/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * 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.
 */

#include <queue>
#include <vector>

#include <folly/logging/Init.h>
#include <folly/logging/LogConfigParser.h>
#include <folly/logging/LogFormatter.h>
#include <folly/logging/LogHandlerFactory.h>
#include <folly/logging/LogWriter.h>
#include <folly/logging/LoggerDB.h>
#include <folly/logging/StandardLogHandler.h>
#include <folly/logging/StandardLogHandlerFactory.h>
#include <folly/logging/xlog.h>
#include <folly/portability/GMock.h>
#include <folly/test/TestUtils.h>

namespace folly {

class TestLogFormatter : public LogFormatter {
 public:
  std::string formatMessage(
      const LogMessage& logMessage,
      const LogCategory* /* handlerCategory */) override {
    return "Test Formatter! " + logMessage.getMessage();
  }
};

class TestLogWriter : public LogWriter {
 public:
  void writeMessage(
      folly::StringPiece buffer, uint32_t /* flags */ = 0) override {
    messages.push_back(buffer.str());
  }

  void flush() override {}

  std::vector<std::string> messages;

  bool ttyOutput() const override { return false; }
};

class TestHandlerFactory : public LogHandlerFactory {
 public:
  explicit TestHandlerFactory(
      const std::shared_ptr<TestLogWriter> writer,
      const std::shared_ptr<TestLogFormatter> formatter = nullptr)
      : writer_(writer), formatter_(formatter) {}

  StringPiece getType() const override { return "test"; }

  std::shared_ptr<LogHandler> createHandler(const Options& options) override {
    TestWriterFactory writerFactory{writer_};
    if (formatter_ == nullptr) {
      return StandardLogHandlerFactory::createHandler(
          getType(), &writerFactory, options);
    }
    TestFormatterFactory formatterFactory{formatter_};
    return StandardLogHandlerFactory::createHandler(
        getType(), &writerFactory, &formatterFactory, options);
  }

 private:
  std::shared_ptr<TestLogWriter> writer_;
  std::shared_ptr<TestLogFormatter> formatter_;
  class TestWriterFactory : public StandardLogHandlerFactory::WriterFactory {
   public:
    explicit TestWriterFactory(std::shared_ptr<TestLogWriter> writer)
        : writer_(writer) {}

    bool processOption(
        StringPiece /* name */, StringPiece /* value */) override {
      return false;
    }

    std::shared_ptr<LogWriter> createWriter() override { return writer_; }

   private:
    std::shared_ptr<TestLogWriter> writer_;
  };

  class TestFormatterFactory
      : public StandardLogHandlerFactory::FormatterFactory {
   public:
    explicit TestFormatterFactory(std::shared_ptr<LogFormatter> formatter)
        : formatter_(formatter) {}

    bool processOption(
        StringPiece /* name */, StringPiece /* value */) override {
      return false;
    }

    std::shared_ptr<LogFormatter> createFormatter(
        const std::shared_ptr<LogWriter>& /* logWriter */) override {
      return formatter_;
    }

   private:
    std::shared_ptr<LogFormatter> formatter_;
  };
};

} // namespace folly

using namespace folly;

namespace {
class StandardLogHandlerFactoryTest : public testing::Test {
 public:
  StandardLogHandlerFactoryTest() {
    writer = std::make_shared<TestLogWriter>();
    db.registerHandlerFactory(
        std::make_unique<TestHandlerFactory>(writer), true);
  }

  LoggerDB db{LoggerDB::TESTING};
  std::shared_ptr<TestLogWriter> writer;
};
} // namespace

TEST_F(StandardLogHandlerFactoryTest, LogLevelTest) {
  Logger logger{&db, "test"};
  db.resetConfig(parseLogConfig("test=DBG4:default; default=test:level=WARN"));

  FB_LOG(logger, DBG9) << "DBG9";
  FB_LOG(logger, DBG3) << "DBG3";
  FB_LOG(logger, WARN) << "WARN 1";
  FB_LOG(logger, WARN) << "WARN 2";

  EXPECT_EQ(writer->messages.size(), 2);
}

TEST_F(StandardLogHandlerFactoryTest, LogLevelReverseTest) {
  Logger logger{&db, "test"};
  // log category level is WARN, log handler level is DBG3
  db.resetConfig(parseLogConfig("test=WARN:default; default=test:level=DBG3"));

  FB_LOG(logger, DBG9) << "DBG9";
  FB_LOG(logger, DBG3) << "DBG3";
  FB_LOG(logger, DBG2) << "DBG2";
  FB_LOG(logger, WARN) << "WARN 1";

  EXPECT_EQ(writer->messages.size(), 1);
}

TEST_F(StandardLogHandlerFactoryTest, MultipleLoggerTest) {
  Logger logger{&db, "test"};

  // log category level is DBG4
  // log handler "default" level is DBG3
  // log handler "other" level is WARN
  db.resetConfig(
      parseLogConfig("test=DBG4:default:other;"
                     "default=test:level=DBG3;"
                     "other=test:level=WARN"));

  FB_LOG(logger, DBG9) << "DBG9"; // no handler should log this
  FB_LOG(logger, DBG3) << "DBG3"; // only "default" logs this
  FB_LOG(logger, WARN) << "WARN 1"; // both log handlers log this

  EXPECT_EQ(writer->messages.size(), 3);
}

TEST_F(StandardLogHandlerFactoryTest, CustomFormatterTest) {
  Logger logger{&db, "test"};
  db.resetConfig(parseLogConfig("test=WARN:default; default=test"));

  // Log once with default formatter
  FB_LOG(logger, WARN) << "pollution secretary bean";

  // Switch to test formatter and log again
  db.registerHandlerFactory(
      std::make_unique<TestHandlerFactory>(
          writer, std::make_shared<TestLogFormatter>()),
      true);
  db.resetConfig(parseLogConfig("test=WARN:default; default=test"));

  FB_LOG(logger, WARN) << "ethereal potato kick";

  EXPECT_EQ(writer->messages.size(), 2);
  EXPECT_THAT(
      writer->messages[0],
      testing::MatchesRegex("^.+pollution secretary bean.+$"));
  EXPECT_EQ(writer->messages[1], "Test Formatter! ethereal potato kick");
}
