// Theme handling: "undefined mode" defaults to system unless explicitly toggled
(function initTheme() {
  const root = document.documentElement;
  const saved = localStorage.getItem('theme-mode'); // 'light' | 'dark'
  const prefersDark = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches;

  const apply = (mode) => {
    root.classList.toggle('dark', mode === 'dark');
  };

  if (saved === 'light' || saved === 'dark') {
    apply(saved);
  } else {
    apply(prefersDark ? 'dark' : 'light');
  }
})();

const themeToggle = document.getElementById('themeToggle');
if (themeToggle) {
  themeToggle.addEventListener('click', () => {
    const root = document.documentElement;
    const isDark = root.classList.toggle('dark');
    localStorage.setItem('theme-mode', isDark ? 'dark' : 'light');
  });
}

// Elements
const chatBox = document.getElementById('chatBox');
const composerForm = document.getElementById('composerForm');
const messageInput = document.getElementById('messageInput');
const sendBtn = document.getElementById('sendBtn');
const imageInput = document.getElementById('imageInput');
const codeInput = document.getElementById('codeInput');
const uploadImageBtn = document.getElementById('uploadImageBtn');
const uploadCodeBtn = document.getElementById('uploadCodeBtn');
const connectGitHubBtn = document.getElementById('connectGitHubBtn');
const githubConnectHeaderBtn = document.getElementById('githubConnectBtn');
const attachmentPreview = document.getElementById('attachmentPreview');
const modeIndicator = document.getElementById('modeIndicator');

const modeButtons = document.querySelectorAll('.mode-btn');
let currentMode = 'code';
updateModeIndicator();

// Helpers
function formatTime(date = new Date()) {
  return date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' });
}

function scrollToBottom() {
  chatBox.scrollTop = chatBox.scrollHeight;
}

function createAvatar(initials, seed = 0) {
  const palette = ['bg-undefined-500', 'bg-blue-500', 'bg-teal-500', 'bg-violet-500', 'bg-rose-500'];
  const color = palette[seed % palette.length];
  return `<div class="h-10 w-10 rounded-full ${color} grid place-items-center text-white font-bold">${initials}</div>`;
}

function agentBubble({ name = 'Agent', message = '', attachments = [] }) {
  const idx = Math.floor(Math.random() * 5);
  return `
    <div class="flex items-start gap-3">
      ${createAvatar(name.slice(0,1).toUpperCase(), idx)}
      <div class="max-w-[85%] sm:max-w-[80%]">
        <div class="text-xs text-zinc-600 dark:text-zinc-400 mb-1">${name}</div>
        <div class="prose prose-sm dark:prose-invert max-w-none bg-zinc-100 dark:bg-zinc-800 rounded-2xl rounded-tl-sm px-4 py-2">
          ${message ? `<p class="m-0">${escapeHtml(message)}</p>` : ''}
          ${attachments.length ? `<div class="mt-2 grid gap-2">${attachments.join('')}</div>` : ''}
        </div>
        <div class="text-[10px] text-zinc-500 mt-1">${formatTime()}</div>
      </div>
    </div>
  `;
}

function userBubble({ message = '', attachments = [] }) {
  return `
    <div class="flex items-start gap-3 justify-end">
      <div class="max-w-[85%] sm:max-w-[80%]">
        <div class="text-xs text-right text-zinc-600 dark:text-zinc-400 mb-1">You</div>
        <div class="bg-undefined-500 text-white rounded-2xl rounded-tr-sm px-4 py-2">
          ${message ? `<p class="m-0">${escapeHtml(message)}</p>` : ''}
          ${attachments.length ? `<div class="mt-2 grid gap-2">${attachments.join('')}</div>` : ''}
        </div>
        <div class="text-[10px] text-right text-zinc-500 mt-1">${formatTime()}</div>
      </div>
      ${createAvatar('Y')}
    </div>
  `;
}

function escapeHtml(str) {
  return str
    .replaceAll('&', '&amp;')
    .replaceAll('<', '&lt;')
    .replaceAll('>', '&gt;');
}

// Attachments UI
function showAttachmentPreview(items) {
  if (!items.length) {
    attachmentPreview.classList.add('hidden');
    attachmentPreview.innerHTML = '';
    return;
  }
  attachmentPreview.classList.remove('hidden');
  attachmentPreview.innerHTML = items.map((item) => {
    if (item.type.startsWith('image/')) {
      return `<div class="rounded-lg border border-zinc-200 dark:border-zinc-700 p-2 bg-zinc-50 dark:bg-zinc-900">
        <div class="flex items-center gap-3">
          <img src="${item.url}" alt="preview" class="h-12 w-12 object-cover rounded-md"/>
          <div class="text-xs"><div class="font-medium truncate">${item.file?.name || 'image'}</div><div class="text-zinc-600 dark:text-zinc-400">${(item.file?.size / 1024).toFixed(1)} KB</div></div>
          <button class="ml-auto text-sm text-red-600 hover:underline" data-remove>Remove</button>
        </div>
      </div>`;
    }
    // code file preview
    return `<div class="rounded-lg border border-zinc-200 dark:border-zinc-700 p-2 bg-zinc-50 dark:bg-zinc-900">
      <div class="flex items-center gap-2">
        <span class="text-sm">📄</span>
        <div class="text-xs">
          <div class="font-medium truncate">${item.file?.name || 'code'}</div>
          <div class="text-zinc-600 dark:text-zinc-400">${(item.file?.size / 1024).toFixed(1)} KB</div>
        </div>
        <button class="ml-auto text-sm text-red-600 hover:underline" data-remove>Remove</button>
      </div>
    </div>`;
  }).join('');

