// 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.plugins.codeowners.backend;

import com.google.gerrit.entities.SubmitRecord;
import com.google.gerrit.extensions.annotations.PluginName;
import com.google.gerrit.server.logging.TraceContext;
import com.google.gerrit.server.logging.TraceContext.TraceTimer;
import com.google.gerrit.server.query.change.ChangeData;
import com.google.gerrit.server.query.change.SubmitRequirementPredicate;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import java.util.Optional;

/**
 * A predicate that checks if a given change has all necessary code owner approvals. Matches with
 * changes that have a code owner approval or a code owner override. This predicate wraps the
 * existing {@link CodeOwnerSubmitRule} to perform the logic.
 *
 * <p>We implement the {@link SubmitRequirementPredicate} interface to make this predicate available
 * for submit requirement expressions. As a consequence, this predicate does not work with search
 * queries. We do that since the computation of code owner approvals is expensive.
 *
 * <p>TODO(ghareeb): exclude code owner overrides from this predicate.
 */
@Singleton
public class CodeOwnerApprovalPredicate extends SubmitRequirementPredicate {
  private final CodeOwnerSubmitRule codeOwnerSubmitRule;

  @Inject
  public CodeOwnerApprovalPredicate(
      @PluginName String pluginName, CodeOwnerSubmitRule codeOwnerSubmitRule) {
    super("has", CodeOwnerApprovalHasOperand.OPERAND + "_" + pluginName);
    this.codeOwnerSubmitRule = codeOwnerSubmitRule;
  }

  @Override
  public boolean match(ChangeData changeData) {
    try (TraceTimer timer =
        TraceContext.newTimer(
            String.format(
                "Run code owners submit rule for 'has:%s' predicate",
                CodeOwnerApprovalHasOperand.OPERAND))) {
      Optional<SubmitRecord> submitRecord = codeOwnerSubmitRule.evaluate(changeData);
      return submitRecord.isPresent() && submitRecord.get().status == SubmitRecord.Status.OK;
    }
  }

  @Override
  public int getCost() {
    // Running the code owner approval predicate is expensive
    return 10;
  }
}