//
//  LogHandler.cpp
//  libraries/shared/src
//
//  Created by Stephen Birarda on 2014-10-28.
//  Migrated from Logging.cpp created on 6/11/13
//  Copyright 2014 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

#ifndef hifi_LogHandler_h
#define hifi_LogHandler_h

#include <QObject>
#include <QString>
#include <QRegExp>
#include <QMutex>
#include <vector>
#include <memory>

const int VERBOSE_LOG_INTERVAL_SECONDS = 5;

enum LogMsgType {
    LogInfo = QtInfoMsg,
    LogDebug = QtDebugMsg,
    LogWarning = QtWarningMsg,
    LogCritical = QtCriticalMsg,
    LogFatal = QtFatalMsg,
    LogSuppressed = 100
};

/// Handles custom message handling and sending of stats/logs to Logstash instance
class LogHandler : public QObject {
    Q_OBJECT
public:
    static LogHandler& getInstance();

    /// sets the target name to output via the verboseMessageHandler, called once before logging begins
    /// \param targetName the desired target name to output in logs
    void setTargetName(const QString& targetName);

    void setShouldOutputProcessID(bool shouldOutputProcessID);
    void setShouldOutputThreadID(bool shouldOutputThreadID);
    void setShouldDisplayMilliseconds(bool shouldDisplayMilliseconds);

    QString printMessage(LogMsgType type, const QMessageLogContext& context, const QString &message);

    /// a qtMessageHandler that can be hooked up to a target that links to Qt
    /// prints various process, message type, and time information
    static void verboseMessageHandler(QtMsgType type, const QMessageLogContext& context, const QString &message);

    const QString& addRepeatedMessageRegex(const QString& regexString);
    const QString& addOnlyOnceMessageRegex(const QString& regexString);
    int newRepeatedMessageID();
    void printRepeatedMessage(int messageID, LogMsgType type, const QMessageLogContext& context, const QString &message);

private slots:
    void setupRepeatedMessageFlusher();

private:
    LogHandler();
    ~LogHandler();

    void flushRepeatedMessages();

    QString _targetName;
    bool _shouldOutputProcessID { false };
    bool _shouldOutputThreadID { false };
    bool _shouldDisplayMilliseconds { false };

    struct RepeatedMessage {
        QRegExp regexp;
        int messageCount { 0 };
        QString lastMessage;
    };
    std::vector<RepeatedMessage> _repeatedMessages;

    struct OnceOnlyMessage {
        QRegExp regexp;
        int messageCount { 0 };
    };
    std::vector<OnceOnlyMessage> _onetimeMessages;

    int _currentMessageID { 0 };
    std::vector<int> _repeatCounts;
    std::vector<QString> _repeatedMessageStrings;
    static QMutex _mutex;
};

#endif // hifi_LogHandler_h