use core::panic;
use std::collections::HashSet;

pub fn process_part1(input: &str) -> i64 {
    let mut visited_coords = HashSet::new();
    let mut last_coord = (0, 0);
    visited_coords.insert(last_coord);
    input.chars().for_each(|char| {
        if char == '^' {
            last_coord.1 += 1;
            visited_coords.insert(last_coord);
        } else if char == '>' {
            last_coord.0 += 1;
            visited_coords.insert(last_coord);
        } else if char == '<' {
            last_coord.0 -= 1;
            visited_coords.insert(last_coord);
        } else if char == 'v' {
            last_coord.1 -= 1;
            visited_coords.insert(last_coord);
        } else if char == '\n' {
            println!("The end");
        } else {
            panic!("Could not parse direction");
        }
    });
    visited_coords.len() as i64
}

pub fn process_part2(input: &str) -> i64 {
    let mut visited_coords = HashSet::new();
    let mut last_coord = (0, 0);
    let mut is_robot = false;
    let mut last_robo_coord = (0, 0);
    visited_coords.insert(last_coord);
    input.chars().for_each(|char| {
        if is_robot {
            if char == '^' {
                last_robo_coord.1 += 1;
                visited_coords.insert(last_robo_coord);
            } else if char == '>' {
                last_robo_coord.0 += 1;
                visited_coords.insert(last_robo_coord);
            } else if char == '<' {
                last_robo_coord.0 -= 1;
                visited_coords.insert(last_robo_coord);
            } else if char == 'v' {
                last_robo_coord.1 -= 1;
                visited_coords.insert(last_robo_coord);
            } else if char == '\n' {
                println!("The end");
            } else {
                panic!("Could not parse direction");
            }
        } else if char == '^' {
            last_coord.1 += 1;
            visited_coords.insert(last_coord);
        } else if char == '>' {
            last_coord.0 += 1;
            visited_coords.insert(last_coord);
        } else if char == '<' {
            last_coord.0 -= 1;
            visited_coords.insert(last_coord);
        } else if char == 'v' {
            last_coord.1 -= 1;
            visited_coords.insert(last_coord);
        } else if char == '\n' {
            println!("The end");
        } else {
            panic!("Could not parse direction");
        }
        is_robot = !is_robot;
    });
    visited_coords.len() as i64
}

#[cfg(test)]
mod tests_3 {
    use super::*;

    const INPUT: &str = ">
^v
^>v<
^v^v^v^v^v";

    #[test]
    fn it_works() {
        let mut lines = INPUT.lines();
        let result = process_part1(lines.next().unwrap());
        assert_eq!(result, 2);
        let result = process_part1(lines.next().unwrap());
        assert_eq!(result, 2);
        let result = process_part1(lines.next().unwrap());
        assert_eq!(result, 4);
        let result = process_part1(lines.next().unwrap());
        assert_eq!(result, 2);
    }

    #[test]
    fn part2() {
        let mut lines = INPUT.lines();
        let result = process_part2(lines.next().unwrap());
        assert_eq!(result, 2);
        let result = process_part2(lines.next().unwrap());
        assert_eq!(result, 3);
        let result = process_part2(lines.next().unwrap());
        assert_eq!(result, 3);
        let result = process_part2(lines.next().unwrap());
        assert_eq!(result, 11);
    }
}