use std::{fs::File, io::{self, BufRead}, path::Path, process::exit};
#[derive(Debug)]
struct Coord{
    line_index: usize,
    char_index: usize,
}

fn main() {
    let symbol_ignore_list = ".123456789";
    let mut result = 0;
    // symbol_array is a list of a list of coords.
    // each list this array represents a line
    // inside the line is the list of the coords of each symbol 
    let mut symbol_array: Vec<Vec<Coord>> = Vec::new();
    // File hosts.txt must exist in the current path
    if let Ok(lines) = read_lines("./input") {
        // Consumes the iterator, returns an (Optional) String
        let lines_array = lines.flatten().collect::<Vec<String>>();
        // collect a list of all symbols
        for line_index in 0..lines_array.len(){
            let mut line_symbol_array: Vec<Coord> = Vec::new();
            for char_index in 0..lines_array[line_index].len(){
                let cur_char = lines_array[line_index].chars().collect::<Vec<char>>()[char_index];
                if !symbol_ignore_list.contains(cur_char){
                    let c = Coord{line_index:line_index,char_index:char_index};
                    line_symbol_array.push(c);
                }
            }
            symbol_array.push(line_symbol_array);
        }

        for line_index in 0..lines_array.len(){
            for char_index in 0..lines_array[line_index].len(){
        }
    }
}

// The output is wrapped in a Result to allow matching on errors.
// Returns an Iterator to the Reader of the lines of the file.
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())
}