// helpers-core.js — foundational helpers extracted from helpers.js.
// escHtml + file/link button builder + chat-bubble/image-zoom/download UI +
// dynamic CDN loaders (SheetJS, Luckysheet, PDF.js) + timeAgo/openOllamaInfo.
// Plain globals; loaded before the other split helper files and before app.js.
function escHtml(str) {
  if (!str) return '';
  return String(str).replace(/&/g,'&amp;').replace(/\\/g,'&#92;').replace(/`/g,'&#96;').replace(/\$/g,'&#36;').replace(/</g,'&lt;').replace(/>/g,'&gt;').replace(/"/g,'&quot;');
}

function _normalizeFileUrl(url) {
  // Convert sandbox:/mnt/... or /mnt/user-data/... paths to /api/files/... URLs
  if (/^sandbox:/i.test(url)) {
    var p = url.replace(/^sandbox:\/*/i, '');
    var idx = p.indexOf('uploads/');
    return '/api/files/' + (idx !== -1 ? p.slice(idx) : 'uploads/' + p.split('/').pop());
  }
  if (/^\/mnt\/(user-data|data)\//i.test(url)) {
    var idx = url.indexOf('uploads/');
    return '/api/files/' + (idx !== -1 ? url.slice(idx) : 'uploads/' + url.split('/').pop());
  }
  return url;
}

function _renderLinkButton(text, url, opts) {
  var hideDownload = opts && opts.hideDownload;
  url = _normalizeFileUrl(url);
  var fileExts = ['.pptx','.pdf','.xlsx','.xls','.docx','.doc','.zip','.csv','.mp4','.mp3'];
  var isDownload = fileExts.some(function(ext) { return text.toLowerCase().endsWith(ext); })
    || fileExts.some(function(ext) { return decodeURIComponent(url).toLowerCase().indexOf(ext) !== -1; });
  var decodedUrl = decodeURIComponent(url).toLowerCase();
  var isPptx = decodedUrl.indexOf('.pptx') !== -1 || text.toLowerCase().endsWith('.pptx');
  var isPdf  = decodedUrl.indexOf('.pdf')  !== -1 || text.toLowerCase().endsWith('.pdf');
  var isXlsx = /\.(xlsx|xls)(\?.*)?$/i.test(decodedUrl) || /\.(xlsx|xls)$/i.test(text.toLowerCase());
  if (isPptx) {
    var previewId = 'pptx-preview-' + Math.random().toString(36).substr(2, 9);
    return '<div class="pptx-file-row">'
      + '<a href="' + url + '" onclick="downloadFile(event, this)" class="download-btn" title="Download ' + text + '">'
      + '<span class="download-icon">&#11015;</span> ' + text + '</a>'
      + ' <button class="pptx-preview-btn" onclick="togglePptxPreview(\'' + escHtml(url) + '\', \'' + previewId + '\', this)" title="미리보기">&#9664; 미리보기</button>'
      + '<div id="' + previewId + '" class="pptx-preview-strip" style="display:none"></div>'
      + '</div>';
  }
  if (isPdf) {
    var pdfId = 'pdf-embed-' + Math.random().toString(36).substr(2, 9);
    return '<div class="pdf-file-row" style="display:flex;flex-direction:column;gap:6px;margin:4px 0">'
      + '<div style="display:flex;align-items:center;gap:8px;flex-wrap:wrap">'
      + '<a href="' + url + '" target="_blank" rel="noopener" class="download-btn" title="새 탭에서 열기">'
      + '<span style="font-size:14px">📄</span> ' + text + '</a>'
      + '<button class="pptx-preview-btn" onclick="togglePdfEmbed(\'' + escHtml(url) + '\',\'' + pdfId + '\',this)">&#9664; 미리보기</button>'
      + (hideDownload ? '' : '<a href="' + url + '" onclick="downloadFile(event,this)" class="pptx-preview-btn" style="text-decoration:none">&#11015; 저장</a>')
      + '</div>'
      + '<div id="' + pdfId + '" style="display:none">'
      + '<iframe style="width:100%;height:600px;border:1px solid var(--line);border-radius:8px" allowfullscreen></iframe>'
      + '</div>'
      + '</div>';
  }
  if (isXlsx) {
    var xlsxSafeUrl = escHtml(url);
    return '<div class="pdf-file-row xlsx-card" style="display:flex;flex-direction:column;gap:6px;margin:4px 0">'
      + '<div style="display:flex;align-items:center;gap:8px;flex-wrap:wrap">'
      + '<span style="font-size:14px">📊</span>'
      + '<span style="font-weight:600;color:var(--text)">' + escHtml(text) + '</span>'
      + '<button class="pptx-preview-btn" data-xlsx-url="' + xlsxSafeUrl + '" data-xlsx-save-url="' + xlsxSafeUrl + '" onclick="toggleXlsxEmbedBtn(this)" style="background:linear-gradient(135deg,#3b82f6,#2563eb)">✏️ 편집</button>'
      + '<button class="pptx-preview-btn" onclick="openXlsxNewWindow(\'' + xlsxSafeUrl + '\',\'' + escHtml(text) + '\')" style="background:linear-gradient(135deg,#6366f1,#4f46e5)" title="새 창에서 열기">↗ 새 창</button>'
      + '<a href="' + xlsxSafeUrl + '" download class="pptx-preview-btn" style="text-decoration:none">&#11015; 다운로드</a>'
      + '</div>'
      + ''
      + '</div>';
  }
  var isTxt = /\.txt(\?[^"]*)?$/i.test(decodedUrl) || /\.txt$/i.test(text.toLowerCase());
  if (isTxt) {
    var txtLabel = escHtml(text.replace(/^📝\s*/, ''));
    return '<div class="pdf-file-row txt-card" style="display:flex;flex-direction:column;gap:6px;margin:4px 0">'
      + '<div style="display:flex;align-items:center;gap:8px;flex-wrap:wrap">'
      + '<span style="font-size:14px">📝</span>'
      + '<span style="font-weight:600;color:var(--text)">' + txtLabel + '</span>'
      + '<button class="pptx-preview-btn" data-txt-url="' + escHtml(url) + '" onclick="toggleTxtEmbedBtn(this)">&#9664; 미리보기</button>'
      + '<a href="' + escHtml(url) + '" download="' + txtLabel + '" class="pptx-preview-btn" style="text-decoration:none">&#11015; 저장</a>'
      + '</div>'
      + '<div class="txt-preview-body" style="display:none;max-height:420px;overflow-y:auto;background:var(--panel-1);border:1px solid var(--line);border-radius:8px;padding:12px;font-size:12px;white-space:pre-wrap;word-break:break-word;line-height:1.7;color:var(--text);font-family:inherit"></div>'
      + '</div>';
  }
  if (isDownload) {
    return '<a href="' + url + '" onclick="downloadFile(event, this)" class="download-btn" title="Download ' + text + '">'
      + '<span class="download-icon">&#11015;</span> ' + text + '</a>';
  }
  return '<a href="' + url + '" target="_blank" rel="noopener">' + text + '</a>';
}
function appendChatBubble(role, html) {
  var wrap = document.getElementById('chat-messages');
  if (!wrap) return;
  var div = document.createElement('div');
  div.className = 'msg msg-' + role;
  div.innerHTML = '<div class="msg-content">' + html + '</div>';
  wrap.appendChild(div);
  wrap.scrollTop = wrap.scrollHeight;
}

