use std::{
    env,
    error::Error,
    fs::File,
    io::{BufReader, prelude::*},
};

fn load_map(input_file: &str) -> Result<(Vec<Vec<bool>>, (usize, usize)), Box<dyn Error>> {
    let buffer = BufReader::new(File::open(input_file)?);
    let mut lines = buffer.lines().peekable();

    let width = match lines.peek() {
        Some(l) => match l {
            Ok(li) => li.len(),
            Err(_) => Err("Error reading first line of map file")?,
        },
        None => Err("Cannot load empty map file.")?,
    };

    let mut data: Vec<Vec<bool>> = Vec::new();
    let mut guard_position = (0, 0);

    for (y, line) in lines.enumerate() {
        let line = line?;
        if line.len() != width {
            println!("{}", line);
            Err("Line length of input are not consistent")?;
        }
        let parsed_data: Vec<bool> = line
            .chars()
            .enumerate()
            .map(|(x, c)| {
                if c == '^' {
                    guard_position = (x, y);
                };
                c == '#'
            })
            .collect();
        data.push(parsed_data);
    }
    let height = data.len();

    Ok((data, guard_position))
}

fn main() -> Result<(), Box<dyn Error>> {
    // Handle command input
    let args: Vec<String> = env::args().collect();
    if args.len() != 2 {
        panic!(
            "{} must be run with a single argument of files name!",
            &args[0]
        )
    }
    let input_file = &args[1];
    let data = load_map(input_file)?;
    println!("{:?}", data);

    Ok(())
}