
#include "uSynergy.h"
#include <stdio.h>
#include <string.h>



//---------------------------------------------------------------------------------------------------------------------
//	Internal helpers
//---------------------------------------------------------------------------------------------------------------------



/**
@brief Read 16 bit integer in network byte order and convert to native byte order
**/
static int16_t sNetToNative16(const unsigned char *value)
{
#ifdef USYNERGY_LITTLE_ENDIAN
	return value[1] | (value[0] << 8);
#else
	return value[0] | (value[1] << 8);
#endif
}



/**
@brief Read 32 bit integer in network byte order and convert to native byte order
**/
static int32_t sNetToNative32(const unsigned char *value)
{
#ifdef USYNERGY_LITTLE_ENDIAN
	return value[3] | (value[2] << 8) | (value[1] << 16) | (value[0] << 24);
#else
	return value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24);
#endif
}



/**
@brief Trace text to client
**/
static void sTrace(uSynergyContext *context, const char* text)
{
	// Don't trace if we don't have a trace function
	if (context->m_traceFunc != 0L)
		context->m_traceFunc(context->m_cookie, text);
}



/**
@brief Add string to reply packet
**/
static void sAddString(uSynergyContext *context, const char *string)
{
	size_t len = strlen(string);
	memcpy(context->m_replyCur, string, len);
	context->m_replyCur += len;
}



/**
@brief Add uint8 to reply packet
**/
static void sAddUInt8(uSynergyContext *context, uint8_t value)
{
	*context->m_replyCur++ = value;
}



/**
@brief Add uint16 to reply packet
**/
static void sAddUInt16(uSynergyContext *context, uint16_t value)
{
	uint8_t *reply = context->m_replyCur;
	*reply++ = (uint8_t)(value >> 8);
	*reply++ = (uint8_t)value;
	context->m_replyCur = reply;
}



/**
@brief Add uint32 to reply packet
**/
static void sAddUInt32(uSynergyContext *context, uint32_t value)
{
	uint8_t *reply = context->m_replyCur;
	*reply++ = (uint8_t)(value >> 24);
	*reply++ = (uint8_t)(value >> 16);
	*reply++ = (uint8_t)(value >> 8);
	*reply++ = (uint8_t)value;
	context->m_replyCur = reply;
}



/**
@brief Send reply packet
**/
static uSynergyBool sSendReply(uSynergyContext *context)
{
	// Set header size
	uint8_t		*reply_buf	= context->m_replyBuffer;
	uint32_t	reply_len	= (uint32_t)(context->m_replyCur - reply_buf);				/* Total size of reply */
	uint32_t	body_len	= reply_len - 4;											/* Size of body */
	uSynergyBool ret;
	reply_buf[0] = (uint8_t)(body_len >> 24);
	reply_buf[1] = (uint8_t)(body_len >> 16);
	reply_buf[2] = (uint8_t)(body_len >> 8);
	reply_buf[3] = (uint8_t)body_len;

	// Send reply
	ret = context->m_sendFunc(context->m_cookie, context->m_replyBuffer, reply_len);

	// Reset reply buffer write pointer
	context->m_replyCur = context->m_replyBuffer+4;
	return ret;
}



/**
@brief Call mouse callback after a mouse event
**/
static void sSendMouseCallback(uSynergyContext *context)
{
	// Skip if no callback is installed
	if (context->m_mouseCallback == 0L)
		return;

	// Send callback
	context->m_mouseCallback(context->m_cookie, context->m_mouseX, context->m_mouseY, context->m_mouseWheelX,
		context->m_mouseWheelY, context->m_mouseButtonLeft, context->m_mouseButtonRight, context->m_mouseButtonMiddle);
}



/**
@brief Send keyboard callback when a key has been pressed or released
**/
static void sSendKeyboardCallback(uSynergyContext *context, uint16_t key, uint16_t modifiers, uSynergyBool down, uSynergyBool repeat)
{
	// Skip if no callback is installed
	if (context->m_keyboardCallback == 0L)
		return;

	// Send callback
	context->m_keyboardCallback(context->m_cookie, key, modifiers, down, repeat);
}



/**
@brief Send joystick callback
**/
static void sSendJoystickCallback(uSynergyContext *context, uint8_t joyNum)
{
	int8_t *sticks;

