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},
    util::form_decode,
    AuthContext, User,
};

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

const LAST_SEEN_QUERY: &str = "update witches set last_seen = (select unixepoch()) where id = $1";

//-************************************************************************
// 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 => (
                StatusCode::INTERNAL_SERVER_ERROR,
                "An unknown error occurred; you cursed, brah?",
            )
                .into_response(),
            _ => (StatusCode::BAD_REQUEST, 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::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)?;

            // update last_seen; maybe this is ok to fail?
            sqlx::query(LAST_SEEN_QUERY)
                .bind(user.id)
                .execute(&pool)
                .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 {
    todo!()
}

pub async fn post_logout() -> impl IntoResponse {
    todo!()
}