#ifndef TLOGGER_INCLUDED
#define TLOGGER_INCLUDED

#include <memory>

//
// TLogger
//
// usage example:
//
//    TFilePath fp;
//    TLogger::info() << "Loading " << fp << " ...";
//    TLogger::error() << "File " << fp << "not found";
//
// N.B.
//    TLogger::debug() << ....
//    is automatically removed in the release
//

#include "tcommon.h"

#undef DVAPI
#undef DVVAR
#ifdef TSYSTEM_EXPORTS
#define DVAPI DV_EXPORT_API
#define DVVAR DV_EXPORT_VAR
#else
#define DVAPI DV_IMPORT_API
#define DVVAR DV_IMPORT_VAR
#endif

class TFilePath;

class DVAPI TLogger
{ // singleton
	class Imp;
	std::unique_ptr<Imp> m_imp;

	TLogger();

public:
	~TLogger();

	static TLogger *instance();

	enum MessageType {
		Debug = 1,
		Info,
		Warning,
		Error
	};

	class DVAPI Message
	{
		MessageType m_type;
		std::string m_timestamp;
		std::string m_text;

	public:
		Message(MessageType type, std::string text);
		MessageType getType() const { return m_type; }
		std::string getTimestamp() const { return m_timestamp; }
		std::string getText() const { return m_text; }
	};

	class Listener
	{
	public:
		virtual void onLogChanged() = 0;
		virtual ~Listener() {}
	};

	void addMessage(const Message &msg);
	void clearMessages();
	int getMessageCount() const;
	Message getMessage(int index) const;

	void addListener(Listener *listener);
	void removeListener(Listener *listener);

	class DVAPI Stream
	{
		MessageType m_type;
		std::string m_text;

	public:
		Stream(MessageType type);
		~Stream();

		Stream &operator<<(std::string v);
		Stream &operator<<(int v);
		Stream &operator<<(double v);
		Stream &operator<<(const TFilePath &v);
	};

	class DVAPI NullStream
	{
	public:
		NullStream() {}
		~NullStream() {}

		NullStream &operator<<(std::string) { return *this; }
		NullStream &operator<<(int) { return *this; }
		NullStream &operator<<(double) { return *this; }
		NullStream &operator<<(const TFilePath &) { return *this; }
	};

#ifdef NDEBUG
	static NullStream debug()
	{
		return NullStream();
	}
#else
	static Stream debug()
	{
		return Stream(Debug);
	}
#endif
	static Stream info()
	{
		return Stream(Info);
	}
	static Stream warning() { return Stream(Warning); }
	static Stream error() { return Stream(Error); }
};

#endif