'use strict';
 
var META_SCHEMA_ID = 'http://json-schema.org/draft-06/schema';
 
module.exports = function (ajv) {
  var defaultMeta = ajv._opts.defaultMeta;
  var metaSchemaRef = typeof defaultMeta == 'string'
                      ? { $ref: defaultMeta }
                      : ajv.getSchema(META_SCHEMA_ID)
                        ? { $ref: META_SCHEMA_ID }
                        : {};
 
  ajv.addKeyword('patternGroups', {
    // implemented in properties.jst
    metaSchema: {
      type: 'object',
      additionalProperties: {
        type: 'object',
        required: [ 'schema' ],
        properties: {
          maximum: {
            type: 'integer',
            minimum: 0
          },
          minimum: {
            type: 'integer',
            minimum: 0
          },
          schema: metaSchemaRef
        },
        additionalProperties: false
      }
    }
  });
  ajv.RULES.all.properties.implements.push('patternGroups');
};