'use strict';

/**
 * @ngdoc filter
 * @name ng.filter:filter
 * @function
 *
 * @description
 * Selects a subset of items from `array` and returns it as a new array.
 *
 * Note: This function is used to augment the `Array` type in Angular expressions. See
 * {@link ng.$filter} for more information about Angular arrays.
 *
 * @param {Array} array The source array.
 * @param {string|Object|function()} expression The predicate to be used for selecting items from
 *   `array`.
 *
 *   Can be one of:
 *
 *   - `string`: Predicate that results in a substring match using the value of `expression`
 *     string. All strings or objects with string properties in `array` that contain this string
 *     will be returned. The predicate can be negated by prefixing the string with `!`.
 *
 *   - `Object`: A pattern object can be used to filter specific properties on objects contained
 *     by `array`. For example `{name:"M", phone:"1"}` predicate will return an array of items
 *     which have property `name` containing "M" and property `phone` containing "1". A special
 *     property name `$` can be used (as in `{$:"text"}`) to accept a match against any
 *     property of the object. That's equivalent to the simple substring match with a `string`
 *     as described above.
 *
 *   - `function`: A predicate function can be used to write arbitrary filters. The function is
 *     called for each element of `array`. The final result is an array of those elements that
 *     the predicate returned true for.
 *
 * @example
   <doc:example>
     <doc:source>
       <div ng-init="friends = [{name:'John', phone:'555-1276'},
                                {name:'Mary', phone:'800-BIG-MARY'},
                                {name:'Mike', phone:'555-4321'},
                                {name:'Adam', phone:'555-5678'},
                                {name:'Julie', phone:'555-8765'}]"></div>

       Search: <input ng-model="searchText">
       <table id="searchTextResults">
         <tr><th>Name</th><th>Phone</th><tr>
         <tr ng-repeat="friend in friends | filter:searchText">
           <td>{{friend.name}}</td>
           <td>{{friend.phone}}</td>
         <tr>
       </table>
       <hr>
       Any: <input ng-model="search.$"> <br>
       Name only <input ng-model="search.name"><br>
       Phone only <input ng-model="search.phone"å><br>
       <table id="searchObjResults">
         <tr><th>Name</th><th>Phone</th><tr>
         <tr ng-repeat="friend in friends | filter:search">
           <td>{{friend.name}}</td>
           <td>{{friend.phone}}</td>
         <tr>
       </table>
     </doc:source>
     <doc:scenario>
       it('should search across all fields when filtering with a string', function() {
         input('searchText').enter('m');
         expect(repeater('#searchTextResults tr', 'friend in friends').column('friend.name')).
           toEqual(['Mary', 'Mike', 'Adam']);

         input('searchText').enter('76');
         expect(repeater('#searchTextResults tr', 'friend in friends').column('friend.name')).
           toEqual(['John', 'Julie']);
       });

       it('should search in specific fields when filtering with a predicate object', function() {
         input('search.$').enter('i');
         expect(repeater('#searchObjResults tr', 'friend in friends').column('friend.name')).
           toEqual(['Mary', 'Mike', 'Julie']);
       });
     </doc:scenario>
   </doc:example>
 */
function filterFilter() {
  return function(array, expression) {
    if (!(array instanceof Array)) return array;
    var predicates = [];
    predicates.check = function(value) {
      for (var j = 0; j < predicates.length; j++) {
        if(!predicates[j](value)) {
          return false;
        }
      }
      return true;
    };
    var search = function(obj, text){
      if (text.charAt(0) === '!') {
        return !search(obj, text.substr(1));
      }
      switch (typeof obj) {
        case "boolean":
        case "number":
        case "string":
          return ('' + obj).toLowerCase().indexOf(text) > -1;
        case "object":
          for ( var objKey in obj) {
            if (objKey.charAt(0) !== '$' && search(obj[objKey], text)) {
              return true;
            }
          }
          return false;
        case "array":
          for ( var i = 0; i < obj.length; i++) {
            if (search(obj[i], text)) {
              return true;
            }
          }
          return false;
        default:
          return false;
      }
    };
    switch (typeof expression) {
      case "boolean":
      case "number":
      case "string":
        expression = {$:expression};
      case "object":
        for (var key in expression) {
          if (key == '$') {
            (function() {
              var text = (''+expression[key]).toLowerCase();
              if (!text) return;
              predicates.push(function(value) {
                return search(value, text);
              });
            })();
          } else {
            (function() {
              var path = key;
              var text = (''+expression[key]).toLowerCase();
              if (!text) return;
              predicates.push(function(value) {
                return search(getter(value, path), text);
              });
            })();
          }
        }
        break;
      case 'function':
        predicates.push(expression);
        break;
      default:
        return array;
    }
    var filtered = [];
    for ( var j = 0; j < array.length; j++) {
      var value = array[j];
      if (predicates.check(value)) {
        filtered.push(value);
      }
    }
    return filtered;
  }
}