	// Skip if no callback is installed
	if (context->m_joystickCallback == 0L)
		return;

	// Send callback
	sticks = context->m_joystickSticks[joyNum];
	context->m_joystickCallback(context->m_cookie, joyNum, context->m_joystickButtons[joyNum], sticks[0], sticks[1], sticks[2], sticks[3]);
}



/**
@brief Parse a single client message, update state, send callbacks and send replies
**/
#define USYNERGY_IS_PACKET(pkt_id)	memcmp(message+4, pkt_id, 4)==0
static void sProcessMessage(uSynergyContext *context, const uint8_t *message)
{
	// We have a packet!
	if (memcmp(message+4, "Synergy", 7)==0)
	{
		// Welcome message
		//		kMsgHello			= "Synergy%2i%2i"
		//		kMsgHelloBack		= "Synergy%2i%2i%s"
		sAddString(context, "Synergy");
		sAddUInt16(context, USYNERGY_PROTOCOL_MAJOR);
		sAddUInt16(context, USYNERGY_PROTOCOL_MINOR);
		sAddUInt32(context, (uint32_t)strlen(context->m_clientName));
		sAddString(context, context->m_clientName);
		if (!sSendReply(context))
		{
			// Send reply failed, let's try to reconnect
			sTrace(context, "SendReply failed, trying to reconnect in a second");
			context->m_connected = USYNERGY_FALSE;
			context->m_sleepFunc(context->m_cookie, 1000);
		}
		else
		{
			// Let's assume we're connected
			char buffer[256+1];
			sprintf(buffer, "Connected as client \"%s\"", context->m_clientName);
			sTrace(context, buffer);
			context->m_hasReceivedHello = USYNERGY_TRUE;
		}
		return;
	}
	else if (USYNERGY_IS_PACKET("QINF"))
	{
		// Screen info. Reply with DINF
		//		kMsgQInfo			= "QINF"
		//		kMsgDInfo			= "DINF%2i%2i%2i%2i%2i%2i%2i"
		uint16_t x = 0, y = 0, warp = 0;
		sAddString(context, "DINF");
		sAddUInt16(context, x);
		sAddUInt16(context, y);
		sAddUInt16(context, context->m_clientWidth);
		sAddUInt16(context, context->m_clientHeight);
		sAddUInt16(context, warp);
		sAddUInt16(context, 0);		// mx?
		sAddUInt16(context, 0);		// my?
		sSendReply(context);
		return;
	}
	else if (USYNERGY_IS_PACKET("CIAK"))
	{
		// Do nothing?
		//		kMsgCInfoAck		= "CIAK"
		return;
	}
	else if (USYNERGY_IS_PACKET("CROP"))
	{
		// Do nothing?
		//		kMsgCResetOptions	= "CROP"
		return;
	}
	else if (USYNERGY_IS_PACKET("CINN"))
	{
		// Screen enter. Reply with CNOP
		//		kMsgCEnter 			= "CINN%2i%2i%4i%2i"

		// Obtain the Synergy sequence number
		context->m_sequenceNumber = sNetToNative32(message + 12);
		context->m_isCaptured = USYNERGY_TRUE;

		// Call callback
		if (context->m_screenActiveCallback != 0L)
			context->m_screenActiveCallback(context->m_cookie, USYNERGY_TRUE);
	}
	else if (USYNERGY_IS_PACKET("COUT"))
	{
		// Screen leave
		//		kMsgCLeave 			= "COUT"
		context->m_isCaptured = USYNERGY_FALSE;

