#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <ctype.h>
#include <string.h>
#include <netdb.h>
#define MAX_THREADS 5
//#define SERVER "mail.informatik.htw-dresden.de"
#define SERVER "localhost"
#include "server.h"

pthread_t threads[MAX_THREADS];
int jthreads[MAX_THREADS];

int s;

int main(int argc, char *argv[])
{
    int i,  ns;
    unsigned int fromlen;
    struct sockaddr_in servAd;
    struct sockaddr_in clieAd;
    unsigned short port;
    void * value;
    fd_set fds;
    struct timeval tv;
    int erg;

    port = atoi(argv[1]);
    memset(jthreads,0,sizeof(jthreads));

    if ((s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
        perror("server: socket");
        return -1;
    }

    memset(&servAd,0,sizeof(servAd));
    servAd.sin_family = AF_INET;
    servAd.sin_addr.s_addr = htonl(INADDR_ANY);
    servAd.sin_port = htons(port);

    if (bind(s, (struct sockaddr *)&servAd, sizeof(servAd)) < 0) {
        perror("server: bind");
        return -1;
    }

    printf("opened socket as fd (%d) for family (%d)\n",s,servAd.sin_family);

    if (listen(s, 2) < 0) {
        perror("server: listen");
        return -1;
    }

  for (;;) { 

    for(i=0;i<MAX_THREADS;i++){
	if(jthreads[i]==1){
    		pthread_join(threads[i],&value);
		threads[i]=0;
		jthreads[i]=0;
	}
    }

    FD_ZERO(&fds);
    FD_SET(s,&fds);
    tv.tv_sec=0;
    tv.tv_usec=500000;

    erg=select(s+1,&fds,NULL,NULL,&tv);
    if(erg==0) continue;
    else if(erg<0) perror("server: select");


    for(i=0; i<MAX_THREADS;i++){
	if(threads[i]==0) break;
    }

    if(i==MAX_THREADS){
	usleep(10000);
	continue;
    }

    printf("stelle: %d\n",i);

    fromlen=sizeof(struct sockaddr);

    ns = accept(s,(struct sockaddr *)&clieAd, &fromlen);
    if ( ns < 0) perror("server: accept");

    printf("Handling client %s\n",inet_ntoa(clieAd.sin_addr));

    erg=pthread_create(&threads[i],0, (void*)client, (void*) &ns);
    if(erg!=0) perror("server: pthread_create");

  }

    close(s);
}

int checkmail(char * ret){
	
	ret = strtok(ret,"\015\012");
	char mail [128];
	strcpy(mail,ret);
	if(strchr(ret,'<')!=NULL){
		ret++;
		strtok(ret,">");
	}
	int len = 0, len2 = 0;
	if(strchr(ret,' ')!=NULL) return 0;
	if(strchr(ret,'.')==NULL) return 0;
	if(strchr(ret,'@')==NULL) return 0;
	len=strlen(strrchr(ret,'.'))-1;
	if(len<2) return 0;
	len2=strlen(strchr(ret,'@'))-1;
	if(len2-len-1<3) return 0;
	if(strlen(ret)-len2-1<1) return 0;
	if(strchr(mail,'<')!=NULL) ret--;
	strcpy(ret,mail);
	return 1;
}

void client(void* arg){

    int len=0,erg,i;
    int so = *((int*)arg);
    char buf[128];
    struct timeval tv;
    fd_set fds;
    char * helo = (char *)malloc(1);
    char * from = (char *)malloc(1);
    char * to = (char *)malloc(1);
    char * data = (char *)malloc(1);
    char * ret = (char *)malloc(1024);
    char * test = (char *)malloc(128);
    char * text = (char *)malloc(128);
    int status=0;
    struct hostent * host;

    send(so, "220 localhost server\n", 22, 0);

