/*

 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include "Log.h"

#include "SysInfo.h"

#include "FileUtils.h"

namespace {

    //

    // IMPORTANT: Static objects with non-trivial constructors are NOT allowed

    // in logger module. Allocate buffers only and do lazy initialization of

    // globals in Logger::getDefault().

    //

    // Logging subsystem is used almost in every module, and logging API can be

    // called from constructors of static objects in various modules. As

    // ordering of static objects initialization between modules is undefined,

    // this means some module may call logging api before logging static

    // variables are initialized if any. This will result in AV. To avoid such

    // use cases keep logging module free from static variables that require

    // initialization with functions called by CRT.

    //

    // by default log everything

    const Logger::LogLevel defaultLogLevel = Logger::LOG_TRACE;

    char defaultLogAppenderMemory[sizeof(StderrLogAppender)] = {};

    char defaultLoggerMemory[sizeof(Logger)] = {};

    NopLogAppender nopLogApender;

    LPCTSTR getLogLevelStr(Logger::LogLevel level) {

        switch (level) {

        case Logger::LOG_TRACE:

            return _T("TRACE");

        case Logger::LOG_INFO:

            return _T("INFO");

        case Logger::LOG_WARNING:

            return _T("WARNING");

        case Logger::LOG_ERROR:

            return _T("ERROR");

        }

        return _T("UNKNOWN");

    }

    tstring retrieveModuleName() {

        try {

            return FileUtils::basename(SysInfo::getCurrentModulePath());

        } catch (const std::exception&) {

            return _T("Unknown");

        }

    }

    TCHAR moduleName[MAX_PATH] = { 'U', 'n', 'k', 'o', 'w', 'n', TCHAR(0) };

    const LPCTSTR format = _T("[%04u/%02u/%02u %02u:%02u:%02u.%03u, %s (PID: %u, TID: %u), %s:%u (%s)]\n\t%s: %s\n");

    enum State { NotInitialized, Initializing, Initialized };

    State state = NotInitialized;

}

LogEvent::LogEvent() {

    memset(this, 0, sizeof(*this));

    moduleName = tstring();

    logLevel = tstring();

    fileName = tstring();

    funcName = tstring();

    message = tstring();

}

StderrLogAppender::StderrLogAppender() {

}

/*static*/

Logger& Logger::defaultLogger() {

    Logger* reply = reinterpret_cast<Logger*>(defaultLoggerMemory);

    if (!reply->appender) {

        // Memory leak by design. Not an issue at all as this is global

        // object. OS will do resources clean up anyways when application

        // terminates and the default log appender should live as long as

        // application lives.

        reply->appender = new (defaultLogAppenderMemory) StderrLogAppender();

    }

    if (Initializing == state) {

        // Recursive call to Logger::defaultLogger.

        moduleName[0] = TCHAR(0);

    } else if (NotInitialized == state) {

        state = Initializing;

        tstring mname = retrieveModuleName();

        mname.resize(_countof(moduleName) - 1);

        std::memcpy(moduleName, mname.c_str(), mname.size());

        moduleName[mname.size()] = TCHAR(0);

        // if JPACKAGE_DEBUG environment variable is NOT set to "true" disable

        // logging.

        if (SysInfo::getEnvVariable(std::nothrow,

                L"JPACKAGE_DEBUG") != L"true") {

            reply->appender = &nopLogApender;

        }

        state = Initialized;

    }

    return *reply;

}

Logger::Logger(LogAppender& appender, LogLevel logLevel)

        : level(logLevel), appender(&appender) {

}

void Logger::setLogLevel(LogLevel logLevel) {

    level = logLevel;

}

Logger::~Logger() {

}

bool Logger::isLoggable(LogLevel logLevel) const {

    return logLevel >= level;

}

void Logger::log(LogLevel logLevel, LPCTSTR fileName, int lineNum,

        LPCTSTR funcName, const tstring& message) const {

    LogEvent logEvent;

    // [YYYY/MM/DD HH:MM:SS.ms, <module> (PID: processID, TID: threadID),

    // fileName:lineNum (funcName)] <tab>LEVEL: message

    GetLocalTime(&logEvent.ts);

    logEvent.pid = GetCurrentProcessId();

    logEvent.tid = GetCurrentThreadId();

    logEvent.moduleName = moduleName;

    logEvent.fileName = FileUtils::basename(fileName);

    logEvent.funcName = funcName;

    logEvent.logLevel = getLogLevelStr(logLevel);

    logEvent.lineNum = lineNum;

    logEvent.message = message;

    appender->append(logEvent);

}

void StderrLogAppender::append(const LogEvent& v)

{

    const tstring out = tstrings::unsafe_format(format,

        unsigned(v.ts.wYear), unsigned(v.ts.wMonth), unsigned(v.ts.wDay),

        unsigned(v.ts.wHour), unsigned(v.ts.wMinute), unsigned(v.ts.wSecond),

                unsigned(v.ts.wMilliseconds),

        v.moduleName.c_str(), v.pid, v.tid,

        v.fileName.c_str(), v.lineNum, v.funcName.c_str(),

        v.logLevel.c_str(),

        v.message.c_str());

    std::cerr << tstrings::toUtf8(out);

}

// Logger::ScopeTracer

Logger::ScopeTracer::ScopeTracer(Logger &logger, LogLevel logLevel,

        LPCTSTR fileName, int lineNum, LPCTSTR funcName,

        const tstring& scopeName) : log(logger), level(logLevel),

        file(fileName), line(lineNum),

        func(funcName), scope(scopeName), needLog(logger.isLoggable(logLevel)) {

    if (needLog) {

        log.log(level, file.c_str(), line, func.c_str(),

                tstrings::any() << "Entering " << scope);

    }

}

Logger::ScopeTracer::~ScopeTracer() {

    if (needLog) {

        // we don't know what line is end of scope at, so specify line 0

        // and add note about line when the scope begins

        log.log(level, file.c_str(), 0, func.c_str(),

                tstrings::any() << "Exiting " << scope << " (entered at "

                << FileUtils::basename(file) << ":" << line << ")");

    }

}