/*
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Open Asset Import Library (assimp)
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*/

/** @file  DefaultLogger.cpp
 *  @brief Implementation of DefaultLogger (and Logger)
 */

// Default log streams
#include "FileLogStream.h"
#include "StdOStreamLogStream.h"
#include "Win32DebugLogStream.h"
#include <assimp/StringUtils.h>

#include <assimp/DefaultIOSystem.h>
#include <assimp/ai_assert.h>
#include <stdio.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/NullLogger.hpp>
#include <iostream>

#ifndef ASSIMP_BUILD_SINGLETHREADED
#include <mutex>
#include <thread>
std::mutex loggerMutex;
#endif

namespace Assimp {

// ----------------------------------------------------------------------------------
NullLogger DefaultLogger::s_pNullLogger;
Logger *DefaultLogger::m_pLogger = &DefaultLogger::s_pNullLogger;

static const unsigned int SeverityAll = Logger::Info | Logger::Err | Logger::Warn | Logger::Debugging;

// ----------------------------------------------------------------------------------
// Represents a log-stream + its error severity
struct LogStreamInfo {
    unsigned int m_uiErrorSeverity;
    LogStream *m_pStream;

    // Constructor
    LogStreamInfo(unsigned int uiErrorSev, LogStream *pStream) :
            m_uiErrorSeverity(uiErrorSev),
            m_pStream(pStream) {
        // empty
    }

    // Destructor
    ~LogStreamInfo() {
        delete m_pStream;
    }
};

// ----------------------------------------------------------------------------------
// Construct a default log stream
LogStream *LogStream::createDefaultStream(aiDefaultLogStream streams,
        const char *name /*= "AssimpLog.txt"*/,
        IOSystem *io /*= nullptr*/) {
    switch (streams) {
        // This is a platform-specific feature
    case aiDefaultLogStream_DEBUGGER:
#ifdef WIN32
        return new Win32DebugLogStream();
#else
        return nullptr;
#endif

    // Platform-independent default streams
    case aiDefaultLogStream_STDERR:
        return new StdOStreamLogStream(std::cerr);
    case aiDefaultLogStream_STDOUT:
        return new StdOStreamLogStream(std::cout);
    case aiDefaultLogStream_FILE:
        return (name && *name ? new FileLogStream(name, io) : nullptr);
    default:
        // We don't know this default log stream, so raise an assertion
        ai_assert(false);
    };

    // For compilers without dead code path detection
    return nullptr;
}

// ----------------------------------------------------------------------------------
//  Creates the only singleton instance
Logger *DefaultLogger::create(const char *name /*= "AssimpLog.txt"*/,
        LogSeverity severity /*= NORMAL*/,
        unsigned int defStreams /*= aiDefaultLogStream_DEBUGGER | aiDefaultLogStream_FILE*/,
        IOSystem *io /*= nullptr*/) {
    // enter the mutex here to avoid concurrency problems
#ifndef ASSIMP_BUILD_SINGLETHREADED
    std::lock_guard<std::mutex> lock(loggerMutex);
#endif

    if (m_pLogger && !isNullLogger()) {
        delete m_pLogger;
    }

    m_pLogger = new DefaultLogger(severity);

    // Attach default log streams
    // Stream the log to the MSVC debugger?
    if (defStreams & aiDefaultLogStream_DEBUGGER) {
        m_pLogger->attachStream(LogStream::createDefaultStream(aiDefaultLogStream_DEBUGGER));
    }

    // Stream the log to COUT?
    if (defStreams & aiDefaultLogStream_STDOUT) {
        m_pLogger->attachStream(LogStream::createDefaultStream(aiDefaultLogStream_STDOUT));
    }

    // Stream the log to CERR?
    if (defStreams & aiDefaultLogStream_STDERR) {
        m_pLogger->attachStream(LogStream::createDefaultStream(aiDefaultLogStream_STDERR));
    }

    // Stream the log to a file
    if (defStreams & aiDefaultLogStream_FILE && name && *name) {
        m_pLogger->attachStream(LogStream::createDefaultStream(aiDefaultLogStream_FILE, name, io));
    }

    return m_pLogger;
}

// ----------------------------------------------------------------------------------
void Logger::debug(const char *message) {

