/* vim:set ts=2 sw=2 sts=2 et: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

this.EXPORTED_SYMBOLS = ["SplitView"];

/* this must be kept in sync with CSS (ie. splitview.css) */
const LANDSCAPE_MEDIA_QUERY = "(min-width: 701px)";

var bindings = new WeakMap();

/**
 * SplitView constructor
 *
 * Initialize the split view UI on an existing DOM element.
 *
 * A split view contains items, each of those having one summary and one details
 * elements.
 * It is adaptive as it behaves similarly to a richlistbox when there the aspect
 * ratio is narrow or as a pair listbox-box otherwise.
 *
 * @param DOMElement aRoot
 * @see appendItem
 */
this.SplitView = function SplitView(aRoot)
{
  this._root = aRoot;
  this._controller = aRoot.querySelector(".splitview-controller");
  this._nav = aRoot.querySelector(".splitview-nav");
  this._side = aRoot.querySelector(".splitview-side-details");
  this._activeSummary = null

  this._mql = aRoot.ownerDocument.defaultView.matchMedia(LANDSCAPE_MEDIA_QUERY);

  // items list focus and search-on-type handling
  this._nav.addEventListener("keydown", (aEvent) => {
    function getFocusedItemWithin(nav) {
      let node = nav.ownerDocument.activeElement;
      while (node && node.parentNode != nav) {
        node = node.parentNode;
      }
      return node;
    }

    // do not steal focus from inside iframes or textboxes
    if (aEvent.target.ownerDocument != this._nav.ownerDocument ||
        aEvent.target.tagName == "input" ||
        aEvent.target.tagName == "textbox" ||
        aEvent.target.tagName == "textarea" ||
        aEvent.target.classList.contains("textbox")) {
      return false;
    }

    // handle keyboard navigation within the items list
    let newFocusOrdinal;
    if (aEvent.keyCode == aEvent.DOM_VK_PAGE_UP ||
        aEvent.keyCode == aEvent.DOM_VK_HOME) {
      newFocusOrdinal = 0;
    } else if (aEvent.keyCode == aEvent.DOM_VK_PAGE_DOWN ||
               aEvent.keyCode == aEvent.DOM_VK_END) {
      newFocusOrdinal = this._nav.childNodes.length - 1;
    } else if (aEvent.keyCode == aEvent.DOM_VK_UP) {
      newFocusOrdinal = getFocusedItemWithin(this._nav).getAttribute("data-ordinal");
      newFocusOrdinal--;
    } else if (aEvent.keyCode == aEvent.DOM_VK_DOWN) {
      newFocusOrdinal = getFocusedItemWithin(this._nav).getAttribute("data-ordinal");
      newFocusOrdinal++;
    }
    if (newFocusOrdinal !== undefined) {
      aEvent.stopPropagation();
      let el = this.getSummaryElementByOrdinal(newFocusOrdinal);
      if (el) {
        el.focus();
      }
      return false;
    }
  }, false);
}

SplitView.prototype = {
  /**
    * Retrieve whether the UI currently has a landscape orientation.
    *
    * @return boolean
    */
  get isLandscape()
  {
    return this._mql.matches;
  },

  /**
    * Retrieve the root element.
    *
    * @return DOMElement
    */
  get rootElement()
  {
    return this._root;
  },

  /**
    * Retrieve the active item's summary element or null if there is none.
    *
    * @return DOMElement
    */
  get activeSummary()
  {
    return this._activeSummary;
  },

  /**
    * Set the active item's summary element.
    *
    * @param DOMElement aSummary
    */
  set activeSummary(aSummary)
  {
    if (aSummary == this._activeSummary) {
      return;
    }

    if (this._activeSummary) {
      let binding = bindings.get(this._activeSummary);

      if (binding.onHide) {
        binding.onHide(this._activeSummary, binding._details, binding.data);
      }

      this._activeSummary.classList.remove("splitview-active");
      binding._details.classList.remove("splitview-active");
    }

    if (!aSummary) {
      return;
    }

    let binding = bindings.get(aSummary);
    aSummary.classList.add("splitview-active");
    binding._details.classList.add("splitview-active");

    this._activeSummary = aSummary;

    if (binding.onShow) {
      binding.onShow(aSummary, binding._details, binding.data);
    }
  },

  /**
    * Retrieve the active item's details element or null if there is none.
    * @return DOMElement
    */
  get activeDetails()
  {
    let summary = this.activeSummary;
    return summary ? bindings.get(summary)._details : null;
  },

