/****************************************************************************
 Module
   DOG_RX pseudo code

 Description
   This is the receiver service for the DOG which receives messages from the farmer
/*----------------------------- Module Defines ----------------------------*/

these times assume a 1.000mS/tick timing:
#define ONE_SEC 1000
#define HALF_SEC (ONE_SEC/2)
#define TWO_SEC (ONE_SEC*2)
#define FIVE_SEC (ONE_SEC*5)
#define LARGEST_FRAME_DATA 50

packet byte definition:
#define CHECKSUM_OFFSET			0xFF
#define	START_BYTE 0x7E
#define API_TX_ID 0x01
#define OPTION_BYTE 0x00
#define	MSB_LEN 0x00
#define MAX_XBEE_PACKET_SIZE 9
#define API_RX_ID				0x81
#define API_TX_STATUS_ID		0x89
#define	ACK_STATUS				0
#define NACK_STATUS				1
#define AD_CHANNEL_NUM		1

/*---------------------------- Module Functions ---------------------------*/
/* prototypes for private functions for this service.They should be functions
   relevant to the behavior of this service
*/

static void ClearDataPacket(void)
static void AnalyzeRXPacket(void)
static void ClearEncryption(void)
static void PrintOutReceivedPacket(void)

/*---------------------------- Module Variables ---------------------------*/
init a priority variable
init variables to store the packet lengths
init variables for check sum and received check sum
init variables for the API and frame IDs
init variable to store the transmission status
init variable to store the status of a byte remaining
init variables for length of MSB and LSB
init variables to store MSB and LSB addresses for receiving
init variable to store the DOG ID
init variable to store the FARMER address
init variables to store MSB and LSB addresses for transmitting
init variable for encryption index
init an array for the data packet
init an array for the Xbee packet
init a variable for the encryption key length
init an array for the encryption key
init variable for the rx index
init variable for the length of the control message
init variable for the control message
init boolean to track whether we're in control mode
init array for AD data for dog tag reading
init variables for tolerances and set points of the dog tag voltages


/*------------------------------ Module Code ------------------------------*/
/****************************************************************************
 Function
     InitDogRX

 Parameters
     uint8_t : the priorty of this service

 Returns
     bool, false if error in initialization, true otherwise

 Description
     Saves away the priority, and does any 
     other required initialization for this service
****************************************************************************/
bool InitDogRX ( uint8_t Priority )
{
		declare ThisEvent variable
		set MyPriority to Priority
	
		/********************************************
		 Initialization Code
		 *******************************************/
	
		initialize current state to waiting to pair
		
		Initialize data and Xbee packet lengths to 0
	
		enable RX interrupt
	
		call ReadID()
		
		print "Finished initializing Dog RX Service"

		post the initial transition event
}

/****************************************************************************
 Function
     PostDogRX

 Parameters
     EF_Event ThisEvent ,the event to post to the queue

 Returns
     bool false if the Enqueue operation failed, true otherwise

 Description
     Posts an event to this state machine's queue

****************************************************************************/
bool PostDogRX( ES_Event ThisEvent )
{
  post ThisEvent to this service using MyPriority
}

/****************************************************************************
 Function
    RunDogRX

 Parameters
   ES_Event : the event to process

 Returns
   ES_Event, ES_NO_EVENT if no error ES_ERROR otherwise

****************************************************************************/
ES_Event RunDogRX( ES_Event ThisEvent )
{
	declare ReturnEvent variable
	set ReturnEvent type to ES_NO_EVENT -- assume no errors
	
	if ThisEvent type is VALID_PACKET_RECEIVED
			set DataPacket_Length to the parameter in ThisEvent
			for all elements in DataPacket
					set DataPacket[i] to corresponding value in the buffer
			call PrintOutReceivedPacket() for debugging
			call AnalyzeRXPacket() to process the data

	return ReturnEvent
}

/***************************************************************************
 private functions
 ***************************************************************************/

/*
 *	This function print out the received packet content
 */
static void PrintOutReceivedPacket(){
		(prints the received element for debugging only)
}

/*
 *	This function updates dog id from the attached dog tag
 */
void ReadID(){
	call ADC_MultiRead(AD_data) to store AD value in AD_data
	declare raw_id_value as AD data value
	print "Raw id reading: " and raw_id_value
	if raw_id_value is in range for dog tag 1
		set dog_id to 0x01
	else if raw_id_value is in range for dog tag 2
		set dog_id to 0x02
	else
		set dog_id to 0x03
	
	print "Set dog id to " and the dog ID
}

/*
 *	This function clears data packet content
 */
static void ClearDataPacket(){
	for all set bits in data packet
		clear dat shit
}

/*
 *	This function clears encryption key array
 */
static void ClearEncryption(){
	for all bits in encryption key
		clear it, yo
}

/*
 *	This function reset the encryption key index
 */
void ResetEncryptKeyIndex(){
	reset encryption key index to 0
}

/*
 *	This function decrypts the data packet
 */
static void DecryptMessage(int message_len){
	print "Decrypt key: " and the encryption key, "index: " and the index

	for every bit in the message
		xor the bit by the correct encryption key bit
		increment the encryption key index
		if index is 32
			reset it to 0x00
}

/*
 *	This function analyzes the recieved data packet
 */
static void AnalyzeRXPacket(){
	set API_id to the 0 bit in the data packet

	if api id is API_TX_STATUS_ID(this is transmit status message)
		set frame_id to the 1 bit in the packet
		set tx_status to the 2 bit in the packet
		init event ThisEvent

		if tx_status is ACK_STATUS (acknowledge)
			set event type to ACK_RECEIVED
			set event parameter to frame_id
			post ThisEvent to DOG_TX
		else if tx_status is NACK_STATUS (not acknowledge)
			set event type to NACK_RECEIVED
			set event parameter to frame_id
			post ThisEvent to DOG_TX
		
	else if API_id is API_RX_ID (this is a receive data message)
		save source address to Source_Address_LSB/MSB variables
		set farmer address to the source address
		
		if rx is not in control mode (message will not be decrypted)
			if data packet type is request to pair
				call ReadID() to read the ID

				if received dog id is the same as on board one
					post get valid dog id response message to farmer top SM
			else if data packet is encryption key message
				update encryption key from DataPacket using for loop
				
				Save Farmer Address to Paired_Farmer_Address variable
				
				post encryption key received event with param Farmer_Address

		else (rx is in control command, we need to decrypt data packet)
			if Farmer_Address equals the saved Paired_Farmer_Address
				first decrypt the data packet
				if the decrypted data header is CTRL
					post CTRL_COMMAND_RECEIVED to farmer top SM
					-> event param is the control message from DataPacket data
					-> (get valid dog id response)
				
				else (received header is not CTRL)
					post INVALID_CTRL_COMMAND_RECEIVED to farmer top SM
			else
				print "Received message from other unpaired farmer: (Farmer_Address), ignore it"
			

/*
 *	This function updates control mode according to the input
 */
void SetInControlMode(bool input){
		set InControlMode to input value
}

uint32_t GetControlMessage(){
		return ControlMessage
}

/*------------------------------- Footnotes -------------------------------*/
/*------------------------------ End of file ------------------------------*/