// Copyright (C) 2020 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,
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package com.google.gerrit.acceptance.testsuite.change;

import com.google.auto.value.AutoValue;
import com.google.common.collect.ImmutableList;
import com.google.gerrit.acceptance.testsuite.ThrowingFunction;
import com.google.gerrit.entities.PatchSet;
import com.google.gerrit.server.edit.tree.TreeModification;
import java.util.Optional;

/** Initial attributes of the patchset. If not provided, arbitrary values will be used. */
@AutoValue
public abstract class TestPatchsetCreation {

  public abstract Optional<String> commitMessage();

  public abstract ImmutableList<TreeModification> treeModifications();

  public abstract Optional<ImmutableList<TestCommitIdentifier>> parents();

  abstract ThrowingFunction<TestPatchsetCreation, PatchSet.Id> patchsetCreator();

  public static TestPatchsetCreation.Builder builder(
      ThrowingFunction<TestPatchsetCreation, PatchSet.Id> patchsetCreator) {
    return new AutoValue_TestPatchsetCreation.Builder().patchsetCreator(patchsetCreator);
  }

  @AutoValue.Builder
  public abstract static class Builder {

    public abstract Builder commitMessage(String commitMessage);

    /** Modified file of the patchset. The file content is specified via the returned builder. */
    public FileContentBuilder<Builder> file(String filePath) {
      return new FileContentBuilder<>(this, filePath, 0, treeModificationsBuilder()::add);
    }

    /** Modified file of the patchset. The file content is specified via the returned builder. */
    public FileContentBuilder<Builder> file(String filePath, int newGitFileMode) {
      return new FileContentBuilder<>(
          this, filePath, newGitFileMode, treeModificationsBuilder()::add);
    }

    abstract ImmutableList.Builder<TreeModification> treeModificationsBuilder();

    /**
     * Parent commit of the change. The commit can be specified via various means in the returned
     * builder.
     *
     * <p>This method will just change the parent but not influence the contents of the patchset
     * commit.
     *
     * <p>It's possible to switch from a change representing a merge commit to a change not being a
     * merge commit with this method.
     */
    public ParentBuilder<Builder> parent() {
      return new ParentBuilder<>(parent -> parents(ImmutableList.of(parent)));
    }

    /**
     * Parent commits of the change. Each parent commit can be specified via various means in the
     * returned builder. The order of the parents matters and is preserved (first parent commit in
     * fluent change -> first parent of the change).
     *
     * <p>This method will just change the parents but not influence the contents of the patchset
     * commit.
     *
     * <p>It's possible to switch from a change representing a non-merge commit to a change which is
     * a merge commit with this method.
     */
    public ParentBuilder<MultipleParentBuilder<Builder>> parents() {
      return new ParentBuilder<>(parent -> new MultipleParentBuilder<>(this::parents, parent));
    }

    abstract Builder parents(ImmutableList<TestCommitIdentifier> value);

    abstract TestPatchsetCreation.Builder patchsetCreator(
        ThrowingFunction<TestPatchsetCreation, PatchSet.Id> patchsetCreator);

    abstract TestPatchsetCreation autoBuild();

    /**
     * Creates the patchset.
     *
     * @return the {@code PatchSet.Id} of the created patchset
     */
    public PatchSet.Id create() {
      TestPatchsetCreation patchsetCreation = autoBuild();
      return patchsetCreation.patchsetCreator().applyAndThrowSilently(patchsetCreation);
    }
  }
}