// Copyright 2006 Google Inc.
// All Rights Reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 
//  * Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//  * Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in
//    the documentation and/or other materials provided with the
//    distribution.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE. 

/**
 * @fileoverview Utilities for adding, removing and setting classes.
 *
 */


goog.provide('goog.dom.classes');


goog.require('goog.array');


/**
 * Sets the entire class name of an element.
 * @param {Element} element DOM node to set class of.
 * @param {string} className Class name(s) to apply to element.
 */
goog.dom.classes.set = function(element, className) {
  element.className = className;
};


/**
 * Gets an array of class names on an element
 * @param {Element} element DOM node to get class of.
 * @return {Array} Class names on {@code element}.
 */
goog.dom.classes.get = function(element) {
  var className = element.className;
  // Some types of elements don't have a className in IE (e.g. iframes).
  // Furthermore, in Firefox, className is not a string when the element is
  // an SVG element.
  return className && typeof className.split == 'function' ?
      className.split(' ') : [];
};


/**
 * Adds a class or classes to an element. Does not add multiples of class names.
 * @param {Element} element DOM node to add class to.
 * @param {string} var_args Class names to add.
 * @return {boolean} Whether class was added (or all classes were added).
 */
goog.dom.classes.add = function(element, var_args) {
  var classes = goog.dom.classes.get(element);
  var args = goog.array.slice(arguments, 1);

  var b = goog.dom.classes.add_(classes, args);
  element.className = classes.join(' ');

  return b;
};


/**
 * Removes a class or classes from an element.
 * @param {Element} element DOM node to remove class from.
 * @param {string} var_args Class name(s) to remove.
 * @return {boolean} Whether all classes in {@code var_args} were found and
 *     removed.
 */
goog.dom.classes.remove = function(element, var_args) {
  var classes = goog.dom.classes.get(element);
  var args = goog.array.slice(arguments, 1);

  var b = goog.dom.classes.remove_(classes, args);
  element.className = classes.join(' ');

  return b;
};


/**
 * Helper method for {@link goog.dom.classes.add} and
 * {@link goog.dom.classes.addRemove}. Adds one or more classes to the supplied
 * classes array.
 * @param {Array.<string>} classes All class names for the element, will be
 *     updated to have the classes supplied in {@code args} added.
 * @param {Array.<string>} args Class names to add.
 * @return {boolean} Whether all classes in were added.
 * @private
 */
goog.dom.classes.add_ = function(classes, args) {
  var rv = 0;
  for (var i = 0; i < args.length; i++) {
    if (!goog.array.contains(classes, args[i])) {
      classes.push(args[i]);
      rv++;
    }
  }
  return rv == args.length;
};


/**
 * Helper method for {@link goog.dom.classes.remove} and
 * {@link goog.dom.classes.addRemove}. Removes one or more classes from the
 * supplied classes array.
 * @param {Array.<string>} classes All class names for the element, will be
 *     updated to have the classes supplied in {@code args} removed.
 * @param {Array.<string>} args Class names to remove.
 * @return {boolean} Whether all classes in were found and removed.
 * @private
 */
goog.dom.classes.remove_ = function(classes, args) {
  var rv = 0;
  for (var i = 0; i < classes.length; i++) {
    if (goog.array.contains(args, classes[i])) {
      goog.array.splice(classes, i--, 1);
      rv++;
    }
  }
  return rv == args.length;
};


/**
 * Switches a class on an element from one to another without disturbing other
 * classes. If the fromClass isn't removed, the toClass won't be added.
 * @param {Element} element DOM node to swap classes on.
 * @param {string} fromClass Class to remove.
 * @param {string} toClass Class to add.
 * @return {boolean} Whether classes were switched.
 */
goog.dom.classes.swap = function(element, fromClass, toClass) {
  var classes = goog.dom.classes.get(element);

  var removed = false;
  for (var i = 0; i < classes.length; i++) {
    if (classes[i] == fromClass) {
      goog.array.splice(classes, i--, 1);
      removed = true;
    }
  }

  if (removed) {
    classes.push(toClass);
    element.className = classes.join(' ');
  }

  return removed;
};


/**
 * Adds zero or more classes to and element and and removes zero or more as a
 * single operation. Unlike calling {@link goog.dom.classes.add} and
 * {@link goog.dom.classes.remove} separately this is more efficient as it only
 * parses the class property once.
 * @param {Element} element DOM node to swap classes on.
 * @param {string|Array.<string>|null} classesToRemove Class or classes to
 *     remove, if null no classes are removed.
 * @param {string|Array.<string>|null} classesToAdd Class or classes to add, if
 *     null no classes are added.
 */
goog.dom.classes.addRemove = function(element, classesToRemove, classesToAdd) {
  var classes = goog.dom.classes.get(element);
  if (goog.isString(classesToRemove)) {
    goog.array.remove(classes, classesToRemove);
  } else if (goog.isArray(classesToRemove)) {
    goog.dom.classes.remove_(classes, classesToRemove);
  }

  if (goog.isString(classesToAdd) &&
      !goog.array.contains(classes, classesToAdd)) {
    classes.push(classesToAdd);
  } else if (goog.isArray(classesToAdd)) {
    goog.dom.classes.add_(classes, classesToAdd);
  }

  element.className = classes.join(' ');
};


/**
 * Returns true if an element has a class.
 * @param {Element} element DOM node to test.
 * @param {string} className Class name to test for.
 * @return {boolean} Whether element has the class.
 */
goog.dom.classes.has = function(element, className) {
  return goog.array.contains(goog.dom.classes.get(element), className);
};


/**
 * Adds or removes a class depending on the enabled argument.
 * @param {Element} element DOM node to add or remove the class on.
 * @param {string} className Class name to add or remove.
 * @param {boolean} enabled Whether to add or remove the class (true adds,
 *     false removes).
 */
goog.dom.classes.enable = function(element, className, enabled) {
  if (enabled) {
    goog.dom.classes.add(element, className);
  } else {
    goog.dom.classes.remove(element, className);
  }
};


/**
 * Removes a class if an element has it, and adds it the element doesn't have
 * it.  Won't affect other classes on the node.
 * @param {Element} element DOM node to toggle class on.
 * @param {string} className Class to toggle.
 * @return {boolean} True if class was added, false if it was removed
 *     (in other words, whether element has the class after this function has
 *     been called).
 */
goog.dom.classes.toggle = function(element, className) {
  var add = !goog.dom.classes.has(element, className);
  goog.dom.classes.enable(element, className, add);
  return add;
};