/*
    * 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.JsonObject;
  import java.util.Map;
  import org.mal_lang.langspec.Asset;
  import org.mal_lang.langspec.Variable;
  import org.mal_lang.langspec.builders.step.StepAttackStepBuilder;
  import org.mal_lang.langspec.builders.step.StepCollectBuilder;
  import org.mal_lang.langspec.builders.step.StepDifferenceBuilder;
  import org.mal_lang.langspec.builders.step.StepExpressionBuilder;
  import org.mal_lang.langspec.builders.step.StepFieldBuilder;
  import org.mal_lang.langspec.builders.step.StepIntersectionBuilder;
  import org.mal_lang.langspec.builders.step.StepSubTypeBuilder;
  import org.mal_lang.langspec.builders.step.StepTransitiveBuilder;
  import org.mal_lang.langspec.builders.step.StepUnionBuilder;
  import org.mal_lang.langspec.builders.step.StepVariableBuilder;
  
  /**
   * Immutable class representing a step expression in a MAL language.
   *
   * @since 1.0.0
   */
  public abstract class StepExpression {
    private final Asset sourceAsset;
    private final Asset targetAsset;
  
    StepExpression(Asset sourceAsset, Asset targetAsset) {
      this.sourceAsset = requireNonNull(sourceAsset);
      this.targetAsset = requireNonNull(targetAsset);
    }
  
    /**
     * Returns the source asset of this {@code StepExpression} object.
     *
     * @return the source asset of this {@code StepExpression} object
     * @since 1.0.0
     */
    public Asset getSourceAsset() {
      return this.sourceAsset;
    }
  
    /**
     * Returns the target asset of this {@code StepExpression} object.
     *
     * @return the target asset of this {@code StepExpression} object
     * @since 1.0.0
     */
    public Asset getTargetAsset() {
      return this.targetAsset;
    }
  
    /**
     * Returns the JSON representation of this {@code StepExpression} object.
     *
     * @return the JSON representation of this {@code StepExpression} object
     * @since 1.0.0
     */
    public abstract JsonObject toJson();
  
    /**
     * Creates a new {@code StepExpression} object from a {@link
     * org.mal_lang.langspec.builders.step.StepExpressionBuilder}.
     *
     * @param builder the {@link org.mal_lang.langspec.builders.step.StepExpressionBuilder}
     * @param sourceAsset the source asset of the step expression
     * @param assets all assets of the language
     * @param variableTargets a map of target assets of variables
     * @return a new {@code StepExpression} object
     * @throws java.lang.NullPointerException if {@code builder}, {@code sourceAsset}, or {@code
     *     assets} is {@code null}
     * @since 1.0.0
     */
    public static StepExpression fromBuilder(
        StepExpressionBuilder builder,
        Asset sourceAsset,
        Map<String, Asset> assets,
        Map<Variable, Asset> variableTargets) {
      requireNonNull(builder);
      requireNonNull(sourceAsset);
      requireNonNull(assets);
      requireNonNull(variableTargets);
     if (builder instanceof StepUnionBuilder) {
       return StepUnion.fromBuilder(
           (StepUnionBuilder) builder, sourceAsset, assets, variableTargets);
     }
     if (builder instanceof StepIntersectionBuilder) {
       return StepIntersection.fromBuilder(
           (StepIntersectionBuilder) builder, sourceAsset, assets, variableTargets);
     }
     if (builder instanceof StepDifferenceBuilder) {
       return StepDifference.fromBuilder(
           (StepDifferenceBuilder) builder, sourceAsset, assets, variableTargets);
     }
     if (builder instanceof StepCollectBuilder) {
       return StepCollect.fromBuilder(
           (StepCollectBuilder) builder, sourceAsset, assets, variableTargets);
     }
     if (builder instanceof StepTransitiveBuilder) {
       return StepTransitive.fromBuilder(
           (StepTransitiveBuilder) builder, sourceAsset, assets, variableTargets);
     }
     if (builder instanceof StepSubTypeBuilder) {
       return StepSubType.fromBuilder(
           (StepSubTypeBuilder) builder, sourceAsset, assets, variableTargets);
     }
     if (builder instanceof StepFieldBuilder) {
       return StepField.fromBuilder(
           (StepFieldBuilder) builder, sourceAsset, assets, variableTargets);
     }
     if (builder instanceof StepAttackStepBuilder) {
       return StepAttackStep.fromBuilder(
           (StepAttackStepBuilder) builder, sourceAsset, assets, variableTargets);
     }
     if (builder instanceof StepVariableBuilder) {
       return StepVariable.fromBuilder(
           (StepVariableBuilder) builder, sourceAsset, assets, variableTargets);
     }
     throw new RuntimeException(
         String.format(
             "Invalid %s sub-type %s",
             StepExpressionBuilder.class.getName(), builder.getClass().getName()));
   }
 }