// Copyright (C) 2017 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.server.change;

import com.google.common.base.Strings;
import com.google.gerrit.common.TimeUtil;
import com.google.gerrit.extensions.api.changes.DeleteCommentInput;
import com.google.gerrit.extensions.common.CommentInfo;
import com.google.gerrit.extensions.restapi.ResourceConflictException;
import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
import com.google.gerrit.extensions.restapi.RestApiException;
import com.google.gerrit.extensions.restapi.RestModifyView;
import com.google.gerrit.reviewdb.client.Comment;
import com.google.gerrit.reviewdb.client.PatchSet;
import com.google.gerrit.reviewdb.server.ReviewDb;
import com.google.gerrit.server.CommentsUtil;
import com.google.gerrit.server.CurrentUser;
import com.google.gerrit.server.notedb.ChangeNotes;
import com.google.gerrit.server.permissions.GlobalPermission;
import com.google.gerrit.server.permissions.PermissionBackend;
import com.google.gerrit.server.permissions.PermissionBackendException;
import com.google.gerrit.server.update.BatchUpdate;
import com.google.gerrit.server.update.BatchUpdateOp;
import com.google.gerrit.server.update.ChangeContext;
import com.google.gerrit.server.update.UpdateException;
import com.google.gwtorm.server.OrmException;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;
import java.io.IOException;
import java.util.List;
import java.util.Optional;
import org.eclipse.jgit.errors.ConfigInvalidException;

@Singleton
public class DeleteComment implements RestModifyView<CommentResource, DeleteCommentInput> {

  private final Provider<CurrentUser> userProvider;
  private final Provider<ReviewDb> dbProvider;
  private final PermissionBackend permissionBackend;
  private final BatchUpdate.Factory batchUpdateFactory;
  private final CommentsUtil commentsUtil;
  private final Provider<CommentJson> commentJson;
  private final ChangeNotes.Factory notesFactory;

  @Inject
  public DeleteComment(
      Provider<CurrentUser> userProvider,
      Provider<ReviewDb> dbProvider,
      PermissionBackend permissionBackend,
      BatchUpdate.Factory batchUpdateFactory,
      CommentsUtil commentsUtil,
      Provider<CommentJson> commentJson,
      ChangeNotes.Factory notesFactory) {
    this.userProvider = userProvider;
    this.dbProvider = dbProvider;
    this.permissionBackend = permissionBackend;
    this.batchUpdateFactory = batchUpdateFactory;
    this.commentsUtil = commentsUtil;
    this.commentJson = commentJson;
    this.notesFactory = notesFactory;
  }

  @Override
  public CommentInfo apply(CommentResource rsrc, DeleteCommentInput input)
      throws RestApiException, IOException, ConfigInvalidException, OrmException,
          PermissionBackendException, UpdateException {
    CurrentUser user = userProvider.get();
    permissionBackend.user(user).check(GlobalPermission.ADMINISTRATE_SERVER);

    String newMessage = getCommentNewMessage(user.asIdentifiedUser().getName(), input.reason);
    DeleteCommentOp deleteCommentOp = new DeleteCommentOp(rsrc, newMessage);
    try (BatchUpdate batchUpdate =
        batchUpdateFactory.create(
            dbProvider.get(), rsrc.getRevisionResource().getProject(), user, TimeUtil.nowTs())) {
      batchUpdate.addOp(rsrc.getRevisionResource().getChange().getId(), deleteCommentOp).execute();
    }

    ChangeNotes updatedNotes =
        notesFactory.createChecked(rsrc.getRevisionResource().getChange().getId());
    List<Comment> changeComments = commentsUtil.publishedByChange(dbProvider.get(), updatedNotes);
    Optional<Comment> updatedComment =
        changeComments.stream().filter(c -> c.key.equals(rsrc.getComment().key)).findFirst();
    if (!updatedComment.isPresent()) {
      // This should not happen as this endpoint should not remove the whole comment.
      throw new ResourceNotFoundException("comment not found: " + rsrc.getComment().key);
    }

    return commentJson.get().newCommentFormatter().format(updatedComment.get());
  }

  private static String getCommentNewMessage(String name, String reason) {
    StringBuilder stringBuilder = new StringBuilder("Comment removed by: ").append(name);
    if (!Strings.isNullOrEmpty(reason)) {
      stringBuilder.append("; Reason: ").append(reason);
    }
    return stringBuilder.toString();
  }

  private class DeleteCommentOp implements BatchUpdateOp {
    private final CommentResource rsrc;
    private final String newMessage;

    DeleteCommentOp(CommentResource rsrc, String newMessage) {
      this.rsrc = rsrc;
      this.newMessage = newMessage;
    }

    @Override
    public boolean updateChange(ChangeContext ctx)
        throws ResourceConflictException, OrmException, ResourceNotFoundException {
      PatchSet.Id psId = ctx.getChange().currentPatchSetId();
      commentsUtil.deleteCommentByRewritingHistory(
          ctx.getDb(),
          ctx.getUpdate(psId),
          rsrc.getComment().key,
          rsrc.getPatchSet().getId(),
          newMessage);
      return true;
    }
  }
}

@@ -1057,68 +1057,8 @@
 on;%0A
-import com.google.gerrit.extensions.restapi.RestModifyView;%0A
 impo
@@ -1103,16 +1103,16 @@
 omment;%0A
+
 import c
@@ -1705,16 +1705,131 @@
 ontext;%0A
+import com.google.gerrit.server.update.RetryHelper;%0Aimport com.google.gerrit.server.update.RetryingRestModifyView;%0A
 import c
@@ -2197,28 +2197,37 @@
 eComment
- implement
+%0A    extend
 s 
+Retrying
 RestModi
@@ -2268,16 +2268,29 @@
 entInput
+, CommentInfo
 %3E %7B%0A%0A  p
@@ -2442,64 +2442,8 @@
 nd;%0A
-  private final BatchUpdate.Factory batchUpdateFactory;%0A
   pr
@@ -2749,46 +2749,31 @@
     
-BatchUpdate.Factory batchUpdateFactory
+RetryHelper retryHelper
 ,%0A  
@@ -2882,24 +2882,48 @@
 sFactory) %7B%0A
+    super(retryHelper);%0A
     this.use
@@ -3034,58 +3034,8 @@
 nd;%0A
-    this.batchUpdateFactory = batchUpdateFactory;%0A
     
@@ -3185,17 +3185,68 @@
 fo apply
-(
+Impl(%0A      BatchUpdate.Factory batchUpdateFactory, 
 CommentR

Convert DeleteComment to RetryHelper