		// Call callback
		if (context->m_screenActiveCallback != 0L)
			context->m_screenActiveCallback(context->m_cookie, USYNERGY_FALSE);
	}
	else if (USYNERGY_IS_PACKET("DMDN"))
	{
		// Mouse down
		//		kMsgDMouseDown		= "DMDN%1i"
		char btn = message[8]-1;
		if (btn==2)
			context->m_mouseButtonRight		= USYNERGY_TRUE;
		else if (btn==1)
			context->m_mouseButtonMiddle	= USYNERGY_TRUE;
		else
			context->m_mouseButtonLeft		= USYNERGY_TRUE;
		sSendMouseCallback(context);
	}
	else if (USYNERGY_IS_PACKET("DMUP"))
	{
		// Mouse up
		//		kMsgDMouseUp		= "DMUP%1i"
		char btn = message[8]-1;
		if (btn==2)
			context->m_mouseButtonRight		= USYNERGY_FALSE;
		else if (btn==1)
			context->m_mouseButtonMiddle	= USYNERGY_FALSE;
		else
			context->m_mouseButtonLeft		= USYNERGY_FALSE;
		sSendMouseCallback(context);
	}
	else if (USYNERGY_IS_PACKET("DMMV"))
	{
		// Mouse move. Reply with CNOP
		//		kMsgDMouseMove		= "DMMV%2i%2i"
		context->m_mouseX = sNetToNative16(message+8);
		context->m_mouseY = sNetToNative16(message+10);
		sSendMouseCallback(context);
	}
	else if (USYNERGY_IS_PACKET("DMWM"))
	{
		// Mouse wheel
		//		kMsgDMouseWheel		= "DMWM%2i%2i"
		//		kMsgDMouseWheel1_0	= "DMWM%2i"
		context->m_mouseWheelX += sNetToNative16(message+8);
		context->m_mouseWheelY += sNetToNative16(message+10);
		sSendMouseCallback(context);
	}
	else if (USYNERGY_IS_PACKET("DKDN"))
	{
		// Key down
		//		kMsgDKeyDown		= "DKDN%2i%2i%2i"
		//		kMsgDKeyDown1_0		= "DKDN%2i%2i"
		//uint16_t id = sNetToNative16(message+8);
		uint16_t mod = sNetToNative16(message+10);
		uint16_t key = sNetToNative16(message+12);
		sSendKeyboardCallback(context, key, mod, USYNERGY_TRUE, USYNERGY_FALSE);
	}
	else if (USYNERGY_IS_PACKET("DKRP"))
	{
		// Key repeat
		//		kMsgDKeyRepeat		= "DKRP%2i%2i%2i%2i"
		//		kMsgDKeyRepeat1_0	= "DKRP%2i%2i%2i"
		uint16_t mod = sNetToNative16(message+10);
//		uint16_t count = sNetToNative16(message+12);
		uint16_t key = sNetToNative16(message+14);
		sSendKeyboardCallback(context, key, mod, USYNERGY_TRUE, USYNERGY_TRUE);
	}
	else if (USYNERGY_IS_PACKET("DKUP"))
	{
		// Key up
		//		kMsgDKeyUp			= "DKUP%2i%2i%2i"
		//		kMsgDKeyUp1_0		= "DKUP%2i%2i"
		//uint16 id=Endian::sNetToNative(sbuf[4]);
		uint16_t mod = sNetToNative16(message+10);
		uint16_t key = sNetToNative16(message+12);
		sSendKeyboardCallback(context, key, mod, USYNERGY_FALSE, USYNERGY_FALSE);
	}
	else if (USYNERGY_IS_PACKET("DGBT"))
	{
		// Joystick buttons
		//		kMsgDGameButtons	= "DGBT%1i%2i";
		uint8_t	joy_num = message[8];
		if (joy_num<USYNERGY_NUM_JOYSTICKS)
		{
			// Copy button state, then send callback
			context->m_joystickButtons[joy_num] = (message[9] << 8) | message[10];
			sSendJoystickCallback(context, joy_num);
		}
	}
	else if (USYNERGY_IS_PACKET("DGST"))
	{
		// Joystick sticks
		//		kMsgDGameSticks		= "DGST%1i%1i%1i%1i%1i";
		uint8_t	joy_num = message[8];
		if (joy_num<USYNERGY_NUM_JOYSTICKS)
		{
			// Copy stick state, then send callback
			memcpy(context->m_joystickSticks[joy_num], message+9, 4);
			sSendJoystickCallback(context, joy_num);
		}
	}
	else if (USYNERGY_IS_PACKET("DSOP"))
	{
		// Set options
		//		kMsgDSetOptions		= "DSOP%4I"
	}
	else if (USYNERGY_IS_PACKET("CALV"))
	{
		// Keepalive, reply with CALV and then CNOP
		//		kMsgCKeepAlive		= "CALV"
		sAddString(context, "CALV");
		sSendReply(context);
		// now reply with CNOP
	}
	else if (USYNERGY_IS_PACKET("DCLP"))
	{
		// Clipboard message
		//		kMsgDClipboard		= "DCLP%1i%4i%s"
		//
		// The clipboard message contains:
		//		1 uint32:	The size of the message
		//		4 chars: 	The identifier ("DCLP")
		//		1 uint8: 	The clipboard index
		//		1 uint32:	The sequence number. It's zero, because this message is always coming from the server?
		//		1 uint32:	The total size of the remaining 'string' (as per the Synergy %s string format (which is 1 uint32 for size followed by a char buffer (not necessarily null terminated)).
		//		1 uint32:	The number of formats present in the message
		// And then 'number of formats' times the following:
		//		1 uint32:	The format of the clipboard data
		//		1 uint32:	The size n of the clipboard data
		//		n uint8:	The clipboard data
		const uint8_t *	parse_msg	= message+17;
		uint32_t		num_formats = sNetToNative32(parse_msg);
		parse_msg += 4;
		for (; num_formats; num_formats--)
		{
			// Parse clipboard format header
			uint32_t format	= sNetToNative32(parse_msg);
			uint32_t size	= sNetToNative32(parse_msg+4);
			parse_msg += 8;
			
