pub mod day1 {
    fn day1_preprocess(input: &str) -> Vec<i16> {
        input
            .lines()
            .map(|line| {
                (
                    line.starts_with('L'),
                    line.chars()
                        .skip(1)
                        .collect::<String>()
                        .parse::<i16>()
                        .unwrap(),
                )
            })
            .map(|(is_left, distance)| if is_left { -distance } else { distance })
            .collect()
    }
    pub fn day1_part1(input: &str) -> String {
        let rotations = day1_preprocess(input);
        let mut popcnt = 0;
        let mut pointing_at = 50;
        for rotation in rotations {
            pointing_at += rotation;
            pointing_at %= 100;
            if pointing_at == 0 {
                popcnt += 1;
            }
        }
        popcnt.to_string()
    }
    pub fn day1_part2(input: &str) -> String {
        let rotations = day1_preprocess(input);
        let mut popcnt = 0;
        let mut pointing_at = 50;
        for mut rotation in rotations {
            while rotation != 0 {
                if rotation < 0 {
                    let distance =
                        rotation.max(-(if pointing_at != 0 { pointing_at } else { 100 }));
                    pointing_at += distance;
                    rotation -= distance;
                } else if rotation > 0 {
                    let distance = rotation.min(100 - pointing_at);
                    pointing_at += distance;
                    rotation -= distance;
                }
                pointing_at %= 100;
                if pointing_at < 0 {
                    pointing_at += 100;
                } else if pointing_at == 0 {
                    popcnt += 1;
                }
            }
        }
        popcnt.to_string()
    }
}

pub mod day2 {
    use std::ops::RangeInclusive;

    pub fn day2_part1(input: &str) -> String {
        let ranges = parse(input);
        let invalid = ranges
            .into_iter()
            .flatten()
            .filter(|&id| !is_id_valid(id, true));
        let invalid_sum: u64 = invalid.sum();
        invalid_sum.to_string()
    }
    pub fn day2_part2(input: &str) -> String {
        let ranges = parse(input);
        let invalid = ranges
            .into_iter()
            .flatten()
            .filter(|&id| !is_id_valid(id, false));
        let invalid_sum: u64 = invalid.sum();
        invalid_sum.to_string()
    }
    fn parse(input: &str) -> Vec<RangeInclusive<u64>> {
        input
            .split(',')
            .map(|range| range.split_once('-').unwrap())
            .map(|(from, to)| from.parse().unwrap()..=to.parse().unwrap())
            .collect()
    }
    fn is_id_valid(id: u64, max_two_chunks: bool) -> bool {
        let charnum = id.ilog10() as usize + 1;
        for chunk_count in 2..=if max_two_chunks { 2 } else { charnum } {
            if !charnum.is_multiple_of(chunk_count) {
                continue;
            }
            let chunk_size = charnum / chunk_count;
            let mut equal = true;
            'chunking: for intra_chunk_index in 0..chunk_size {
                let first_digit = index(id, intra_chunk_index);
                for inter_chunk_index in 1..chunk_count {
                    let digit_under_test =
                        index(id, inter_chunk_index * chunk_size + intra_chunk_index);
                    if digit_under_test != first_digit {
                        equal = false;
                        break 'chunking;
                    }
                }
            }
            if equal {
                return false;
            }
        }
        true
    }
    #[inline]
    fn index(id: u64, index: usize) -> u64 {
        (id / 10u64.pow(index as u32)) % 10
    }
}

pub mod day3;
pub mod day4;
pub mod day5;
pub mod day6;
pub mod day7;
pub mod day8;
pub mod day9;
mod spatial;
mod union_find;

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

    #[test]
    fn day9_part1_test() {
        let test_result = day9::day9_part1(include_str!("../input/day9.test.txt"));
        assert_eq!(test_result, "50");
        let result = day9::day9_part1(include_str!("../input/day9.txt"));
        assert_eq!(result, "4760959496");
    }
    #[test]
    fn day9_part2_test() {
        let test_result = day9::day9_part2(include_str!("../input/day9.test.txt"));
        assert_eq!(test_result, "24");
        let result = day9::day9_part2(include_str!("../input/day9.txt"));
        assert_eq!(result, "1343576598");
    }


