//FILE: client/app_stress_client.c
//
//Description: this is the stress test client application code. The client first connects to the local SNP process. Then it initializes the SRT client by calling srt_client_init(). It creates a socket and connects to the server  by calling srt_client_sock() and srt_client_connect(). Then it reads text data from file sampletext.txt, and sends the length of the file and file data to the server. After some time, the client disconnects from the server by calling srt_client_disconnect(). Finally the client closes the socket by calling srt_client_close(). The client then disconnects from the local SNP process.

//Date: May 6, 2008

//Input: None

//Output: SRT client states

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include "../common/constants.h"
#include "../topology/topology.h"
#include "srt_client.h"

//One connection is created using client port CLIENTPORT1 and server port SVRPORT1. 
#define CLIENTPORT1 87
#define SVRPORT1 88

//After connecting to tehe local SNP process, wait STARTDELAY for server to start.
#define STARTDELAY 1
//After the file is sent, the client waits for WAITTIME seconds, and then closes the connection.
#define WAITTIME 5

//This function connects to the local SNP process on port NETWORK_PORT. If TCP connection fails, return -1. The TCP socket desciptor returned will be used by SRT to send segments.
int connectToNetwork() {
	struct sockaddr_in servaddr;
	
	servaddr.sin_family = AF_INET;	
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	servaddr.sin_port = htons(NETWORK_PORT);

	int network_conn = socket(AF_INET,SOCK_STREAM,0);  
	if(network_conn<0)
		return -1;
	if(connect(network_conn, (struct sockaddr*)&servaddr, sizeof(servaddr))!=0) 
		return -1;

	//succefully connected
	return network_conn;
}

//This function disconnects from the local SNP process by closing the local TCP connection to the local SNP process. 
void disconnectToNetwork(int network_conn) {
	close(network_conn);
}


int main() {
	//random seed for loss rate
	srand(time(NULL));

	//connect to SNP process and get the TCP socket descriptor	
	int network_conn = connectToNetwork();
	if(network_conn<0) {
		printf("fail to connect to the local SNP process\n");
		exit(1);
	}

	//initialize srt client
	srt_client_init(network_conn);
	sleep(STARTDELAY);

	char hostname[50];
	printf("Enter server name to connect:");
	scanf("%s",hostname);
	int svr_nodeID = topology_getNodeIDfromname(hostname);
	if(svr_nodeID == -1) {
		printf("host name error!\n");
		exit(1);
	} else {
		printf("connecting to node %d\n",svr_nodeID);
	}


	//create a srt client sock on port CLIENTPORT1 and connect to srt server port SVRPORT1
	int sockfd = srt_client_sock(CLIENTPORT1);
	if(sockfd<0) {
		printf("fail to create srt client sock");
		exit(1);
	}
	if(srt_client_connect(sockfd,svr_nodeID,SVRPORT1)<0) {
		printf("fail to connect to srt server\n");
		exit(1);
	}
	printf("client connected to server, client port:%d, server port %d\n",CLIENTPORT1,SVRPORT1);
	
	//get sampletext.txt file length,
	//create a buffer and read the file data in
	FILE *f;
	f = fopen("send_this_text.txt","r");
	assert(f!=NULL);
	fseek(f,0,SEEK_END);
	int fileLen = ftell(f);
	fseek(f,0,SEEK_SET);
	char *buffer = (char*)malloc(fileLen);
	fread(buffer,fileLen,1,f);
	fclose(f);
	//send file length first, then send the whole file
	srt_client_send(sockfd,&fileLen,sizeof(int));
      	srt_client_send(sockfd, buffer, fileLen);
	free(buffer);
	//wait for a while and close the connections
	sleep(WAITTIME);

	if(srt_client_disconnect(sockfd)<0) {
		printf("fail to disconnect from srt server\n");
		exit(1);
	}
	if(srt_client_close(sockfd)<0) {
		printf("fail to close srt client\n");
		exit(1);
	}
	

	//disconnect from the SNP process
	disconnectToNetwork(network_conn);
}