/*
Open Asset Import Library (assimp)
----------------------------------------------------------------------

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* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
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* Neither the name of the assimp team, nor the names of its
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/

/** @file Logger.hpp
 *  @brief Abstract base class 'Logger', base of the logging system.
 */
#ifndef INCLUDED_AI_LOGGER_H
#define INCLUDED_AI_LOGGER_H

#include <assimp/types.h>
#include <assimp/TinyFormatter.h>

namespace Assimp {

class LogStream;

// Maximum length of a log message. Longer messages are rejected.
#define MAX_LOG_MESSAGE_LENGTH 1024u

// ----------------------------------------------------------------------------------
/** @brief CPP-API: Abstract interface for logger implementations.
 *  Assimp provides a default implementation and uses it for almost all
 *  logging stuff ('DefaultLogger'). This class defines just basic logging
 *  behavior and is not of interest for you. Instead, take a look at #DefaultLogger. */
class ASSIMP_API Logger
#ifndef SWIG
    : public Intern::AllocateFromAssimpHeap
#endif
{
public:

    // ----------------------------------------------------------------------
    /** @enum   LogSeverity
     *  @brief  Log severity to describe the granularity of logging.
     */
    enum LogSeverity {
        NORMAL,     ///< Normal granularity of logging
        DEBUGGING,  ///< Debug messages will be logged, but not verbose debug messages.
        VERBOSE     ///< All messages will be logged
    };

    // ----------------------------------------------------------------------
    /** @enum   ErrorSeverity
     *  @brief  Description for severity of a log message.
     *
     *  Every LogStream has a bitwise combination of these flags.
     *  A LogStream doesn't receive any messages of a specific type
     *  if it doesn't specify the corresponding ErrorSeverity flag.
     */
    enum ErrorSeverity {
        Debugging   = 1,    //!< Debug log message
        Info        = 2,    //!< Info log message
        Warn        = 4,    //!< Warn log message
        Err         = 8     //!< Error log message
    };

public:

    /** @brief  Virtual destructor */
    virtual ~Logger();

    // ----------------------------------------------------------------------
    /** @brief  Writes a info message
     *  @param  message Info message*/
    void debug(const char* message);

    template<typename... T>
    void debug(T&&... args) {
        debug(formatMessage(std::forward<T>(args)...).c_str());
    }

    // ----------------------------------------------------------------------
	/** @brief  Writes a debug message
     *   @param message Debug message*/
    void verboseDebug(const char* message);
    
    template<typename... T>
    void verboseDebug(T&&... args) {
        verboseDebug(formatMessage(std::forward<T>(args)...).c_str());
    }

    // ----------------------------------------------------------------------
    /** @brief  Writes a info message
     *  @param  message Info message*/
    void info(const char* message);

    template<typename... T>
    void info(T&&... args) {
        info(formatMessage(std::forward<T>(args)...).c_str());
    }

    // ----------------------------------------------------------------------
    /** @brief  Writes a warning message
     *  @param  message Warn message*/
    void warn(const char* message);

    template<typename... T>
    void warn(T&&... args) {
        warn(formatMessage(std::forward<T>(args)...).c_str());
    }

    // ----------------------------------------------------------------------
    /** @brief  Writes an error message
     *  @param  message Info message*/
    void error(const char* message);

    template<typename... T>
    void error(T&&... args) {
        error(formatMessage(std::forward<T>(args)...).c_str());
    }

    // ----------------------------------------------------------------------
    /** @brief  Set a new log severity.
     *  @param  log_severity New severity for logging*/
    void setLogSeverity(LogSeverity log_severity);

    // ----------------------------------------------------------------------
    /** @brief Get the current log severity*/
    LogSeverity getLogSeverity() const;

    // ----------------------------------------------------------------------
    /** @brief  Attach a new log-stream
     *
     *  The logger takes ownership of the stream and is responsible
     *  for its destruction (which is done using ::delete when the logger
     *  itself is destroyed). Call detachStream to detach a stream and to
     *  gain ownership of it again.
     *   @param pStream  Log-stream to attach
     *  @param severity  Message filter, specified which types of log
     *    messages are dispatched to the stream. Provide a bitwise
     *    combination of the ErrorSeverity flags.
     *  @return true if the stream has been attached, false otherwise.*/
    virtual bool attachStream(LogStream *pStream,
        unsigned int severity = Debugging | Err | Warn | Info) = 0;

