// Site-wide file transfer manager - loaded once via mainpagetemplate.jet
// (see its own script tag, outside #content) so the floating panel and
// any in-progress transfer survive spa.js's own #content-only swaps
// when navigating to a different page mid-upload/download.
(function() {
  var panel = document.getElementById('filemgr-panel');
  if (!panel)
    return;

  var toggle = document.getElementById('filemgr-toggle');
  var badge = document.getElementById('filemgr-badge');
  var list = document.getElementById('filemgr-list');
  var clearBtn = document.getElementById('filemgr-clear');

  var transfers = {};
  var nextId = 1;

  function escapeHtml(s) {
    var div = document.createElement('div');
    div.textContent = s == null ? '' : String(s);
    return div.innerHTML;
  }

  function updateBadge() {
    var activeCount = 0;
    for (var k in transfers) {
      if (transfers[k].status === 'active')
        activeCount++;
    }
    badge.textContent = activeCount > 0 ? String(activeCount) : '';
  }

  function removeEmptyPlaceholder() {
    var empty = document.getElementById('filemgr-empty');
    if (empty)
      empty.remove();
  }

  function showEmptyPlaceholderIfNeeded() {
    if (Object.keys(transfers).length === 0 && !document.getElementById('filemgr-empty'))
      list.innerHTML = '<div id="filemgr-empty">No transfers yet.</div>';
  }

  var UPLOAD_ICON = '<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 19V6M5 12l7-7 7 7"/></svg>';
  var DOWNLOAD_ICON = '<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M12 5v13M5 12l7 7 7-7"/></svg>';

  function addTransfer(name, direction) {
    var id = 'xfer' + (nextId++);
    removeEmptyPlaceholder();

    var el = document.createElement('div');
    el.className = 'filemgr-item';
    el.innerHTML =
      '<div class="filemgr-item-row">' +
      '<span class="filemgr-item-icon">' + (direction === 'upload' ? UPLOAD_ICON : DOWNLOAD_ICON) + '</span>' +
      '<span class="filemgr-item-name">' + escapeHtml(name) + '</span>' +
      '<span class="filemgr-item-status">0%</span>' +
      '</div>' +
      '<div class="filemgr-progress-track"><div class="filemgr-progress-fill"></div></div>';
    list.insertBefore(el, list.firstChild);

    transfers[id] = { el: el, status: 'active' };
    panel.classList.add('filemgr-expanded');
    updateBadge();
    return id;
  }

  function updateProgress(id, percent) {
    var t = transfers[id];
    if (!t)
      return;
    t.el.querySelector('.filemgr-progress-fill').style.width = percent + '%';
    t.el.querySelector('.filemgr-item-status').textContent = percent + '%';
  }

  function markDone(id, statusText) {
    var t = transfers[id];
    if (!t)
      return;
    t.status = 'done';
    t.el.classList.add('filemgr-done');
    t.el.querySelector('.filemgr-progress-fill').style.width = '100%';
    t.el.querySelector('.filemgr-item-status').textContent = statusText || 'Done';
    updateBadge();
  }

  function markFailed(id, statusText) {
    var t = transfers[id];
    if (!t)
      return;
    t.status = 'failed';
    t.el.classList.add('filemgr-failed');
    t.el.querySelector('.filemgr-item-status').textContent = statusText || 'Failed';
    updateBadge();
  }

  // Uploads a FileList/array of File objects, each as its own
  // concurrent XHR request - the browser's own HTTP connection pooling
  // runs several at once, tracked here as separate panel entries with
  // independent progress via xhr.upload's own progress event (fetch()
  // has no equivalent for the request/upload side, only the response).
  window.fileManagerUpload = function(files) {
    for (var i = 0; i < files.length; i++) {
      (function(file) {
        var id = addTransfer(file.name, 'upload');
        var xhr = new XMLHttpRequest();
        transfers[id].xhr = xhr;
        xhr.open('POST', '/documents/api/upload');
        xhr.upload.addEventListener('progress', function(e) {
          if (e.lengthComputable)
            updateProgress(id, Math.round((e.loaded / e.total) * 100));
        });
        xhr.addEventListener('load', function() {
          var res = null;
          try { res = JSON.parse(xhr.responseText); } catch (e) {}
          if (xhr.status === 200 && res && res.ok) {
            markDone(id);
            document.dispatchEvent(new CustomEvent('documents:changed'));
          } else {
            markFailed(id, (res && res.error) || 'Failed');
          }
        });
        xhr.addEventListener('error', function() { markFailed(id); });
        var fd = new FormData();
        fd.append('name', file.name);
        fd.append('filedata', file);
        xhr.send(fd);
      })(files[i]);
    }
  };

  // Downloads a document by id via XHR (responseType 'blob') instead
  // of a plain <a href> so it gets real tracked progress in the same
  // panel as uploads, then hands the fetched bytes to the browser's
  // normal save flow via a Blob URL + synthetic <a download> click.
  window.fileManagerDownload = function(id, name) {
    var xferId = addTransfer(name, 'download');
    var xhr = new XMLHttpRequest();
    transfers[xferId].xhr = xhr;
    xhr.open('GET', '/documents/download?id=' + encodeURIComponent(id));
    xhr.responseType = 'blob';
    xhr.addEventListener('progress', function(e) {
      if (e.lengthComputable)
        updateProgress(xferId, Math.round((e.loaded / e.total) * 100));
    });
    xhr.addEventListener('load', function() {
      if (xhr.status !== 200) {
        markFailed(xferId);
        return;
      }
      var blobUrl = URL.createObjectURL(xhr.response);
      var a = document.createElement('a');
      a.href = blobUrl;
      a.download = name;
      document.body.appendChild(a);
      a.click();
      document.body.removeChild(a);
      setTimeout(function() { URL.revokeObjectURL(blobUrl); }, 30000);
      markDone(xferId);
    });
    xhr.addEventListener('error', function() { markFailed(xferId); });
    xhr.send();
  };

  toggle.addEventListener('click', function() {
    panel.classList.toggle('filemgr-expanded');
  });

  clearBtn.addEventListener('click', function() {
    for (var k in transfers) {
      if (transfers[k].status !== 'active') {
        transfers[k].el.remove();
        delete transfers[k];
      }
    }
    showEmptyPlaceholderIfNeeded();
  });
})();