import { registerClearHandler } from './devtools.js';

function renderNode(node, depth, maxExpand) {
  if (node.type === 'text') {
    const text = node.text.trim();
    if (!text) return '';
    return `<div class="el-node"><span class="el-text">${escapeHtml(text)}</span></div>`;
  }

  const hasChildren = node.children && node.children.length > 0;
  const expanded = depth < maxExpand;

  let attrs = '';
  if (node.attrs) {
    for (const a of node.attrs) {
      attrs += ` <span class="el-attr-name">${escapeHtml(a.name)}</span>=<span class="el-attr-value">"${escapeHtml(a.value)}"</span>`;
    }
  }

  let html = '<div class="el-node">';
  html += `<div class="el-node-header" data-has-children="${hasChildren}">`;
  html += `<span class="el-toggle">${hasChildren ? (expanded ? '▼' : '▶') : ' '}</span>`;
  html += `<span>&lt;<span class="el-tag">${escapeHtml(node.tag)}</span>${attrs}&gt;</span>`;

  // Inline short text content
  if (hasChildren && node.children.length === 1 && node.children[0].type === 'text' && node.children[0].text.trim().length < 60) {
    html += `<span class="el-text">${escapeHtml(node.children[0].text.trim())}</span>`;
    html += `<span>&lt;/<span class="el-tag">${escapeHtml(node.tag)}</span>&gt;</span>`;
    html += '</div></div>';
    return html;
  }

  html += '</div>';

  if (hasChildren) {
    html += `<div class="el-children ${expanded ? 'expanded' : ''}">`;
    for (const child of node.children) {
      html += renderNode(child, depth + 1, maxExpand);
    }
    html += `<div style="padding-left:16px">&lt;/<span class="el-tag">${escapeHtml(node.tag)}</span>&gt;</div>`;
    html += '</div>';
  }

  html += '</div>';
  return html;
}

function escapeHtml(str) {
  return str.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
}

function bindToggleHandlers(container) {
  container.querySelectorAll('.el-node-header[data-has-children="true"]').forEach(header => {
    header.addEventListener('click', () => {
      const children = header.nextElementSibling;
      if (!children || !children.classList.contains('el-children')) return;
      const toggle = header.querySelector('.el-toggle');
      const isExpanded = children.classList.contains('expanded');
      children.classList.toggle('expanded');
      toggle.textContent = isExpanded ? '▶' : '▼';
    });
  });
}

let lastTree = null;

function render(tree) {
  lastTree = tree;
  const out = document.getElementById('elements-output');
  if (!tree) {
    out.innerHTML = '<div style="padding:12px;color:var(--text-dim);font-size:11px;">No elements captured. Run your code to see the DOM tree.</div>';
    return;
  }
  out.innerHTML = renderNode(tree, 0, 2);
  bindToggleHandlers(out);
}

export function clearElements() {
  lastTree = null;
  document.getElementById('elements-output').innerHTML = '';
}

export function initElements() {
  registerClearHandler('elements', clearElements);

  window.addEventListener('message', (e) => {
    if (!e.data || e.data.type !== 'devtools' || e.data.tab !== 'elements') return;
    if (e.data.tree) render(e.data.tree);
  });
}