    // ----------------------------------------------------------------------
    /** @brief  Detach a still attached stream from the logger (or
     *          modify the filter flags bits)
     *   @param pStream Log-stream instance for detaching
     *  @param severity Provide a bitwise combination of the ErrorSeverity
     *    flags. This value is &~ed with the current flags of the stream,
     *    if the result is 0 the stream is detached from the Logger and
     *    the caller retakes the possession of the stream.
     *  @return true if the stream has been detached, false otherwise.*/
    virtual bool detachStream(LogStream *pStream,
        unsigned int severity = Debugging | Err | Warn | Info) = 0;

protected:
    /**
     *  Default constructor
     */
    Logger() AI_NO_EXCEPT;

    /**
     *  Construction with a given log severity
     */
    explicit Logger(LogSeverity severity);

    // ----------------------------------------------------------------------
    /**
     *  @brief Called as a request to write a specific debug message
     *  @param  message Debug message. Never longer than
     *    MAX_LOG_MESSAGE_LENGTH characters (excluding the '0').
     *  @note  The message string is only valid until the scope of
     *    the function is left.
     */
    virtual void OnDebug(const char* message)= 0;

    // ----------------------------------------------------------------------
	/**
     *  @brief Called as a request to write a specific verbose debug message
     *  @param  message Debug message. Never longer than
     *    MAX_LOG_MESSAGE_LENGTH characters (excluding the '0').
     *  @note  The message string is only valid until the scope of
     *    the function is left.
     */
	virtual void OnVerboseDebug(const char *message) = 0;

    // ----------------------------------------------------------------------
    /**
     *  @brief Called as a request to write a specific info message
     *  @param  message Info message. Never longer than
     *    MAX_LOG_MESSAGE_LENGTH characters (ecxluding the '0').
     *  @note  The message string is only valid until the scope of
     *    the function is left.
     */
    virtual void OnInfo(const char* message) = 0;

    // ----------------------------------------------------------------------
    /**
     *  @brief Called as a request to write a specific warn message
     *  @param  message Warn message. Never longer than
     *    MAX_LOG_MESSAGE_LENGTH characters (exluding the '0').
     *  @note  The message string is only valid until the scope of
     *    the function is left.
     */
    virtual void OnWarn(const char* essage) = 0;

    // ----------------------------------------------------------------------
    /**
     *  @brief Called as a request to write a specific error message
     *  @param  message Error message. Never longer than
     *    MAX_LOG_MESSAGE_LENGTH characters (exluding the '0').
     *  @note  The message string is only valid until the scope of
     *    the function is left.
     */
    virtual void OnError(const char* message) = 0;
protected:
    std::string formatMessage(Assimp::Formatter::format f) {
        return f;
    }

    template<typename... T, typename U>
    std::string formatMessage(Assimp::Formatter::format f, U&& u, T&&... args) {
        return formatMessage(std::move(f << std::forward<U>(u)), std::forward<T>(args)...);
    }

protected:
    LogSeverity m_Severity;
};

// ----------------------------------------------------------------------------------
//  Default constructor
inline
Logger::Logger() AI_NO_EXCEPT
: m_Severity(NORMAL) {
    // empty
}

// ----------------------------------------------------------------------------------
//  Virtual destructor
inline
Logger::~Logger() {
    // empty
}

// ----------------------------------------------------------------------------------
// Construction with given logging severity
inline
Logger::Logger(LogSeverity severity)
: m_Severity(severity) {
    // empty
}

// ----------------------------------------------------------------------------------
// Log severity setter
inline
void Logger::setLogSeverity(LogSeverity log_severity){
    m_Severity = log_severity;
}

// ----------------------------------------------------------------------------------
// Log severity getter
inline
Logger::LogSeverity Logger::getLogSeverity() const {
    return m_Severity;
}

} // Namespace Assimp

// ------------------------------------------------------------------------------------------------
#define ASSIMP_LOG_WARN(...) \
	Assimp::DefaultLogger::get()->warn(__VA_ARGS__)

#define ASSIMP_LOG_ERROR(...) \
	Assimp::DefaultLogger::get()->error(__VA_ARGS__)

#define ASSIMP_LOG_DEBUG(...) \
	Assimp::DefaultLogger::get()->debug(__VA_ARGS__)

#define ASSIMP_LOG_VERBOSE_DEBUG(...) \
	Assimp::DefaultLogger::get()->verboseDebug(__VA_ARGS__)

#define ASSIMP_LOG_INFO(...) \
	Assimp::DefaultLogger::get()->info(__VA_ARGS__)

#endif // !! INCLUDED_AI_LOGGER_H
