use argon2::{
    password_hash::{PasswordHash, PasswordVerifier},
    Argon2,
};
use axum::{
    extract::State,
    http::StatusCode,
    response::{IntoResponse, Redirect, Response},
    Form,
};
use sqlx::SqlitePool;

use crate::{
    templates::{LoginGet, LoginPost, LogoutGet, LogoutPost},
    util::form_decode,
    AuthContext, User,
};

//-************************************************************************
// Constants
//-************************************************************************

//-************************************************************************
// Login error and success types
//-************************************************************************

#[Error]
pub struct LoginError(#[from] LoginErrorKind);

#[Error]
#[non_exhaustive]
pub enum LoginErrorKind {
    Internal,
    BadPassword,
    BadUsername,
    Unknown,
}

impl IntoResponse for LoginError {
    fn into_response(self) -> Response {
        match self.0 {
            LoginErrorKind::Unknown | LoginErrorKind::Internal => (
                StatusCode::INTERNAL_SERVER_ERROR,
                "An unknown error occurred; you cursed, brah?",
            )
                .into_response(),
            _ => (StatusCode::OK, format!("{self}")).into_response(),
        }
    }
}

//-************************************************************************
// Login handlers
//-************************************************************************

/// Handle login queries
#[axum::debug_handler]
pub async fn post_login(
    mut auth: AuthContext,
    State(pool): State<SqlitePool>,
    Form(login): Form<LoginPost>,
) -> Result<impl IntoResponse, LoginError> {
    let username = form_decode(&login.username, LoginErrorKind::BadUsername)?;
    let username = username.trim();

    let pw = form_decode(&login.password, LoginErrorKind::BadPassword)?;
    let pw = pw.trim();

    let user = User::try_get(username, &pool)
        .await
        .map_err(|_| LoginErrorKind::Unknown)?;

    let verifier = Argon2::default();
    let hash = PasswordHash::new(&user.pwhash).map_err(|_| LoginErrorKind::Internal)?;
    match verifier.verify_password(pw.as_bytes(), &hash) {
        Ok(_) => {
            // log them in and set a session cookie
            auth.login(&user)
                .await
                .map_err(|_| LoginErrorKind::Internal)?;

            Ok(Redirect::temporary("/"))
        }
        _ => Err(LoginErrorKind::BadPassword.into()),
    }
}

pub async fn get_login() -> impl IntoResponse {
    LoginGet::default()
}

pub async fn get_logout() -> impl IntoResponse {
    LogoutGet
}

pub async fn post_logout(mut auth: AuthContext) -> impl IntoResponse {
    if auth.current_user.is_some() {
        auth.logout().await;
    }
    LogoutPost
}

#[cfg(test)]
mod test {
    use std::time::Duration;

    use axum::body::Bytes;
    use axum_test::TestServer;

    use crate::{
        db,
        signup::create_user,
        templates::{LoginGet, LogoutGet, LogoutPost},
    };

    async fn tserver() -> TestServer {
        let pool = db::get_pool().await;
        let secret = [0u8; 64];

        tokio::time::sleep(Duration::from_secs(2)).await;

        let _user = create_user(
            "test_user",
            &Some("Test User".to_string()),
            &Some("mail@email".to_string()),
            "aaaa".as_bytes(),
            &pool,
        )
        .await
        .unwrap();

        let r = sqlx::query("select count(*) from witches")
            .fetch_one(&pool)
            .await;
        assert!(r.is_ok());

        let app = crate::app(pool, &secret).await.into_make_service();

        TestServer::new(app).unwrap()
    }

    #[tokio::test]
    async fn get_login() {
        let s = tserver().await;
        let resp = s.get("/login").await;
        let body = std::str::from_utf8(resp.bytes()).unwrap().to_string();
        assert_eq!(body, LoginGet::default().to_string());
    }

    #[tokio::test]
    async fn post_login_success() {
        let s = tserver().await;

        let form = "username=test_user&password=aaaa".to_string();
        let bytes = form.as_bytes();
        let body = Bytes::copy_from_slice(bytes);

        let resp = s
            .post("/login")
            .expect_failure()
            .content_type("application/x-www-form-urlencoded")
            .bytes(body)
            .await;
        assert_eq!(resp.status_code(), 303);
    }

    #[tokio::test]
    async fn post_login_bad_user() {
        let s = tserver().await;

        let form = "username=test_LOSER&password=aaaa".to_string();
        let bytes = form.as_bytes();
        let body = Bytes::copy_from_slice(bytes);

        let resp = s
            .post("/login")
            .expect_success()
            .content_type("application/x-www-form-urlencoded")
            .bytes(body)
            .await;
        assert_eq!(resp.status_code(), 200);
    }

    #[tokio::test]
    async fn get_logout() {
        let s = tserver().await;
        let resp = s.get("/logout").await;
        let body = std::str::from_utf8(resp.bytes()).unwrap().to_string();
        assert_eq!(body, LogoutGet.to_string());
    }

    #[tokio::test]
    async fn post_logout() {
        let s = tserver().await;
        let resp = s.post("/logout").await;
        resp.assert_status_ok();
        let body = std::str::from_utf8(resp.bytes()).unwrap();
        let default = LogoutPost.to_string();
        assert_eq!(body, &default);
    }
}