// Copyright (C) 2021 The Android Open Source Project
//
// 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 com.google.gerrit.entities;

import com.google.auto.value.AutoValue;
import com.google.gerrit.extensions.annotations.ExtensionPoint;
import com.google.gson.Gson;
import com.google.gson.TypeAdapter;
import java.util.Optional;

/**
 * Entity describing a requirement that should be met for a change to become submittable.
 *
 * <p>There are two ways to contribute {@link SubmitRequirement}:
 *
 * <ul>
 *   <li>Set per-project in project.config (see {@link
 *       com.google.gerrit.server.project.ProjectState#getSubmitRequirements()}
 *   <li>Bind a global {@link SubmitRequirement} that will be evaluated for all projects.
 * </ul>
 */
@ExtensionPoint
@AutoValue
public abstract class SubmitRequirement {
  /** Requirement name. */
  public abstract String name();

  /** Description of what this requirement means. */
  public abstract Optional<String> description();

  /**
   * Expression of the condition that makes the requirement applicable. The expression should be
   * evaluated for a specific {@link Change} and if it returns false, the requirement becomes
   * irrelevant for the change (i.e. {@link #submittabilityExpression()} and {@link
   * #overrideExpression()} are not evaluated).
   *
   * <p>An empty {@link Optional} indicates that the requirement is applicable for any change.
   */
  public abstract Optional<SubmitRequirementExpression> applicabilityExpression();

  /**
   * Expression of the condition that allows the submission of a change. The expression should be
   * evaluated for a specific {@link Change} and if it returns true, the requirement becomes
   * fulfilled for the change.
   */
  public abstract SubmitRequirementExpression submittabilityExpression();

  /**
   * Expression that, if evaluated to true, causes the submit requirement to be fulfilled,
   * regardless of the submittability expression. This expression should be evaluated for a specific
   * {@link Change}.
   *
   * <p>An empty {@link Optional} indicates that the requirement is not overridable.
   */
  public abstract Optional<SubmitRequirementExpression> overrideExpression();

  /**
   * Boolean value indicating if the {@link SubmitRequirement} definition can be overridden in child
   * projects.
   *
   * <p>For globally bound {@link SubmitRequirement}, indicates if can be overridden by {@link
   * SubmitRequirement} in project.config.
   *
   * <p>Default is false.
   */
  public abstract boolean allowOverrideInChildProjects();

  public static SubmitRequirement.Builder builder() {
    return new AutoValue_SubmitRequirement.Builder();
  }

  public static TypeAdapter<SubmitRequirement> typeAdapter(Gson gson) {
    return new AutoValue_SubmitRequirement.GsonTypeAdapter(gson);
  }

  @AutoValue.Builder
  public abstract static class Builder {

    public abstract Builder setName(String name);

    public abstract Builder setDescription(Optional<String> description);

    public abstract Builder setApplicabilityExpression(
        Optional<SubmitRequirementExpression> applicabilityExpression);

    public abstract Builder setSubmittabilityExpression(
        SubmitRequirementExpression submittabilityExpression);

    public abstract Builder setOverrideExpression(
        Optional<SubmitRequirementExpression> overrideExpression);

    public abstract Builder setAllowOverrideInChildProjects(boolean allowOverrideInChildProjects);

    public abstract SubmitRequirement build();
  }
}