#include <stdio.h>
#include <stdlib.h>

#include <unistd.h> 		// close socket
#include <string.h>
 #include <sys/time.h>          // datetime


#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <pthread.h>

//* forward declarations prototypes
int create_tcp_socket();
char *get_ip(char *host);
char *build_get_query(char *host, char *page);
void usage();

void *client(void *arg);
int timeval_subtract(struct timeval *result, struct timeval *t2, struct timeval *t1);

#define HOST "coding.debuntu.org"
#define PAGE "/"
#define USERAGENT "HTMLGET 1.0"

#define MAX_THREAD 50

char *host;
char *page;
int port;

int main(int argc, char **argv)
{
 	struct timeval tvBegin, tvEnd, tvDiff;


	if( argc < 3 )
	{
		usage();
		exit(2);
	}

  	host = argv[1];
	port = atoi(argv[2]);
	if(argc > 3)
	{
		page = argv[3];
	}
	else
	{
		page = PAGE;
	}

	gettimeofday(&tvBegin, NULL);

	pthread_t p[MAX_THREAD];

	int i;
	for( i = 0; i < MAX_THREAD; i++ )
	{
		pthread_create(&(p[i]), NULL, client, NULL);
	}

	for( i = 0; i < MAX_THREAD; i++ )
	{
		pthread_join(p[i], NULL);
	}


	gettimeofday(&tvEnd, NULL);
	timeval_subtract(&tvDiff, &tvEnd, &tvBegin);
	printf("Time to handle %d requests: %ld.%06d sec\n", MAX_THREAD, tvDiff.tv_sec, tvDiff.tv_usec);
}



void *client( void *arg )
{
	struct sockaddr_in *remote;
	int sock;
	int tmpres;
	char *get;
	char buf[BUFSIZ+1];
	char **argv = arg;
	char *ip;

	sock = create_tcp_socket();
	ip = get_ip(host);

	//fprintf(stderr, "IP is %s:%d\n", ip, port); 
	remote = (struct sockaddr_in *)malloc(sizeof(struct sockaddr_in *));
	remote->sin_family = AF_INET;
	tmpres = inet_pton(AF_INET, ip, (void *)(&(remote->sin_addr.s_addr)));
	if( tmpres < 0)  
	{
		perror("Can't set remote->sin_addr.s_addr");
		exit(1);
	}
	else if(tmpres == 0)
	{
		fprintf(stderr, "%s is not a valid IP address\n", ip);
		exit(1);
	}
	remote->sin_port = htons(port);

	if(connect(sock, (struct sockaddr *)remote, sizeof(struct sockaddr)) < 0)
	{
		perror("Could not connect");
		exit(1);
	}

	get = build_get_query(host, page);
	//fprintf(stderr, "Query is:\n<<START>>\n%s<<END>>\n", get);
	//Send the query to the server

	int sent = 0;
	while(sent < strlen(get))
	{ 
		tmpres = send(sock, get+sent, strlen(get)-sent, 0);
		if(tmpres == -1)
		{
			perror("Can't send query");
			exit(1);
		}
		sent += tmpres;
	}

	//now it is time to receive the page
	memset(buf, 0, sizeof(buf));
	int htmlstart = 0;
	char * htmlcontent;
	while((tmpres = recv(sock, buf, BUFSIZ, 0)) > 0);

	if(tmpres < 0)
	{
		perror("Error receiving data");
	}

	free(get);
	free(remote);
	free(ip);
	close(sock);
	return 0;
}

void usage()
{
	fprintf(stderr, "USAGE: htmlget host port [page]\n\
				\thost: the website hostname. ex: coding.debuntu.org\n\
				\tpage: the page to retrieve. ex: index.html, default: /\n");
}


int create_tcp_socket()
{
	int sock;
	if((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
	{
		perror("Can't create TCP socket");
		exit(1);
	}
	return sock;

}


char *get_ip(char *host)
{
	struct hostent *hent;
	int iplen = 15; //XXX.XXX.XXX.XXX

	char *ip = (char *) malloc(iplen+1);
	memset(ip, 0, iplen+1);

	if(( hent = gethostbyname(host)) == NULL )
	{
		herror("Can't get IP");
		exit(1);
	}

	if( inet_ntop(AF_INET, (void *)hent->h_addr_list[0], ip, iplen) == NULL )
	{
		perror("Can't resolve host");
		exit(1);
	}

	return ip;
}

char *build_get_query(char *host, char *page)
{
	char *query;
	char *getpage = page;
	char *tpl = "GET /%s HTTP/1.0\r\nHost: %s\r\nUser-Agent: %s\r\n\r\n";
	if(getpage[0] == '/')
	{
		getpage = getpage + 1;
		fprintf(stderr,"Removing leading \"/\", converting %s to %s\n", page, getpage);
	}

	// -5 is to consider the %s %s %s in tpl and the ending \0
	query = (char *)malloc(strlen(host)+strlen(getpage)+strlen(USERAGENT)+strlen(tpl)-5);
	sprintf(query, tpl, getpage, host, USERAGENT);
	return query;
}

int timeval_subtract(struct timeval *result, struct timeval *t2, struct timeval *t1)
{
	long int diff = (t2->tv_usec + 1000000 * t2->tv_sec) - (t1->tv_usec + 1000000 * t1->tv_sec);
	result->tv_sec = diff / 1000000;
	result->tv_usec = diff % 1000000;
	return (diff<0);
}