/*
    *    Copyright 2016-2025 the original author or authors.
    *
    *    Licensed under the Apache License, Version 2.0 (the "License");
    *    you may not use this file except in compliance with the License.
    *    You may obtain a copy of the License at
    *
    *       https://www.apache.org/licenses/LICENSE-2.0
    *
   *    Unless required by applicable law or agreed to in writing, software
   *    distributed under the License is distributed on an "AS IS" BASIS,
   *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *    See the License for the specific language governing permissions and
   *    limitations under the License.
   */
  package org.mybatis.dynamic.sql.util;
  
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.function.UnaryOperator;
  
  import org.jspecify.annotations.Nullable;
  
  public class FragmentAndParameters {
  
      private final String fragment;
      private final Map<String, Object> parameters;
  
      private FragmentAndParameters(Builder builder) {
          fragment = Objects.requireNonNull(builder.fragment);
          parameters = Collections.unmodifiableMap(builder.parameters);
      }
  
      public String fragment() {
          return fragment;
      }
  
      public Map<String, Object> parameters() {
          return parameters;
      }
  
      /**
       * Return a new instance with the same parameters and a transformed fragment.
       *
       * @param mapper a function that can change the value of the fragment
       * @return a new instance with the same parameters and a transformed fragment
       */
      public FragmentAndParameters mapFragment(UnaryOperator<String> mapper) {
          return withFragment(mapper.apply(fragment))
                  .withParameters(parameters)
                  .build();
      }
  
      public static Builder withFragment(String fragment) {
          return new Builder().withFragment(fragment);
      }
  
      public static FragmentAndParameters fromFragment(String fragment) {
          return new Builder().withFragment(fragment).build();
      }
  
      public static class Builder {
          private @Nullable String fragment;
          private final Map<String, Object> parameters = new HashMap<>();
  
          public Builder withFragment(String fragment) {
              this.fragment = fragment;
              return this;
          }
  
          public Builder withParameter(String key, @Nullable Object value) {
              // the value can be null because a parameter type converter may return null
  
              //noinspection DataFlowIssue
              parameters.put(key, value);
              return this;
          }
  
          public Builder withParameters(Map<String, Object> parameters) {
              this.parameters.putAll(parameters);
              return this;
          }
  
          public FragmentAndParameters build() {
              return new FragmentAndParameters(this);
          }
  
          public Optional<FragmentAndParameters> buildOptional() {
              return Optional.of(build());
          }
      }
  }