by-idb/game.js

A simple terminal snake game library with no external dependencies

const Snake = require('./snake');
const Food = require('./food');
const { initSystem } = require('./utils');

class Game {
    constructor(width = 20, height = 10, speed = 200) {
        this.width = width;
        this.height = height;
        this.speed = speed;
        this.score = 0;
        this.isRunning = false;
        this.snake = new Snake(width, height);
        this.food = new Food(width, height);
        initSystem();
    }

    start() {
        this.isRunning = true;
        this.score = 0;
        this.snake.reset();
        this.food.generate(this.snake.body);
        this.setupInput();
        this.gameLoop();
    }

    setupInput() {
        const readline = require('readline');
        readline.emitKeypressEvents(process.stdin);
        process.stdin.setRawMode(true);

        process.stdin.on('keypress', (str, key) => {
            if (key.name === 'q') {
                this.isRunning = false;
                process.exit();
            }
            if (key.name === 'r') {
                this.start();
                return;
            }

            const directions = {
                'up': 'up',
                'down': 'down',
                'left': 'left',
                'right': 'right'
            };

            if (directions[key.name]) {
                this.snake.changeDirection(directions[key.name]);
            }
        });
    }

    gameLoop() {
        if (!this.isRunning) return;

        // Move the snake
        const ateFood = this.snake.move(this.food.getPosition());

        // Check for collisions
        if (this.snake.checkCollision()) {
            this.gameOver();
            return;
        }

        // If food is eaten
        if (ateFood) {
            this.score += 10;
            this.food.generate(this.snake.body);
        }

        // Render the game screen
        this.render();

        // Continue the game loop
        setTimeout(() => this.gameLoop(), this.speed);
    }

    render() {
        // Clear screen
        console.clear();

        // Create game area
        const board = Array(this.height).fill().map(() =>
            Array(this.width).fill(' ')
        );

        // Place food
        const foodPos = this.food.getPosition();
        board[foodPos.y][foodPos.x] = '*';

        // Place snake
        this.snake.body.forEach((segment, index) => {
            board[segment.y][segment.x] = index === 0 ? 'O' : 'o';
        });

        // Render borders and game area
        console.log('┌' + '─'.repeat(this.width) + '┐');
        board.forEach(row => {
            console.log('│' + row.join('') + '│');
        });
        console.log('└' + '─'.repeat(this.width) + '┘');

        // Display score
        console.log(`\nScore: ${this.score}`);
        console.log('Press Q to quit, R to restart');
    }

    gameOver() {
        console.clear();
        console.log('Game Over!');
        console.log(`Final Score: ${this.score}`);
        console.log('Press R to restart, Q to quit');
        this.isRunning = false;
    }
}

module.exports = Game;