/*
    * 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.step;
  
  import static java.util.Objects.requireNonNull;
  
  import jakarta.json.Json;
  import jakarta.json.JsonObject;
  import java.util.Map;
  import org.mal_lang.langspec.Asset;
  import org.mal_lang.langspec.Field;
  import org.mal_lang.langspec.Variable;
  import org.mal_lang.langspec.builders.step.StepFieldBuilder;
  
  /**
   * Immutable class representing a field step in a MAL language.
   *
   * @since 1.0.0
   */
  public final class StepField extends StepReference {
    private final Field field;
  
    private StepField(Asset sourceAsset, Asset targetAsset, Field field) {
      super(sourceAsset, targetAsset);
      this.field = requireNonNull(field);
    }
  
    /**
     * Returns the field of this {@code StepField} object.
     *
     * @return the field of this {@code StepField} object
     * @since 1.0.0
     */
    public Field getField() {
      return this.field;
    }
  
    @Override
    public JsonObject toJson() {
      return Json.createObjectBuilder()
          .add("type", "field")
          .add("name", this.field.getName())
          .build();
    }
  
    static StepField fromBuilder(
        StepFieldBuilder builder,
        Asset sourceAsset,
        Map<String, Asset> assets,
        Map<Variable, Asset> variableTargets) {
      requireNonNull(builder);
      requireNonNull(sourceAsset);
      requireNonNull(assets);
      requireNonNull(variableTargets);
      if (!sourceAsset.hasField(builder.getName())) {
        throw new IllegalArgumentException(
            String.format("Field \"%s\" not found", builder.getName()));
      }
      var field = sourceAsset.getField(builder.getName());
      return new StepField(sourceAsset, field.getTarget().getAsset(), field);
    }
  }