main.js

document.addEventListener('DOMContentLoaded', async () => {
  const images = await fetch('images.json').then(resp => resp.json());

  // 全ての確率の合計を計算
  const totalProbability = images.reduce((total, image) => total + image.probability, 0);

  // 各画像の確率を正規化（合計が1になるように調整）
  images.forEach(image => image.probability /= totalProbability);

  const randomImage = document.querySelector('#randomImage');
  let previousImageIndex = 0;

  // 画像のプリロード
  images.forEach(image => {
    const img = new Image();
    img.src = image.src;
  });

  randomImage.src = images[previousImageIndex].src;

  randomImage.addEventListener('click', () => {
    let newImageIndex = 0;
    const randomNumber = Math.random();

    let cumulativeProbability = 0;
    for (let i = 0; i < images.length; i++) {
      if (i === previousImageIndex) continue;

      cumulativeProbability += images[i].probability;
      if (randomNumber < cumulativeProbability) {
        newImageIndex = i;
        break;
      }
    }

    randomImage.src = images[newImageIndex].src;
    previousImageIndex = newImageIndex;
  });

  // スペースキーが押された時のイベントを追加
  document.addEventListener('keydown', (e) => {
    if (e.key === " ") { // スペースキーのイベントを検出
      randomImage.click();
      randomImage.classList.add('active');
      setTimeout(() => {
        randomImage.classList.remove('active');
      }, 80);
    }
  });
});