/***************************************************************************************
File:			pop3_client.c

Date:			20.8.2002

Version:		0.1

Author:			Jari Lahti (jari@violasystems.com)

Description:	This file contains POP3 E-mail client implementation that uses Viola
				TCP API.

Version Info:	20.8.2002 - First version (JaL)
***************************************************************************************/

#include "opentcp.h"


UINT8 pop3c_init_done = 0;
struct POP3CStruct POP3Client;


/* The applications that use TCP must implement following function stubs			*/
/* void application_name_init (void) - call once when processor starts				*/
/* void application_name_run (void) - call periodically on main loop				*/
/* INT32 application_name_eventlistener (INT8, UINT8, UINT32, UINT32)				*/
/* - called by TCP input process to inform arriving data, errors etc				*/


/* POP3 Client application		*/


/********************************************************************************
Function:		pop3c_connect

Parameters:		UINT32 ip - ip address of POP3 server
				UINT16 port - port on server (remote port)

Return val:		INT8 - (-1) = Error
					 -  >0 = Connection procedure started (OK)

Date:			11.9.2002

Desc:			This function is called by user when she wants to start E-mail
				reading procedure. The function is responsible of establishing
				connection to POP3 server. After connection is established the
				POP3 client engine starts to make callbacks to user functions
				in order to get username information, data etc.
*********************************************************************************/

INT8 pop3c_connect (UINT32 ip, UINT16 port)
{
	/* Do we have socket	*/

	if( POP3Client.sochandle < 0 )
	{
		DEBUGOUT("pop3c_connect() called but no socket\r\n");
		return(-1);
	}

	if( POP3Client.state < POP3C_CLOSED )
	{
		DEBUGOUT("pop3c_connect() called but uninitialized\r\n");
		return(-1);
	}

	if( POP3Client.state == POP3C_CLOSED )
	{
		DEBUGOUT("POP3 Connection request going to be processed\r\n");
		POP3Client.remip = ip;
		POP3Client.remport = port;
		pop3c_changestate(POP3C_OPEN_REQUESTED);
		return(1);
	}

	return(-1);

}


/********************************************************************************
Function:		pop3c_init

Parameters:		void

Return val:		void

Date:			12.8.2002

Desc:			This function should be called once when system starts.
				Make sure that system services e.g. timers, TCP are initialized
				before initializing applications!
*********************************************************************************/

void pop3c_init (void)
{

	if(pop3c_init_done)
	{
		DEBUGOUT("POP3 client already initialized\r\n");
		return;
	}


	/* Get timer handle	*/

	POP3Client.tmrhandle = get_timer();

	/* Get TCP Socket	*/

	POP3Client.sochandle = tcp_getsocket(TCP_TYPE_CLIENT, TCP_TOS_NORMAL, TCP_DEF_TOUT, pop3c_eventlistener);

	if( POP3Client.sochandle < 0 )
	{
		DEBUGOUT("pop3c_init() uncapable of getting socket\r\n");
		RESET_SYSTEM();
	}

	pop3c_changestate(POP3C_CLOSED);
	POP3Client.remip = 0;
	POP3Client.remport = 0;
	POP3Client.unacked = 0;
	POP3Client.msgtotal = 0;
	POP3Client.curmsgindex = 0;
	POP3Client.curmsgtotlen = 0;
	POP3Client.curmsghlen = 0;
	POP3Client.headerbuf[0] = '\0';
	POP3Client.charsinheaderbuf = 0;
	POP3Client.from[0] = '\0';
	POP3Client.subject[0] = '\0';

	pop3c_init_done = 0x01;				/* We are initialized now	*/

}

/********************************************************************************
Function:		pop3c_getstate

Parameters:		void

Return val:		UINT8 state

Date:			10.10.2002

Desc:			Returns the state of POP3 client
*********************************************************************************/

UINT8 pop3c_getstate (void)
{
	return(POP3Client.state);

}


/********************************************************************************
Function:		pop3c_eventlistener

Parameters:		INT8 cbhandle - handle to TCP socket where event is coming from
				UINT8 event - type of event
				UINT32 par1 - parameter the meaning of depends on event
				UINT32 par2 - parameter the meaning of depends on event

Return val:		INT32 - depends on event but usually (-1) is error of some
						kind and positive reply means OK

Date:			21.8.2002

Desc:			This function is given to TCP socket as function pointer to be
				used by TCP engine to make callbacks to inform about events
				on TCP e.g. arriving data. Main functionality of this function
				is to parse data from TCP to detect POP3 server reply commands,
				handling out retransmissions and making state changes
*********************************************************************************/


