extern crate chrono;
extern crate feed_rs;
extern crate maud;
extern crate reqwest;

use rand::seq::SliceRandom;
use rand::thread_rng;
use std::collections::HashSet;
use std::error::Error;
use std::fs::write;
use std::fs::DirBuilder;
use std::path::Path;
mod site_generator;
mod utilities;
mod web_fetchers;
use rayon::prelude::*;

fn main() -> Result<(), Box<dyn Error>> {
    simple_logger::init_with_level(log::Level::Info).unwrap();

    let all_posts = utilities::read_feed("feeds.txt");

    let mut posts = all_posts.clone();
    posts.retain(|post| post.score.is_positive());

    // Keep only the first occurence of each main_url
    {
        let mut seen_urls = HashSet::new();
        posts.retain(|post| seen_urls.insert(post.main_url.clone()));
    }

    let mut featured = utilities::read_feed("featured_feeds.txt");
    // Give featured a small boost in points
    featured = featured
        .iter_mut()
        .map(|post| {
            post.score = (post.score as f64 * 1.5) as i64;
            post.clone()
        })
        .collect::<Vec<_>>();

    posts.extend(featured);

    posts.par_iter_mut().for_each(utilities::find_image);
    posts.par_iter_mut().for_each(utilities::validate);

    posts.sort();

    // Move the post with an image_url to the head of the list
    if let Some(pos) = posts.iter().position(|post| post.image_url.is_some()) {
        let post_with_image = posts.remove(pos);
        posts.insert(0, post_with_image);
    }

    utilities::retain_first_main_url(&mut posts);

    posts.truncate(16);

    let mut old_posts = all_posts;

    old_posts.retain(|p| !posts.contains(p));
    old_posts.shuffle(&mut thread_rng());

    let mut archive_posts: Vec<utilities::Post> = Vec::new();
    let archive_size = 100;

    while (archive_posts.len() < archive_size) && (old_posts.len() > 50) {
        let iter_size = archive_size - archive_posts.len();

        let mut extracted = old_posts
            .drain(0..=(iter_size + 50))
            .collect::<Vec<utilities::Post>>();

        extracted.par_iter_mut().for_each(utilities::validate);
        extracted.retain(|post| post.score != 0);

        archive_posts.extend(extracted);
    }

    archive_posts.truncate(archive_size);

    let index = site_generator::generate_index(posts.clone(), archive_posts.clone());
    let index_path = Path::new("output/index.html");
    DirBuilder::new()
        .recursive(true)
        .create(index_path.parent().unwrap())
        .unwrap();

    match write(index_path, index.into_string()) {
        Ok(_) => log::info!("Successfully wrote to {}", index_path.display()),
        Err(e) => log::error!("Failed to write to {}: {}", index_path.display(), e),
    }

    let feed = site_generator::generate_rss(posts.clone());
    let feed_path = Path::new("output/feed.xml");
    DirBuilder::new()
        .recursive(true)
        .create(feed_path.parent().unwrap())
        .unwrap();

    match write(feed_path, feed) {
        Ok(_) => log::info!("Successfully wrote to {}", feed_path.display()),
        Err(e) => log::error!("Failed to write to {}: {}", feed_path.display(), e),
    }

    Ok(())
}