use std::ops::RangeInclusive;

use aoc_runner_derive::{aoc, aoc_generator};

fn parse_range(range: &str) -> RangeInclusive<u64> {
    let (start, end) = range.split_once('-').unwrap();
    start.parse().unwrap()..=end.parse().unwrap()
}

#[aoc_generator(day4)]
pub fn input_generator(input: &str) -> Vec<(RangeInclusive<u64>, RangeInclusive<u64>)> {
    input
        .lines()
        .map(|l| {
            let (first, second) = l.split_once(',').unwrap();
            (parse_range(first), parse_range(second))
        })
        .collect()
}

fn contains_range(slf: &RangeInclusive<u64>, other: &RangeInclusive<u64>) -> bool {
    slf.start() <= other.start() && slf.end() >= other.end()
}

fn overlaps_with_range(slf: &RangeInclusive<u64>, other: &RangeInclusive<u64>) -> bool {
    slf.contains(other.start()) || slf.contains(other.end())
}

#[aoc(day4, part1)]
pub fn solve_part1(input: &[(RangeInclusive<u64>, RangeInclusive<u64>)]) -> usize {
    input
        .iter()
        .filter(|(first, second)| contains_range(first, second) | contains_range(second, first))
        .count()
}

#[aoc(day4, part2)]
pub fn solve_part2(input: &[(RangeInclusive<u64>, RangeInclusive<u64>)]) -> usize {
    input
        .iter()
        .filter(|(first, second)| {
            overlaps_with_range(first, second) | overlaps_with_range(second, first)
        })
        .count()
}