/// --- Day 4: Camp Cleanup ---
///
/// Space needs to be cleared before the last supplies can be unloaded from the ships, and so
/// several Elves have been assigned the job of cleaning up sections of the camp.  Every section
/// has a unique ID number, and each Elf is assigned a range of section IDs.
///
/// However, as some of the Elves compare their section assignments with each other, they've
/// noticed that many of the assignments overlap.  To try to quickly find overlaps and reduce
/// duplicated effort, the Elves pair up and make a big list of the section assignments for each
/// pair (your puzzle input).
///
/// For example, consider the following list of section assignment pairs:
///
/// ```
/// 2-4,6-8
/// 2-3,4-5
/// 5-7,7-9
/// 2-8,3-7
/// 6-6,4-6
/// 2-6,4-8
/// ```
///
/// For the first few pairs, this list means:
///
///     Within the first pair of Elves, the first Elf was assigned sections 2-4 (sections 2, 3, and
///     4), while the second Elf was assigned sections 6-8 (sections 6, 7, 8).
///     The Elves in the second pair were each assigned two sections.
///     The Elves in the third pair were each assigned three sections: one got sections 5, 6, and
///     7, while the other also got 7, plus 8 and 9.
///
/// This example list uses single-digit section IDs to make it easier to draw; your actual list
/// might contain larger numbers. Visually, these pairs of section assignments look like this:
///
/// .234.....  2-4
/// .....678.  6-8
///
/// .23......  2-3
/// ...45....  4-5
///
/// ....567..  5-7
/// ......789  7-9
///
/// .2345678.  2-8
/// ..34567..  3-7
///
/// .....6...  6-6
/// ...456...  4-6
///
/// .23456...  2-6
/// ...45678.  4-8
///
/// Some of the pairs have noticed that one of their assignments fully contains the other.  For
/// example, 2-8 fully contains 3-7, and 6-6 is fully contained by 4-6.  In pairs where one
/// assignment fully contains the other, one Elf in the pair would be exclusively cleaning sections
/// their partner will already be cleaning, so these seem like the most in need of
/// reconsideration.  In this example, there are 2 such pairs.
///
/// In how many assignment pairs does one range fully contain the other?
use clap::Parser;
use itertools::Itertools;

use std::fs::File;
use std::io::prelude::*;
use std::io::BufReader;
use std::path::PathBuf;

const FILEPATH: &'static str = "examples/input.txt";

#[derive(Parser, Debug)]
#[clap(author, version, about, long_about = None)]
struct Cli {
    #[clap(short, long, default_value = FILEPATH)]
    file: PathBuf,
}

fn main() {
    let args = Cli::parse();

    let file = File::open(&args.file).unwrap();
    let reader = BufReader::new(file);
    let res = reader
        .lines()
        .map(|l| {
            l.unwrap()
                .split(',')
                .map(|s| {
                    s.split('-')
                        .map(|v| v.parse::<usize>().unwrap())
                        .collect_tuple::<(usize, usize)>()
                        .unwrap()
                })
                .collect_tuple::<((usize, usize), (usize, usize))>()
                .unwrap()
        })
        .filter(|((l1, l2), (r1, r2))| (l1 <= r1 && l2 >= r2) || (r1 <= l1 && r2 >= l2))
        .count();

    println!("{res}");
}