'use strict';

const api = window.clockApi;

const els = {
  readoutTime: document.getElementById('readoutTime'),
  readoutMeta: document.getElementById('readoutMeta'),
  toggleClockWindow: document.getElementById('toggleClockWindow'),
  aotClock: document.getElementById('aotClock'),
  aotControl: document.getElementById('aotControl'),
  styleGroup: document.getElementById('styleGroup'),
  hh: document.getElementById('hh'),
  mm: document.getElementById('mm'),
  ss: document.getElementById('ss'),
  applyTime: document.getElementById('applyTime'),
  fillNow: document.getElementById('fillNow'),
  rate: document.getElementById('rate'),
  applyRate: document.getElementById('applyRate'),
  togglePause: document.getElementById('togglePause')
};

let snapshot = { baseMs: Date.now(), baseRealMs: Date.now(), rate: 1, style: 'digital', paused: false, clockWindowOpen: false };

function pad2(value) {
  return String(value).padStart(2, '0');
}

function displayMs(now) {
  return snapshot.baseMs + (now - snapshot.baseRealMs) * snapshot.rate;
}

function clampInt(value, min, max, fallback) {
  const n = Number.parseInt(value, 10);
  if (!Number.isFinite(n)) return fallback;
  return Math.min(max, Math.max(min, n));
}

function renderReadout() {
  const ms = displayMs(Date.now());
  const date = new Date(ms);
  els.readoutTime.textContent = `${pad2(date.getHours())}:${pad2(date.getMinutes())}:${pad2(date.getSeconds())}`;

  const rateText = snapshot.rate === 0 ? '暂停' : `×${snapshot.rate}`;
  const runText = snapshot.rate === 0 ? '已暂停' : snapshot.rate < 0 ? '倒转中' : '运行中';
  els.readoutMeta.textContent = `${rateText} · ${runText} · 时钟窗口${snapshot.clockWindowOpen ? '已打开' : '已关闭'}`;
  requestAnimationFrame(renderReadout);
}

function syncControls() {
  els.toggleClockWindow.textContent = snapshot.clockWindowOpen ? '关闭时钟窗口' : '打开时钟窗口';
  els.toggleClockWindow.classList.toggle('is-on', snapshot.clockWindowOpen);

  els.aotClock.checked = Boolean(snapshot.alwaysOnTop.clock);
  els.aotControl.checked = Boolean(snapshot.alwaysOnTop.control);

  for (const button of els.styleGroup.querySelectorAll('.seg')) {
    button.classList.toggle('is-active', button.dataset.style === snapshot.style);
  }

  // 用户正在输入时不要抢走他的光标和内容
  if (document.activeElement !== els.rate) els.rate.value = String(snapshot.rate);

  if (snapshot.rate === 0) {
    els.togglePause.textContent = `继续（回到 ×${snapshot.lastRate}）`;
    els.togglePause.classList.add('is-on');
  } else {
    els.togglePause.textContent = '暂停';
    els.togglePause.classList.remove('is-on');
  }
}

function accept(next) {
  if (next) {
    snapshot = next;
    syncControls();
  }
}

els.toggleClockWindow.addEventListener('click', async () => accept(await api.toggleClockWindow()));

els.aotClock.addEventListener('change', async () => accept(await api.setAlwaysOnTop('clock', els.aotClock.checked)));
els.aotControl.addEventListener('change', async () => accept(await api.setAlwaysOnTop('control', els.aotControl.checked)));

for (const button of els.styleGroup.querySelectorAll('.seg')) {
  button.addEventListener('click', async () => accept(await api.setStyle(button.dataset.style)));
}

els.applyTime.addEventListener('click', async () => {
  const h = clampInt(els.hh.value, 0, 23, 0);
  const m = clampInt(els.mm.value, 0, 59, 0);
  const s = clampInt(els.ss.value, 0, 59, 0);
  els.hh.value = String(h);
  els.mm.value = String(m);
  els.ss.value = String(s);
  accept(await api.setTime(h, m, s));
});

els.fillNow.addEventListener('click', () => {
  // 三格都要补零：`String(0)` 是 "0"，而输入框按 HH:MM:SS 解析，
  // 上午 9 点前会填出 "0:39:27" 这种非法值，点应用时解析失败。
  const date = new Date(displayMs(Date.now()));
  els.hh.value = pad2(date.getHours());
  els.mm.value = pad2(date.getMinutes());
  els.ss.value = pad2(date.getSeconds());
});

function applyRateInput() {
  const value = Number(els.rate.value);
  if (!Number.isFinite(value)) {
    els.rate.value = String(snapshot.rate);
    return;
  }
  api.setRate(value).then(accept);
}

els.applyRate.addEventListener('click', applyRateInput);

els.rate.addEventListener('keydown', (event) => {
  if (event.key === 'Enter') applyRateInput();
});

els.togglePause.addEventListener('click', async () => accept(await api.togglePause()));

document.body.addEventListener('click', (event) => {
  const rate = event.target.dataset?.rate;
  if (rate !== undefined) {
    api.setRate(Number(rate)).then(accept);
    return;
  }
  const delta = event.target.dataset?.delta;
  if (delta !== undefined) {
    api.fastForward(Number(delta)).then(accept);
  }
});

api.onState((next) => {
  snapshot = next;
  syncControls();
});

api.getState().then((initial) => {
  snapshot = initial;
  syncControls();
  renderReadout();
});