/**
 * Main Application - Data Visualization Display Wall
 */
(function () {
  'use strict';

  // ---- Config ----
  const REFRESH_INTERVAL = 5000; // 5 seconds
  const NETWORK_HISTORY_INTERVAL = 60000; // 1 minute

  // ---- DOM Elements ----
  const dom = {
    clock: document.getElementById('clock'),
    serverCountText: document.getElementById('serverCountText'),
    sourceCount: document.getElementById('sourceCount'),
    totalServers: document.getElementById('totalServers'),
    cpuPercent: document.getElementById('cpuPercent'),
    cpuDetail: document.getElementById('cpuDetail'),
    memPercent: document.getElementById('memPercent'),
    memDetail: document.getElementById('memDetail'),
    diskPercent: document.getElementById('diskPercent'),
    diskDetail: document.getElementById('diskDetail'),
    totalBandwidth: document.getElementById('totalBandwidth'),
    bandwidthDetail: document.getElementById('bandwidthDetail'),
    traffic24hRx: document.getElementById('traffic24hRx'),
    traffic24hTx: document.getElementById('traffic24hTx'),
    traffic24hTotal: document.getElementById('traffic24hTotal'),
    networkCanvas: document.getElementById('networkCanvas'),
    gaugeCpuFill: document.getElementById('gaugeCpuFill'),
    gaugeRamFill: document.getElementById('gaugeRamFill'),
    gaugeDiskFill: document.getElementById('gaugeDiskFill'),
    gaugeCpuValue: document.getElementById('gaugeCpuValue'),
    gaugeRamValue: document.getElementById('gaugeRamValue'),
    gaugeDiskValue: document.getElementById('gaugeDiskValue'),
    serverTableBody: document.getElementById('serverTableBody'),
    btnSettings: document.getElementById('btnSettings'),
    settingsModal: document.getElementById('settingsModal'),
    modalClose: document.getElementById('modalClose'),
    sourceName: document.getElementById('sourceName'),
    sourceUrl: document.getElementById('sourceUrl'),
    sourceDesc: document.getElementById('sourceDesc'),
    btnTest: document.getElementById('btnTest'),
    btnAdd: document.getElementById('btnAdd'),
    formMessage: document.getElementById('formMessage'),
    sourceItems: document.getElementById('sourceItems'),
    // Site Settings
    modalTabs: document.querySelectorAll('.modal-tab'),
    tabContents: document.querySelectorAll('.tab-content'),
    pageNameInput: document.getElementById('pageNameInput'),
    siteTitleInput: document.getElementById('siteTitleInput'),
    logoUrlInput: document.getElementById('logoUrlInput'),
    btnSaveSiteSettings: document.getElementById('btnSaveSiteSettings'),
    siteSettingsMessage: document.getElementById('siteSettingsMessage'),
    logoText: document.getElementById('logoText'),
    logoIconContainer: document.getElementById('logoIconContainer'),
    defaultThemeInput: document.getElementById('defaultThemeInput'),
    // Auth & Theme elements
    themeToggle: document.getElementById('themeToggle'),
    sunIcon: document.querySelector('.sun-icon'),
    moonIcon: document.querySelector('.moon-icon'),
    userSection: document.getElementById('userSection'),
    btnLogin: document.getElementById('btnLogin'),
    loginModal: document.getElementById('loginModalOverlay'),
    closeLoginModal: document.getElementById('closeLoginModal'),
    loginForm: document.getElementById('loginForm'),
    loginError: document.getElementById('loginError')
  };

  // ---- State ----
  let previousMetrics = null;
  let networkChart = null;
  let user = null; // Currently logged in user

  // ---- Initialize ----
  function init() {
    // Add SVG gradient definitions for gauges
    addGaugeSvgDefs();

    // Clock
    updateClock();
    setInterval(updateClock, 1000);

    // Initial theme check (localStorage handled after site settings load to ensure priority)

    // Network chart
    networkChart = new AreaChart(dom.networkCanvas);

