use std::fs::File;
use std::io::{BufReader};
use std::io::prelude::*;

const RADIX: u32 = 10;

static mut LINE_VEC: Vec<Vec<u32>> = Vec::new();
static mut TOTAL_FLASHES: u32 = 0;

const STEPS: u32 = 300;

fn main(){
    let file = File::open("./input.txt").expect("Read failed");
    let reader = BufReader::new(file);



   for line in reader.lines(){
    let line_as_string = line.unwrap();
    let line_as_int_vec = line_as_string.chars().map(|x| x.to_digit(RADIX).unwrap()).collect::<Vec<u32>>();
    unsafe{LINE_VEC.push(line_as_int_vec);}

   }
   unsafe {
        let height = LINE_VEC.len();
        let width = LINE_VEC[0].len();


        for _i in 1..=STEPS {
            // Energy of each Octopus increases by 1
            for line_nr in 0..height {
                for column_nr in 0..width {
                    LINE_VEC[line_nr][column_nr] += 1;
                }
            }

            // Flash all Octopus over 9 and reset to 9
            for line_nr in 0..height {
                for column_nr in 0..width {
                    if LINE_VEC[line_nr][column_nr] > 9 {
                        flash(line_nr, column_nr, height, width);
                    }
                }
            }
            // Reset all flashed to 0
            for line_nr in 0..height {
                for column_nr in 0..width {
                    if LINE_VEC[line_nr][column_nr] >98 {
                        LINE_VEC[line_nr][column_nr] = 0;
                    }
                }
            }
            // Check if all flash
            let mut all_flashed = true;
            for line_nr in 0..height {
                for column_nr in 0..width {
                    if LINE_VEC[line_nr][column_nr] != 0 {
                        all_flashed = false;
                    }
                }
            }
            if all_flashed {println!("All Flashed at step {}", _i);}
        }

    }

    unsafe { println!("Total flashes: {}", TOTAL_FLASHES); }
}


fn flash(line_nr: usize, column_nr: usize, height: usize, width: usize) {
    unsafe {
        //Set Current Octopus to 0
        if LINE_VEC[line_nr][column_nr] == 10 || LINE_VEC[line_nr][column_nr] == 9 {
            LINE_VEC[line_nr][column_nr] = 99;
            TOTAL_FLASHES += 1;

            if line_nr > 0 && column_nr > 0 {flash(line_nr - 1, column_nr - 1, height, width);}
            if line_nr > 0 {flash(line_nr - 1, column_nr, height, width);}
            if line_nr > 0 && column_nr < width - 1 {flash(line_nr - 1, column_nr + 1, height, width);}

            if column_nr > 0 {flash(line_nr, column_nr - 1, height, width);}
            if column_nr < width - 1 {flash(line_nr , column_nr + 1, height, width);}

            if line_nr < height - 1 && column_nr > 0 {flash(line_nr + 1, column_nr - 1, height, width);}
            if line_nr < height - 1 {flash(line_nr + 1, column_nr, height, width);}
            if line_nr < height - 1 && column_nr < width - 1 {flash(line_nr + 1, column_nr + 1, height, width);}
        } else {
            LINE_VEC[line_nr][column_nr] += 1;
        }
    }
}