/* ============================================================
   待办事项悬浮窗 Demo 交互逻辑
   三组动画：
   1. 创建：逐行从左向右进入（stagger）
   2. 完成：横线从左往右划过 + 文字变灰
   3. 更新：旧行逐行向左移出（高度收拢）→ 新行逐行进入
   ============================================================ */

const ENTER_STAGGER = 60;   // 进入动画每行间隔 ms
const LEAVE_STAGGER = 45;   // 移出动画每行间隔 ms
const LEAVE_DURATION = 260; // 单行移出动画时长 ms

const listEl = document.getElementById('todoList');
const windowEl = document.getElementById('todoWindow');
const counterEl = document.getElementById('todoCounter');

const state = { items: [], busy: false };

/* ---------------- 演示数据 ---------------- */

const SCENARIOS = {
  initial: [
    { text: '梳理对话区布局，确定悬浮窗挂载位置' },
    { text: '实现悬浮窗容器：圆角、最小 / 最大宽度' },
    { text: '待办行直接铺在窗口上，去掉嵌套卡片' },
    { text: '编写创建 / 完成 / 更新三组动画' },
    { text: '联调后端 todo 事件，接入真实数据' },
  ],
  updated: [
    { text: '复核悬浮窗最大 / 最小宽度表现', done: true },
    { text: '把划线动画时序再调顺手一点' },
    { text: '超长任务名省略号验证（这一条故意写得特别特别长来测试溢出）' },
    { text: '设计文件编辑记录窗口的数据结构' },
    { text: '子智能体与后台指令窗口渲染方案' },
    { text: '三种主题下核对一遍配色' },
  ],
  long: [
    { text: '拉取最新代码并跑一遍冒烟测试' },
    { text: '检查待办窗口在窄屏下的最小宽度' },
    { text: '把完成动画的横线改成从左向右' },
    { text: '补五条以上时的内部滚动' },
    { text: '写一条特别长的任务用来验证文字溢出时省略号效果到底行不行' },
    { text: '同步更新 AGENTS.md 的布局说明' },
    { text: '给悬浮窗预留多窗口上下排布的间距' },
    { text: '收拾 demo 控制台，准备演示' },
  ],
};

/* ---------------- 工具 ---------------- */

const wait = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

function updateCounter() {
  const done = state.items.filter((t) => t.done).length;
  counterEl.textContent = `${done}/${state.items.length}`;
}

function ensureWindowVisible() {
  if (!windowEl.hidden) return;
  windowEl.hidden = false;
  windowEl.classList.add('window-enter');
  windowEl.addEventListener('animationend', () => windowEl.classList.remove('window-enter'), { once: true });
}

/* ---------------- 渲染 ---------------- */

function renderTodos(items) {
  listEl.innerHTML = '';
  items.forEach((item, i) => {
    const li = document.createElement('li');
    li.className = 'todo-item is-entering' + (item.done ? ' is-done' : '');
    li.style.animationDelay = `${i * ENTER_STAGGER}ms`;

    const dot = document.createElement('span');
    dot.className = 'todo-dot';
    const text = document.createElement('span');
    text.className = 'todo-text';
    text.textContent = item.text;

    li.append(dot, text);
    li.addEventListener('animationend', () => {
      li.classList.remove('is-entering');
      li.style.animationDelay = '';
    }, { once: true });

    listEl.appendChild(li);
  });
  updateCounter();
}

/* 让当前列表逐行向左移出，返回动画总耗时 */
async function playLeaveAnimation() {
  const rows = [...listEl.children];
  if (!rows.length) return;
  rows.forEach((li, i) => {
    li.style.animationDelay = `${i * LEAVE_STAGGER}ms`;
    li.classList.add('is-leaving');
  });
  await wait(rows.length * LEAVE_STAGGER + LEAVE_DURATION + 20);
}

/* ---------------- 三个核心动作 ---------------- */

/* 1. 创建 / 整表替换（收到新 todo 列表） */
async function replaceTodos(newItems) {
  if (state.busy) return;
  state.busy = true;

  await playLeaveAnimation();          // 旧列表逐行移出
  state.items = newItems.map((t) => ({ text: t.text, done: !!t.done }));
  ensureWindowVisible();
  renderTodos(state.items);            // 新列表逐行进入

  state.busy = false;
}

/* 若目标行未完全显示，先平滑滚动到可见位置；已可见则立即 resolve */
function scrollRowIntoView(li) {
  return new Promise((resolve) => {
    const listRect = listEl.getBoundingClientRect();
    const liRect = li.getBoundingClientRect();
    const fullyVisible = liRect.top >= listRect.top && liRect.bottom <= listRect.bottom;
    if (fullyVisible) { resolve(); return; }

    let done = false;
    let timer;
    const finish = () => {
      if (done) return;
      done = true;
      clearTimeout(timer);
      listEl.removeEventListener('scroll', onScroll);
      resolve();
    };
    const onScroll = () => {
      clearTimeout(timer);
      timer = setTimeout(finish, 90);   // 滚动停止 90ms 后认为到位
    };
    listEl.addEventListener('scroll', onScroll);
    li.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
    setTimeout(finish, 800);            // 兜底，避免意外卡死
  });
}

/* 2. 完成下一项（先滚动到可见 → 再划线动画） */
async function completeNext() {
  if (state.busy) return;
  const idx = state.items.findIndex((t) => !t.done);
  if (idx === -1) return;

  state.busy = true;
  const li = listEl.children[idx];
  if (li) await scrollRowIntoView(li);   // 未完全显示的先滚出来

  state.items[idx].done = true;
  if (li) {
    li.classList.add('is-done', 'just-done');
    setTimeout(() => li.classList.remove('just-done'), 400);
  }
  updateCounter();
  state.busy = false;
}

/* 3. 清空（移出后隐藏窗口） */
async function clearTodos() {
  if (state.busy || !state.items.length) return;
  state.busy = true;

  await playLeaveAnimation();
  state.items = [];
  renderTodos(state.items);

  windowEl.classList.add('window-leave');
  windowEl.addEventListener('animationend', () => {
    windowEl.classList.remove('window-leave');
    windowEl.hidden = true;
  }, { once: true });

  state.busy = false;
}

/* ---------------- 绑定演示按钮 ---------------- */

document.getElementById('btnCreate').addEventListener('click', () => replaceTodos(SCENARIOS.initial));
document.getElementById('btnComplete').addEventListener('click', completeNext);
document.getElementById('btnUpdate').addEventListener('click', () => replaceTodos(SCENARIOS.updated));
document.getElementById('btnLong').addEventListener('click', () => replaceTodos(SCENARIOS.long));
document.getElementById('btnClear').addEventListener('click', clearTodos);

/* 页面加载后自动演示一次创建 */
window.addEventListener('load', () => {
  setTimeout(() => replaceTodos(SCENARIOS.initial), 500);
});