    memset(buf,0,sizeof(buf));
    for(;;){
    	memset(ret,0,sizeof(ret));
    	memset(buf,0,sizeof(buf));
	FD_ZERO(&fds);
    	FD_SET(so,&fds);
    	tv.tv_sec=10;
    	tv.tv_usec=0;
    	erg=select(so+1,&fds,NULL,NULL,&tv);
    	if(erg==0) continue;
    	else if(erg<0) perror("server: select");
	len = read(so,buf,127);
	printf("|%s|\n",buf);
	if(len<=2) continue;
	for(i=0;i<len;i++) buf[i]=tolower(buf[i]);
 	buf[127]='\0';
	if(strncmp(buf,"quit",4)==0){
		send(so, "221 See you later\n", 18, 0);
		close(so);
		for(i=0;i<MAX_THREADS;i++){
			if(threads[i]==pthread_self()) break;
		}
		jthreads[i]=1;
		pthread_exit(0);
		free(helo);
		free(from);
		free(to);
		free(data);
		free(ret);
		host=NULL;
	}else
	if(strncmp(buf,"rset",4)==0){
		helo="";
		from="";
		to="";
		data="";
		memset(buf,0,sizeof(buf));
		host=NULL;
		status=0;
	}else
	if(strncmp(buf,"noop",4)==0){
		send(so, "250 OK\n", 7, 0);
	}else
	if(strncmp(buf,"vrfy",4)==0){
		if(strlen(buf)<8){
			send(so, "501 Syntax: VRFY adress\n", 24, 0);	
			continue;
		}
		strtok(buf," ");
		ret = strtok(NULL,"\n\0");
		send(so, "252 ", 4, 0);
		send(so, ret, strlen(ret)-1, 0);
		send(so, "\n", 1, 0);		
	}else
	if(strncmp(buf,"expn",4)==0){
		if(strlen(buf)<8){
			send(so, "501 Syntax: EXPN adress\n", 24, 0);	
			continue;
		}
		strtok(buf," ");
		ret = strtok(NULL,"\n\0");
		send(so, "252 ", 4, 0);
		send(so, ret, strlen(ret)-1, 0);
		send(so, "\n", 1, 0);		
	}else
	if(strncmp(buf,"helo",4)==0){
		strtok(buf," ");
		ret = strtok(NULL,"\n\0");
		memset(test,0,sizeof(test));
		strncpy(test,ret,strlen(ret)-1);
		host = gethostbyname(test);
		if(!host){
			send(so, "501 Bad hostname\n", 18, 0);
			continue;
		}
		free(helo);
		helo = (char *)malloc(strlen(test));
		strncpy(helo,test,strlen(test)+1);
		strcpy(text,"250 Hello ");		
		strcat(text,helo);
		strcat(text,", nice to meet you\n");
		send(so, text, strlen(text), 0);
		free(text);
		free(test);
		status=1;
	}else
	if(strncmp(buf,"mail from:",10)==0){
		if(status==0&&strlen(helo)>0) helo="";
		strtok(buf,":");
		ret = strtok(NULL,"\n\0");
		if(!checkmail(ret)){
 			send(so, "501 Bad adress syntax\n", 22, 0);
			continue;
		}
		free(from);
		from = (char *)malloc(strlen(ret));
		strncpy(from,ret,strlen(ret)+1);
		send(so, "250 Sender OK\n", 14, 0);
		status=2;
	}else
	if(strncmp(buf,"rcpt to:",8)==0){
		if(status==0||status==1){
			send(so, "503 Mail first\n", 15, 0);
			continue;
		}
		strtok(buf,":");
		ret = strtok(NULL,"\n\0");
		if(!checkmail(ret)){
			send(so, "501 Bad adress syntax\n", 22, 0);
			continue;
		}
		if(strlen(to)>0&&status==3){
			to=(char*)realloc(to,strlen(ret)+strlen(to)+1);
			strcat(to,",");
			strcat(to,ret);	
		}
		else{
			free(to);
			to = (char *)malloc(strlen(ret));
			strncpy(to,ret,strlen(ret)+1);
		}
		send(so, "250 Recipient OK\n", 17, 0);
		status=3;
	}else
	if(strncmp(buf,"data",4)==0){
		if(status==0||status==1){
			send(so, "503 Mail first\n", 15, 0);
			continue;
		}
		if(status==2){
			send(so, "554 Error: no valid recipients\n", 31, 0);
			continue;
		}
		send(so, "354 End data with <CR><LF>.<CR><LF>\n", 36, 0);
		strcpy(data,"");
		while(read(so,buf,127)){
			printf("|%s|\n",buf);
			if(strncmp(buf,".\015\012",3)==0) break;
			data=(char*)realloc(data,strlen(buf)+strlen(data)+1);
			strcat(data,buf);
			bzero(buf,128);
		}
		send(so, "250 Message accepted for delivery\n", 34, 0);
		status=4;
	}else{
		send(so, "502 Error: command not implemented\n", 35, 0);
	}
	if(status==4){
		printf("erhalten:\nHelo: %s\nMail From: %s\nRCPT to: %s\ndata\n%s\n",helo,from,to,data);
		int status2=0;
		int sock;
		struct hostent * host = gethostbyname("localhost");

		if(host){
			struct sockaddr_in server;
			struct in_addr a;
			unsigned long addr;
			if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) perror("client: socket");
			memset(&server,0,sizeof(server));
			bcopy(*host->h_addr_list,(char*)&a,sizeof(a));
			addr=inet_addr(inet_ntoa(a));
			memcpy((char *)&server.sin_addr, &addr, sizeof(addr));
			server.sin_family = AF_INET;
			server.sin_port = htons(25);

			if(connect(sock,(struct sockaddr*)&server,sizeof(server))<0) perror("client: connect");
			while(status2<4){
				bzero(buf,128);
				switch(status2){
				case 0:
					if(read(sock,buf,127)<0) perror("ERROR: reading");
					printf("%s",buf);
					strcpy(text,"helo ");
					strcat(text,helo);
					break;
				case 1:
					strcpy(text,"mail from:");
					strncat(text,from,strlen(from));
					break;
				case 2:
					break;
				case 3:
					strcpy(text,"");
					strncat(text,data,strlen(data)-1);
					break;
				}
				if(status2==3){
					send(sock, "data\015\012", 6, 0);
					if(read(sock,buf,127)<0) perror("ERROR: reading");
					printf("%s",buf);
					char * tok;
					tok = strtok(data,"\012");
					while(tok!=NULL){
						strcpy(text,tok);
						strcat(text,"\012");
						send(sock, text, strlen(text), 0);
						tok=strtok(NULL,"\012");
					}
					send(sock, ".\015\012",3, 0);
					if(read(sock,buf,127)<0) perror("ERROR: reading");
					printf("%s",buf);
				}	
				if(status2==2){
					char * tok;
					tok = strtok(to,",");
					while(tok!=NULL){
						strcpy(text,"rcpt to:");
						strcat(text,tok);
						strcat(text,"\015\012");
						send(sock, text, strlen(text), 0);
						if(read(sock,buf,127)<0) perror("ERROR: reading");
						printf("%s",buf);
						tok=strtok(NULL,",");
					}
				}
				else
				if(status2<2){
					strcat(text,"\015\012");
					send(sock, text, strlen(text), 0);
					if(read(sock,buf,127)<0) perror("ERROR: reading");
					printf("%s",buf);
				}
				status2++;
			}
			close(sock);
		}
		else perror("host unreacheble\n");
		helo="";
		from="";
		to="";
		data="";
		host=NULL;
		status=0;
	}
    }

}