    // Event listeners
    dom.btnSettings.addEventListener('click', openSettings);
    dom.modalClose.addEventListener('click', closeSettings);
    dom.settingsModal.addEventListener('click', (e) => {
      if (e.target === dom.settingsModal) closeSettings();
    });
    dom.btnTest.addEventListener('click', testConnection);
    dom.btnAdd.addEventListener('click', addSource);

    // Auth & Theme listeners
    dom.themeToggle.addEventListener('click', toggleTheme);
    dom.btnLogin.addEventListener('click', openLoginModal);
    dom.closeLoginModal.addEventListener('click', closeLoginModal);
    dom.loginForm.addEventListener('submit', handleLogin);
    dom.loginModal.addEventListener('click', (e) => {
      if (e.target === dom.loginModal) closeLoginModal();
    });

    // Tab switching
    dom.modalTabs.forEach(tab => {
      tab.addEventListener('click', () => {
        const targetTab = tab.getAttribute('data-tab');
        switchTab(targetTab);
      });
    });

    // Site settings
    dom.btnSaveSiteSettings.addEventListener('click', saveSiteSettings);

    // Keyboard shortcut
    document.addEventListener('keydown', (e) => {
      if (e.key === 'Escape') {
        closeSettings();
        closeLoginModal();
      }
    });

    // Check auth status
    checkAuthStatus();

    // Start data fetching
    fetchMetrics();
    fetchNetworkHistory();
    loadSiteSettings();
    setInterval(fetchMetrics, REFRESH_INTERVAL);
    setInterval(fetchNetworkHistory, NETWORK_HISTORY_INTERVAL);
  }

  // ---- Theme Switching ----
  function toggleTheme() {
    const isLight = document.documentElement.classList.toggle('light-theme');
    const theme = isLight ? 'light' : 'dark';
    localStorage.setItem('theme', theme);
    updateThemeIcons(theme);
  }

  function applyTheme(theme) {
    const isLight = theme === 'light';
    document.documentElement.classList.toggle('light-theme', isLight);
    updateThemeIcons(theme);
  }

  function updateThemeIcons(theme) {
    if (theme === 'light') {
      dom.sunIcon.style.display = 'none';
      dom.moonIcon.style.display = 'block';
    } else {
      dom.sunIcon.style.display = 'block';
      dom.moonIcon.style.display = 'none';
    }
  }

  // ---- Auth Logic ----
  async function checkAuthStatus() {
    try {
      const resp = await fetch('/api/auth/status');
      const data = await resp.json();
      if (data.authenticated) {
        updateUserUI(data.username);
      } else {
        updateUserUI(null);
      }
    } catch (err) {
      updateUserUI(null);
    }
  }

  function updateUserUI(username) {
    if (username) {
      user = username;
      dom.userSection.innerHTML = `
        <div class="user-info">
          <span class="username">${escapeHtml(username)}</span>
          <button class="btn btn-logout" id="btnLogout">退出</button>
        </div>
      `;
      document.getElementById('btnLogout').addEventListener('click', handleLogout);
    } else {
      user = null;
      dom.userSection.innerHTML = `<button class="btn btn-login" id="btnLogin">登录</button>`;
      document.getElementById('btnLogin').addEventListener('click', openLoginModal);
    }
  }

  function openLoginModal() {
    dom.loginModal.classList.add('active');
    dom.loginError.style.display = 'none';
  }

  function closeLoginModal() {
    dom.loginModal.classList.remove('active');
    dom.loginForm.reset();
  }

  async function handleLogin(e) {
    e.preventDefault();
    const username = document.getElementById('username').value;
    const password = document.getElementById('password').value;

    try {
      const resp = await fetch('/api/auth/login', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ username, password })
      });
      const data = await resp.json();
      if (resp.ok) {
        updateUserUI(data.username);
        closeLoginModal();
      } else {
        dom.loginError.textContent = data.error || '登录失败';
        dom.loginError.style.display = 'block';
      }
    } catch (err) {
      dom.loginError.textContent = '服务器错误';
      dom.loginError.style.display = 'block';
    }
  }

  async function handleLogout() {
    try {
      await fetch('/api/auth/logout', { method: 'POST' });
      updateUserUI(null);
    } catch (err) {
      console.error('Logout failed:', err);
    }
  }

