/*
    *    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;
  
  import java.sql.JDBCType;
  import java.util.Objects;
  import java.util.Optional;
  
  import org.jspecify.annotations.Nullable;
  import org.mybatis.dynamic.sql.render.RenderingContext;
  import org.mybatis.dynamic.sql.util.FragmentAndParameters;
  
  /**
   * A derived column is a column that is not directly related to a table. This is primarily
   * used for supporting sub-queries. The main difference in this class and {@link SqlColumn} is
   * that this class does not have a related {@link SqlTable} and therefore ignores any table
   * qualifier set in a query. If a table qualifier is required it can be set directly in the
   * builder for this class.
   *
   * @param <T>
   *            The Java type that corresponds to this column - not used except for compiler type checking for conditions
   */
  public class DerivedColumn<T> implements BindableColumn<T> {
      private final String name;
      private final @Nullable String tableQualifier;
      private final @Nullable String columnAlias;
      private final @Nullable JDBCType jdbcType;
      private final @Nullable String typeHandler;
  
      protected DerivedColumn(Builder<T> builder) {
          this.name = Objects.requireNonNull(builder.name);
          this.tableQualifier = builder.tableQualifier;
          this.columnAlias = builder.columnAlias;
          this.jdbcType = builder.jdbcType;
          this.typeHandler = builder.typeHandler;
      }
  
      @Override
      public Optional<String> alias() {
          return Optional.ofNullable(columnAlias);
      }
  
      @Override
      public Optional<JDBCType> jdbcType() {
          return Optional.ofNullable(jdbcType);
      }
  
      @Override
      public Optional<String> typeHandler() {
          return Optional.ofNullable(typeHandler);
      }
  
      @Override
      public FragmentAndParameters render(RenderingContext renderingContext) {
          String fragment = tableQualifier == null ? name : tableQualifier + "." + name; //$NON-NLS-1$
          return FragmentAndParameters.fromFragment(fragment);
      }
  
      @Override
      public DerivedColumn<T> as(String columnAlias) {
          return new Builder<T>()
                  .withName(name)
                  .withColumnAlias(columnAlias)
                  .withJdbcType(jdbcType)
                  .withTypeHandler(typeHandler)
                  .withTableQualifier(tableQualifier)
                  .build();
      }
  
      public static <T> DerivedColumn<T> of(String name) {
          return new Builder<T>()
                  .withName(name)
                  .build();
      }
  
      public static <T> DerivedColumn<T> of(String name, String tableQualifier) {
          return new Builder<T>()
                  .withName(name)
                  .withTableQualifier(tableQualifier)
                  .build();
      }
  
      public static class Builder<T> {
          private @Nullable String name;
          private @Nullable String tableQualifier;
          private @Nullable String columnAlias;
         private @Nullable JDBCType jdbcType;
         private @Nullable String typeHandler;
 
         public Builder<T> withName(String name) {
             this.name = name;
             return this;
         }
 
         public Builder<T> withTableQualifier(@Nullable String tableQualifier) {
             this.tableQualifier = tableQualifier;
             return this;
         }
 
         public Builder<T> withColumnAlias(String columnAlias) {
             this.columnAlias = columnAlias;
             return this;
         }
 
         public Builder<T> withJdbcType(@Nullable JDBCType jdbcType) {
             this.jdbcType = jdbcType;
             return this;
         }
 
         public Builder<T> withTypeHandler(@Nullable String typeHandler) {
             this.typeHandler = typeHandler;
             return this;
         }
 
         public DerivedColumn<T> build() {
             return new DerivedColumn<>(this);
         }
     }
 }