INT32 pop3c_eventlistener (INT8 cbhandle, UINT8 event, UINT32 par1, UINT32 par2)
{
	/* This function is called by TCP stack to inform about events	*/

	UINT8 cmd;
	UINT16 i;
	static UINT16 match;
	static UINT8  end_detect;
	UINT8 ch;

	if( cbhandle != POP3Client.sochandle)		/* Not our handle	*/
		return(-1);

	switch( event )
	{

		case TCP_EVENT_CONREQ:

			/* We don't allow incoming connections	*/

			return(-1);

		case TCP_EVENT_ABORT:

			if(POP3Client.state > POP3C_CLOSED)
			{
				/* Inform application	*/
				pop3c_error();
			}

			pop3c_changestate(POP3C_CLOSED);
			POP3Client.unacked = 0;

			return(1);

			break;

		case TCP_EVENT_CONNECTED:

			if(POP3Client.state == POP3C_CONNECTIONOPEN_SENT)
			{
				DEBUGOUT("POP3 TCP connection opened\r\n");
				pop3c_changestate(POP3C_CONNECTION_OPENED);
				POP3Client.unacked = 0;
				return(-1);
			}

			break;

		case TCP_EVENT_CLOSE:

			pop3c_changestate(POP3C_CLOSED);
			POP3Client.unacked = 0;
			return(1);

			break;

		case TCP_EVENT_ACK:

			/* Our message is acked	*/

			POP3Client.unacked = 0;

			break;

		case TCP_EVENT_DATA:

			/* Do we have unacked data?	*/

			if(POP3Client.unacked)
				return(-1);

			/* Get reply from server	*/

			if(par1 < 3)					/* Long enough?	*/
				return(-1);

			/* Get command				*/

			NETWORK_RECEIVE_INITIALIZE(ReceivedTCPPacket.BufIndex);
			cmd = RECEIVE_NETWORK_B();
			NETWORK_RECEIVE_INITIALIZE(ReceivedTCPPacket.BufIndex);

			switch(POP3Client.state)
			{

				case POP3C_CONNECTION_OPENED:

					if(cmd == POP3C_OK)
					{
						DEBUGOUT("POP3 Server is ready\r\n");
						pop3c_changestate(POP3C_SERVER_READY);
						return(1);
					}

					break;

				case POP3C_USERNAME_SENT:

					if(cmd == POP3C_OK)
					{
						DEBUGOUT("USER +OK by POP3 server\r\n");
						pop3c_changestate(POP3C_USERNAME_ACKED);
						return(1);
					}

					break;

				case POP3C_PASSWORD_SENT:

					if(cmd == POP3C_OK)
					{
						DEBUGOUT("PASS +OK by POP3 server\r\n");
						pop3c_changestate(POP3C_PASSWORD_ACKED);
						return(1);
					}

					break;

				case POP3C_STAT_SENT:

					if(cmd == POP3C_OK)
					{
						DEBUGOUT("STAT get from POP3 server\r\n");

						/* Parse number of messages	*/

						NETWORK_RECEIVE_INITIALIZE(ReceivedTCPPacket.BufIndex);

						POP3Client.msgtotal = 0;
						POP3Client.curmsgindex = 0;
						POP3Client.curmsgtotlen = 0;
						POP3Client.curmsghlen = 0;
						if( pop3c_parsestat() < 0 )
						{
							/* Error parsing STAT reply	*/
							/* Inform application		*/
							pop3c_error();
							tcp_abort(POP3Client.sochandle);
							pop3c_changestate(POP3C_CLOSED);
							POP3Client.unacked = 0;
							return(1);
						}

						/* Inform application about the nmbr of messages	*/
						pop3c_messages(POP3Client.msgtotal);

						pop3c_changestate(POP3C_STAT_GET);
						return(1);
					}

					break;

				case POP3C_LIST_SENT:

					if(cmd == POP3C_OK)
					{
						DEBUGOUT("LIST get from POP3 server\r\n");

						/* Parse message total len	*/

						NETWORK_RECEIVE_INITIALIZE(ReceivedTCPPacket.BufIndex);

						POP3Client.curmsgtotlen = 0;

						if(pop3c_parselist() < 0)
						{
							/* Error parsing LIST reply	*/
							/* Inform application		*/
							pop3c_error();
							tcp_abort(POP3Client.sochandle);
							pop3c_changestate(POP3C_CLOSED);
							POP3Client.unacked = 0;
							return(1);

