/*
    * Copyright 2020-2022 Foreseeti AB <https://foreseeti.com>
    *
    * 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
    *
    *     http://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.mal_lang.langspec;
  
  import static java.util.Objects.requireNonNull;
  
  import jakarta.json.Json;
  import jakarta.json.JsonObject;
  import java.util.Map;
  import org.mal_lang.langspec.builders.AssociationBuilder;
  
  /**
   * Immutable class representing an association in a MAL language.
   *
   * @since 1.0.0
   */
  public final class Association {
    private final String name;
    private final Meta meta;
    private final Field leftField;
    private final Field rightField;
  
    private Association(String name, Meta meta, Field leftField, Field rightField) {
      this.name = requireNonNull(name);
      this.meta = requireNonNull(meta);
      this.leftField = requireNonNull(leftField);
      this.rightField = requireNonNull(rightField);
      leftField.setAssociation(this);
      rightField.setAssociation(this);
    }
  
    /**
     * Returns the name of this {@code Association} object.
     *
     * @return the name of this {@code Association} object
     * @since 1.0.0
     */
    public String getName() {
      return this.name;
    }
  
    /**
     * Returns the meta info of this {@code Association} object.
     *
     * @return the meta info of this {@code Association} object
     * @since 1.0.0
     */
    public Meta getMeta() {
      return this.meta;
    }
  
    /**
     * Returns the left field of this {@code Association} object.
     *
     * @return the left field of this {@code Association} object
     * @since 1.0.0
     */
    public Field getLeftField() {
      return this.leftField;
    }
  
    /**
     * Returns the right field of this {@code Association} object.
     *
     * @return the right field of this {@code Association} object
     * @since 1.0.0
     */
    public Field getRightField() {
      return this.rightField;
    }
  
    JsonObject toJson() {
      return Json.createObjectBuilder()
          .add("name", this.name)
          .add("meta", this.meta.toJson())
          .add("leftAsset", this.rightField.getAsset().getName())
          .add("leftField", this.leftField.getName())
          .add("leftMultiplicity", this.leftField.getMultiplicity().toJson())
          .add("rightAsset", this.leftField.getAsset().getName())
          .add("rightField", this.rightField.getName())
          .add("rightMultiplicity", this.rightField.getMultiplicity().toJson())
          .build();
    }
  
    static Association fromBuilder(AssociationBuilder builder, Map<String, Asset> assets) {
     requireNonNull(builder);
     requireNonNull(assets);
     if (!assets.containsKey(builder.getLeftAsset())) {
       throw new IllegalArgumentException(
           String.format("Asset \"%s\" not found", builder.getLeftAsset()));
     }
     if (!assets.containsKey(builder.getRightAsset())) {
       throw new IllegalArgumentException(
           String.format("Asset \"%s\" not found", builder.getRightAsset()));
     }
     var leftField =
         new Field(
             builder.getLeftField(),
             assets.get(builder.getRightAsset()),
             builder.getLeftMultiplicity());
     var rightField =
         new Field(
             builder.getRightField(),
             assets.get(builder.getLeftAsset()),
             builder.getRightMultiplicity());
     leftField.setTarget(rightField);
     rightField.setTarget(leftField);
     return new Association(
         builder.getName(), Meta.fromBuilder(builder.getMeta()), leftField, rightField);
   }
 }