// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

/**
 * WebUI to monitor File Metadata per Extension ID.
 */
var FileMetadata = (function() {
'use strict';

var FileMetadata = {};

/**
 * Gets extension data so the select drop down can be filled.
 */
function getExtensions() {
  chrome.send('getExtensions');
}

/**
 * Renders result of getFileMetadata as a table.
 * @param {Array} list of dictionaries containing 'extensionName',
 *     'extensionID', 'status'.
 */
FileMetadata.onGetExtensions = function(extensionStatuses) {
  var select = $('extensions-select');

  // Record existing drop down extension ID. If it's still there after the
  // refresh then keep it as the selected value.
  var oldSelectedExtension = getSelectedExtensionId();

  select.textContent = '';
  for (var i = 0; i < extensionStatuses.length; i++) {
    var originEntry = extensionStatuses[i];
    var tr = document.createElement('tr');
    var title = originEntry.extensionName + ' [' + originEntry.status + ']';
    select.options.add(new Option(title, originEntry.extensionID));

    // If option was the previously only selected, make it selected again.
    if (originEntry.extensionID != oldSelectedExtension)
      continue;
    select.options[select.options.length - 1].selected = true;
  }

  // After drop down has been loaded with options, file metadata can be loaded
  getFileMetadata();
}

/**
 * @return {string} extension ID that's currently selected in drop down box.
 */
function getSelectedExtensionId() {
  var dropDown = $('extensions-select').options;
  if (dropDown.selectedIndex >= 0)
    return dropDown[dropDown.selectedIndex].value;

  return null;
}

/**
 * Get File Metadata depending on which extension is selected from the drop down
 * if any.
 */
function getFileMetadata() {
  var dropDown = $('extensions-select');
  if (dropDown.options.length === 0) {
    $('file-metadata-header').textContent = '';
    $('file-metadata-entries').textContent = 'No file metadata available.';
    return;
  }

  var selectedExtensionId = getSelectedExtensionId();
  chrome.send('getFileMetadata', [selectedExtensionId]);
}

/**
 * Renders result of getFileMetadata as a table.
 */
FileMetadata.onGetFileMetadata = function(fileMetadataMap) {
  var header = $('file-metadata-header');
  // Only draw the header if it hasn't been drawn yet
  if (header.children.length === 0) {
    var tr = document.createElement('tr');
    tr.appendChild(createElementFromText('td', 'Type'));
    tr.appendChild(createElementFromText('td', 'Status'));
    tr.appendChild(createElementFromText('td', 'Path', {width: '250px'}));
    tr.appendChild(createElementFromText('td', 'Details'));
    header.appendChild(tr);
  }

  // Add row entries.
  var itemContainer = $('file-metadata-entries');
  itemContainer.textContent = '';
  for (var i = 0; i < fileMetadataMap.length; i++) {
    var metadatEntry = fileMetadataMap[i];
    var tr = document.createElement('tr');
    tr.appendChild(createFileIconCell(metadatEntry.type));
    tr.appendChild(createElementFromText('td', metadatEntry.status));
    tr.appendChild(createElementFromText('td', metadatEntry.path));
    tr.appendChild(createElementFromDictionary('td', metadatEntry.details));
    itemContainer.appendChild(tr);
  }
}

/**
 * @param {string} file type string.
 * @return {HTMLElement} TD with file or folder icon depending on type.
 */
function createFileIconCell(type) {
  var td = createElementFromText('td', type);
  td.setAttribute('class', type.toLowerCase() + '-icon');
  return td;
}

function main() {
  getExtensions();
  $('refresh-metadata-button').addEventListener('click', getExtensions);
  $('extensions-select').addEventListener('change', getFileMetadata);
}

document.addEventListener('DOMContentLoaded', main);
return FileMetadata;
})();