    // SECURITY FIX: otherwise it's easy to produce overruns since
    // sometimes importers will include data from the input file
    // (i.e. node names) in their messages.
    if (strlen(message) > MAX_LOG_MESSAGE_LENGTH) {
        return OnDebug("<fixme: long message discarded>");
    }
    return OnDebug(message);
}

// ----------------------------------------------------------------------------------
void Logger::verboseDebug(const char *message) {

    // SECURITY FIX: see above
    if (strlen(message) > MAX_LOG_MESSAGE_LENGTH) {
        return OnVerboseDebug("<fixme: long message discarded>");
    }
    return OnVerboseDebug(message);
}

// ----------------------------------------------------------------------------------
void Logger::info(const char *message) {

    // SECURITY FIX: see above
    if (strlen(message) > MAX_LOG_MESSAGE_LENGTH) {
        return OnInfo("<fixme: long message discarded>");
    }
    return OnInfo(message);
}

// ----------------------------------------------------------------------------------
void Logger::warn(const char *message) {

    // SECURITY FIX: see above
    if (strlen(message) > MAX_LOG_MESSAGE_LENGTH) {
        return OnWarn("<fixme: long message discarded>");
    }
    return OnWarn(message);
}

// ----------------------------------------------------------------------------------
void Logger::error(const char *message) {
    // SECURITY FIX: see above
    if (strlen(message) > MAX_LOG_MESSAGE_LENGTH) {
        return OnError("<fixme: long message discarded>");
    }
    return OnError(message);
}

// ----------------------------------------------------------------------------------
void DefaultLogger::set(Logger *logger) {
    // enter the mutex here to avoid concurrency problems
#ifndef ASSIMP_BUILD_SINGLETHREADED
    std::lock_guard<std::mutex> lock(loggerMutex);
#endif

    if (nullptr == logger) {
        logger = &s_pNullLogger;
    }
    if (nullptr != m_pLogger && !isNullLogger()) {
        delete m_pLogger;
    }

    DefaultLogger::m_pLogger = logger;
}

// ----------------------------------------------------------------------------------
bool DefaultLogger::isNullLogger() {
    return m_pLogger == &s_pNullLogger;
}

// ----------------------------------------------------------------------------------
Logger *DefaultLogger::get() {
    return m_pLogger;
}

// ----------------------------------------------------------------------------------
//  Kills the only instance
void DefaultLogger::kill() {
    // enter the mutex here to avoid concurrency problems
#ifndef ASSIMP_BUILD_SINGLETHREADED
    std::lock_guard<std::mutex> lock(loggerMutex);
#endif

    if (m_pLogger == &s_pNullLogger) {
        return;
    }
    delete m_pLogger;
    m_pLogger = &s_pNullLogger;
}

// ----------------------------------------------------------------------------------
//  Debug message
void DefaultLogger::OnDebug(const char *message) {
    if (m_Severity < Logger::DEBUGGING) {
        return;
    }

    static const size_t Size = MAX_LOG_MESSAGE_LENGTH + 16;
    char msg[Size];
    ai_snprintf(msg, Size, "Debug, T%u: %s", GetThreadID(), message);

    WriteToStreams(msg, Logger::Debugging);
}

//  Verbose debug message
void DefaultLogger::OnVerboseDebug(const char *message) {
    if (m_Severity < Logger::VERBOSE) {
        return;
    }

    static const size_t Size = MAX_LOG_MESSAGE_LENGTH + 16;
    char msg[Size];
    ai_snprintf(msg, Size, "Debug, T%u: %s", GetThreadID(), message);

    WriteToStreams(msg, Logger::Debugging);
}

// ----------------------------------------------------------------------------------
//  Logs an info
void DefaultLogger::OnInfo(const char *message) {
    static const size_t Size = MAX_LOG_MESSAGE_LENGTH + 16;
    char msg[Size];
    ai_snprintf(msg, Size, "Info,  T%u: %s", GetThreadID(), message);

    WriteToStreams(msg, Logger::Info);
}

// ----------------------------------------------------------------------------------
//  Logs a warning
void DefaultLogger::OnWarn(const char *message) {
    static const size_t Size = MAX_LOG_MESSAGE_LENGTH + 16;
    char msg[Size];
    ai_snprintf(msg, Size, "Warn,  T%u: %s", GetThreadID(), message);

