use aoc_runner_derive::{aoc, aoc_generator};
use itertools::Itertools;
use std::io::BufRead;

#[aoc_generator(day1)]
// Sum the calories of each elf's food items
fn parse(input: &[u8]) -> Vec<u64> {
    let mut result = Vec::new();
    let mut cur_elf = 0u64;
    for line in input.lines() {
        if let Ok(calories) = line.unwrap().parse::<u64>() {
            cur_elf += calories
        } else {
            result.push(cur_elf);
            cur_elf = 0
        }
    }
    result.push(cur_elf);
    result
}

#[aoc(day1, part1)]
fn part1(input: &Vec<u64>) -> u64 {
    *input.iter().max().unwrap()
}

#[aoc(day1, part2)]
fn part2(input: &Vec<u64>) -> u64 {
    input.iter().sorted().rev().take(3).sum::<u64>()
}

#[cfg(test)]
mod tests {
    use super::*;

    const EXAMPLE: &[u8] = b"1000
2000
3000

4000

5000
6000

7000
8000
9000

10000";

    #[test]
    fn part1_example() {
        assert_eq!(part1(&parse(EXAMPLE)), 24000);
    }

    #[test]
    fn part2_example() {
        assert_eq!(part2(&parse(EXAMPLE)), 45000);
    }
}