text: // This file is part of Moodle - http://moodle.org/
  //
  // Moodle is free software: you can redistribute it and/or modify
  // it under the terms of the GNU General Public License as published by
  // the Free Software Foundation, either version 3 of the License, or
  // (at your option) any later version.
  //
  // Moodle is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  // GNU General Public License for more details.
  //
  // You should have received a copy of the GNU General Public License
  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  
  /**
   * Javascript helper function for IMS Content Package module.
   *
   * @package    mod
   * @subpackage imscp
   * @copyright  2009 Petr Skoda  {@link http://skodak.org}
   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
   */
  
  M.mod_imscp = {};
  
  M.mod_imscp.init = function(Y) {
  
      var imscp_layout_widget;
      var imscp_current_node;
      var imscp_buttons = [];
      var imscp_bloody_labelclick = false;
  
      Y.use('yui2-resize', 'yui2-dragdrop', 'yui2-container', 'yui2-button', 'yui2-layout', 'yui2-treeview', 'yui2-json', 'yui2-event', function(Y) {
  
          var imscp_activate_item_by_index = function(index) {
              imscp_activate_item(Y.YUI2.widget.TreeView.getNode('imscp_tree', index));
          };
  
          var imscp_activate_item = function(node) {
              if (!node) {
                  return;
              }
              imscp_current_node = node;
              imscp_current_node.highlight();
  
              var content = new Y.YUI2.util.Element('imscp_content');
              var obj;
              if (node.href) {
                  try {
                      // First try IE way - it can not set name attribute later
                      // and also it has some restrictions on DOM access from object tag.
                      obj = document.createElement('<iframe id="imscp_object" src="' + node.href + '">');
                  } catch (e) {
                      obj = document.createElement('object');
                      obj.setAttribute('id', 'imscp_object');
                      obj.setAttribute('type', 'text/html');
                      obj.setAttribute('data', node.href);
                  }
              } else {
                  // No href, so create links to children.
                  obj = document.createElement('div');
                  obj.setAttribute('id', 'imscp_child_list');
  
                  var title = document.createElement('h2');
                  title.appendChild(document.createTextNode(node.label));
                  title.setAttribute('class', 'sectionname');
                  obj.appendChild(title);
  
                  var ul = document.createElement('ul');
                  obj.appendChild(ul);
                  for (var i = 0; i < node.children.length; i++) {
                      var childnode = node.children[i];
                      var li = document.createElement('li');
                      var a = document.createElement('a');
                      a.appendChild(document.createTextNode(childnode.label));
                      a.setAttribute('id', 'ref_' + childnode.index);
                      Y.YUI2.util.Event.addListener(a, "click", function () {
                          imscp_activate_item_by_index(this.id.substr(4));
                      });
                      ul.appendChild(li);
                      li.appendChild(a);
                  }
              }
              var old = Y.YUI2.util.Dom.get('imscp_object');
              if (old) {
                  content.replaceChild(obj, old);
              } else {
                  old = Y.YUI2.util.Dom.get('imscp_child_list');
                  if (old) {
                      content.replaceChild(obj, old);
                  } else {
                      content.appendChild(obj);
                  }
              }
              imscp_resize_frame();
  
              imscp_current_node.focus();
              imscp_fixnav();
          };
  
          /**
           * Enables/disables navigation buttons as needed.
           * @return void
           */
          var imscp_fixnav = function() {
              imscp_buttons[0].set('disabled', (imscp_skipprev(imscp_current_node) == null));
              imscp_buttons[1].set('disabled', (imscp_prev(imscp_current_node) == null));
              imscp_buttons[2].set('disabled', (imscp_up(imscp_current_node) == null));
              imscp_buttons[3].set('disabled', (imscp_next(imscp_current_node) == null));
              imscp_buttons[4].set('disabled', (imscp_skipnext(imscp_current_node) == null));
          };
  
          var imscp_resize_layout = function(alsowidth) {
              if (alsowidth) {
                  var layout = Y.YUI2.util.Dom.get('imscp_layout');
                  var newwidth = imscp_get_htmlelement_size('maincontent', 'width');
                  layout.style.width = '600px';
                  if (newwidth > 600) {
                      layout.style.width = newwidth + 'px';
                  }
              }
              // Make sure that the max width of the TOC doesn't go to far.
  