function openImageZoom(src) {
  var modal = document.getElementById('image-zoom-modal');
  var img = document.getElementById('image-zoom-img');
  if (modal && img) {
    img.src = src;
    modal.style.display = 'flex';
  }
}

function closeImageZoom() {
  var modal = document.getElementById('image-zoom-modal');
  if (modal) modal.style.display = 'none';
}

// Cache of checked /api/files/ URLs: url -> true (exists) | false (not found)
var _dlLinkCache = {};

function markDownloadLinkError(btn) {
  var href = btn.getAttribute ? btn.getAttribute('href') : (btn.href || '');
  var filename = decodeURIComponent((href || '').split('/').pop() || '파일');
  _dlLinkCache[href] = false;
  var span = document.createElement('span');
  span.className = 'download-btn-error';
  span.title = '파일을 찾을 수 없음: ' + filename;
  span.textContent = '⚠ ' + filename + ' (파일 없음)';
  if (btn.parentNode) btn.parentNode.replaceChild(span, btn);
}

function validateDownloadLinks(container) {
  var buttons = (container || document).querySelectorAll('a.download-btn[href]');
  buttons.forEach(function(btn) {
    var url = btn.getAttribute('href');
    if (!url || url.indexOf('/api/files/') === -1) return;
    if (_dlLinkCache[url] === false) { markDownloadLinkError(btn); return; }
    if (_dlLinkCache[url] === true || _dlLinkCache[url] === 'pending') return;
    _dlLinkCache[url] = 'pending';
    fetch(url, { method: 'HEAD', headers: authHeaders() })
      .then(function(r) {
        _dlLinkCache[url] = r.ok;
        if (!r.ok) {
          var found = (container || document).querySelector('a.download-btn[href="' + url.replace(/"/g, '\\"') + '"]');
          if (found) markDownloadLinkError(found);
        }
      })
      .catch(function() { _dlLinkCache[url] = false; });
  });
}

function downloadFile(e, el) {
  e.preventDefault();
  e.stopPropagation();
  var url = el.getAttribute('href');
  if (!url) return;

