package org.jboss.resteasy.test.resource.param.resource;

import javax.ws.rs.ext.ParamConverter;

public class MultiValuedPathParamConverter implements ParamConverter<MultiValuedPathParam<?>> {

   private final ParamConverter<?> paramConverter;

   public MultiValuedPathParamConverter(final ParamConverter<?> paramConverter) {
      this.paramConverter = paramConverter;
   }

   @Override
   public MultiValuedPathParam<?> fromString(String param) {
      if (param == null || param.trim().isEmpty()) {
         return null;
      }
      return parse(param.split("/"), this.paramConverter);
   }

   @Override
   public String toString(MultiValuedPathParam<?> multiValuedPathParam) {
      if (multiValuedPathParam == null || multiValuedPathParam.isEmpty()) {
         return null;
      }
      return format(multiValuedPathParam, this.paramConverter);
   }

   private static <T> MultiValuedPathParam<T> parse(String[] params, ParamConverter<T> paramConverter) {
      MultiValuedPathParam<T> multiValuedPathParam = new MultiValuedPathParam<>();
      for (String param : params) {
         multiValuedPathParam.add(paramConverter.fromString(param));
      }
      return multiValuedPathParam;
   }

   @SuppressWarnings("unchecked")
   private static <T> String format(MultiValuedPathParam<?> multiValuedPathParam,
         ParamConverter<T> paramConverter) {
      StringBuilder stringBuilder = new StringBuilder();
      int size = multiValuedPathParam.size();
      for (int i = 0; i < size; i++) {
         stringBuilder.append(paramConverter.toString((T) multiValuedPathParam.get(i)));
         if (i != size - 1) {
            stringBuilder.append('/');
         }
      }
      return stringBuilder.toString();
   }

}
