// MultithreadTCPEchoServer.cpp : Defines the entry point for the console application.
//

#include "stdio.h"
#include "conio.h"
#include "string.h"
#include "ws2tcpip.h"
#include "winsock2.h"
#include "process.h"
#define SERVER_PORT 5500
#define SERVER_ADDR "127.0.0.1"
#define BUFF_SIZE 2048

/* echoThread - Thread to receive the message from client and echo*/
unsigned __stdcall echoThread(void *param){
	char buff[BUFF_SIZE];
	int ret;
	
	SOCKET connectedSocket = (SOCKET) param;
	ret = recv(connectedSocket, buff, BUFF_SIZE, 0);
	if (ret == SOCKET_ERROR)
		printf("Error %d: Cannot receive data.\n", WSAGetLastError());
	else if (ret == 0)
		printf("Client disconnects.\n");
	else if (strlen(buff) > 0) {
		buff[ret] = 0;
		printf("Receive from client[%s:%d] %s\n", clientIP, clientPort, buff);
		//Echo to client
		ret = send(connSock, buff, strlen(buff), 0);
		if (ret == SOCKET_ERROR)
			printf("Error %d: Cannot send data.\n", WSAGetLastError());
	}	
	
	closesocket(connectedSocket);
	return 0;
}

int main(int argc, char* argv[])
{
	//Step 1: Initiate WinSock
	WSADATA wsaData;
	WORD wVersion = MAKEWORD(2,2);
	if (WSAStartup(wVersion, &wsaData)){
		printf("Winsock 2.2 is not supported\n");
		return 0;
	}

	//Step 2: Construct socket	
	SOCKET listenSock;
	listenSock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

	//Step 3: Bind address to socket
	sockaddr_in serverAddr;	
	serverAddr.sin_family = AF_INET;
	serverAddr.sin_port = htons(SERVER_PORT);
	inet_pton(AF_INET, SERVER_ADDR, &serverAddr.sin_addr);
	if (bind(listenSock, (sockaddr *)&serverAddr, sizeof(serverAddr)))
	{
		printf("Error %d: Cannot associate a local address with server socket.", WSAGetLastError());
		return 0;
	}
	
	//Step 4: Listen request from client
	if (listen(listenSock, 10)) {
		printf("Error %d: Cannot place server socket in state LISTEN.", WSAGetLastError());
		return 0;
	}

	printf("Server started!\n");

	//Step 5: Communicate with client
	SOCKET connSocket;
	sockaddr_in clientAddr;
	char clientIP[INET_ADDRSTRLEN];
	int clientAddrLen = sizeof(clientAddr), clientPort;
	while(1){
		connSock = accept(listenSock, (sockaddr *)& clientAddr, &clientAddrLen);
		if (connSock == SOCKET_ERROR)
			printf("Error %d: Cannot permit incoming connection.\n", WSAGetLastError());
		else {
			inet_ntop(AF_INET, &clientAddr.sin_addr, clientIP, sizeof(clientIP));
			clientPort = ntohs(clientAddr.sin_port);
			printf("Accept incoming connection from %s:%d\n", clientIP, clientPort);
			_beginthreadex(0, 0, echoThread, (void *)connSocket, 0, 0); //start thread
		}		
	}
	
	closesocket(listenSock);
	
	WSACleanup();
	
	return 0;
}