/*    Copyright 2013 10gen Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects
 *    for all of the code used other than as permitted herein. If you modify
 *    file(s) with this exception, you may extend this exception to your
 *    version of the file(s), but you are not obligated to do so. If you do not
 *    wish to do so, delete this exception statement from your version. If you
 *    delete this exception statement from all source files in the program,
 *    then also delete it in the license file.
 */

#include "mongo/platform/basic.h"

#include "mongo/logger/logstream_builder.h"

#include <memory>

#include "mongo/base/init.h"
#include "mongo/base/status.h"
#include "mongo/logger/message_event_utf8_encoder.h"
#include "mongo/logger/tee.h"
#include "mongo/stdx/memory.h"
#include "mongo/util/assert_util.h"  // TODO: remove apple dep for this in threadlocal.h
#include "mongo/util/concurrency/threadlocal.h"
#include "mongo/util/time_support.h"

namespace mongo {

namespace {

/// This flag indicates whether the system providing a per-thread cache of ostringstreams
/// for use by LogstreamBuilder instances is initialized and ready for use.  Until this
/// flag is true, LogstreamBuilder instances must not use the cache.
bool isThreadOstreamCacheInitialized = false;

MONGO_INITIALIZER(LogstreamBuilder)(InitializerContext*) {
    isThreadOstreamCacheInitialized = true;
    return Status::OK();
}

}  // namespace

TSP_DECLARE(std::unique_ptr<std::ostringstream>, threadOstreamCache);
TSP_DEFINE(std::unique_ptr<std::ostringstream>, threadOstreamCache);

namespace {
// During unittests, where we don't use quickExit(), static finalization may destroy the
// cache before its last use, so mark it as not initialized in that case.
// This must be after the TSP_DEFINE so that it is destroyed first.
struct ThreadOstreamCacheFinalizer {
    ~ThreadOstreamCacheFinalizer() {
        isThreadOstreamCacheInitialized = false;
    }
} threadOstreamCacheFinalizer;
}  // namespace

namespace logger {

LogstreamBuilder::LogstreamBuilder(MessageLogDomain* domain,
                                   std::string contextName,
                                   LogSeverity severity)
    : LogstreamBuilder(
          domain, std::move(contextName), std::move(severity), LogComponent::kDefault) {}

LogstreamBuilder::LogstreamBuilder(MessageLogDomain* domain,
                                   std::string contextName,
                                   LogSeverity severity,
                                   LogComponent component)
    : _domain(domain),
      _contextName(std::move(contextName)),
      _severity(std::move(severity)),
      _component(std::move(component)),
      _tee(nullptr) {}

LogstreamBuilder::LogstreamBuilder(logger::MessageLogDomain* domain,
                                   const std::string& contextName,
                                   LabeledLevel labeledLevel)
    : LogstreamBuilder(domain, std::move(contextName), static_cast<LogSeverity>(labeledLevel)) {
    setBaseMessage(labeledLevel.getLabel());
}

LogstreamBuilder::LogstreamBuilder(LogstreamBuilder&& other)
    : _domain(std::move(other._domain)),
      _contextName(std::move(other._contextName)),
      _severity(std::move(other._severity)),
      _component(std::move(other._component)),
      _baseMessage(std::move(other._baseMessage)),
      _os(std::move(other._os)),
      _tee(std::move(other._tee)),
      _isTruncatable(other._isTruncatable) {}

LogstreamBuilder& LogstreamBuilder::operator=(LogstreamBuilder&& other) {
    _domain = std::move(other._domain);
    _contextName = std::move(other._contextName);
    _severity = std::move(other._severity);
    _component = std::move(other._component);
    _baseMessage = std::move(other._baseMessage);
    _os = std::move(other._os);
    _tee = std::move(other._tee);
    _isTruncatable = std::move(other._isTruncatable);
    return *this;
}


LogstreamBuilder::~LogstreamBuilder() {
    if (_os) {
        if (!_baseMessage.empty())
            _baseMessage.push_back(' ');
        _baseMessage += _os->str();
        MessageEventEphemeral message(
            Date_t::now(), _severity, _component, _contextName, _baseMessage);
        message.setIsTruncatable(_isTruncatable);
        _domain->append(message);
        if (_tee) {
            _os->str("");
            logger::MessageEventDetailsEncoder teeEncoder;
            teeEncoder.encode(message, *_os);
            _tee->write(_os->str());
        }
        _os->str("");
        if (isThreadOstreamCacheInitialized && !threadOstreamCache.getMake()->get()) {
            *threadOstreamCache.get() = std::move(_os);
        }
    }
}

void LogstreamBuilder::operator<<(Tee* tee) {
    makeStream();  // Adding a Tee counts for purposes of deciding to make a log message.
    // TODO: dassert(!_tee);
    _tee = tee;
}

void LogstreamBuilder::makeStream() {
    if (!_os) {
        if (isThreadOstreamCacheInitialized && threadOstreamCache.getMake()->get()) {
            _os = std::move(*threadOstreamCache.get());
        } else {
            _os = stdx::make_unique<std::ostringstream>();
        }
    }
}

}  // namespace logger
}  // namespace mongo