// Copyright 2017 The Nomulus Authors. All Rights Reserved.
//
// 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 google.registry.testing;

import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.truth.Truth.assertAbout;
import static com.google.common.truth.Truth.assertWithMessage;

import com.google.common.collect.ImmutableList;
import com.google.common.testing.TestLogHandler;
import com.google.common.truth.Correspondence;
import com.google.common.truth.FailureMetadata;
import com.google.common.truth.SimpleSubjectBuilder;
import com.google.common.truth.StringSubject;
import com.google.common.truth.Subject;
import google.registry.testing.TruthChainer.Which;
import java.util.List;
import java.util.Objects;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogRecord;

/** Utility methods for asserting things about logging {@link Handler} instances. */
public class LogsSubject extends Subject {

  private final TestLogHandler actual;

  public LogsSubject(FailureMetadata failureMetadata, TestLogHandler subject) {
    super(failureMetadata, subject);
    this.actual = subject;
  }

  private static final Correspondence<String, String> CONTAINS_CORRESPONDENCE =
      Correspondence.from(String::contains, "contains");

  private static final Correspondence<Throwable, Throwable> THROWABLE_CORRESPONDENCE =
      Correspondence.from(
          (t1, t2) ->
              t1.getClass().equals(t2.getClass()) && t1.getMessage().equals(t2.getMessage()),
          "throwableEquivalent");

  private List<String> getMessagesAtLevel(Level level) {
    ImmutableList.Builder<String> builder = new ImmutableList.Builder<>();
    for (LogRecord log : actual.getStoredLogRecords()) {
      if (log.getLevel().equals(level)) {
        builder.add(log.getMessage());
      }
    }
    return builder.build();
  }

  public void hasNoLogsAtLevel(Level level) {
    check("atLevel(%s)", level).that(getMessagesAtLevel(level)).isEmpty();
  }

  public void hasSevereLogWithCause(Throwable throwable) {
    ImmutableList<Throwable> actualThrowables =
        actual.getStoredLogRecords().stream()
            .filter(record -> record.getLevel().equals(Level.SEVERE))
            .map(LogRecord::getThrown)
            .filter(Objects::nonNull)
            .collect(toImmutableList());
    check("atSevere")
        .that(actualThrowables)
        .comparingElementsUsing(THROWABLE_CORRESPONDENCE)
        .contains(throwable);
  }

  public Which<StringSubject> hasLogAtLevelWithMessage(Level level, String message) {
    List<String> messagesAtLevel = getMessagesAtLevel(level);
    check("atLevel(%s)", level)
        .that(messagesAtLevel)
        .comparingElementsUsing(CONTAINS_CORRESPONDENCE)
        .contains(message);
    for (String messageCandidate : messagesAtLevel) {
      if (messageCandidate.contains(message)) {
        return new Which<>(
            assertWithMessage("log message at %s matching '%s'", level, message)
                .that(messageCandidate));
      }
    }
    throw new AssertionError("Message check passed yet matching message not found");
  }

  public static SimpleSubjectBuilder<LogsSubject, TestLogHandler> assertAboutLogs() {
    return assertAbout(LogsSubject::new);
  }
}