  // ---- Add SVG Gradient Defs ----
  function addGaugeSvgDefs() {
    const svgs = document.querySelectorAll('.gauge svg');
    const gradients = [
      { id: 'gaugeCpuGrad', colors: ['#6366f1', '#818cf8'] },
      { id: 'gaugeRamGrad', colors: ['#06b6d4', '#22d3ee'] },
      { id: 'gaugeDiskGrad', colors: ['#f59e0b', '#fbbf24'] }
    ];

    svgs.forEach((svg, i) => {
      const defs = document.createElementNS('http://www.w3.org/2000/svg', 'defs');
      const grad = document.createElementNS('http://www.w3.org/2000/svg', 'linearGradient');
      grad.setAttribute('id', gradients[i].id);
      grad.setAttribute('x1', '0%');
      grad.setAttribute('y1', '0%');
      grad.setAttribute('x1', '100%');
      grad.setAttribute('y2', '100%');

      gradients[i].colors.forEach((color, ci) => {
        const stop = document.createElementNS('http://www.w3.org/2000/svg', 'stop');
        stop.setAttribute('offset', ci === 0 ? '0%' : '100%');
        stop.setAttribute('stop-color', color);
        grad.appendChild(stop);
      });

      defs.appendChild(grad);
      svg.insertBefore(defs, svg.firstChild);
    });
  }

  // ---- Clock ----
  function updateClock() {
    dom.clock.textContent = formatClock();
  }

  // ---- Fetch Metrics ----
  async function fetchMetrics() {
    try {
      const response = await fetch('/api/metrics/overview');
      const data = await response.json();
      updateDashboard(data);
    } catch (err) {
      console.error('Error fetching metrics:', err);
    }
  }

  // ---- Update Dashboard ----
  function updateDashboard(data) {
    // Server count
    dom.totalServers.textContent = data.totalServers;
    dom.serverCountText.textContent = `${data.totalServers} 台服务器`;

    // CPU
    const cpuPct = data.cpu.percent;
    dom.cpuPercent.textContent = formatPercent(cpuPct);
    dom.cpuDetail.textContent = `${data.cpu.used.toFixed(1)} / ${data.cpu.total.toFixed(0)} 核心`;

    // Memory
    const memPct = data.memory.percent;
    dom.memPercent.textContent = formatPercent(memPct);
    dom.memDetail.textContent = `${formatBytes(data.memory.used)} / ${formatBytes(data.memory.total)}`;

    // Disk
    const diskPct = data.disk.percent;
    dom.diskPercent.textContent = formatPercent(diskPct);
    dom.diskDetail.textContent = `${formatBytes(data.disk.used)} / ${formatBytes(data.disk.total)}`;

    // Bandwidth
    dom.totalBandwidth.textContent = formatBandwidth(data.network.total || 0);
    dom.bandwidthDetail.textContent = `↓ ${formatBandwidth(data.network.rx)} ↑ ${formatBandwidth(data.network.tx)}`;

    // 24h traffic
    dom.traffic24hRx.textContent = formatBytes(data.traffic24h.rx);
    dom.traffic24hTx.textContent = formatBytes(data.traffic24h.tx);
    dom.traffic24hTotal.textContent = formatBytes(data.traffic24h.total || (data.traffic24h.rx + data.traffic24h.tx));

    // Update gauges
    updateGauge(dom.gaugeCpuFill, dom.gaugeCpuValue, cpuPct);
    updateGauge(dom.gaugeRamFill, dom.gaugeRamValue, memPct);
    updateGauge(dom.gaugeDiskFill, dom.gaugeDiskValue, diskPct);

    // Update server table
    updateServerTable(data.servers);

