/* 第 3 页场景数据
   前景：演职员表；背景：电线、麻雀、枪、草。
   本页不铺「天」，空白格保持为空。 */

(() => {
  /* 固定种子的噪声，保证每次渲染一致 */
  const noise = (x, y) => {
    let h = Math.imul(x, 374761393) + Math.imul(y, 668265263);
    h = Math.imul(h ^ (h >>> 13), 1274126177);
    return ((h ^ (h >>> 16)) >>> 0) / 4294967296;
  };

  /* 火山：占据下半屏，下 2/3 为山体、上 1/3 为熔岩棋盘格 */
  const volcano = [];
  const VOLCANO_TOP = 21;
  const VOLCANO_BOTTOM = 42;

  /* 每列的熔岩下沿，形成不规则的熔岩流 */
  const lavaBottom = Array.from({ length: 28 }, (_, x) => {
    return VOLCANO_TOP + 6 + Math.floor(noise(x, 3) * 3);
  });
  [5, 13, 21].forEach((x) => {
    lavaBottom[x] += 4 + Math.floor(noise(x, 9) * 3);
  });

  /* 两层熔岩的分界：按列小幅随机起伏 */
  const lavaSplit = Array.from({ length: 28 }, (_, x) => {
    const offset = Math.round((noise(x, 13) - 0.5) * 4);
    return Math.max(
      VOLCANO_TOP + 2,
      Math.min(VOLCANO_TOP + 5, VOLCANO_TOP + 3 + offset)
    );
  });

  /* 主熔岩区以下为山体，两侧做对称平滑处理 */
  const ROCK_START = VOLCANO_TOP + 7;

  for (let y = VOLCANO_TOP; y <= VOLCANO_BOTTOM; y++) {
    /* 距底部 5 格起铺满整幅宽度，避免山体过陡 */
    const fullWidthAt = VOLCANO_BOTTOM - 5;
    const t = (y - VOLCANO_TOP) / (fullWidthAt - VOLCANO_TOP);
    const baseWidth =
      y >= fullWidthAt ? 28 : Math.round(10 + 18 * Math.min(1, Math.max(0, t)));

    let width;
    let left;

    if (y < ROCK_START) {
      /* 熔岩区保持原有随机形状 */
      const jitter =
        y >= fullWidthAt ? 0 : Math.round((noise(0, y) - 0.5) * 2);
      width = Math.max(4, Math.min(28, baseWidth + jitter));
      left = Math.floor((28 - width) / 2);
      left += Math.round((noise(1, y) - 0.5) * 2);
      left = Math.max(0, Math.min(28 - width, left));
      if (y === VOLCANO_TOP + 1) left = Math.max(0, left - 1);
    } else {
      /* 山体左右对称，宽度取偶数和，保留低频小幅随机 */
      const wobble = Math.round((noise(7, Math.floor(y / 3)) - 0.5) * 2);
      let w = y >= fullWidthAt ? 28 : Math.min(28, baseWidth + wobble);
      w -= w % 2;
      width = Math.max(4, w);
      left = (28 - width) / 2;
    }

    /* 顶部火山口：仅两行凹下，第一行缺口更宽 */
    const craterGap = y < ROCK_START ? [4, 2][y - VOLCANO_TOP] || 0 : 0;
    const gapStart = craterGap ? Math.floor((width - craterGap) / 2) : 0;

    for (let i = 0; i < width; i++) {
      if (craterGap && i >= gapStart && i < gapStart + craterGap) continue;

      const x = left + i;
      const isLava = y <= lavaBottom[x];
      const isUpperLava = isLava && y <= lavaSplit[x];

      volcano.push({
        text: isLava ? ((x + y) % 2 === 0 ? '熔' : '岩') : '石',
        x,
        y,
        cls: isLava ? (isUpperLava ? 'lava-a' : 'lava-b') : 'rock',
      });
    }
  }

  /* 第十行左侧补一个「熔」 */
  const row10 = volcano.filter((cell) => cell.y === VOLCANO_TOP + 9);
  const row10Left = Math.min(...row10.map((cell) => cell.x));
  volcano.push({
    text: '熔',
    x: row10Left - 1,
    y: VOLCANO_TOP + 9,
    cls: 'lava-b',
  });

  TextScene.render({
    cols: 28,
    rows: 44,
    skyChar: '',
    glyphs: [
      /* 电线：整行贯穿页面 */
      { text: '电线'.repeat(14), x: 0, y: 8, cls: 'wire' },
      /* 麻雀：竖排于从左到右第四格，落在电线上方 */
      { text: '麻雀', x: 3, y: 6, cls: 'sparrow', vertical: true },
      /* 火山铺在底部背景，枪、草、消防栓在其上层 */
      ...volcano,
      /* 枪：多个「枪」拼出枪形，占最右 4 列，枪口指向左上方的麻雀 */
      { text: '枪', x: 24, y: 20, cls: 'gun' },
      { text: '枪', x: 25, y: 20, cls: 'gun' },
      { text: '枪', x: 25, y: 21, cls: 'gun' },
      { text: '枪', x: 26, y: 21, cls: 'gun' },
      { text: '枪', x: 26, y: 22, cls: 'gun' },
      { text: '枪', x: 27, y: 22, cls: 'gun' },
      { text: '枪', x: 27, y: 23, cls: 'gun' },
      { text: '枪', x: 27, y: 24, cls: 'gun' },
      /* 草：最底部一排 */
      { text: '草'.repeat(28), x: 0, y: 43, cls: 'grass' },
      /* 消防栓：最后三行分散竖排九根，左侧留 2 格 */
      ...[2, 5, 8, 10, 13, 16, 19, 23, 25].map((x) => ({
        text: '消防栓',
        x,
        y: 41,
        cls: 'hydrant',
        vertical: true,
      })),
    ],
  });

  const scene = document.querySelector('.scene');
  const credits = document.createElement('h1');
  credits.className = 'credits';
  credits.textContent = '演职员表';
  scene.append(credits);
})();