  // Remove handler
  attachmentPreview.querySelectorAll('[data-remove]').forEach(btn => {
    btn.addEventListener('click', () => {
      const card = btn.closest('[class*=rounded-lg]');
      const index = Array.from(attachmentPreview.children).indexOf(card);
      pendingAttachments.splice(index, 1);
      showAttachmentPreview(pendingAttachments);
    });
  });
}

const pendingAttachments = [];

// Mode handling
function updateModeIndicator() {
  if (modeIndicator) modeIndicator.textContent = `Mode: ${currentMode}`;
  modeButtons.forEach(b => {
    const isActive = b.dataset.mode === currentMode;
    b.classList.toggle('bg-undefined-500', isActive);
    b.classList.toggle('text-white', isActive);
    b.classList.toggle('hover:opacity-90', isActive);
  });
}

modeButtons.forEach(btn => {
  btn.addEventListener('click', () => {
    currentMode = btn.dataset.mode;
    updateModeIndicator();
    // Post a small status message
    const statusMsg = `Mode switched to: ${currentMode}`;
    chatBox.insertAdjacentHTML('beforeend', agentBubble({ name: 'System', message: statusMsg }));
    scrollToBottom();
  });
});

// Composer events
composerForm.addEventListener('submit', (e) => {
  e.preventDefault();
  const message = messageInput.value.trim();
  const attachments = pendingAttachments.slice();

  if (!message && !attachments.length) return;

  chatBox.insertAdjacentHTML('beforeend', userBubble({ message, attachments }));
  scrollToBottom();

  // Simulate agent response
  setTimeout(() => {
    const reply = agentReply(message, currentMode, attachments);
    chatBox.insertAdjacentHTML('beforeend', reply);
    scrollToBottom();
  }, 600);

  // Reset composer
  messageInput.value = '';
  pendingAttachments.length = 0;
  showAttachmentPreview(pendingAttachments);
  messageInput.focus();
});

function agentReply(text, mode, attachments) {
  let message = '';
  if (attachments.some(a => a.type.startsWith('image/'))) {
    message += 'Got your image(s). ';
  }
  if (attachments.some(a => !a.type.startsWith('image/'))) {
    message += 'I also see code/file attachments. ';
  }

  const modeHints = {
    design: 'I can suggest UI/UX and styling tweaks.',
    architect: 'I can outline components, data flow, and constraints.',
    plan: 'I can draft a plan with milestones and tasks.',
    debug: 'I can help triage issues and propose fixes.',
    code: 'I can produce and refine code based on your input.'
  };

  message += `${modeHints[mode] || ''}${text ? ` Regarding "${escapeHtml(text)}"` : ''} — what would you like to do next?`;
  return agentBubble({ name: 'Agent', message });
}

// Input attachments
uploadImageBtn.addEventListener('click', () => imageInput.click());
uploadCodeBtn.addEventListener('click', () => codeInput.click());

imageInput.addEventListener('change', async (e) => {
  const files = Array.from(e.target.files || []);
  files.forEach(file => {
    if (!file.type.startsWith('image/')) return;
    const url = URL.createObjectURL(file);
    pendingAttachments.push({ type: file.type, file, url });
  });
  showAttachmentPreview(pendingAttachments);
  imageInput.value = '';
});

codeInput.addEventListener('change', async (e) => {
  const files = Array.from(e.target.files || []);
  files.forEach(file => {
    // accept text-based files
    const isText = /(\.|\/)(txt|md|json|js|ts|jsx|tsx|html|css|scss|py|rb|go|rs|java|c|cpp|cs|yml|yaml|ini|env)$/i.test(file.name);
    if (!isText) return;
    const url = URL.createObjectURL(file);
    pendingAttachments.push({ type: 'text/x-code', file, url });
  });
  showAttachmentPreview(pendingAttachments);
  codeInput.value = '';
});

// GitHub connect
function connectGitHub() {
  // In a real app, redirect to your backend OAuth route
  const token = prompt('Paste a personal access token (classic or fine-grained) to simulate GitHub connection:');
  if (!token) return;
  const shortToken = token.slice(0, 6) + '...' + token.slice(-4);
  const msg = `Connected to GitHub (token: ${shortToken}). You can now fetch repos, issues, and PRs.`;
  chatBox.insertAdjacentHTML('beforeend', agentBubble({ name: 'GitHub', message: msg }));
  scrollToBottom();
}
connectGitHubBtn?.addEventListener('click', connectGitHub);
githubConnectHeaderBtn?.addEventListener('click', connectGitHub);

// Auto-resize textarea
messageInput.addEventListener('input', () => {
  messageInput.style.height = 'auto';
  messageInput.style.height = Math.min(messageInput.scrollHeight, 160) + 'px';
});

// Accessibility: focus input on load
messageInput.focus();