mod deleter;
mod file_kind;
mod multipart;

use actix_files::{Files, NamedFile};
use actix_multipart::Multipart;
use actix_web::{
    error,
    http::header::{ContentDisposition, DispositionParam, DispositionType},
    middleware,
    web::{self, Bytes},
    App, Error, FromRequest, HttpRequest, HttpResponse, HttpServer,
};
use async_std::{
    fs,
    path::PathBuf,
    sync::{channel, Sender},
    task,
};
use file_kind::FileKind;
use sqlx::{
    postgres::{PgPool, PgRow},
    Cursor, Row,
};
use std::env;

const INDEX_HTML: &str = include_str!("../template/index.html");
const UPLOAD_HTML: &str = include_str!("../template/upload.html");
const VIEW_HTML: &str = include_str!("../template/view.html");

async fn index() -> Result<HttpResponse, Error> {
    Ok(HttpResponse::Ok()
        .content_type("text/html")
        .body(INDEX_HTML))
}

async fn upload(
    payload: Multipart,
    db: web::Data<PgPool>,
    sender: web::Data<Sender<()>>,
    config: web::Data<Config>,
) -> Result<HttpResponse, Error> {
    let file_id = format!("{:x?}", rand::random::<u32>());
    let mut filename = config.files_dir.clone();
    filename.push(&file_id);

    let (original_name, valid_till, kind) =
        match multipart::parse_multipart(payload, &file_id, &filename).await {
            Ok(data) => data,
            Err(err) => {
                if filename.exists().await {
                    fs::remove_file(filename)
                        .await
                        .map_err(|_| error::ErrorInternalServerError("could not remove file"))?;
                }
                return Err(err);
            }
        };

    sqlx::query("INSERT INTO Files (file_id, file_name, valid_till, kind) VALUES ($1, $2, $3, $4)")
        .bind(&file_id)
        .bind(original_name.unwrap_or_else(|| file_id.clone()))
        .bind(valid_till.naive_local())
        .bind(kind.to_string())
        .execute(db.as_ref())
        .await
        .map_err(|_| error::ErrorInternalServerError("could not insert file into database"))?;

    log::info!(
        "create new file {} (valid_till: {}, kind: {})",
        file_id,
        valid_till,
        kind
    );

    sender.send(()).await;

    Ok(HttpResponse::SeeOther()
        .header("location", format!("/upload/{}", file_id))
        .finish())
}

async fn uploaded(id: web::Path<String>, config: web::Data<Config>) -> Result<HttpResponse, Error> {
    let upload_html = UPLOAD_HTML
        .replace("{id}", id.as_ref())
        .replace("{server}", &config.server_url);
    Ok(HttpResponse::Ok()
        .content_type("text/html")
        .body(upload_html))
}

async fn download(
    req: HttpRequest,
    id: web::Path<String>,
    db: web::Data<PgPool>,
    config: web::Data<Config>,
) -> Result<HttpResponse, Error> {
    let mut cursor = sqlx::query("SELECT file_id, file_name, kind from files WHERE file_id = $1")
        .bind(id.as_ref())
        .fetch(db.as_ref());
    let row: PgRow = cursor
        .next()
        .await
        .map_err(|_| error::ErrorInternalServerError("could not run select statement"))?
        .ok_or_else(|| error::ErrorNotFound("file does not exist or has expired"))?;

    let file_id: String = row.get("file_id");
    let file_name: String = row.get("file_name");
    let kind: String = row.get("kind");
    let mut path = config.files_dir.clone();
    path.push(&file_id);

    if kind == FileKind::TEXT.to_string() {
        let content = fs::read_to_string(path).await.map_err(|_| {
            error::ErrorInternalServerError("this file should be here but could not be found")
        })?;
        let encoded = htmlescape::encode_minimal(&content);
        let view_html = VIEW_HTML.replace("{text}", &encoded);
        let response = HttpResponse::Ok().content_type("text/html").body(view_html);
        Ok(response)
    } else {
        let file = NamedFile::open(path)
            .map_err(|_| {
                error::ErrorInternalServerError("this file should be here but could not be found")
            })?
            .set_content_disposition(ContentDisposition {
                disposition: DispositionType::Attachment,
                parameters: vec![DispositionParam::Filename(file_name)],
            });
        file.into_response(&req)
    }
}

async fn setup_db() -> PgPool {
    let pool = PgPool::builder()
        .max_size(5)
        .connect_timeout(std::time::Duration::from_secs(5))
        .build(&env::var("DATABASE_URL").unwrap_or_else(|_| "postgresql://localhost".to_owned()))
        .await
        .expect("could not create db pool");

    sqlx::query(include_str!("../init-db.sql"))
        .execute(&pool)
        .await
        .expect("could not create table Files");

    pool
}

#[derive(Clone)]
struct Config {
    server_url: String,
    files_dir: PathBuf,
}

#[actix_rt::main]
async fn main() -> std::io::Result<()> {
    env::set_var(
        "RUST_LOG",
        env::var("RUST_LOG").unwrap_or_else(|_| "info".to_string()),
    );
    env_logger::init();

    let pool: PgPool = setup_db().await;

    let config = Config {
        server_url: env::var("SERVER_URL").unwrap_or_else(|_| "http://localhost:8000".to_owned()),
        files_dir: PathBuf::from(env::var("FILES_DIR").unwrap_or_else(|_| "./files".to_owned())),
    };

    fs::create_dir_all(&config.files_dir)
        .await
        .expect("could not create directory for storing files");

    log::info!("omnomnom");

    let (send, recv) = channel(1);
    task::spawn(deleter::delete_old_files(
        recv,
        pool.clone(),
        config.files_dir.clone(),
    ));

    let db = web::Data::new(pool);
    let send = web::Data::new(send);
    let max_bytes: usize = env::var("UPLOAD_MAX_BYTES")
        .ok()
        .and_then(|variable| variable.parse().ok())
        .unwrap_or(8_388_608);
    let bind_address = env::var("BIND_ADDRESS").unwrap_or_else(|_| "0.0.0.0:8000".to_owned());

    HttpServer::new({
        move || {
            App::new()
                .wrap(middleware::Logger::default())
                .app_data(db.clone())
                .app_data(send.clone())
                .app_data(Bytes::configure(|cfg| cfg.limit(max_bytes)))
                .data(config.clone())
                .service(web::resource("/").route(web::get().to(index)))
                .service(web::resource("/upload").route(web::post().to(upload)))
                .service(web::resource("/upload/{id}").route(web::get().to(uploaded)))
                .service(web::resource("/file/{id}").route(web::get().to(download)))
                .service(Files::new("/static", "static").disable_content_disposition())
        }
    })
    .bind(bind_address)?
    .run()
    .await
}