use std::sync::{Arc, Mutex};

use askama::Template;
use axum::{
    Router,
    extract::{MatchedPath, Path, State},
    http::Request,
    response::Html,
    routing::{get, post},
};
use rusqlite::Connection;
use tower_http::trace::TraceLayer;
use tower_request_id::{RequestId, RequestIdLayer};
use tracing::{debug, error, info, info_span};
use tracing_subscriber::{layer::SubscriberExt as _, util::SubscriberInitExt as _};

#[derive(Template)]
#[template(path = "index.html")]
struct IndexTemplate {
    foods: Vec<Food>,
    sum: i32,
}

#[derive(Template)]
#[template(path = "food-update.html")]
struct FoodUpdateTemplate {
    food: Food,
    sum: i32,
}

#[derive(Debug, Clone, PartialEq)]
struct Food {
    id: i32,
    portion: String,
    name: String,
    kc_per_serving: i32,
    target_servings: i32,
    actual_servings: i32,
    color: String,
}

#[tokio::main]
async fn main() -> Result<(), std::io::Error> {
    tracing_subscriber::registry()
        .with(
            tracing_subscriber::EnvFilter::try_from_default_env().unwrap_or_else(|_| {
                // axum logs rejections from built-in extractors with the `axum::rejection`
                // target, at `TRACE` level. `axum::rejection=trace` enables showing those events
                format!(
                    "{}=debug,tower_http=debug,axum::rejection=trace",
                    env!("CARGO_CRATE_NAME")
                )
                .into()
            }),
        )
        .with(tracing_subscriber::fmt::layer())
        .init();

    let db_connecion_str = "./foods.db".to_string();
    debug!(db_connecion_str, "opening database");
    let conn = Connection::open(db_connecion_str).expect("failed to open database");
    if let Err(e) = conn.execute(include_str!("create_tables.sql"), ()) {
        error!(?e, "failed to create tables");
        panic!("failed to create tables: {:#?}", e);
    }
    let conn = Arc::new(Mutex::new(conn));

    let app = Router::new()
        .route("/", get(root))
        .route("/increase/{id}", post(increase))
        .route("/decrease/{id}", post(decrease))
        .layer(
            TraceLayer::new_for_http().make_span_with(|request: &Request<_>| {
                let matched_path = request
                    .extensions()
                    .get::<MatchedPath>()
                    .map(MatchedPath::as_str);
                let request_id = request
                    .extensions()
                    .get::<RequestId>()
                    .map(ToString::to_string)
                    .unwrap_or_else(|| "unknown".into());
                info_span!(
                    "request",
                    method = ?request.method(),
                    matched_path,
                    uri = ?request.uri(),
                    id = %request_id,
                )
            }),
        )
        .layer(RequestIdLayer)
        .with_state(conn);

    let address = "0.0.0.0:3001";
    let listener = tokio::net::TcpListener::bind(address)
        .await
        .expect("failed to bind to address");
    info!(
        "listening on {}",
        listener
            .local_addr()
            .expect("failed to get local listening address")
    );
    axum::serve(listener, app).await
}

fn get_foods(conn: &Arc<Mutex<Connection>>) -> Vec<Food> {
    let conn = conn.lock().unwrap();
    let mut stmt = conn
        .prepare(
            "SELECT id, portion, name, kc_per_serving, target_servings, actual_servings, color FROM food",
        )
        .unwrap();
    let foods: Vec<_> = stmt
        .query_map((), |row| {
            Ok(Food {
                id: row.get(0).unwrap(),
                portion: row.get(1).unwrap(),
                name: row.get(2).unwrap(),
                kc_per_serving: row.get(3).unwrap(),
                target_servings: row.get(4).unwrap(),
                actual_servings: row.get(5).unwrap(),
                color: row.get(6).unwrap(),
            })
        })
        .unwrap()
        .collect::<Result<_, _>>()
        .unwrap();
    debug!(num_foods = foods.len());
    foods
}

fn get_sum(conn: &Arc<Mutex<Connection>>) -> i32 {
    let conn = conn.lock().unwrap();
    let mut stmt = conn
        .prepare("SELECT SUM(kc_per_serving * actual_servings) as kc FROM food")
        .unwrap();
    let sum = stmt.query_one((), |row| row.get(0)).unwrap();
    debug!(sum);
    sum
}

async fn root(State(conn): State<Arc<Mutex<Connection>>>) -> Html<String> {
    let foods = get_foods(&conn);
    let sum = get_sum(&conn);
    let index = IndexTemplate { foods, sum };
    Html(index.render().unwrap())
}

fn do_increase(conn: &Arc<Mutex<Connection>>, id: i32) {
    let conn = conn.lock().unwrap();
    let mut stmt = conn.prepare("UPDATE food SET actual_servings = (SELECT actual_servings FROM food WHERE id = ?1) + 1 WHERE id = ?1 RETURNING actual_servings").unwrap();
    let new: i32 = stmt.query_one((id,), |row| row.get(0)).unwrap();
    debug!(id, new_serving_count = new, "increase");
}

fn get_food(conn: &Arc<Mutex<Connection>>, id: i32) -> Food {
    let conn = conn.lock().unwrap();
    let mut stmt = conn.prepare("SELECT id, portion, name, kc_per_serving, target_servings, actual_servings, color FROM food WHERE id = ?1").unwrap();
    let food = stmt
        .query_one((id,), |row| {
            Ok(Food {
                id: row.get(0).unwrap(),
                portion: row.get(1).unwrap(),
                name: row.get(2).unwrap(),
                kc_per_serving: row.get(3).unwrap(),
                target_servings: row.get(4).unwrap(),
                actual_servings: row.get(5).unwrap(),
                color: row.get(6).unwrap(),
            })
        })
        .unwrap();
    debug!(?food);
    food
}

async fn increase(State(conn): State<Arc<Mutex<Connection>>>, Path(id): Path<i32>) -> Html<String> {
    do_increase(&conn, id);
    let food = get_food(&conn, id);
    let sum = get_sum(&conn);
    let update = FoodUpdateTemplate { food, sum };
    Html(update.render().unwrap())
}

fn do_decrease(conn: &Arc<Mutex<Connection>>, id: i32) {
    let conn = conn.lock().unwrap();
    let mut stmt = conn.prepare("UPDATE food SET actual_servings = MAX((SELECT actual_servings FROM food WHERE id = ?1) - 1, 0) WHERE id = ?1 RETURNING actual_servings").unwrap();
    let new: i32 = stmt.query_one((id,), |row| row.get(0)).unwrap();
    debug!(id, new_serving_count = new, "decrease");
}

async fn decrease(State(conn): State<Arc<Mutex<Connection>>>, Path(id): Path<i32>) -> Html<String> {
    do_decrease(&conn, id);
    let food = get_food(&conn, id);
    let sum = get_sum(&conn);
    let update = FoodUpdateTemplate { food, sum };
    Html(update.render().unwrap())
}