/**
 * Copyright 2013 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @providesModule DOMProperty
 * @typechecks static-only
 */

/*jslint bitwise: true */

"use strict";

var invariant = require('invariant');

var DOMPropertyInjection = {
  /**
   * Mapping from normalized, camelcased property names to a configuration that
   * specifies how the associated DOM property should be accessed or rendered.
   */
  MUST_USE_ATTRIBUTE: 0x1,
  MUST_USE_PROPERTY:  0x2,
  HAS_BOOLEAN_VALUE:  0x4,
  HAS_SIDE_EFFECTS:   0x8,

  /**
   * Inject some specialized knowledge about the DOM. This takes a config object
   * with the following properties:
   *
   * isCustomAttribute: function that given an attribute name will return true
   * if it can be inserted into the DOM verbatim. Useful for data-* or aria-*
   * attributes where it's impossible to enumerate all of the possible
   * attribute names,
   *
   * Properties: object mapping DOM property name to one of the
   * DOMPropertyInjection constants or null. If your attribute isn't in here,
   * it won't get written to the DOM.
   *
   * DOMAttributeNames: object mapping React attribute name to the DOM
   * attribute name. Attribute names not specified use the **lowercase**
   * normalized name.
   *
   * DOMPropertyNames: similar to DOMAttributeNames but for DOM properties.
   * Property names not specified use the normalized name.
   *
   * DOMMutationMethods: Properties that require special mutation methods. If
   * `value` is undefined, the mutation method should unset the property.
   *
   * @param {object} domPropertyConfig the config as described above.
   */
  injectDOMPropertyConfig: function(domPropertyConfig) {
    var Properties = domPropertyConfig.Properties || {};
    var DOMAttributeNames = domPropertyConfig.DOMAttributeNames || {};
    var DOMPropertyNames = domPropertyConfig.DOMPropertyNames || {};
    var DOMMutationMethods = domPropertyConfig.DOMMutationMethods || {};

    if (domPropertyConfig.isCustomAttribute) {
      DOMProperty._isCustomAttributeFunctions.push(
        domPropertyConfig.isCustomAttribute
      );
    }

    for (var propName in Properties) {
      invariant(
        !DOMProperty.isStandardName[propName],
        'injectDOMPropertyConfig(...): You\'re trying to inject DOM property ' +
        '\'%s\' which has already been injected. You may be accidentally ' +
        'injecting the same DOM property config twice, or you may be ' +
        'injecting two configs that have conflicting property names.',
        propName
      );

      DOMProperty.isStandardName[propName] = true;

      var lowerCased = propName.toLowerCase();
      DOMProperty.getPossibleStandardName[lowerCased] = propName;

      var attributeName = DOMAttributeNames[propName];
      if (attributeName) {
        DOMProperty.getPossibleStandardName[attributeName] = propName;
      }

      DOMProperty.getAttributeName[propName] = attributeName || lowerCased;

      DOMProperty.getPropertyName[propName] =
        DOMPropertyNames[propName] || propName;

      var mutationMethod = DOMMutationMethods[propName];
      if (mutationMethod) {
        DOMProperty.getMutationMethod[propName] = mutationMethod;
      }

      var propConfig = Properties[propName];
      DOMProperty.mustUseAttribute[propName] =
        propConfig & DOMPropertyInjection.MUST_USE_ATTRIBUTE;
      DOMProperty.mustUseProperty[propName] =
        propConfig & DOMPropertyInjection.MUST_USE_PROPERTY;
      DOMProperty.hasBooleanValue[propName] =
        propConfig & DOMPropertyInjection.HAS_BOOLEAN_VALUE;
      DOMProperty.hasSideEffects[propName] =
        propConfig & DOMPropertyInjection.HAS_SIDE_EFFECTS;

      invariant(
        !DOMProperty.mustUseAttribute[propName] ||
          !DOMProperty.mustUseProperty[propName],
        'DOMProperty: Cannot use require using both attribute and property: %s',
        propName
      );
      invariant(
        DOMProperty.mustUseProperty[propName] ||
          !DOMProperty.hasSideEffects[propName],
        'DOMProperty: Properties that have side effects must use property: %s',
        propName
      );
    }
  }
};
var defaultValueCache = {};

/**
 * DOMProperty exports lookup objects that can be used like functions:
 *
 *   > DOMProperty.isValid['id']
 *   true
 *   > DOMProperty.isValid['foobar']
 *   undefined
 *
 * Although this may be confusing, it performs better in general.
 *
 * @see http://jsperf.com/key-exists
 * @see http://jsperf.com/key-missing
 */
var DOMProperty = {

  /**
   * Checks whether a property name is a standard property.
   * @type {Object}
   */
  isStandardName: {},

  /**
   * Mapping from lowercase property names to the properly cased version, used
   * to warn in the case of missing properties.
   * @type {Object}
   */
  getPossibleStandardName: {},

  /**
   * Mapping from normalized names to attribute names that differ. Attribute
   * names are used when rendering markup or with `*Attribute()`.
   * @type {Object}
   */
  getAttributeName: {},

  /**
   * Mapping from normalized names to properties on DOM node instances.
   * (This includes properties that mutate due to external factors.)
   * @type {Object}
   */
  getPropertyName: {},

  /**
   * Mapping from normalized names to mutation methods. This will only exist if
   * mutation cannot be set simply by the property or `setAttribute()`.
   * @type {Object}
   */
  getMutationMethod: {},

  /**
   * Whether the property must be accessed and mutated as an object property.
   * @type {Object}
   */
  mustUseAttribute: {},

  /**
   * Whether the property must be accessed and mutated using `*Attribute()`.
   * (This includes anything that fails `<propName> in <element>`.)
   * @type {Object}
   */
  mustUseProperty: {},

  /**
   * Whether the property should be removed when set to a falsey value.
   * @type {Object}
   */
  hasBooleanValue: {},

  /**
   * Whether or not setting a value causes side effects such as triggering
   * resources to be loaded or text selection changes. We must ensure that
   * the value is only set if it has changed.
   * @type {Object}
   */
  hasSideEffects: {},

  /**
   * All of the isCustomAttribute() functions that have been injected.
   */
  _isCustomAttributeFunctions: [],

  /**
   * Checks whether a property name is a custom attribute.
   * @method
   */
  isCustomAttribute: function(attributeName) {
    return DOMProperty._isCustomAttributeFunctions.some(
      function(isCustomAttributeFn) {
        return isCustomAttributeFn.call(null, attributeName);
      }
    );
  },

  /**
   * Returns the default property value for a DOM property (i.e., not an
   * attribute). Most default values are '' or false, but not all. Worse yet,
   * some (in particular, `type`) vary depending on the type of element.
   *
   * TODO: Is it better to grab all the possible properties when creating an
   * element to avoid having to create the same element twice?
   */
  getDefaultValueForProperty: function(nodeName, prop) {
    var nodeDefaults = defaultValueCache[nodeName];
    var testElement;
    if (!nodeDefaults) {
      defaultValueCache[nodeName] = nodeDefaults = {};
    }
    if (!(prop in nodeDefaults)) {
      testElement = document.createElement(nodeName);
      nodeDefaults[prop] = testElement[prop];
    }
    return nodeDefaults[prop];
  },

  injection: DOMPropertyInjection
};

module.exports = DOMProperty;
