app = State::<App>::from_request_parts(parts, state).await?;
        app.tokens()
            .validate(&secret, &used_at)
            .await
            .map_err(|err| match err {
                ValidateError::InvalidToken => LoginError::Unauthorized,
                other => other.into(),
            })
    }
}

impl OptionalFromRequestParts<App> for Identity {
    type Rejection = LoginError<Internal>;

    async fn from_request_parts(
        parts: &mut Parts,
        state: &App,
    ) -> Result<Option<Self>, Self::Rejection> {
        match <Self as FromRequestParts<App>>::from_request_parts(parts, state).await {
            Ok(identity) => Ok(Some(identity)),
            Err(LoginError::Unauthorized) => Ok(None),
            Err(other) => Err(other),
        }
    }
}

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())
    }
}