  // Ensure absolute URL (handle sandboxed environments where origin may be sandbox:/)
  if (!url.match(/^https?:\/\//)) {
    if (url.charAt(0) === '/') {
      // Already an absolute path — use relative to current host
      url = url;
    } else {
      url = new URL(url, window.location.origin).href;
    }
  }

  var filename = decodeURIComponent(url.split('/').pop() || 'download');

  fetch(url, {
    headers: authHeaders()
  })
    .then(function(r) {
      if (!r.ok) throw new Error(r.status);
      return r.blob();
    })
    .then(function(blob) {
      var blobUrl = URL.createObjectURL(blob);
      var a = document.createElement('a');
      a.href = blobUrl;
      a.download = filename;
      document.body.appendChild(a);
      a.click();
      document.body.removeChild(a);
      URL.revokeObjectURL(blobUrl);
    })
    .catch(function(err) {
      markDownloadLinkError(el);
    });
}
var _sheetJsLoaded = false;
function loadSheetJS(cb) {
  if (_sheetJsLoaded) return cb();
  var s = document.createElement('script');
  s.src = 'https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.18.5/xlsx.full.min.js';
  s.onload = function() { _sheetJsLoaded = true; cb(); };
  document.head.appendChild(s);
}

var _luckyLoaded = false;
function loadLuckysheet(cb) {
  if (_luckyLoaded) return cb();
  var cssList = [
    'https://cdn.jsdelivr.net/npm/luckysheet@2.1.13/dist/plugins/css/pluginsCss.css',
    'https://cdn.jsdelivr.net/npm/luckysheet@2.1.13/dist/plugins/plugins.css',
    'https://cdn.jsdelivr.net/npm/luckysheet@2.1.13/dist/css/luckysheet.css',
    'https://cdn.jsdelivr.net/npm/luckysheet@2.1.13/dist/assets/iconfont/iconfont.css',
  ];
  cssList.forEach(function(href) {
    var l = document.createElement('link'); l.rel = 'stylesheet'; l.href = href;
    document.head.appendChild(l);
  });
  var scripts = [
    'https://cdn.jsdelivr.net/npm/luckysheet@2.1.13/dist/plugins/js/plugin.js',
    'https://cdn.jsdelivr.net/npm/luckysheet@2.1.13/dist/luckysheet.umd.js',
    'https://cdn.jsdelivr.net/npm/luckyexcel@1.0.1/dist/luckyexcel.umd.js',
  ];
  function next(i) {
    if (i >= scripts.length) { _luckyLoaded = true; cb(); return; }
    var s = document.createElement('script');
    s.src = scripts[i]; s.onload = function() { next(i + 1); };
    s.onerror = function() { next(i + 1); }; // 실패해도 진행
    document.head.appendChild(s);
  }
  next(0);
}

var _pdfJsLoaded = false;
function loadPdfJs(cb) {
  if (_pdfJsLoaded) return cb();
  var s = document.createElement('script');
  s.src = 'https://cdnjs.cloudflare.com/ajax/libs/pdf.js/3.11.174/pdf.min.js';
  s.onload = function() {
    pdfjsLib.GlobalWorkerOptions.workerSrc = 'https://cdnjs.cloudflare.com/ajax/libs/pdf.js/3.11.174/pdf.worker.min.js';
    _pdfJsLoaded = true; cb();
  };
  document.head.appendChild(s);
}

function timeAgo(ts) {
  const diff = Date.now() - ts;
  if (diff < 60000) return 'just now';
  if (diff < 3600000) return `${Math.floor(diff/60000)}m ago`;
  if (diff < 86400000) return `${Math.floor(diff/3600000)}h ago`;
  return `${Math.floor(diff/86400000)}d ago`;
}

function openOllamaInfo() { window.open('http://localhost:11434','_blank'); }