// UDP server that use blocking sockets
#define _WINSOCK_DEPRECATED_NO_WARNINGS

#define WIN32_LEAN_AND_MEAN

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include "conio.h"

#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")

#define SERVER_PORT 15000   // Port number of server that will be used for communication with clients
#define BUFFER_SIZE 512     // Size of buffer that will be used for sending and receiving messages to clients

struct Client
{
    char nadimak[32];
    char IP[16];
    int port;
};

void mySend(SOCKET soket, char* msg, sockaddr_in dest)
{
    int result = sendto(soket, msg, strlen(msg), 0, (sockaddr*)&dest, sizeof(dest));
    if (result == SOCKET_ERROR)
    {
        printf("Sendto failed with code %d!\n", WSAGetLastError());
        closesocket(soket);
        WSACleanup();
        exit(1);
    }
}

Client makeClient(sockaddr_in client, char* name)
{
    Client c;
    strcpy_s(c.IP, inet_ntoa(client.sin_addr));
    strcpy_s(c.nadimak, name);
    c.port = htons(client.sin_port);
    return c;
}

void initWSA(WSADATA* data)
{
    if (WSAStartup(MAKEWORD(2, 2), data) != 0)
    {
        printf("WSAStartup failed with error: %d\n", WSAGetLastError());
        exit(1);
    }

}

int main()
{
    WSADATA data;
    initWSA(&data);

    sockaddr_in serverAddress;
    memset((char*)&serverAddress, 0, sizeof(serverAddress));
    serverAddress.sin_family = AF_INET;             // set server address protocol family
    serverAddress.sin_addr.s_addr = INADDR_ANY;     // use all available addresses of server
    serverAddress.sin_port = htons(SERVER_PORT);

    SOCKET serverSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (serverSocket == INVALID_SOCKET)
    {
        printf("Creating socket failed with error: %d\n", WSAGetLastError());
        WSACleanup();
        return 1;
    }

    int iResult = bind(serverSocket, (SOCKADDR *)&serverAddress, sizeof(serverAddress));
    if (iResult == SOCKET_ERROR)
    {
        printf("Socket bind failed with error: %d\n", WSAGetLastError());
        closesocket(serverSocket);
        WSACleanup();
        return 1;
    }


    while (true)
    {


        printf("Server ceka vase nadimke...\n");
        sockaddr_in client1, client2;
        int client1Len = sizeof(client1), client2Len = sizeof(client2);
        char nadimak1[32] = { 0 }, nadimak2[32] = { 0 };

        memset(&client1, 0, sizeof(client1));
        memset(&client2, 0, sizeof(client2));

        char pozdrav[50] = { 0 };
        int result;

        result = recvfrom(serverSocket, nadimak1, 32, 0, (sockaddr*)&client1, &client1Len);
        //nadimak1[result] = '\0';
        sprintf_s(pozdrav, "Welcome, %s!\n", nadimak1);
        mySend(serverSocket, pozdrav, client1);


        result = recvfrom(serverSocket, nadimak2, 32, 0, (sockaddr*)&client2, &client2Len);
        //nadimak2[result] = '\0';
        sprintf_s(pozdrav, "Welcome, %s!\n", nadimak2);
        mySend(serverSocket, pozdrav, client2);


        Client k1 = makeClient(client1, nadimak1);
        Client k2 = makeClient(client2, nadimak2);


        printf("%s - %s : %d\n", k1.nadimak, k1.IP, k1.port);
        printf("%s - %s : %d\n", k2.nadimak, k2.IP, k2.port);

        printf("---------------------------------------------------------\n");
        printf("-------------------Pocetak dopisivanja-------------------\n");
        printf("---------------------------------------------------------\n");


        // Main server loop
        char dataBuffer[BUFFER_SIZE];
        while (1)
        {
            memset(dataBuffer, 0, BUFFER_SIZE);

            sockaddr_in clientAddress;
            memset(&clientAddress, 0, sizeof(clientAddress));
            int sockAddrLen = sizeof(clientAddress);

            iResult = recvfrom(serverSocket, dataBuffer, BUFFER_SIZE, 0, (SOCKADDR *)&clientAddress, &sockAddrLen);
            dataBuffer[iResult] = '\0';

            int port = htons(clientAddress.sin_port);
            if (port == k1.port)
            {
                // Prvi je
                mySend(serverSocket, dataBuffer, client2);

                printf("%s - %s\n", nadimak1, dataBuffer);
                if (!strcmp(dataBuffer, "Goodbye"))
                    break;
            }
            else if (port == k2.port)
            {
                //Drugi je
                mySend(serverSocket, dataBuffer, client1);

                printf("%s - %s\n", nadimak2, dataBuffer);
                if (!strcmp(dataBuffer, "Goodbye"))
                    break;
            }

        }

        printf("---------------------------------------------------------\n");
        printf("----------------------Kraj dopisivanja-------------------\n");
        printf("---------------------------------------------------------\n");
    }


    iResult = closesocket(serverSocket);
    if (iResult == SOCKET_ERROR)
    {
        printf("closesocket failed with error: %ld\n", WSAGetLastError());
        WSACleanup();
        return 1;
    }
    printf("Server successfully shut down.\n");
    WSACleanup();
    return 0;
}