import { ValidationOptions } from '../ValidationOptions';
import { buildMessage, ValidateBy } from '../common/ValidateBy';
import { isObject } from '../typechecker/IsObject';

export const IS_NOT_EMPTY_OBJECT = 'isNotEmptyObject';

/**
 * Checks if the value is valid Object & not empty.
 * Returns false if the value is not an object or an empty valid object.
 */
export function isNotEmptyObject(value: unknown, options?: { nullable?: boolean }): boolean {
  if (!isObject(value)) {
    return false;
  }

  if (options?.nullable === true) {
    return !Object.values(value).every(propertyValue => propertyValue === null || propertyValue === undefined);
  }

  for (const key in value) {
    if (value.hasOwnProperty(key)) {
      return true;
    }
  }

  return false;
}

/**
 * Checks if the value is valid Object & not empty.
 * Returns false if the value is not an object or an empty valid object.
 */
export function IsNotEmptyObject(
  options?: { nullable?: boolean },
  validationOptions?: ValidationOptions
): PropertyDecorator {
  return ValidateBy(
    {
      name: IS_NOT_EMPTY_OBJECT,
      constraints: [options],
      validator: {
        validate: (value, args): boolean => isNotEmptyObject(value, args.constraints[0]),
        defaultMessage: buildMessage(
          eachPrefix => eachPrefix + '$property must be a non-empty object',
          validationOptions
        ),
      },
    },
    validationOptions
  );
}