use axum::{
    extract::{BodyStream, Extension},
    http::StatusCode,
    response::IntoResponse,
    routing::{get_service, post},
    Router,
};
use flate2::read::GzDecoder;
use futures_util::TryStreamExt;
use std::collections::HashSet;
use std::io::ErrorKind;
use std::net::SocketAddr;
use std::path::Path;
use tar::Archive;
use tokio_util::io::StreamReader;
use tower_http::{auth::RequireAuthorizationLayer, services::ServeDir, trace::TraceLayer};
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};

const STATIC_DIR_NAME: &str = "static";

#[tokio::main]
async fn main() {
    // Enable tracing
    tracing_subscriber::registry()
        .with(tracing_subscriber::EnvFilter::new(
            std::env::var("RUST_LOG")
                .unwrap_or_else(|_| "site_backend=debug,tower_http=debug".into()),
        ))
        .with(tracing_subscriber::fmt::layer())
        .init();

    // Get required variables from env vars
    let api_key = std::env::var("API_KEY").expect("No API_KEY was provided.");
    let data_dir = std::env::var("DATA_DIR").expect("No DATA_DIR was provided.");
    let static_dir = format!("{}/{}", data_dir, STATIC_DIR_NAME);

    std::fs::create_dir_all(&static_dir);

    let app = Router::new()
        .route(
            "/api/deploy",
            post(post_deploy).layer(RequireAuthorizationLayer::bearer(&api_key)),
        )
        // The fallback option is to serve the actual static files
        .fallback(get_service(ServeDir::new(static_dir)).handle_error(
            |error: std::io::Error| async move {
                (
                    StatusCode::INTERNAL_SERVER_ERROR,
                    format!("Unhandled internal error: {}", error),
                )
            },
        ))
        .layer(TraceLayer::new_for_http())
        .layer(Extension(data_dir));

    let addr = SocketAddr::from(([0, 0, 0, 0], 3000));
    tracing::debug!("listening on {}", addr);
    axum::Server::bind(&addr)
        .serve(app.into_make_service())
        .await
        .unwrap();
}

async fn post_deploy(Extension(data_dir): Extension<String>, res: BodyStream) -> impl IntoResponse {
    // This converts a stream into something that implements AsyncRead, which we can then use to
    // asynchronously write the file to disk
    let mut read =
        StreamReader::new(res.map_err(|axum_err| std::io::Error::new(ErrorKind::Other, axum_err)));
    let uuid = uuid::Uuid::new_v4();
    let file_path = Path::new(&data_dir).join(uuid.as_hyphenated().to_string());
    let mut file = tokio::fs::File::create(&file_path).await.unwrap();
    tokio::io::copy(&mut read, &mut file).await;

    // Extract the contents of the tarball synchronously
    match tokio::task::spawn_blocking(move || {
        let file = match std::fs::File::open(file_path) {
            Ok(v) => v,
            Err(_) => return StatusCode::INTERNAL_SERVER_ERROR,
        };
        let tar = GzDecoder::new(file);
        let mut archive = Archive::new(tar);

        let mut paths = HashSet::new();

        let entries = match archive.entries() {
            Ok(e) => e,
            Err(_) => return StatusCode::INTERNAL_SERVER_ERROR,
        };

        // Extract each entry into the output directory
        let static_dir = Path::new(&data_dir).join(STATIC_DIR_NAME);
        for entry_res in entries {
            if let Ok(mut entry) = entry_res {
                if let Err(_) = entry.unpack_in(&static_dir) {
                    return StatusCode::INTERNAL_SERVER_ERROR;
                }

                if let Ok(path) = entry.path() {
                    paths.insert(path.into_owned());
                }
            } else {
                return StatusCode::INTERNAL_SERVER_ERROR;
            }
        }

        // Remove any old files that weren't present in new archive
        let mut items = vec![];

        // Start by populating the vec with the initial files
        let iter = match static_dir.read_dir() {
            Ok(v) => v,
            Err(_) => return StatusCode::INTERNAL_SERVER_ERROR,
        };
        iter.filter_map(|r| r.ok())
            .for_each(|e| items.push(e.path()));

        // As long as there are still items in the vec, we keep going
        while items.len() > 0 {
            let item = items.pop().unwrap();
            tracing::debug!("{:?}", item);

            if !paths.contains(item.strip_prefix(&static_dir).unwrap()) {
                if item.is_dir() {
                    std::fs::remove_dir_all(item);
                } else {
                    std::fs::remove_file(item);
                }
            } else if let Ok(iter) = item.read_dir() {
                iter.filter_map(|r| r.ok())
                    .for_each(|e| items.push(e.path()));
            }
        }

        StatusCode::OK
    })
    .await
    {
        Ok(s) => s,
        Err(_) => StatusCode::INTERNAL_SERVER_ERROR,
    }
}