/*
 * Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */

(function(scope) {

  function noopHandler(value) {
    return value;
  }

  // helper for deserializing properties of various types to strings
  var typeHandlers = {
    string: noopHandler,
    'undefined': noopHandler,
    date: function(value) {
      return new Date(Date.parse(value) || Date.now());
    },
    boolean: function(value) {
      if (value === '') {
        return true;
      }
      return value === 'false' ? false : !!value;
    },
    number: function(value) {
      var n = parseFloat(value);
      // hex values like "0xFFFF" parseFloat as 0
      if (n === 0) {
        n = parseInt(value);
      }
      return isNaN(n) ? value : n;
      // this code disabled because encoded values (like "0xFFFF")
      // do not round trip to their original format
      //return (String(floatVal) === value) ? floatVal : value;
    },
    object: function(value, currentValue) {
      if (currentValue === null) {
        return value;
      }
      try {
        // If the string is an object, we can parse is with the JSON library.
        // include convenience replace for single-quotes. If the author omits
        // quotes altogether, parse will fail.
        return JSON.parse(value.replace(/'/g, '"'));
      } catch(e) {
        // The object isn't valid JSON, return the raw value
        return value;
      }
    },
    // avoid deserialization of functions
    'function': function(value, currentValue) {
      return currentValue;
    }
  };

  function deserializeValue(value, currentValue) {
    // attempt to infer type from default value
    var inferredType = typeof currentValue;
    // invent 'date' type value for Date
    if (currentValue instanceof Date) {
      inferredType = 'date';
    }
    // delegate deserialization via type string
    return typeHandlers[inferredType](value, currentValue);
  }

  // exports

  scope.deserializeValue = deserializeValue;

})(Polymer);