						}


						pop3c_changestate(POP3C_LIST_GET);
						return(1);
					}

					break;

				case POP3C_TOP0_SENT:

					if(cmd == POP3C_OK)
					{
						DEBUGOUT("TOP x 0 get from POP3 server\r\n");

						/* Continue imediately to receive header	*/
						POP3Client.curmsghlen = 0;
						POP3Client.from[0] = '\0';
						POP3Client.subject[0] = '\0';
						match = 0;

						/* Receive untill LF found	*/

						for(i=0; i<(UINT16)par1; i++)
						{
							ch = RECEIVE_NETWORK_B();

							if(ch == '\n')
							{	i++;
								break;
							}
						}

						par1 = i;


						pop3c_changestate(POP3C_RECEIVING_HEADER);
					}
					else
						break;

				case POP3C_RECEIVING_HEADER:
				case POP3C_RECEIVING_HDR_FROM:
				case POP3C_RECEIVING_HDR_SUBJ:


					POP3Client.curmsghlen += (UINT16)par1;

					if( POP3Client.curmsghlen > (POP3Client.curmsgtotlen + 100) )
					{
						/* Somebody tries to fool us	*/
						/* Move to next msg				*/

						pop3c_changestate(POP3C_MESSAGE_RECEIVED);
						break;

					}

					/* We try to find 'from:', or 'subject:'	*/

					NETWORK_RECEIVE_INITIALIZE(ReceivedTCPPacket.BufIndex);

					for( i=0; i<(UINT16)par1; i++)
					{

						ch = RECEIVE_NETWORK_B();

						if( POP3Client.state == POP3C_RECEIVING_HEADER)
						{

							if( ch == '\r')
							{
								POP3Client.charsinheaderbuf = 0;
								continue;
							}

							if( ch == '\n')
							{
								POP3Client.charsinheaderbuf = 0;
								continue;
							}

							if( ch == ' ')		/* Remove spaces	*/
								continue;

							/* Buffer already full for this line?	*/

							if(POP3Client.charsinheaderbuf > 8)
								continue;

							/* End of header? (parsing of that is not absolutely correct)	*/
							/* We detect it from CRLF. or LFCR. or CR. or LF.				*/
							/* the correct indication being CRLF.CRLF						*/

							if( (ch == '.') && (POP3Client.charsinheaderbuf == 0) )
							{
								/* Remove CRLF.CRLF from header length	*/

								if( POP3Client.curmsghlen >= 5 )
									POP3Client.curmsghlen -= 5;

								pop3c_changestate(POP3C_TOP0_GET);
								break;
							}


							ch = otcp_tolower(ch);

							POP3Client.headerbuf[POP3Client.charsinheaderbuf] = ch;
							POP3Client.charsinheaderbuf++;
							POP3Client.headerbuf[POP3Client.charsinheaderbuf] = '\0';

							/* Is it 'from:' ?	*/

							if(otcp_bufsearch(&POP3Client.headerbuf[0],POP3Client.charsinheaderbuf,(UINT8*)"from:",1) == 0)
							{
								/* Continue imidiately to read sender	*/

								POP3Client.from[0] = '\0';
								POP3Client.charsinheaderbuf = 0;
								pop3c_changestate(POP3C_RECEIVING_HDR_FROM);
								continue;
							}

							/* Is it 'subject:' ?	*/

							if(otcp_bufsearch(&POP3Client.headerbuf[0],POP3Client.charsinheaderbuf,(UINT8*)"subject:",1) == 0)
							{
								/* Continue imidiately to read subject	*/

								POP3Client.subject[0] = '\0';
								POP3Client.charsinheaderbuf = 0;
								pop3c_changestate(POP3C_RECEIVING_HDR_SUBJ);
								continue;
							}

						}	/* of RECEIVING_HEADER	*/


						if( POP3Client.state == POP3C_RECEIVING_HDR_FROM)
						{
							if( ch == ' ')		/* Remove spaces	*/
							{
								if(POP3Client.charsinheaderbuf == 0)
									continue;
							}

							if( ch == '\r')
							{
								POP3Client.charsinheaderbuf = 0;
								pop3c_changestate(POP3C_RECEIVING_HEADER);
								continue;
							}

							if( ch == '\n')
							{
								POP3Client.charsinheaderbuf = 0;
								pop3c_changestate(POP3C_RECEIVING_HEADER);
								continue;
							}

