/* 文字画共享渲染引擎
   页面脚本调用 TextScene.render({...}) 提供数据即可，示例见 page1.js。
   网格坐标：x 0–cols-1，y 0–rows-1；空白格自动填充天空字符。 */

(() => {
  const BIRD_WORDS = {
    sparrow: '麻雀',
    magpie: '喜鹊',
    crow: '乌鸦',
  };

  function render({
    cols,
    rows,
    skyChar = '天',
    skyClass = 'sky',
    clouds = [],
    sun = [],
    birds = [],
    antennas = [],
    buildings = [],
    glyphs = [],
    title,
    container = '.scene',
  }) {
    if (!cols || !rows) throw new Error('TextScene.render 需要 cols 与 rows');

    // skyChar 传空字符串时不铺背景字，空格仍占满整格
    const blank = skyChar
      ? { ch: skyChar, cls: skyClass }
      : { ch: '　', cls: 'void' };

    const grid = Array.from({ length: rows }, () =>
      Array.from({ length: cols }, () => ({ ...blank }))
    );

    const put = (x, y, ch, cls) => {
      if (x < 0 || x >= cols || y < 0 || y >= rows) {
        throw new Error(`元素超出网格范围：(${x}, ${y})`);
      }
      grid[y][x] = { ch, cls };
    };

    const putRow = (y, x, n, ch, cls) => {
      for (let i = 0; i < n; i++) put(x + i, y, ch, cls);
    };

    for (const { x, y, tone } of clouds) {
      const cls = `cloud cloud-${tone}`;
      putRow(y, x + 1, 3, '云', cls);
      putRow(y + 1, x, 5, '云', cls);
      putRow(y + 2, x + 1, 3, '云', cls);
    }

    sun.forEach(({ y, x, w }, i) => {
      const tone = `sun-t${i + 1}`;
      for (let dx = 0; dx < w; dx++) put(x + dx, y, '日', `sun ${tone}`);
    });

    for (const { x, y, kind } of birds) {
      const word = BIRD_WORDS[kind];
      if (!word) throw new Error(`未知鸟种：${kind}`);
      const [a, b] = [...word];
      put(x, y, a, `bird-${kind}`);
      put(x + 1, y, b, `bird-${kind}`);
    }

    for (const { x, y, h, cls = 'ant' } of antennas) {
      for (let i = 0; i < h; i++) put(x, y + i, '线', cls);
    }

    for (const { n, x, y, w, h } of buildings) {
      for (let j = 0; j < h; j++) putRow(y + j, x, w, '楼', `bld bld-${n}`);
    }

    for (const { text, x, y, cls = 'glyph', vertical = false } of glyphs) {
      [...text].forEach((ch, i) => {
        put(vertical ? x : x + i, vertical ? y + i : y, ch, cls);
      });
    }

    if (title) {
      for (let y = title.top; y < title.top + title.height; y++) {
        for (let x = title.side; x < cols - title.side; x++) {
          grid[y][x] = { ch: '　', cls: 'cut' };
        }
      }
    }

    /* 把同 class 的连续字符合并成一个 span，减少 DOM 节点 */
    const html = grid
      .map((row) => {
        let line = '';
        for (let i = 0; i < cols; ) {
          let j = i + 1;
          while (j < cols && row[j].cls === row[i].cls) j++;
          const text = row.slice(i, j).map((cell) => cell.ch).join('');
          line += `<span class="${row[i].cls}">${text}</span>`;
          i = j;
        }
        return `<div class="line">${line}</div>`;
      })
      .join('');

    const scene = document.querySelector(container);
    if (!scene) throw new Error(`未找到容器：${container}`);
    scene.innerHTML = html;

    if (!title) return;

    const panel = document.createElement('div');
    panel.className = 'title-panel';
    panel.style.top = `${title.top}em`;
    panel.style.left = `${title.side}em`;
    panel.style.width = `${cols - title.side * 2}em`;
    panel.style.height = `${title.height}em`;

    const titleEl = document.createElement('h1');
    titleEl.className = 'title';

    const { text, emphasis } = title;
    if (emphasis && text.includes(emphasis)) {
      const [before, after] = text.split(emphasis);
      const em = document.createElement('span');
      em.className = 'title-em';
      em.textContent = emphasis;
      titleEl.append(before, em, after);
    } else {
      titleEl.textContent = text;
    }

    panel.append(titleEl);
    scene.append(panel);
  }

  window.TextScene = { render };
})();