use reqwest::header;
use rss::{Channel, ChannelBuilder, ItemBuilder};
use scraper::{Html, Selector};
use std::{error::Error, fs::File, io::BufReader};

use chrono::prelude::*;

const FILE_NAME: &str = "bib.xml";

fn get_last_status(title: &str) -> Result<String, Box<dyn Error>> {
    let file = File::open(FILE_NAME);
    let channel = match file {
        Ok(f) => Channel::read_from(BufReader::new(f)),
        Err(_) => {
            let c = ChannelBuilder::default()
                .title("Bib Watcher".to_string())
                .description("Watches availability status of library books".to_string())
                .link("https://phlaym.net".to_string())
                .build();
            c.pretty_write_to(File::create(FILE_NAME)?, b' ', 4)?;
            Ok(c)
        }
    }?;
    Ok(channel
        .items()
        .iter()
        .filter(|i| i.title().unwrap_or("") == title)
        .last()
        .and_then(|i| i.description())
        .unwrap_or("")
        .into())
}

fn main() -> Result<(), Box<dyn Error>> {
    let searches = [(
        "Klufti Affenhitze",
        "https://webopac.winbiap.de/konstanz/detail.aspx?data=U29ydD1adWdhbmdzZGF0dW0gKEJpYmxpb3RoZWspJmFtcDtjbWQ9MSZhbXA7cFM9MTAmYW1wO0NhdGFsb2d1ZUlkPTEwNjYwNCZhbXA7cEk9MCZhbXA7c0M9Y18wPTAlJW1fMD0xJSVmXzA9MiUlb18wPTglJXZfMD1hZmZlbmhpdHplJSVnXzA9LTEmYW1wO3NDYXRJZD0xMDY2MDQmYW1wO3BhZ2VJZD0yJmFtcDtTcmM9Mg%3d%3d"
    )]
    .iter()
    .cloned()
    .collect::<std::collections::HashMap<&str, &str>>();
    for (title, url) in searches {
        search(url, title)?
    }
    /*
    let url = "https://webopac.winbiap.de/konstanz/detail.aspx?data=U29ydD1adWdhbmdzZGF0dW0gKEJpYmxpb3RoZWspJmFtcDtjbWQ9MSZhbXA7cFM9MTAmYW1wO0NhdGFsb2d1ZUlkPTEwNjYwNCZhbXA7cEk9MCZhbXA7c0M9Y18wPTAlJW1fMD0xJSVmXzA9MiUlb18wPTglJXZfMD1hZmZlbmhpdHplJSVnXzA9LTEmYW1wO3NDYXRJZD0xMDY2MDQmYW1wO3BhZ2VJZD0yJmFtcDtTcmM9Mg%3d%3d";

    if status != "entliehen" {
        Notification::new()
            .summary("Klufti News")
            .body(&format!("Neuer Status: {}", status))
            .show()?;
    }*/
    Ok(())
}

fn search(url: &str, title: &str) -> Result<(), Box<dyn Error>> {
    let mut headers = header::HeaderMap::new();
    headers.append(
        header::ACCEPT,
        header::HeaderValue::from_static(
            "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
        ),
    );
    headers.append(
        header::HOST,
        header::HeaderValue::from_static("webopac.winbiap.de"),
    );
    headers.append(
        header::REFERER,
        header::HeaderValue::from_static("https://webopac.winbiap.de/"),
    );
    let client = reqwest::blocking::Client::builder()
        .default_headers(headers)
        .build()?;
    let request = client.get(url).build()?;
    let response = client.execute(request)?;
    let status = parse(&response.text()?)?;
    let last_status = get_last_status(title)?;
    if status != last_status {
        let file = File::open(FILE_NAME);
        let mut channel = match file {
            Ok(f) => Channel::read_from(BufReader::new(f)),
            Err(_) => Ok(ChannelBuilder::default()
                .title("Bib Watcher".to_string())
                .description("Watches availability status of library books".to_string())
                .link("https://phlaym.net".to_string())
                .build()),
        }?;
        let mut items = channel.clone().into_items();
        items.push(
            ItemBuilder::default()
                .title(Some(title.to_string()))
                .pub_date(Some(Utc::now().to_rfc2822()))
                .link(Some(url.to_string()))
                .description(Some(status))
                .build(),
        );
        channel.set_items(items);
        channel.pretty_write_to(File::create(FILE_NAME)?, b' ', 4)?;
    }
    Ok(())
}

fn parse(html: &str) -> Result<String, Box<dyn Error>> {
    let document = Html::parse_document(html);
    let selector = Selector::parse("#detail-left-wrapper .mediaStatus span")?;
    Ok(document
        .select(&selector)
        .next()
        .map(|r| r.text().collect::<String>())
        .unwrap_or_else(|| "Unknown".into()))
}