    // Flash animation
    if (previousMetrics) {
      [dom.cpuPercent, dom.memPercent, dom.diskPercent, dom.totalBandwidth].forEach(el => {
        el.classList.remove('value-update');
        void el.offsetWidth; // Force reflow
        el.classList.add('value-update');
      });
    }

    previousMetrics = data;
  }

  // ---- Gauge Update ----
  const CIRCUMFERENCE = 2 * Math.PI * 52; // r=52

  function updateGauge(fillEl, valueEl, percent) {
    const clamped = Math.min(100, Math.max(0, percent));
    const offset = CIRCUMFERENCE - (clamped / 100) * CIRCUMFERENCE;
    fillEl.style.strokeDashoffset = offset;
    valueEl.textContent = formatPercent(clamped);
  }

  // ---- Server Table ----
  function updateServerTable(servers) {
    if (!servers || servers.length === 0) {
      dom.serverTableBody.innerHTML = `
        <tr class="empty-row">
          <td colspan="8">暂无数据 - 请先配置 Prometheus 数据源</td>
        </tr>
      `;
      return;
    }

    // Sort servers: online first, then by cpu usage
    servers.sort((a, b) => {
      if (a.up !== b.up) return b.up ? 1 : -1;
      return b.cpuPercent - a.cpuPercent;
    });

    dom.serverTableBody.innerHTML = servers.map(server => {
      const memPct = server.memTotal > 0 ? (server.memUsed / server.memTotal * 100) : 0;
      const diskPct = server.diskTotal > 0 ? (server.diskUsed / server.diskTotal * 100) : 0;

      return `
        <tr>
          <td>
            <span class="status-dot ${server.up ? 'status-dot-online' : 'status-dot-offline'}"></span>
          </td>
          <td>
            <div style="color: var(--text-primary); font-weight: 600; font-family: var(--font-sans);">${escapeHtml(server.job)}</div>
          </td>
          <td>${escapeHtml(server.source)}</td>
          <td>
            <div class="usage-bar">
              <div class="usage-bar-track">
                <div class="usage-bar-fill usage-bar-fill-cpu" style="width: ${Math.min(server.cpuPercent, 100)}%"></div>
              </div>
              <span>${formatPercent(server.cpuPercent)}</span>
            </div>
          </td>
          <td>
            <div class="usage-bar">
              <div class="usage-bar-track">
                <div class="usage-bar-fill usage-bar-fill-mem" style="width: ${Math.min(memPct, 100)}%"></div>
              </div>
              <span>${formatPercent(memPct)}</span>
            </div>
          </td>
          <td>
            <div class="usage-bar">
              <div class="usage-bar-track">
                <div class="usage-bar-fill usage-bar-fill-disk" style="width: ${Math.min(diskPct, 100)}%"></div>
              </div>
              <span>${formatPercent(diskPct)}</span>
            </div>
          </td>
          <td>${formatBandwidth(server.netRx)}</td>
          <td>${formatBandwidth(server.netTx)}</td>
        </tr>
      `;
    }).join('');
  }

  // ---- Network History ----
  async function fetchNetworkHistory() {
    try {
      const response = await fetch('/api/metrics/network-history');
      const data = await response.json();
      networkChart.setData(data);
    } catch (err) {
      console.error('Error fetching network history:', err);
    }
  }

  // ---- Settings Modal ----
  function openSettings() {
    dom.settingsModal.classList.add('active');
    loadSources();
  }

  function closeSettings() {
    dom.settingsModal.classList.remove('active');
    hideMessage();
    hideSiteMessage();
  }

  // ---- Tab Switching ----
  function switchTab(tabId) {
    dom.modalTabs.forEach(tab => {
      tab.classList.toggle('active', tab.getAttribute('data-tab') === tabId);
    });
    dom.tabContents.forEach(content => {
      content.classList.toggle('active', content.id === `tab-${tabId}`);
    });
  }

  // ---- Site Settings ----
  async function loadSiteSettings() {
    try {
      const response = await fetch('/api/settings');
      const settings = await response.json();
      
      // Update inputs
      dom.pageNameInput.value = settings.page_name || '';
      dom.siteTitleInput.value = settings.title || '';
      dom.logoUrlInput.value = settings.logo_url || '';
      dom.defaultThemeInput.value = settings.default_theme || 'dark';
      
