// The MIT License (MIT)
//
// Copyright (c) Itay Grudev 2015 - 2018
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#ifndef SINGLE_APPLICATION_H
#define SINGLE_APPLICATION_H

#include <QtCore/QtGlobal>
#include <QtNetwork/QLocalSocket>
#include <QElapsedTimer>

#ifndef QAPPLICATION_CLASS
  #define QAPPLICATION_CLASS QCoreApplication
#endif

#include QT_STRINGIFY(QAPPLICATION_CLASS)

class SingleApplicationPrivate;

/**
	@brief The SingleApplication class handles multiple instances of the same
	Application
	@see QCoreApplication
*/
class SingleApplication : public QAPPLICATION_CLASS
{
	Q_OBJECT
	
	typedef QAPPLICATION_CLASS app_t;
	
	public:
	/**
		@brief Mode of operation of SingleApplication.
		Whether the block should be user-wide or system-wide and whether the
		primary instance should be notified when a secondary instance had been
		started.
		@note Operating system can restrict the shared memory blocks to the same
		user, in which case the User/System modes will have no effect and the
		block will be user wide.
		@enum
	*/
	enum Mode {
		User                    = 1 << 0,
		System                  = 1 << 1,
		SecondaryNotification   = 1 << 2,
		ExcludeAppVersion       = 1 << 3,
		ExcludeAppPath          = 1 << 4
	};
	Q_DECLARE_FLAGS(Options, Mode)
	
	/**
		@brief Intitializes a SingleApplication instance with argc command line
		arguments in argv
		@arg {int &} argc - Number of arguments in argv
		@arg {const char *[]} argv - Supplied command line arguments
		@arg {bool} allowSecondary - Whether to start the instance as secondary
		if there is already a primary instance.
		@arg {Mode} mode - Whether for the SingleApplication block to be applied
		User wide or System wide.
		@arg {int} timeout - Timeout to wait in milliseconds.
		@note argc and argv may be changed as Qt removes arguments that it
		recognizes
		@note Mode::SecondaryNotification only works if set on both the primary
		instance and the secondary instance.
		@note The timeout is just a hint for the maximum time of blocking
		operations. It does not guarantee that the SingleApplication
		initialisation will be completed in given time, though is a good hint.
		Usually 4*timeout would be the worst case (fail) scenario.
		@see See the corresponding QAPPLICATION_CLASS constructor for reference
	*/
	explicit SingleApplication( int &argc, char *argv[], bool allowSecondary = false, Options options = Mode::User, int timeout = 1000 );
	~SingleApplication();
	
	/**
		@brief Returns if the instance is the primary instance
		@returns {bool}
	*/
	bool isPrimary();
	
	/**
		@brief Returns if the instance is a secondary instance
		@returns {bool}
	*/
	bool isSecondary();
	
	/**
		@brief Returns a unique identifier for the current instance
		@returns {qint32}
	*/
	quint32 instanceId();
	
	/**
		@brief Returns the process ID (PID) of the primary instance
		@returns {qint64}
	*/
	qint64 primaryPid();
	
	/**
		@brief Sends a message to the primary instance. Returns true on success.
		@param {int} timeout - Timeout for connecting
		@returns {bool}
		@note sendMessage() will return false if invoked from the primary
		instance.
	*/
	bool sendMessage( QByteArray message, int timeout = 100 );
	
	Q_SIGNALS:
	void instanceStarted();
	void receivedMessage( quint32 instanceId, QByteArray message );
	
	private:
	SingleApplicationPrivate *d_ptr;
	Q_DECLARE_PRIVATE(SingleApplication)
};

Q_DECLARE_OPERATORS_FOR_FLAGS(SingleApplication::Options)

#endif // SINGLE_APPLICATION_H
