'use strict';

module.exports = defFunc;

var CONSTRUCTORS = {
  Object: Object,
  Array: Array,
  Function: Function,
  Number: Number,
  String: String,
  Date: Date,
  RegExp: RegExp
};

/* istanbul ignore else */
if (typeof Buffer != 'undefined')
  CONSTRUCTORS.Buffer = Buffer;

var definition = defFunc.definition = {
  compile: function (schema) {
    if (typeof schema == 'string') {
      var Constructor = getConstructor(schema);
      return function (data) {
        return data instanceof Constructor;
      };
    }

    var constructors = schema.map(getConstructor);
    return function (data) {
      for (var i=0; i<constructors.length; i++)
        if (data instanceof constructors[i]) return true;
      return false;
    };
  },
  CONSTRUCTORS: CONSTRUCTORS,
  metaSchema: {
    anyOf: [
      { type: 'string' },
      {
        type: 'array',
        items: { type: 'string' }
      }
    ]
  }
};

function defFunc(ajv) {
  ajv.addKeyword('instanceof', definition);
}

function getConstructor(c) {
  var Constructor = CONSTRUCTORS[c];
  if (Constructor) return Constructor;
  throw new Error('invalid "instanceof" keyword value');
}