							/* Store it	*/

							POP3Client.from[POP3Client.charsinheaderbuf] = ch;
							POP3Client.charsinheaderbuf++;
							POP3Client.from[POP3Client.charsinheaderbuf] = '\0';

							if(POP3Client.charsinheaderbuf >= POP3C_SENDERMAXLEN)
							{
								/* The buffer is exceeded	*/
								/* Mark it corrupted		*/

								POP3Client.from[0] = '\0';
								pop3c_changestate(POP3C_RECEIVING_HEADER);
								continue;
							}

						} 	/* of RECEIVING_HDR_FROM	*/


						if( POP3Client.state == POP3C_RECEIVING_HDR_SUBJ)
						{
							if( ch == ' ')		/* Remove spaces	*/
							{
								if(POP3Client.charsinheaderbuf == 0)
									continue;
							}

							if( ch == '\r')
							{
								POP3Client.charsinheaderbuf = 0;
								pop3c_changestate(POP3C_RECEIVING_HEADER);
								continue;
							}

							if( ch == '\n')
							{
								POP3Client.charsinheaderbuf = 0;
								pop3c_changestate(POP3C_RECEIVING_HEADER);
								continue;
							}

							/* Store it	*/

							POP3Client.subject[POP3Client.charsinheaderbuf] = ch;
							POP3Client.charsinheaderbuf++;
							POP3Client.subject[POP3Client.charsinheaderbuf] = '\0';

							if(POP3Client.charsinheaderbuf >= POP3C_SUBJECTMAXLEN)
							{
								/* The buffer is exeeded	*/
								/* Mark it corrupted		*/

								POP3Client.subject[0] = '\0';
								pop3c_changestate(POP3C_RECEIVING_HEADER);
								continue;
							}

						} 	/* of RECEIVING_HDR_SUBJ	*/


					}


					break;


				case POP3C_RETR_SENT:

					if(cmd == POP3C_OK)
					{
						DEBUGOUT("RETR +OK by POP3 server\r\n");

						/* Continue imidiately to receive message	*/

						pop3c_changestate(POP3C_RECEIVING_MSG_HEADER);

					}
					else
						break;

				case POP3C_RECEIVING_MSG_HEADER:

					/* Try to find empty row to detect the start of actual message	*/

					match = 0;
					NETWORK_RECEIVE_INITIALIZE(ReceivedTCPPacket.BufIndex);

					for(i=0; i < (UINT16)par1; i++)
					{
						ch = RECEIVE_NETWORK_B();

						if(match == 0)
						{
							if( (ch == '\r') || (ch == '\n') )
								match++;
							else
								match = 0;
							continue;
						}

						if(match == 1)
						{
							if( (ch == '\r') || (ch == '\n'))
								match++;
							else
								match = 0;
							continue;
						}

						if(match == 2)
						{
							if( (ch == '\r') || (ch == '\n'))
								match++;
							else
								match = 0;
							continue;
						}

						if(match == 3)
						{
							if( (ch == '\r') || (ch == '\n'))
							{
								match++;

								/* Continue to read the actual msg	*/
								par1 -= (i + 1);
								pop3c_changestate(POP3C_RECEIVING_MSG);
								break;
							}
							else
								match = 0;
							continue;
						}

					}

					/* If we don't find the end of header we will timeout	*/
					/* on pop3c_run so no error handling here				*/

					if( POP3Client.state !=	POP3C_RECEIVING_MSG)
						break;

					end_detect = 0;

					case POP3C_RECEIVING_MSG:

						/* Search is this packet end of msg and do not give	*/
						/* CRLF.CRLF to application							*/


						for(i=0; i < (UINT16)par1; i++)
						{
							ch = RECEIVE_NETWORK_B();

							pop3c_data(ch);

							if( (ch == '\r') && (end_detect != 3))
								end_detect = 0;


							if( end_detect == 0 )
							{
								if(ch == '\r')
									end_detect++;
								else
									end_detect = 0;

								continue;
							}

							if( end_detect == 1 )
							{
								if(ch == '\n')
									end_detect++;
								else
									end_detect = 0;

								continue;
							}

							if( end_detect == 2 )
							{
								if(ch == '.')
									end_detect++;
								else
									end_detect = 0;

								continue;
							}

							if( end_detect == 3 )
							{
								if(ch == '\r')
									end_detect++;