use std::env::args;
use std::fs::File;
use std::io::BufRead;
use std::io::BufReader;

fn print_map(map: &Vec<u8>, rows: usize, cols: usize) {
    for row in 0..rows {
        for col in 0..cols {
            print!("{}", match map[row * cols + col] {
                1 => '>',
                2 => 'v',
                _ => '.',
            });
        }
        println!("");
    }
    println!("");
}

fn main() {
    let path = args().nth(1).unwrap();
    let file = File::open(path).unwrap();

    let mut map: Vec<u8> = vec![];
    let mut rows = 0;
    let mut cols = 0;

    for line in BufReader::new(file).lines() {
        let l = line.unwrap();
        cols = l.len();
        rows += 1;

        for c in l.chars() {
            map.push(match c {
                '>' => 1,
                'v' => 2,
                _ => 0,
            });
        }
    }

    print_map(&map, rows, cols);

    for i in 1.. {
        let mut move_x = vec![];
        for row in 0..rows {
            for col in 0..cols {
                let i = row * cols + col;
                let j = row * cols + (col + 1) % cols;
                if map[i] == 1 && map[j] == 0 {
                    move_x.push((i, j));
                }
            }
        }
        for (i, j) in move_x.iter() {
            map[*i] = 0;
            map[*j] = 1;
        }

        let mut move_y = vec![];
        for col in 0..cols {
            for row in 0..rows {
                let i = row * cols + col;
                let j = (row + 1) % rows * cols + col;
                if map[i] == 2 && map[j] == 0 {
                    move_y.push((i, j));
                }
            }
        }
        for (i, j) in move_y.iter() {
            map[*i] = 0;
            map[*j] = 2;
        }

        println!("{}", i);
        print_map(&map, rows, cols);
        if move_x.len() == 0 && move_y.len() == 0 {
            break;
        }
    }
}