/*    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)) {
    }

    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);
        return *this;
    }


    LogstreamBuilder::~LogstreamBuilder() {
        if (_os) {
            if ( !_baseMessage.empty() ) _baseMessage.push_back(' ');
            _baseMessage += _os->str();
            MessageEventEphemeral message(Date_t::now(), _severity, _component, _contextName,
                                          _baseMessage);
            _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