use std::fs::File;
use std::io::{self, BufRead};
use std::path::Path;
use std::collections::HashMap;

fn main() {
    let file_path = String::from("input");
    let mut positions = HashMap::<(i32, i32), u32>::new();
    let mut tail: (i32, i32) = (0, 0);
    let mut head: (i32, i32) = (0, 0);
    *positions.entry(tail).or_insert(0) += 1;


    println!("In file {}", file_path);

    if let Ok(lines) = read_lines(file_path) {
        // Consumes the iterator, returns an (Optional) String
        for line in lines {
            if let Ok(ip) = line {
                let split: Vec<&str> = ip.split(" ").collect();
                let dir = split[0];
                let steps: usize = split[1].parse().unwrap();
                if dir == "U" {
                    for _ in 0..steps {
                        println!("U {}", steps);
                        head.1 += 1;
                        if tail.1 - head.1 == -2 {
                            println!("U move {}", steps);
                            tail.0 = head.0;
                            tail.1 += 1;
                            *positions.entry(tail).or_insert(0) += 1;
                        }
                    }
                }
                else if dir == "D" {
                    for _ in 0..steps {
                        println!("D {}", steps);
                        head.1 -= 1;
                        if tail.1 - head.1 == 2 {
                            println!("D move {}", steps);
                            tail.0 = head.0;
                            tail.1 -= 1;
                            *positions.entry(tail).or_insert(0) += 1;
                        }
                    }
                }
                else if dir == "R" {
                    for _ in 0..steps {
                        println!("R {}", steps);
                        head.0 += 1;
                        if tail.0 - head.0 == -2 {
                            println!("R move {}", steps);
                            tail.1 = head.1;
                            tail.0 += 1;
                            *positions.entry(tail).or_insert(0) += 1;
                        }
                    }
                }
                else if dir == "L" {
                    for _ in 0..steps {
                        println!("L {}", steps);
                        head.0 -= 1;
                        if tail.0 - head.0 == 2 {
                            println!("L move {}", steps);
                            tail.1 = head.1;
                            tail.0 -= 1;
                            *positions.entry(tail).or_insert(0) += 1;
                        }
                    }
                }
            }
        }
    }

    println!("tail {:?}", tail);
    println!("head {:?}", head);
    println!("positions {:?}", positions);
    println!("positions {}", positions.len());
}

fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
where P: AsRef<Path>, {
    let file = File::open(filename)?;
    Ok(io::BufReader::new(file).lines())
}