use askama::Template;
use axum::{
    async_trait,
    extract::{self, FromRef, FromRequestParts},
    http::{request::Parts, StatusCode},
    response::{Html, IntoResponse, Response},
    routing::{get, post},
    Form, Json, Router,
};
use hyper::{header, HeaderMap};
use serde::Deserialize;
use sqlx::{query, SqlitePool};
use std::{env, net::SocketAddr};
use tower_http::services::ServeDir;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};

const DB_URL: &str = "sqlite://sqlite.db";

#[tokio::main]
async fn main() {
    tracing_subscriber::registry()
        .with(
            tracing_subscriber::EnvFilter::try_from_default_env()
                .unwrap_or_else(|_| "example_templates=debug".into()),
        )
        .with(tracing_subscriber::fmt::layer())
        .init();

    let db_pool = SqlitePool::connect(DB_URL)
        .await
        .expect("Failed to connect to the database.");
    let static_path = env::var("STATIC_PATH").unwrap_or("static".to_string());

    // build our application with some routes
    let app = Router::new()
        .nest_service("/static", ServeDir::new(static_path))
        .route("/", get(register_form))
        .route("/register/", post(register))
        .route("/favicon.ico", get(favicon))
        .with_state(db_pool);

    // run it
    let addr = SocketAddr::from(([127, 0, 0, 1], 8035));
    tracing::debug!("listening on {}", addr);
    axum::Server::bind(&addr)
        .serve(app.into_make_service())
        .await
        .unwrap();
}

async fn register_form() -> impl IntoResponse {
    let template = HelloTemplate {};
    HtmlTemplate(template)
}

#[derive(Template)]
#[template(path = "hello.html")]
struct HelloTemplate {}

struct HtmlTemplate<T>(T);

impl<T> IntoResponse for HtmlTemplate<T>
where
    T: Template,
{
    fn into_response(self) -> Response {
        match self.0.render() {
            Ok(html) => Html(html).into_response(),
            Err(err) => (
                StatusCode::INTERNAL_SERVER_ERROR,
                format!("Failed to render template. Error: {}", err),
            )
                .into_response(),
        }
    }
}

#[derive(Deserialize)]
struct RegistrationForm {
    name: String,
    email: String,
    klasse: String,
}

struct DatabaseConnection(sqlx::pool::PoolConnection<sqlx::Sqlite>);

#[async_trait]
impl<S> FromRequestParts<S> for DatabaseConnection
where
    SqlitePool: FromRef<S>,
    S: Send + Sync,
{
    type Rejection = (StatusCode, String);

    async fn from_request_parts(_parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
        let pool = SqlitePool::from_ref(state);

        let conn = pool.acquire().await.map_err(internal_error)?;

        Ok(Self(conn))
    }
}

// register a user
async fn register(
    DatabaseConnection(conn): DatabaseConnection,
    Form(form): Form<RegistrationForm>,
) -> impl IntoResponse {
    let mut conn = conn;
    // Insert the form data into the database
    let result = query!(
        "INSERT INTO anmeldungen (name, email, klasse) VALUES (?, ?, ?)",
        form.name,
        form.email,
        form.klasse
    )
    .execute(&mut conn)
    .await;

    if let Err(error) = result {
        eprintln!("Failed to insert data into database: {:?}", error);
        return StatusCode::INTERNAL_SERVER_ERROR;
    }

    // Return a simple response
    StatusCode::OK
}

/// Utility function for mapping any error into a `500 Internal Server Error`
/// response.
fn internal_error<E>(err: E) -> (StatusCode, String)
where
    E: std::error::Error,
{
    (StatusCode::INTERNAL_SERVER_ERROR, err.to_string())
}

async fn favicon() -> impl IntoResponse {
    let mut headers = HeaderMap::new();
    headers.insert(header::CONTENT_TYPE, "image/x-icon".parse().unwrap());

    let bytes = include_bytes!("../static/favicon.ico");
    (headers, bytes)
}