    WriteToStreams(msg, Logger::Warn);
}

// ----------------------------------------------------------------------------------
//  Logs an error
void DefaultLogger::OnError(const char *message) {
    static const size_t Size = MAX_LOG_MESSAGE_LENGTH + 16;
    char msg[Size];
    ai_snprintf(msg, Size, "Error, T%u: %s", GetThreadID(), message);

    WriteToStreams(msg, Logger::Err);
}

// ----------------------------------------------------------------------------------
//  Will attach a new stream
bool DefaultLogger::attachStream(LogStream *pStream, unsigned int severity) {
    if (nullptr == pStream) {
        return false;
    }

    if (0 == severity) {
        severity = Logger::Info | Logger::Err | Logger::Warn | Logger::Debugging;
    }

    for (StreamIt it = m_StreamArray.begin();
            it != m_StreamArray.end();
            ++it) {
        if ((*it)->m_pStream == pStream) {
            (*it)->m_uiErrorSeverity |= severity;
            return true;
        }
    }

    LogStreamInfo *pInfo = new LogStreamInfo(severity, pStream);
    m_StreamArray.push_back(pInfo);
    return true;
}

// ----------------------------------------------------------------------------------
//  Detach a stream
bool DefaultLogger::detachStream(LogStream *pStream, unsigned int severity) {
    if (nullptr == pStream) {
        return false;
    }

    if (0 == severity) {
        severity = SeverityAll;
    }

    bool res(false);
    for (StreamIt it = m_StreamArray.begin(); it != m_StreamArray.end(); ++it) {
        if ((*it)->m_pStream == pStream) {
            (*it)->m_uiErrorSeverity &= ~severity;
            if ((*it)->m_uiErrorSeverity == 0) {
                // don't delete the underlying stream 'cause the caller gains ownership again
                (**it).m_pStream = nullptr;
                delete *it;
                m_StreamArray.erase(it);
                res = true;
                break;
            }
            return true;
        }
    }
    return res;
}

// ----------------------------------------------------------------------------------
//  Constructor
DefaultLogger::DefaultLogger(LogSeverity severity) :
        Logger(severity), noRepeatMsg(false), lastLen(0) {
    lastMsg[0] = '\0';
}

// ----------------------------------------------------------------------------------
//  Destructor
DefaultLogger::~DefaultLogger() {
    for (StreamIt it = m_StreamArray.begin(); it != m_StreamArray.end(); ++it) {
        // also frees the underlying stream, we are its owner.
        delete *it;
    }
}

// ----------------------------------------------------------------------------------
//  Writes message to stream
void DefaultLogger::WriteToStreams(const char *message, ErrorSeverity ErrorSev) {
    ai_assert(nullptr != message);

    // Check whether this is a repeated message
    if (!::strncmp(message, lastMsg, lastLen - 1)) {
        if (!noRepeatMsg) {
            noRepeatMsg = true;
            message = "Skipping one or more lines with the same contents\n";
        } else
            return;
    } else {
        // append a new-line character to the message to be printed
        lastLen = ::strlen(message);
        ::memcpy(lastMsg, message, lastLen + 1);
        ::strcat(lastMsg + lastLen, "\n");

        message = lastMsg;
        noRepeatMsg = false;
        ++lastLen;
    }
    for (ConstStreamIt it = m_StreamArray.begin();
            it != m_StreamArray.end();
            ++it) {
        if (ErrorSev & (*it)->m_uiErrorSeverity)
            (*it)->m_pStream->write(message);
    }
}

// ----------------------------------------------------------------------------------
//  Returns thread id, if not supported only a zero will be returned.
unsigned int DefaultLogger::GetThreadID() {
    // fixme: we can get this value via std::threads
    // std::this_thread::get_id().hash() returns a (big) size_t, not sure if this is useful in this case.
#ifdef WIN32
    return (unsigned int)::GetCurrentThreadId();
#else
    return 0; // not supported
#endif
}

// ----------------------------------------------------------------------------------

} // namespace Assimp