minesweeper

const cols = 10;
const rows = 10;
const mines = 25;
const mineChar = ".";

let board = new Array(rows).fill(0).map(() => new Array(cols).fill(0));

function printBoard() {
    for (let i = 0; i < rows; i++) {
        for (let j = 0; j < cols; j++) {
            process.stdout.write(board[i][j].toString().padEnd(4, ' '));
        }
        process.stdout.write('\n');
    }
}

require('assert')(mines <= cols * rows, 'too many mines');
let mineCount = 0;
while (mineCount < mines) {
    let y = Math.floor(Math.random() * rows);
    let x = Math.floor(Math.random() * cols);
    if (board[y][x] == mineChar) continue;
    board[y][x] = mineChar;
    mineCount++;
}

const steps = [
    [-1, -1], [-1, 0], [-1, 1],
    [0, -1], [0, 1],
    [1, -1], [1, 0], [1, 1]
];

// printBoard();
for (let i = 0; i < rows; i++) {
    for (let j = 0; j < cols; j++) {
        if (board[i][j] == mineChar) continue;
        let cnt = 0;
        for (let k = 0; k < steps.length; k++) {
            let y = i + steps[k][0];
            let x = j + steps[k][1];
            if (x < 0 || x >= cols || y < 0 || y >= rows) continue;
            if (board[y][x] == mineChar) cnt++;
        }
        board[i][j] = cnt;
        // console.log("i = " + i + "; j = " + j);
        // printBoard();
    }
}

printBoard();