              var left = imscp_layout_widget.getUnitByPosition('left');
              var maxwidth = parseInt(Y.YUI2.util.Dom.getStyle('imscp_layout', 'width'));
              left.set('maxWidth', (maxwidth - 10));
              var cwidth = left.get('width');
              if (cwidth > (maxwidth - 10)) {
                  left.set('width', (maxwidth - 10));
              }
  
              var headerheight = imscp_get_htmlelement_size('page-header', 'height');
              var footerheight = imscp_get_htmlelement_size('page-footer', 'height');
              var newheight = parseInt(Y.YUI2.util.Dom.getViewportHeight()) - footerheight - headerheight - 20;
              if (newheight < 400) {
                  newheight = 400;
              }
              imscp_layout_widget.setStyle('height', newheight + 'px');
  
              imscp_layout_widget.render();
              imscp_resize_frame();
          };
  
          var imscp_get_htmlelement_size = function(el, prop) {
              var val = Y.YUI2.util.Dom.getStyle(el, prop);
              if (val == 'auto') {
                  if (el.get) {
                      el = el.get('element'); // Get real HTMLElement from YUI element.
                  }
                  val = Y.YUI2.util.Dom.getComputedStyle(Y.YUI2.util.Dom.get(el), prop);
              }
              return parseInt(val);
          };
  
          var imscp_resize_frame = function() {
              obj = Y.YUI2.util.Dom.get('imscp_object');
              if (obj) {
                  var content = imscp_layout_widget.getUnitByPosition('center').get('wrap');
                  // Basically trap IE6 and 7.
                  if (Y.YUI2.env.ua.ie > 5 && Y.YUI2.env.ua.ie < 8) {
                      if( obj.style.setAttribute ) {
                          obj.style.setAttribute("cssText", 'width: ' + (content.offsetWidth - 6) + 'px; height: ' + (content.offsetHeight - 10) + 'px;');
                      }
                      else {
                          obj.style.setAttribute('width', (content.offsetWidth - 6) + 'px', 0);
                          obj.style.setAttribute('height', (content.offsetHeight - 10) + 'px', 0);
                      }
                  }
                  else {
                      obj.style.width = (content.offsetWidth - 6) + 'px';
                      obj.style.height = (content.offsetHeight - 10) + 'px';
                  }
              }
          };
  
          var imscp_firstlinked = function(node) {
              // Return first item with an href.
              if (node.href) {
                  return node;
              } else if (node.children) {
                  return imscp_firstlinked(node.children[0]);
              } else {
                  return null;
              }
          };
  
          var imscp_up = function(node) {
              if (node.depth > 0) {
                  return node.parent;
              }
              return null;
          };
  
          var imscp_lastchild = function(node) {
              if (node.children.length) {
                  return imscp_lastchild(node.children[node.children.length - 1]);
              } else {
                  return node;
              }
          };
  
          var imscp_prev = function(node) {
              if (node.previousSibling && node.previousSibling.children.length) {
                  return imscp_lastchild(node.previousSibling);
              }
              return imscp_skipprev(node);
          };
  
          var imscp_skipprev = function(node) {
              if (node.previousSibling) {
                  return node.previousSibling;
              } else if (node.depth > 0) {
                  return node.parent;
              }
              return null;
          };
  
          var imscp_next = function(node) {
              if (node.children.length) {
                  return node.children[0];
              }
              return imscp_skipnext(node);
          };
  
          var imscp_skipnext = function(node) {
              if (node.nextSibling) {
                  return node.nextSibling;
              } else if (node.depth > 0) {
                  return imscp_skipnext(node.parent);
              }
              return null;
          };
  
