use std::io::ErrorKind;

use crate::config::Config;
use crate::file_kind::FileKind;
use crate::multipart::UploadConfig;
use crate::{multipart, template};
use actix_files::NamedFile;
use actix_multipart::Multipart;
use actix_web::http::header::LOCATION;
use actix_web::{error, web, Error, HttpRequest, HttpResponse};
use rand::prelude::SliceRandom;
use sqlx::postgres::PgPool;
use std::path::PathBuf;
use tokio::fs::{self, OpenOptions};
use tokio::sync::mpsc::Sender;

const UPLOAD_HTML: &str = include_str!("../template/upload.html");
const UPLOAD_SHORT_HTML: &str = include_str!("../template/upload-short.html");

const ID_CHARS: &[char] = &[
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'v',
    'w', 'x', 'y', 'z', '1', '2', '3', '4', '5', '6', '7', '8', '9',
];

pub async fn index(config: web::Data<Config>) -> Result<NamedFile, Error> {
    let file = NamedFile::open(config.static_dir.join("index.html")).map_err(|file_err| {
        log::error!("index.html could not be read {:?}", file_err);
        error::ErrorInternalServerError("this file should be here but could not be found")
    })?;
    Ok(file.disable_content_disposition())
}

pub async fn upload(
    req: HttpRequest,
    payload: Multipart,
    db: web::Data<PgPool>,
    expiry_watch_sender: web::Data<Sender<()>>,
    config: web::Data<Config>,
) -> Result<HttpResponse, Error> {
    let (file_id, file_name) = create_unique_file(&config).await.map_err(|file_err| {
        log::error!("could not create file {:?}", file_err);
        error::ErrorInternalServerError("could not create file")
    })?;

    let parsed_multipart = multipart::parse_multipart(payload, &file_id, &file_name, &config).await;
    let UploadConfig {
        original_name,
        valid_till,
        kind,
        delete_on_download,
    } = match parsed_multipart {
        Ok(data) => data,
        Err(err) => {
            match fs::remove_file(file_name).await {
                Ok(()) => {}
                Err(err) if err.kind() == ErrorKind::NotFound => {}
                Err(err) => {
                    log::error!("could not remove file {:?}", err);
                    return Err(error::ErrorInternalServerError(
                        "could not parse multipart; could not remove file",
                    ));
                }
            }
            return Err(err);
        }
    };

    let db_insert = sqlx::query(
        "INSERT INTO Files (file_id, file_name, valid_till, kind, delete_on_download) \
        VALUES ($1, $2, $3, $4, $5)",
    )
    .bind(&file_id)
    .bind(&original_name)
    .bind(valid_till)
    .bind(kind.to_string())
    .bind(delete_on_download)
    .execute(db.as_ref())
    .await;
    if let Err(db_err) = db_insert {
        log::error!("could not insert into datebase {:?}", db_err);
        fs::remove_file(file_name).await.map_err(|file_err| {
            log::error!("could not remove file {:?}", file_err);
            error::ErrorInternalServerError(
                "could not insert file into database; could not remove file",
            )
        })?;
        return Err(error::ErrorInternalServerError(
            "could not insert file into database",
        ));
    }

    log::info!(
        "{} create new file {} (valid_till: {}, kind: {}, delete_on_download: {})",
        req.connection_info().realip_remote_addr().unwrap_or("-"),
        file_id,
        valid_till,
        kind,
        delete_on_download
    );

    expiry_watch_sender.send(()).await.unwrap();

    let redirect = if kind == FileKind::Binary {
        let encoded_name = urlencoding::encode(&original_name);
        format!("/upload/{}/{}", file_id, encoded_name)
    } else {
        format!("/upload/{}", file_id)
    };

    let url = get_file_url(&req, &file_id, Some(&original_name));
    Ok(HttpResponse::SeeOther()
        .insert_header((LOCATION, redirect))
        .body(format!("{}\n", url)))
}

async fn create_unique_file(
    config: &web::Data<Config>,
) -> Result<(String, PathBuf), std::io::Error> {
    loop {
        let file_id = gen_file_id();
        let mut file_name = config.files_dir.clone();
        file_name.push(&file_id);
        match OpenOptions::new()
            .write(true)
            .create_new(true)
            .open(&file_name)
            .await
        {
            Ok(_) => return Ok((file_id, file_name)),
            Err(error) if error.kind() == ErrorKind::AlreadyExists => continue,
            Err(error) => return Err(error),
        }
    }
}

fn gen_file_id() -> String {
    let mut rng = rand::thread_rng();
    let mut id = String::with_capacity(5);
    for _ in 0..5 {
        id.push(*ID_CHARS.choose(&mut rng).expect("ID_CHARS is not empty"));
    }
    id
}

fn get_file_url(req: &HttpRequest, id: &str, name: Option<&str>) -> String {
    if let Some(name) = name {
        let encoded_name = urlencoding::encode(name);
        format!("{}/{}/{}", template::get_host_url(req), id, encoded_name)
    } else {
        format!("{}/{}", template::get_host_url(req), id)
    }
}

pub async fn uploaded(req: HttpRequest) -> Result<HttpResponse, Error> {
    let id = req.match_info().query("id");
    let name = req.match_info().get("name");
    let upload_html = if name.is_some() {
        UPLOAD_SHORT_HTML
            .replace("{link}", &get_file_url(&req, id, name))
            .replace("{shortlink}", &get_file_url(&req, id, None))
    } else {
        UPLOAD_HTML.replace("{link}", &get_file_url(&req, id, name))
    };
    Ok(HttpResponse::Ok()
        .content_type("text/html")
        .body(upload_html))
}