			// Call callback
			if (context->m_clipboardCallback)
				context->m_clipboardCallback(context->m_cookie, format, parse_msg, size);

			parse_msg += size;
		}
	}
	else
	{
		// Unknown packet, could be any of these
		//		kMsgCNoop 			= "CNOP"
		//		kMsgCClose 			= "CBYE"
		//		kMsgCClipboard 		= "CCLP%1i%4i"
		//		kMsgCScreenSaver 	= "CSEC%1i"
		//		kMsgDKeyRepeat		= "DKRP%2i%2i%2i%2i"
		//		kMsgDKeyRepeat1_0	= "DKRP%2i%2i%2i"
		//		kMsgDMouseRelMove	= "DMRM%2i%2i"
		//		kMsgEIncompatible	= "EICV%2i%2i"
		//		kMsgEBusy 			= "EBSY"
		//		kMsgEUnknown		= "EUNK"
		//		kMsgEBad			= "EBAD"
		char buffer[64];
		sprintf(buffer, "Unknown packet '%c%c%c%c'", message[4], message[5], message[6], message[7]);
		sTrace(context, buffer);
		return;
	}

	// Reply with CNOP maybe?
	sAddString(context, "CNOP");
	sSendReply(context);
}
#undef USYNERGY_IS_PACKET



/**
@brief Mark context as being disconnected
**/
static void sSetDisconnected(uSynergyContext *context)
{
	context->m_connected		= USYNERGY_FALSE;
	context->m_hasReceivedHello = USYNERGY_FALSE;
	context->m_isCaptured		= USYNERGY_FALSE;
	context->m_replyCur			= context->m_replyBuffer + 4;
	context->m_sequenceNumber	= 0;
}



/**
@brief Update a connected context
**/
static void sUpdateContext(uSynergyContext *context)
{
	/* Receive data (blocking) */
	int receive_size = USYNERGY_RECEIVE_BUFFER_SIZE - context->m_receiveOfs;
	int num_received = 0;
	int packlen = 0;
	if (context->m_receiveFunc(context->m_cookie, context->m_receiveBuffer + context->m_receiveOfs, receive_size, &num_received) == USYNERGY_FALSE)
	{
		/* Receive failed, let's try to reconnect */
		char buffer[128];
		sprintf(buffer, "Receive failed (%d bytes asked, %d bytes received), trying to reconnect in a second", receive_size, num_received);
		sTrace(context, buffer);
		sSetDisconnected(context);
		context->m_sleepFunc(context->m_cookie, 1000);
		return;
	}
	context->m_receiveOfs += num_received;

	/*	If we didn't receive any data then we're probably still polling to get connected and
		therefore not getting any data back. To avoid overloading the system with a Synergy
		thread that would hammer on polling, we let it rest for a bit if there's no data. */
	if (num_received == 0)
		context->m_sleepFunc(context->m_cookie, 500);

	/* Check for timeouts */
	if (context->m_hasReceivedHello)
	{
		uint32_t cur_time = context->m_getTimeFunc();
		if (num_received == 0)
		{
			/* Timeout after 2 secs of inactivity (we received no CALV) */
			if ((cur_time - context->m_lastMessageTime) > USYNERGY_IDLE_TIMEOUT)
				sSetDisconnected(context);
		}
		else
			context->m_lastMessageTime = cur_time;
	}