      // Apply to UI
      applySiteSettings(settings);

      // Handle Theme Priority: localStorage > Site Default
      const savedTheme = localStorage.getItem('theme');
      if (savedTheme) {
        applyTheme(savedTheme);
      } else if (settings.default_theme) {
        applyTheme(settings.default_theme);
      } else {
        applyTheme('dark'); // Fallback
      }
    } catch (err) {
      console.error('Error loading site settings:', err);
    }
  }

  function applySiteSettings(settings) {
    if (settings.page_name) {
      document.title = settings.page_name;
    }
    if (settings.title) {
      dom.logoText.textContent = settings.title;
    }
    
    // Logo Icon
    if (settings.logo_url) {
      dom.logoIconContainer.innerHTML = `<img src="${escapeHtml(settings.logo_url)}" alt="Logo" class="logo-icon-img">`;
    } else {
      // Restore default SVG
      dom.logoIconContainer.innerHTML = `
        <svg class="logo-icon" id="logoSvg" viewBox="0 0 32 32" fill="none">
          <rect x="2" y="2" width="28" height="28" rx="8" stroke="url(#logoGrad)" stroke-width="2.5"/>
          <path d="M8 22 L12 14 L16 18 L20 10 L24 16" stroke="url(#logoGrad)" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" fill="none"/>
          <circle cx="12" cy="14" r="2" fill="url(#logoGrad)"/>
          <circle cx="20" cy="10" r="2" fill="url(#logoGrad)"/>
          <defs>
            <linearGradient id="logoGrad" x1="0" y1="0" x2="32" y2="32">
              <stop offset="0%" stop-color="#6366f1"/>
              <stop offset="100%" stop-color="#06b6d4"/>
            </linearGradient>
          </defs>
        </svg>
      `;
    }
  }

  async function saveSiteSettings() {
    if (!user) {
      showSiteMessage('请先登录后操作', 'error');
      openLoginModal();
      return;
    }

    const settings = {
      page_name: dom.pageNameInput.value.trim(),
      title: dom.siteTitleInput.value.trim(),
      logo_url: dom.logoUrlInput.value.trim(),
      default_theme: dom.defaultThemeInput.value
    };

    dom.btnSaveSiteSettings.disabled = true;
    dom.btnSaveSiteSettings.textContent = '保存中...';

    try {
      const response = await fetch('/api/settings', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(settings)
      });

      if (response.ok) {
        showSiteMessage('设置保存成功', 'success');
        applySiteSettings(settings);
      } else {
        const err = await response.json();
        showSiteMessage(`保存失败: ${err.error}`, 'error');
        if (response.status === 401) openLoginModal();
      }
    } catch (err) {
      showSiteMessage(`保存失败: ${err.message}`, 'error');
    } finally {
      dom.btnSaveSiteSettings.disabled = false;
      dom.btnSaveSiteSettings.textContent = '保存设置';
    }
  }

  function showSiteMessage(text, type) {
    dom.siteSettingsMessage.textContent = text;
    dom.siteSettingsMessage.className = `form-message ${type}`;
    setTimeout(hideSiteMessage, 5000);
  }

  function hideSiteMessage() {
    dom.siteSettingsMessage.className = 'form-message';
  }

  async function loadSources() {
    try {
      const response = await fetch('/api/sources');
      const sources = await response.json();
      dom.sourceCount.textContent = `${sources.length} 个数据源`;
      renderSources(sources);
    } catch (err) {
      console.error('Error loading sources:', err);
    }
  }

  function renderSources(sources) {
    if (sources.length === 0) {
      dom.sourceItems.innerHTML = '<div class="source-empty">暂无数据源</div>';
      return;
    }

    dom.sourceItems.innerHTML = sources.map(source => `
      <div class="source-item" data-id="${source.id}">
        <div class="source-item-info">
          <div class="source-item-name">
            ${escapeHtml(source.name)}
            <span class="source-status ${source.status === 'online' ? 'source-status-online' : 'source-status-offline'}">
              ${source.status === 'online' ? '在线' : '离线'}
            </span>
          </div>
          <div class="source-item-url">${escapeHtml(source.url)}</div>
          ${source.description ? `<div class="source-item-desc">${escapeHtml(source.description)}</div>` : ''}
        </div>
        <div class="source-item-actions">
          <button class="btn btn-delete" onclick="deleteSource(${source.id})">删除</button>
        </div>
      </div>
    `).join('');
  }

