'use strict';

module.exports = function defFunc(ajv) {
  defFunc.definition = {
    type: 'object',
    macro: function (schema) {
      if (schema.length == 0) return true;
      if (schema.length == 1) return {required: schema};
      var schemas = schema.map(function (prop) {
        return {required: [prop]};
      });
      return {oneOf: schemas};
    },
    metaSchema: {
      type: 'array',
      items: {
        type: 'string'
      }
    }
  };

  ajv.addKeyword('oneRequired', defFunc.definition);
  return ajv;
};