	/* Eat packets */
	for (;;)
	{
		/* Grab packet length and bail out if the packet goes beyond the end of the buffer */
		packlen = sNetToNative32(context->m_receiveBuffer);
		if (packlen+4 > context->m_receiveOfs)
			break;

		/* Process message */
		sProcessMessage(context, context->m_receiveBuffer);

		/* Move packet to front of buffer */
		memmove(context->m_receiveBuffer, context->m_receiveBuffer+packlen+4, context->m_receiveOfs-packlen-4);
		context->m_receiveOfs -= packlen+4;
	}

	/* Throw away over-sized packets */
	if (packlen > USYNERGY_RECEIVE_BUFFER_SIZE)
	{
		/* Oversized packet, ditch tail end */
		char buffer[128];
		sprintf(buffer, "Oversized packet: '%c%c%c%c' (length %d)", context->m_receiveBuffer[4], context->m_receiveBuffer[5], context->m_receiveBuffer[6], context->m_receiveBuffer[7], packlen);
		sTrace(context, buffer);
		num_received = context->m_receiveOfs-4; // 4 bytes for the size field
		while (num_received != packlen)
		{
			int buffer_left = packlen - num_received;
			int to_receive = buffer_left < USYNERGY_RECEIVE_BUFFER_SIZE ? buffer_left : USYNERGY_RECEIVE_BUFFER_SIZE;
			int ditch_received = 0;
			if (context->m_receiveFunc(context->m_cookie, context->m_receiveBuffer, to_receive, &ditch_received) == USYNERGY_FALSE)
			{
				/* Receive failed, let's try to reconnect */
				sTrace(context, "Receive failed, trying to reconnect in a second");
				sSetDisconnected(context);
				context->m_sleepFunc(context->m_cookie, 1000);
				break;
			}
			else
			{
				num_received += ditch_received;
			}
		}
		context->m_receiveOfs = 0;
	}
}


//---------------------------------------------------------------------------------------------------------------------
//	Public interface
//---------------------------------------------------------------------------------------------------------------------



/**
@brief Initialize uSynergy context
**/
void uSynergyInit(uSynergyContext *context)
{
	/* Zero memory */
	memset(context, 0, sizeof(uSynergyContext));

	/* Initialize to default state */
	sSetDisconnected(context);
}


/**
@brief Update uSynergy
**/
void uSynergyUpdate(uSynergyContext *context)
{
	if (context->m_connected)
	{
		/* Update context, receive data, call callbacks */
		sUpdateContext(context);
	}
	else
	{
		/* Try to connect */
		if (context->m_connectFunc(context->m_cookie))
			context->m_connected = USYNERGY_TRUE;
	}
}



/**
@brief Send clipboard data
**/
void uSynergySendClipboard(uSynergyContext *context, const char *text)
{
	// Calculate maximum size that will fit in a reply packet
	uint32_t overhead_size =	4 +					/* Message size */
								4 +					/* Message ID */
								1 +					/* Clipboard index */
								4 +					/* Sequence number */
								4 +					/* Rest of message size (because it's a Synergy string from here on) */
								4 +					/* Number of clipboard formats */
								4 +					/* Clipboard format */
								4;					/* Clipboard data length */
	uint32_t max_length = USYNERGY_REPLY_BUFFER_SIZE - overhead_size;
	
	// Clip text to max length
	uint32_t text_length = (uint32_t)strlen(text);
	if (text_length > max_length)
	{
		char buffer[128];
		sprintf(buffer, "Clipboard buffer too small, clipboard truncated at %d characters", max_length);
		sTrace(context, buffer);
		text_length = max_length;
	}

	// Assemble packet
	sAddString(context, "DCLP");
	sAddUInt8(context, 0);							/* Clipboard index */
	sAddUInt32(context, context->m_sequenceNumber);
	sAddUInt32(context, 4+4+4+text_length);			/* Rest of message size: numFormats, format, length, data */
	sAddUInt32(context, 1);							/* Number of formats (only text for now) */
	sAddUInt32(context, USYNERGY_CLIPBOARD_FORMAT_TEXT);
	sAddUInt32(context, text_length);
	sAddString(context, text);
	sSendReply(context);
}