  // ---- Test Connection ----
  async function testConnection() {
    const url = dom.sourceUrl.value.trim();
    if (!url) {
      showMessage('请输入 Prometheus URL', 'error');
      return;
    }

    dom.btnTest.textContent = '测试中...';
    dom.btnTest.disabled = true;

    try {
      const response = await fetch('/api/sources/test', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ url })
      });
      const data = await response.json();
      if (data.status === 'ok') {
        showMessage(`连接成功！Prometheus 版本: ${data.version}`, 'success');
      } else {
        if (response.status === 401) {
          showMessage('请先登录', 'error');
          openLoginModal();
        } else {
          showMessage(`连接失败: ${data.message || data.error}`, 'error');
        }
      }
    } catch (err) {
      showMessage(`连接失败: ${err.message}`, 'error');
    } finally {
      dom.btnTest.textContent = '测试连接';
      dom.btnTest.disabled = false;
    }
  }

  // ---- Add Source ----
  async function addSource() {
    if (!user) {
      showMessage('请先登录后操作', 'error');
      openLoginModal();
      return;
    }

    const name = dom.sourceName.value.trim();
    const url = dom.sourceUrl.value.trim();
    const description = dom.sourceDesc.value.trim();

    if (!name || !url) {
      showMessage('请填写名称和URL', 'error');
      return;
    }

    dom.btnAdd.textContent = '添加中...';
    dom.btnAdd.disabled = true;

    try {
      const response = await fetch('/api/sources', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ name, url, description })
      });

      if (response.ok) {
        showMessage('数据源添加成功', 'success');
        dom.sourceName.value = '';
        dom.sourceUrl.value = '';
        dom.sourceDesc.value = '';
        loadSources();
        fetchMetrics();
        fetchNetworkHistory();
      } else {
        const err = await response.json();
        showMessage(`添加失败: ${err.error}`, 'error');
        if (response.status === 401) openLoginModal();
      }
    } catch (err) {
      showMessage(`添加失败: ${err.message}`, 'error');
    } finally {
      dom.btnAdd.textContent = '添加';
      dom.btnAdd.disabled = false;
    }
  }

  // ---- Delete Source ----
  window.deleteSource = async function (id) {
    if (!user) {
      showMessage('请先登录后操作', 'error');
      openLoginModal();
      return;
    }
    if (!confirm('确定要删除这个数据源吗？')) return;

    try {
      const response = await fetch(`/api/sources/${id}`, { method: 'DELETE' });
      if (response.ok) {
        loadSources();
        fetchMetrics();
        fetchNetworkHistory();
      } else {
        if (response.status === 401) openLoginModal();
      }
    } catch (err) {
      console.error('Error deleting source:', err);
    }
  };

  // ---- Messages ----
  function showMessage(text, type) {
    dom.formMessage.textContent = text;
    dom.formMessage.className = `form-message ${type}`;
    setTimeout(hideMessage, 5000);
  }

  function hideMessage() {
    dom.formMessage.className = 'form-message';
  }

  // ---- Escape HTML ----
  function escapeHtml(text) {
    const div = document.createElement('div');
    div.textContent = text || '';
    return div.innerHTML;
  }

  // ---- Load source count on page load ----
  async function loadSourceCount() {
    try {
      const response = await fetch('/api/sources');
      const sources = await response.json();
      dom.sourceCount.textContent = `${Array.isArray(sources) ? sources.length : 0} 个数据源`;
    } catch (err) {
      // ignore
    }
  }

  // ---- Start ----
  loadSourceCount();
  init();
})();