import {DIContainer} from '../../di/DIContainer';
import {ConfigContainer} from '../ConfigContainer';
import {ConfigException} from '../error/ConfigException';
import {TypeUtil} from '../../util/TypeUtil';

export function Value(expression: string) {

  return (target: any, key: string, index?: number) => {

    if (typeof index !== 'undefined') {

      const params = (Reflect as any).getMetadata('design:paramtypes', target, key);
      const type = params[index];

      DIContainer.registerParamHandler({
        type: target,
        index,
        getValue: getValue(type, expression)
      });

    } else {

      const type = (Reflect as any).getMetadata('design:type', target, key);

      DIContainer.registerPropertyHandler({
        type: target.constructor,
        key,
        getValue: getValue(type, expression)
      });
    }
  };
}

function getValue(type: Function, expression: string): () => any {
  if (TypeUtil.isSimpleType(type)) {
    return () => ConfigContainer.get(expression);
  } else {
    throw new ConfigException(`[TYPED] Value decorator don't support type ${type}`);
  }
}