#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <wait.h>



void error(const char *msg)
{
    perror(msg);
    exit(1);
}

void signal_handler(int i)
{
    printf("\nCaught signal I have to go now...BYEEE\n");
    exit(i);
}

void wait_handler(int sig)
{
    pid_t pid;

    pid = wait(NULL);

    printf("Pid %d exited.\n", pid);
}

void parse(char *vector[20], char *line){

    int i;


    char * pch;
    pch = strtok (line," ");
    i=0;
    while (pch != NULL)
    {
        vector[i]=pch;
        printf ("%s\n",pch);
        pch = strtok (NULL, " ");
        i++;
    }
    printf("i = %d\n ", i);
    vector[i]=NULL;
    int k=0;
    for(k=0; k<=i; k++) {
        printf("vector %d = %s \n",k,vector[k]);
    }
}

int main(int argc, char *argv[]) {

    signal(SIGINT,signal_handler);
    signal(SIGCHLD, wait_handler);
    int sockfd,newsockfd,portno;
    socklen_t clilen;
    char buffer[256];
    struct sockaddr_in serv_addr, cli_addr;
    int n,pid,status;
    char str[INET6_ADDRSTRLEN];


    if (argc < 2)
    {
        fprintf(stderr,"No port provided\n");
        exit(1);
    }

    sockfd = socket(AF_INET,SOCK_STREAM,0);
    if(sockfd < 0)
        error("ERROR opening socket");

    memset((char *) &serv_addr, 0, sizeof(serv_addr));
    portno = atoi(argv[1]);
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    serv_addr.sin_port = htons(portno);
    if(bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
        error("ERROR on binding");
    listen(sockfd, 5);
    clilen = sizeof(cli_addr);

    printf("Server running\n");
    for(;;) {
        newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);

        if (newsockfd < 0)
            error("ERROR on accept");

        if (inet_ntop(AF_INET, &cli_addr.sin_addr, str, INET_ADDRSTRLEN) == NULL) {
            fprintf(stderr, "Could not convert byte to address \n");
            exit(1);
        }
        fprintf(stdout, "The client address is :%s\n", str);

        pid=fork();
        if (pid < 0){
            error("Error in fork");
        }
        else if (pid > 1){ // Father
            close(newsockfd);
        }
        else if(pid == 0) {
            for(;;)
            {
                bzero(buffer, 256);
                n = read(newsockfd, buffer, 255);
                if (n < 0) error("ERROS reading from socket");
                if (n == 0)
                {
                    printf("Client disconnected\n");
                    exit(1);
                }

                printf("Here is the message: %s\n", buffer);

                n = write(newsockfd, "message received", 17);
                if (n < 0) error("ERROR writing to socket");

                if ((pid=fork())==-1) /*check for error*/
                {
                    error("Error with fork!");
                    exit(1);
                }
                if (pid!=0) /*The parent process*/
                {
                    printf("I am parent process %d\n",getpid());
                    printf("Child terminated with exit code %d\n",
                           status>>8);
                }
                else /*The child process*/
                {
                    char line[1024];
                    int i;
                    char *vector[20];
                    line[strcspn(line, "\n")] = 0;
                    printf("\n");
                    printf("You typed %s\n",buffer);
                    parse(vector,buffer);
                    printf("I am child Process %d \n",getpid());
                    printf("and i will replace myself by %s\n",buffer);
                    execvp(vector[0],vector);
                    perror("execvp");
                    exit(1);
                }
            }
          }
      }
}