/*
 *   Copyright (c) 2021 by Geoffrey Merck F4FXL / KC3FRA
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#pragma once

#include <ctime>
#include <string>
#include <vector>
#include <boost/algorithm/string.hpp>
#include <mutex>
#include <cassert>

#include "StringUtils.h"
#include "LogTarget.h"

class CLog
{
private:
    static std::vector<CLogTarget *> m_targets;
    static bool m_addedTargets;
    static std::recursive_mutex m_targetsMutex;
    static std::string m_prevMsg;
    static uint m_prevMsgCount;
    static uint m_repeatThreshold;

    static void getTimeStamp(std::string &s);

    template <typename... Args>
    static void formatLogMessage(std::string &output, LOG_SEVERITY severity, const std::string &f, Args... args)
    {
        assert(severity != LOG_NONE);

        std::string severityStr("       ");
        switch (severity)
        {
        case LOG_DEBUG:
            severityStr.assign("DEBUG  ");
            break;
        case LOG_ERROR:
            severityStr.assign("ERROR  ");
            break;
        case LOG_FATAL:
            severityStr.assign("FATAL  ");
            break;
        case LOG_INFO:
            severityStr.assign("INFO   ");
            break;
        case LOG_WARNING:
            severityStr.assign("WARNING");
            break;
        case LOG_TRACE:
            severityStr.assign("TRACE  ");
            break;
        default:
            break;
        }

        std::string f2("[%s] ");
        f2.append(f);
        CStringUtils::string_format_in_place(output, f2, severityStr.c_str(), args...);
        boost::trim_if(output, [](char c)
                       { return c == '\n' || c == '\r' || c == ' ' || c == '\t'; });
        output.push_back('\n');
    }

public:
    static void addTarget(CLogTarget *target);
    static void finalise();
    static uint &getRepeatThreshold();

    template <typename... Args>
    static void logTrace(const std::string &f, Args... args)
    {
        log(LOG_TRACE, f, args...);
    }

    template <typename... Args>
    static void logDebug(const std::string &f, Args... args)
    {
        log(LOG_DEBUG, f, args...);
    }

    template <typename... Args>
    static void logInfo(const std::string &f, Args... args)
    {
        log(LOG_INFO, f, args...);
    }

    template <typename... Args>
    static void logWarning(const std::string &f, Args... args)
    {
        log(LOG_WARNING, f, args...);
    }

    template <typename... Args>
    static void logError(const std::string &f, Args... args)
    {
        log(LOG_ERROR, f, args...);
    }

    template <typename... Args>
    static void logFatal(const std::string &f, Args... args)
    {
        log(LOG_FATAL, f, args...);
    }

    template <typename... Args>
    static void log(LOG_SEVERITY severity, const std::string &f, Args... args)
    {
        // Protect against concurrent access to log targets
        std::lock_guard lockTarget(m_targetsMutex);

        if (m_targets.empty())
            return;

        // Format the message with the given arguments
        std::string msg;
        formatLogMessage(msg, severity, f, args...);

        bool repeatedMsg = (msg == m_prevMsg);

        // Handle repeated messages
        if (repeatedMsg && m_repeatThreshold > 0U) {
            m_prevMsgCount++;
            if (m_prevMsgCount >= m_repeatThreshold)
            {
                // If threshold reached, skip logging this duplicate
                return;
            }
        }

        // If we are leaving a repetition sequence, log a summary first
        if (!repeatedMsg && m_repeatThreshold > 0U && m_prevMsgCount >= m_repeatThreshold) {
            std::string summary;
            formatLogMessage(summary, severity,
                             "Previous message repeated %d times",
                             m_prevMsgCount - m_repeatThreshold + 1);

            std::string ts;
            getTimeStamp(ts);

            std::string summaryLine;
            CStringUtils::string_format_in_place(summaryLine, "[%s] %s", ts.c_str(), summary.c_str());

            for (auto target : m_targets)
            {
                if (severity >= target->getLevel())
                    target->printLog(summaryLine);
            }

            // Reset repetition counter after summary
            m_prevMsgCount = 0;
        }

        // Always log the current message
        std::string ts;
        getTimeStamp(ts);

        std::string msgLine;
        CStringUtils::string_format_in_place(msgLine, "[%s] %s", ts.c_str(), msg.c_str());

        for (auto target : m_targets) {
            if (severity >= target->getLevel())
                target->printLog(msgLine);
        }

        // Save current message for repetition detection
        m_prevMsg = msg;
    }
};