    #[test]
    fn day8_part1_test() {
        let test_result = day8::day8_part1(include_str!("../input/day8.test.txt"), 10);
        assert_eq!(test_result, "40");
        let result = day8::day8_part1(include_str!("../input/day8.txt"), 1000);
        assert_eq!(result, "90036");
    }
    #[test]
    fn day8_part2_test() {
        let test_result = day8::day8_part2(include_str!("../input/day8.test.txt"), 1_000_000);
        assert_eq!(test_result, "25272");
        let result = day8::day8_part2(include_str!("../input/day8.txt"), 1_000_000);
        assert_eq!(result, "6083499488");
    }

    #[test]
    fn day7_part1_test() {
        let test_result = day7::day7_part1(include_str!("../input/day7.test.txt"));
        assert_eq!(test_result, "21");
        let result = day7::day7_part1(include_str!("../input/day7.txt"));
        assert_eq!(result, "1490");
    }
    #[test]
    fn day7_part2_test() {
        let test_result = day7::day7_part2(include_str!("../input/day7.test.txt"));
        assert_eq!(test_result, "40");
        let result = day7::day7_part2(include_str!("../input/day7.txt"));
        assert_eq!(result, "3806264447357");
    }

    #[test]
    fn day6_part1_test() {
        let test_result = day6::day6_part1(include_str!("../input/day6.test.txt"));
        assert_eq!(test_result, "4277556");
        let result = day6::day6_part1(include_str!("../input/day6.txt"));
        assert_eq!(result, "4951502530386");
    }
    #[test]
    fn day6_part2_test() {
        let test_result = day6::day6_part2(include_str!("../input/day6.test.txt"));
        assert_eq!(test_result, "3263827");
        let result = day6::day6_part2(include_str!("../input/day6.txt"));
        assert_eq!(result, "8486156119946");
    }

    #[test]
    fn day5_part1_test() {
        let test_result = day5::day5_part1(include_str!("../input/day5.test.txt"));
        assert_eq!(test_result, "3");
        let result = day5::day5_part1(include_str!("../input/day5.txt"));
        assert_eq!(result, "885");
    }
    #[test]
    fn day5_part2_test() {
        let test_result = day5::day5_part2(include_str!("../input/day5.test.txt"));
        assert_eq!(test_result, "14");
        let result = day5::day5_part2(include_str!("../input/day5.txt"));
        assert_eq!(result, "348115621205535");
    }

    #[test]
    fn day4_part1_test() {
        let test_result = day4::day4_part1(include_str!("../input/day4.test.txt"));
        assert_eq!(test_result, "13");
        let result = day4::day4_part1(include_str!("../input/day4.txt"));
        assert_eq!(result, "1372");
    }
    #[test]
    fn day4_part2_test() {
        let test_result = day4::day4_part2(include_str!("../input/day4.test.txt"));
        assert_eq!(test_result, "43");
        let result = day4::day4_part2(include_str!("../input/day4.txt"));
        assert_eq!(result, "7922");
    }

    #[test]
    fn day3_part1_test() {
        let test_result = day3::day3_part1(include_str!("../input/day3.test.txt"));
        assert_eq!(test_result, "357");
        let result = day3::day3_part1(include_str!("../input/day3.txt"));
        assert_eq!(result, "17613");
    }
    #[test]
    fn day3_part2_test() {
        let test_result = day3::day3_part2(include_str!("../input/day3.test.txt"));
        assert_eq!(test_result, "3121910778619");
        let result = day3::day3_part2(include_str!("../input/day3.txt"));
        assert_eq!(result, "175304218462560");
    }

    #[test]
    fn day2_part1_test() {
        let test_result = day2::day2_part1(include_str!("../input/day2.test.txt"));
        assert_eq!(test_result, "1227775554");
        let result = day2::day2_part1(include_str!("../input/day2.txt"));
        assert_eq!(result, "38158151648");
    }
    #[test]
    fn day2_part2_test() {
        let test_result = day2::day2_part2(include_str!("../input/day2.test.txt"));
        assert_eq!(test_result, "4174379265");
        let result = day2::day2_part2(include_str!("../input/day2.txt"));
        assert_eq!(result, "45283684555");
    }

    #[test]
    fn day1_part1_test() {
        let test_result = day1::day1_part1(include_str!("../input/day1.test.txt"));
        assert_eq!(test_result, "3");
        let result = day1::day1_part1(include_str!("../input/day1.txt"));
        assert_eq!(result, "1021");
    }

    #[test]
    fn day1_part2_test() {
        let test_result = day1::day1_part2(include_str!("../input/day1.test.txt"));
        assert_eq!(test_result, "6");
        let result = day1::day1_part2(include_str!("../input/day1.txt"));
        assert_eq!(result, "5933");
    }
}