use std::cmp::min;
use std::io;
use crate::matrix::Matrix;

mod matrix;

const ADD_VAL: i32 = 1;
const MATCH_VAL: i32 = 0;

fn main() -> io::Result<()> {
    let str_a = "String A";
    let str_b = "String B";

    let mut diff_mat = Matrix::new(str_a.len(), str_b.len(), 0i32);

    for col in 1..diff_mat.col_count {
        let previous = diff_mat.get(0, col - 1).unwrap();
        diff_mat.set(previous + ADD_VAL, 0, col).expect("Failed to initialize diff matrix");
    }

    for row in 1..diff_mat.row_count {
        let previous = diff_mat.get(row - 1, 0).unwrap();
        diff_mat.set(previous - ADD_VAL, row, 0).expect("Failed to initialize diff matrix");
    }

    for row in 1..diff_mat.row_count {
        for col in 1..diff_mat.col_count {
            let char_a = str_a.chars().nth(row).unwrap();
            let char_b = str_b.chars().nth(col).unwrap();

            let add_from = diff_mat.get(row, col - 1).unwrap();
            let sub_from = diff_mat.get(row - 1, col).unwrap();
            let substitute_from = diff_mat.get(row - 1, col - 1).unwrap();

            let add = add_from + ADD_VAL;
            let sub = sub_from - ADD_VAL;
            let substitute = substitute_from + if char_a == char_b {
                MATCH_VAL
            } else {
                1
            };

            let val = min(add, min(sub, substitute));
            diff_mat.set(val, row, col).unwrap();
        }
    }

    diff_mat.print();
    Ok(())
}