          // Layout.
          Y.YUI2.widget.LayoutUnit.prototype.STR_COLLAPSE = M.util.get_string('hide', 'moodle');
          Y.YUI2.widget.LayoutUnit.prototype.STR_EXPAND = M.util.get_string('show', 'moodle');
  
          imscp_layout_widget = new Y.YUI2.widget.Layout('imscp_layout', {
              minWidth: 600,
              minHeight: 400,
              units: [
                  { position: 'left', body: 'imscp_toc', header: M.util.get_string('toc', 'imscp'), width: 250, resize: true, gutter: '2px 5px 5px 2px', collapse: true, minWidth:150},
                  { position: 'center', body: '<div id="imscp_content"></div>', gutter: '2px 5px 5px 2px', scroll: true}
              ]
          });
          imscp_layout_widget.render();
          var left = imscp_layout_widget.getUnitByPosition('left');
          left.on('collapse', function() {
              imscp_resize_frame();
          });
          left.on('expand', function() {
              imscp_resize_frame();
          });
  
          // Ugly resizing hack that works around problems with resizing of iframes and objects.
          left._resize.on('startResize', function() {
              obj = Y.YUI2.util.Dom.get('imscp_object');
              obj.style.display = 'none';
          });
          left._resize.on('endResize', function() {
              obj = Y.YUI2.util.Dom.get('imscp_object');
              obj.style.display = 'block';
              imscp_resize_frame();
          });
  
          // TOC tree.
          var tree = new Y.YUI2.widget.TreeView('imscp_tree');
          tree.singleNodeHighlight = true;
          tree.subscribe('clickEvent', function(oArgs) {
              imscp_activate_item(oArgs.node);
              if (oArgs.node.children.length) {
                  imscp_bloody_labelclick = true;
              }
              Y.YUI2.util.Event.preventDefault(oArgs.event);
              return false;
          });
          tree.subscribe('collapse', function(node) {
              if (imscp_bloody_labelclick) {
                  imscp_bloody_labelclick = false;
                  return false;
              }
          });
          tree.subscribe('expand', function(node) {
              if (imscp_bloody_labelclick) {
                  imscp_bloody_labelclick = false;
                  return false;
              }
          });
          tree.expandAll();
          tree.render();
  
          var navbar = Y.YUI2.util.Dom.get('imscp_nav');
          navbar.style.display = 'block';
  
          // Navigation.
          imscp_buttons[0] = new Y.YUI2.widget.Button('nav_skipprev');
          imscp_buttons[1] = new Y.YUI2.widget.Button('nav_prev');
          imscp_buttons[2] = new Y.YUI2.widget.Button('nav_up');
          imscp_buttons[3] = new Y.YUI2.widget.Button('nav_next');
          imscp_buttons[4] = new Y.YUI2.widget.Button('nav_skipnext');
          imscp_buttons[0].on('click', function(ev) {
              imscp_activate_item(imscp_skipprev(imscp_current_node));
          });
          imscp_buttons[1].on('click', function(ev) {
              imscp_activate_item(imscp_prev(imscp_current_node));
          });
          imscp_buttons[2].on('click', function(ev) {
              imscp_activate_item(imscp_up(imscp_current_node));
          });
          imscp_buttons[3].on('click', function(ev) {
              imscp_activate_item(imscp_next(imscp_current_node));
          });
          imscp_buttons[4].on('click', function(ev) {
              imscp_activate_item(imscp_skipnext(imscp_current_node));
          });
  
          // Finally activate the first item.
          imscp_activate_item(imscp_firstlinked(tree.getRoot().children[0]));
  
          // Resizing.
          imscp_resize_layout(false);
  
          // Fix layout if window resized.
          window.onresize = function() {
              imscp_resize_layout(true);
          };
      });
  };
  