  /**
   * Retrieve the summary element for a given ordinal.
   *
   * @param number aOrdinal
   * @return DOMElement
   *         Summary element with given ordinal or null if not found.
   * @see appendItem
   */
  getSummaryElementByOrdinal: function SEC_getSummaryElementByOrdinal(aOrdinal)
  {
    return this._nav.querySelector("* > li[data-ordinal='" + aOrdinal + "']");
  },

  /**
   * Append an item to the split view.
   *
   * @param DOMElement aSummary
   *        The summary element for the item.
   * @param DOMElement aDetails
   *        The details element for the item.
   * @param object aOptions
   *     Optional object that defines custom behavior and data for the item.
   *     All properties are optional :
   *     - function(DOMElement summary, DOMElement details, object data) onCreate
   *         Called when the item has been added.
   *     - function(summary, details, data) onShow
   *         Called when the item is shown/active.
   *     - function(summary, details, data) onHide
   *         Called when the item is hidden/inactive.
   *     - function(summary, details, data) onDestroy
   *         Called when the item has been removed.
   *     - object data
   *         Object to pass to the callbacks above.
   *     - number ordinal
   *         Items with a lower ordinal are displayed before those with a
   *         higher ordinal.
   */
  appendItem: function ASV_appendItem(aSummary, aDetails, aOptions)
  {
    let binding = aOptions || {};

    binding._summary = aSummary;
    binding._details = aDetails;
    bindings.set(aSummary, binding);

    this._nav.appendChild(aSummary);

    aSummary.addEventListener("click", (aEvent) => {
      aEvent.stopPropagation();
      this.activeSummary = aSummary;
    }, false);

    this._side.appendChild(aDetails);

    if (binding.onCreate) {
      binding.onCreate(aSummary, aDetails, binding.data);
    }
  },

  /**
   * Append an item to the split view according to two template elements
   * (one for the item's summary and the other for the item's details).
   *
   * @param string aName
   *        Name of the template elements to instantiate.
   *        Requires two (hidden) DOM elements with id "splitview-tpl-summary-"
   *        and "splitview-tpl-details-" suffixed with aName.
   * @param object aOptions
   *        Optional object that defines custom behavior and data for the item.
   *        See appendItem for full description.
   * @return object{summary:,details:}
   *         Object with the new DOM elements created for summary and details.
   * @see appendItem
   */
  appendTemplatedItem: function ASV_appendTemplatedItem(aName, aOptions)
  {
    aOptions = aOptions || {};
    let summary = this._root.querySelector("#splitview-tpl-summary-" + aName);
    let details = this._root.querySelector("#splitview-tpl-details-" + aName);

    summary = summary.cloneNode(true);
    summary.id = "";
    if (aOptions.ordinal !== undefined) { // can be zero
      summary.style.MozBoxOrdinalGroup = aOptions.ordinal;
      summary.setAttribute("data-ordinal", aOptions.ordinal);
    }
    details = details.cloneNode(true);
    details.id = "";

    this.appendItem(summary, details, aOptions);
    return {summary: summary, details: details};
  },

  /**
    * Remove an item from the split view.
    *
    * @param DOMElement aSummary
    *        Summary element of the item to remove.
    */
  removeItem: function ASV_removeItem(aSummary)
  {
    if (aSummary == this._activeSummary) {
      this.activeSummary = null;
    }

    let binding = bindings.get(aSummary);
    aSummary.parentNode.removeChild(aSummary);
    binding._details.parentNode.removeChild(binding._details);

    if (binding.onDestroy) {
      binding.onDestroy(aSummary, binding._details, binding.data);
    }
  },

  /**
   * Remove all items from the split view.
   */
  removeAll: function ASV_removeAll()
  {
    while (this._nav.hasChildNodes()) {
      this.removeItem(this._nav.firstChild);
    }
  },

  /**
   * Set the item's CSS class name.
   * This sets the class on both the summary and details elements, retaining
   * any SplitView-specific classes.
   *
   * @param DOMElement aSummary
   *        Summary element of the item to set.
   * @param string aClassName
   *        One or more space-separated CSS classes.
   */
  setItemClassName: function ASV_setItemClassName(aSummary, aClassName)
  {
    let binding = bindings.get(aSummary);
    let viewSpecific;

    viewSpecific = aSummary.className.match(/(splitview\-[\w-]+)/g);
    viewSpecific = viewSpecific ? viewSpecific.join(" ") : "";
    aSummary.className = viewSpecific + " " + aClassName;

    viewSpecific = binding._details.className.match(/(splitview\-[\w-]+)/g);
    viewSpecific = viewSpecific ? viewSpecific.join(" ") : "";
    binding._details.className = viewSpecific + " " + aClassName;
  },
};