const game = document.getElementById("game");
const player = document.getElementById("player");
const scoreEl = document.getElementById("score");
const hintEl = document.getElementById("hint");
const gameOverEl = document.getElementById("gameOver");
const finalScoreEl = document.getElementById("finalScore");
const bestScoreEl = document.getElementById("bestScore");

const GROUND = 50;        // высота земли
const GRAVITY = 0.55;
const JUMP_FORCE = 12;
const START_SPEED = 5;

let running = false;
let gameOver = false;
let playerY = 0;          // высота над землёй
let velocity = 0;
let speed = START_SPEED;
let score = 0;
let best = Number(localStorage.getItem("spaceJumpBest")) || 0;
let obstacles = [];
let spawnTimer = 0;
let lastTime = 0;

function startGame() {
  obstacles.forEach((o) => o.el.remove());
  obstacles = [];
  playerY = 0;
  velocity = 0;
  speed = START_SPEED;
  score = 0;
  spawnTimer = 0;
  running = true;
  gameOver = false;
  hintEl.style.display = "none";
  gameOverEl.classList.remove("visible");
  scoreEl.textContent = "0";
  lastTime = performance.now();
  requestAnimationFrame(loop);
}

function jump() {
  if (playerY === 0) {
    velocity = JUMP_FORCE;
  }
}

function spawnObstacle() {
  const el = document.createElement("div");
  el.className = "obstacle";
  const height = 30 + Math.random() * 35;
  el.style.height = height + "px";
  game.appendChild(el);
  obstacles.push({ el, x: game.clientWidth, height });
}

function endGame() {
  running = false;
  gameOver = true;
  best = Math.max(best, score);
  localStorage.setItem("spaceJumpBest", best);
  finalScoreEl.textContent = score;
  bestScoreEl.textContent = best;
  gameOverEl.classList.add("visible");
}

function loop(now) {
  if (!running) return;
  const dt = Math.min((now - lastTime) / 16.67, 3); // нормализация к 60 FPS
  lastTime = now;

  // физика игрока
  velocity -= GRAVITY * dt;
  playerY += velocity * dt;
  if (playerY <= 0) {
    playerY = 0;
    velocity = 0;
  }
  player.style.bottom = GROUND + playerY + "px";

  // спавн препятствий
  spawnTimer -= dt;
  if (spawnTimer <= 0) {
    spawnObstacle();
    spawnTimer = 60 + Math.random() * 70;
  }

  // движение препятствий и столкновения
  const playerLeft = 80;
  const playerRight = playerLeft + 36;

  for (let i = obstacles.length - 1; i >= 0; i--) {
    const o = obstacles[i];
    o.x -= speed * dt;
    o.el.style.left = o.x + "px";

    if (o.x + 22 < 0) {
      o.el.remove();
      obstacles.splice(i, 1);
      score++;
      scoreEl.textContent = score;
      speed += 0.15; // чуть быстрее с каждым очком
      continue;
    }

    const hitX = o.x < playerRight - 6 && o.x + 22 > playerLeft + 6;
    const hitY = playerY < o.height - 4;
    if (hitX && hitY) {
      endGame();
      return;
    }
  }

  requestAnimationFrame(loop);
}

document.addEventListener("keydown", (e) => {
  if (e.code !== "Space") return;
  e.preventDefault();
  if (!running) {
    startGame();
  } else {
    jump();
  }
});

// поддержка тапа/клика для мобильных
game.addEventListener("pointerdown", () => {
  if (!running) {
    startGame();
  } else {
    jump();
  }
});