use std::error::Error;
use std::fs::File;
use std::io::{BufReader, Read, Write};
use std::path::{MAIN_SEPARATOR, PathBuf};

extern crate hyper;
use hyper::client::Client;
use hyper::client::response::Response;
use hyper::header::UserAgent;

extern crate rss;
use rss::Channel;

const EXTENSION: &'static str = "torrent";
const USER_AGENT: &'static str = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/525.19 (KHTML, like Gecko) Chrome/1.0.154.53 Safari/525.19";

const PATH: &'static str = "/tmp";
const URLS: [&'static str; 1] = [
    "https://www.nyaa.se/?page=rss&term=horriblesubs+hibike+euphonium+s2+1080",
];

fn get(client: &Client, url: &str) -> Result<Response, hyper::Error> {
    client.get(url).header(UserAgent(USER_AGENT.to_string())).send()
}

fn save(data: &[u8], name: &str) -> Result<(), Box<Error>> {
    let name = name.replace(MAIN_SEPARATOR, "-");
    let mut buf = PathBuf::from(PATH);
    buf.push(&name);
    buf.set_extension(EXTENSION);
    let path = buf.as_path();
    if !path.exists() {
        let mut file = File::create(path)?;
        file.write(data)?;
    }
    Ok(())
}

fn torrent(client: &Client, url: Option<String>, name: Option<String>) -> Result<(), Box<Error>> {
    let url = url.ok_or("no url")?;
    let name = name.ok_or("no name")?;
    let mut response = get(client, &url)?;
    let mut body = vec![];
    response.read_to_end(&mut body)?;
    save(&body, &name)
}

fn feed(client: &Client, url: &str) -> Result<(), Box<Error>> {
    let response = get(client, url)?;
    let reader = BufReader::new(response);
    let channel = Channel::read_from(reader)?;
    for item in channel.items {
        if let Err(e) = torrent(client, item.link.clone(), item.title.clone()) {
            println!("{} {}", item.link.unwrap_or("item".to_string()), e);
        }
    }
    Ok(())
}

fn main() {
    let client = Client::new();
    for url in URLS.iter() {
        if let Err(e) = feed(&client, url) {
            println!("{} {}", url, e);
        }
    }
}