#include <sys/socket.h>	/* for socket(), connect(), send() and recv() */
#include <arpa/inet.h>	/* for sockaddr_in and inet_addr() */
#include <stdlib.h>	/* for atoi() */
#include <string.h>	/* for memset() */
#include <unistd.h>	/* for close() */
#include <sys/types.h>
#include <netinet/in.h>
#include <errno.h>
#include <stdio.h>
#include <netdb.h>	/* for gethostbyname() */
#include <sys/param.h>	/* for MAXHOSTNAMELEN */


#define RCVBUFSIZE 32	/* Size of receive buffer */


void err_sys( char *);

int main(int argc, char ** argv)
{
 	char *inputName;	/* inputName is the Sever's name you input */
 	char ipAddr[INET_ADDRSTRLEN];
 	char buf[50], wbuf[80];	
 	struct hostent *hostInfo;
 	struct sockaddr_in servaddr;
 	unsigned short ServPort;
 	char *ServIP;
 	int sockfd, n;	/*socket name*/
 	char localhostName[MAXHOSTNAMELEN];	/* store the local host name, MAXHOSTNAMELEN is the max host name length */
	char revaddr[100];	/* for the output for the receiver's address */

  	if ((argc < 2) || (argc > 3)) {
		printf("Usage: %s [MailServerName]> [<IPport>]\n", argv[0]);
		exit(1);
	}


	if (argc == 3) {
		ServPort = atoi(argv[2]);	/* use given port, if any */
	} else {
		ServPort = 25;	/* 25 is the default port number */
	}



	/* get the server's IP address */
   	
        //your code
          	
  	

	/* socket connection */
  	if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0 ){

	err_sys("Socket Error:");
    	exit(0);
  	}


        /* initiaize servaddr object*/
       
        //your code


  	if ( inet_pton(AF_INET,  inet_ntop(AF_INET, hostInfo->h_addr_list[0], ipAddr, INET_ADDRSTRLEN), &servaddr.sin_addr ) <= 0 ){
    	err_sys("System Error:");
    	exit(0);
  	}

	/* connect to server, hint: servaddr*/
        //your code 
 
  	/* get the local host name */
	if (gethostname(localhostName, MAXHOSTNAMELEN) < 0) {
		printf("LocalHostName is not available.\n");
		exit(1);
	}
	strcat(localhostName, "\n");


	/* receive hello message from the server */
	int BytesRcvd = 0 ;
	char RcvBuffer[100];
	char *Rcv220;

        /* receive data from server, the return value is put to BytesRcvd*/


	RcvBuffer[BytesRcvd] = '\0';	/* terminate the RcvBuffer! */
	printf(RcvBuffer);		/* print the Rcv buffer */

	printf("Helo ");

	printf(localhostName,'\n');


	/* send helo message to the server */
	char SendString[100];

	strcpy(SendString, "helo ");
	strcat(SendString, localhostName);


        /* send SendString to server*/
        //your code


	/* get the information of sender's email address */

        /*receive data from server, return value is put to BytesRcvd*/
        // your code

	RcvBuffer[BytesRcvd] = '\0';	/* terminate the string! */
	printf(RcvBuffer);		/* print the echo buffer */

mail:	printf("\nMAIL FROM:");

	strcpy(SendString,"MAIL FROM:");	/* Prepare the sender's message for the Sever */
	fgets(wbuf,80,stdin);
	strcat(SendString,wbuf);

        /*send out SendString to server*/
        //your code

	/*receive data from server, return value is put to BytesRcvd*/
        // your code

	RcvBuffer[BytesRcvd] = '\0';	/* terminate the string! */
	printf(RcvBuffer);		/* print the echo buffer */

	/* if the reply is not ok, then try again */
	int Rcv250 = 250;
	if (atoi(RcvBuffer) != Rcv250){

		goto mail;
	}

	/* get the information of receiver's email address */
	RcvBuffer[BytesRcvd] = '\0';	/* terminate the string! */
	printf(RcvBuffer);		/* print the echo buffer */
	strcpy(revaddr, "To:");

receive:	printf("RCPT to:");


	strcpy(SendString,"RCPT to:");	/* Prepare the sender's message for the Sever */
	fgets(wbuf,80,stdin);
	strcat(SendString,wbuf);
	
	
	wbuf[strlen(wbuf)-1]=0;
	strcat(revaddr,wbuf);
	strcat(revaddr,",");

        /*send SendString to server*/
	//your code

        /*receive data from server*/
        //your code


	RcvBuffer[BytesRcvd] = '\0';	/* terminate the string! */
	printf(RcvBuffer);		/* print the echo buffer */

	
	/* if the reply is not ok, then try again */
	if (atoi(RcvBuffer) != Rcv250){

		goto receive;
	}
 
        char no[]="no\n";


	/* send DATA to the Server */

	strcpy (SendString, "DATA\n");
  
        /*send SendString to server*/

	//your code

        /*receive data from server*/
        // your code


	/* send the content of the email */

	printf ("Subject:");
	strcpy(SendString, revaddr);
	strcat(SendString, "\r\n");

	strcat(SendString,"Subject:");	/* Prepare the sender's message for the Sever */
	fgets(wbuf,80,stdin);
	strcat(SendString,wbuf);
	strcat(SendString,"\r\n");

	printf("Content of Email:(End with <CR><LF>.<CR><LF>)\n");
	fflush(stdout);
	//strcat(SendString,wbuf);


	char mychar[3000];

content:
	fgets(mychar,3000,stdin);


	while ((strcmp(mychar,".\n")) != 0) {
		strcat(SendString,mychar);
		fgets(mychar,3000,stdin);

	}
	
	/* deal with the tricky single period */
	printf("Do you want to send?(Type no to continue inputing the content)");
	if((strcmp(fgets(mychar,3000,stdin),no)) == 0) {
		strcat(SendString,"..\n");
		goto content;
	}

	/* the whole SendSting is ready to send */
	strcat(SendString,"\r\n.\r\n");
	
        /*Send SendString to server*/
        //your code

	printf("send over\n");
	fflush(stdout);

        /*receive data from server*/
        //your code
	/* Quit procedure */

exit:	printf("Type QUIT to quit this program.\n");


	
	char quit[]="QUIT\n";
	fgets(buf,50,stdin);
 	if ((strcmp(buf, quit)) == 0){

		strcpy(SendString,"QUIT\n");


		/*send SendString to server*/

		//your code

		/*receive data from server*/
		// your code


	}
	else{
		goto exit;
	}
	
	/* final stage of the program */
	printf("Thank you for using my SMTP client.\n");
  	exit(0);
	}


void err_sys( char * str)
	{
 	 perror(str);
	}