#[aoc(day1, part1)]
pub fn part1(input: &str) -> i32 {
    let mut dial_counter = DialCounter {
        position: 50,
        zero_count: 0,
    };
    for line in input.lines() {
        dial_counter.rotate(line)
    }
    dial_counter.zero_count
}

#[derive(Debug)]
struct DialCounter {
    position: i32,
    zero_count: i32,
}

impl DialCounter {
    fn rotate(&mut self, operation: &str) {
        self.position = match operation.chars().nth(0).unwrap() {
            'L' => (self.position - operation[1..].parse::<i32>().unwrap()) % 100,
            'R' => (self.position + operation[1..].parse::<i32>().unwrap()) % 100,
            _ => panic!("Unexpected input!"),
        };
        if self.position == 0 {
            self.zero_count = self.zero_count + 1;
        }
    }

    fn rotate_2(&mut self, operation: &str) {
        let direction = operation.chars().nth(0).unwrap();
        let magnitude = operation[1..].parse::<i32>().unwrap();
        match direction {
            'L' => {
                if self.position == 0 {
                    self.position = 100
                }
                self.position = self.position - magnitude;
                while self.position < 0 {
                    self.position = self.position + 100;
                    self.zero_count = self.zero_count + 1;
                }
                if self.position == 0 {
                    self.zero_count = self.zero_count + 1;
                }
            }
            'R' => {
                self.position = self.position + magnitude;
                while self.position > 99 {
                    self.position = self.position - 100;
                    self.zero_count = self.zero_count + 1;
                }
            }
            _ => panic!("Unexpected input!"),
        };
    }
}

#[aoc(day1, part2)]
pub fn part2(input: &str) -> i32 {
    let mut dial_counter = DialCounter {
        position: 50,
        zero_count: 0,
    };
    for line in input.lines() {
        dial_counter.rotate_2(line)
    }
    dial_counter.zero_count
}

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

    struct Setup {
        test_string_1: String,
        test_string_2: String,
    }

    impl Setup {
        fn new() -> Self {
            Self {
                test_string_1: String::from("L68\nL30\nR48\nL5\nR60\nL55\nL1\nL99\nR14\nL82\n"),
                test_string_2: String::from("R27\nL477\n"),
            }
        }
    }

    #[test]
    fn test_part1() {
        let setup = Setup::new();
        assert_eq!(part1(&setup.test_string_1), 3);
        println!(" ");
        assert_eq!(part1(&setup.test_string_2), 1);
    }

    #[test]
    fn test_part2() {
        let setup = Setup::new();
        assert_eq!(part2(&setup.test_string_1), 6);
        println!(" ");
        assert_eq!(part2(&setup.test_string_2), 5);
    }
}