/*
    *    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.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.stream.Collector;
  
  public class FragmentCollector {
      final List<String> fragments = new ArrayList<>();
      final Map<String, Object> parameters = new HashMap<>();
  
      public FragmentCollector() {
          super();
      }
  
      private FragmentCollector(FragmentAndParameters initialFragment) {
          add(initialFragment);
      }
  
      public void add(FragmentAndParameters fragmentAndParameters) {
          fragments.add(fragmentAndParameters.fragment());
          parameters.putAll(fragmentAndParameters.parameters());
      }
  
      public FragmentCollector merge(FragmentCollector other) {
          fragments.addAll(other.fragments);
          parameters.putAll(other.parameters);
          return this;
      }
  
      public Optional<String> firstFragment() {
          return fragments.stream().findFirst();
      }
  
      public String collectFragments(Collector<CharSequence, ?, String> fragmentCollector) {
          return fragments.stream().collect(fragmentCollector);
      }
  
      public FragmentAndParameters toFragmentAndParameters(Collector<CharSequence, ?, String> fragmentCollector) {
          return FragmentAndParameters.withFragment(collectFragments(fragmentCollector))
                  .withParameters(parameters())
                  .build();
      }
  
      public Map<String, Object> parameters() {
          return Collections.unmodifiableMap(parameters);
      }
  
      public boolean hasMultipleFragments() {
          return fragments.size() > 1;
      }
  
      public boolean isEmpty() {
          return fragments.isEmpty();
      }
  
      public static Collector<FragmentAndParameters, FragmentCollector, FragmentCollector> collect() {
          return Collector.of(FragmentCollector::new,
                  FragmentCollector::add,
                  FragmentCollector::merge);
      }
  
      public static Collector<FragmentAndParameters, FragmentCollector, FragmentCollector> collect(
              FragmentAndParameters initialFragment) {
          return Collector.of(() -> new FragmentCollector(initialFragment),
                  FragmentCollector::add,
                  FragmentCollector::merge);
      }
  }