/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * 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.
 */

// Set the executeScriptHarness callback function.
// The function takes a functionObject and a JSON string representing an array
// of arguments. The arguments are applied to the function |functionObject|.
webdriverExecutor.executeScriptHarness = function(functionObject, jsonArgString) {

  // Run the JSON deserialize algorithm on the value.
  // https://www.w3.org/TR/webdriver/#dfn-json-deserialize
  var deserialize = function(value) {
    if (value instanceof Array) {
      // Deserialize each of the array's values;
      var deserializedArray = [];
      var numArgs = value.length;
      for (var i = 0; i < numArgs; i++) {
        deserializedArray.push(deserialize(value[i]));
      }
      return deserializedArray;
    } else if (value instanceof Object && value.ELEMENT) {
      // The argument is a WebElement, as denoted by the presence of the
      // ELEMENT property, so get the actual Element the id is mapped to.
      return webdriverExecutor.idToElement(value.ELEMENT);
    } else if (value instanceof Object) {
      // Deserialize each of the object's values.
      var deserializedObject = {};
      for (var key in value) {
        deserializedObject[key] = deserialize(value[key]);
      }
      return deserializedObject;
    }
    return value;
  };

  // Run the JSON clone algorithm on the value.
  // https://www.w3.org/TR/webdriver/#dfn-internal-json-clone-algorithm
  var serialize = function(value, seen) {
    if (value === undefined || value === null) {
      return null;
    } else if (value instanceof Element) {
      var webElementId = webdriverExecutor.elementToId(value);
      return { "ELEMENT": webElementId };
    } else if (value instanceof Object) {
      if (seen.indexOf(value) != -1) {
        throw "Reference cycle found trying to serialize.";
      }
      seen.push(value);
      if (value instanceof Array || value instanceof NodeList
          || value instanceof HTMLCollection) {
        var serializedArray = [];
        var length = value.length;
        for (var i = 0; i < length; i++) {
          serializedArray.push(serialize(value[i], seen));
        }
        return serializedArray;
      } else {
        // Deserialize each of the object's its values.
        var serializedObject = {};
        for (var key in value) {
          serializedObject[key] = serialize(value[key], seen);
        }
        return serializedObject;
      }
    }
    return value;
  };
  var parameters = deserialize(JSON.parse(jsonArgString));
  var result = functionObject.apply(window, parameters);
  return JSON.stringify(serialize(result, []));

};