/***********************************************************
 * Name of program: UNIKernel
 * Authors: Ryan Wehrman and Sarah Van Norden
 * Description: This will be a custom kernel that will be able to run commands.
 **********************************************************/
/*This Kernel will have the functionality to run programs and not quit out until the user presses CTRL+D or 'quit'. 
I would like to make it so that they can put in a variety of inputs to quit out of the Kernel
In order for this to work we will need to have some intercepts of the keys the user inputs. CTRL+C cannot close out this Kerenl
The commands for quitting should me:
'quit', 'Quit', 'exit', 'Exit', 'Logout', 'logout' or any variation of those.*/


/* These are the included libraries.  You may need to add more. */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <ctype.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>
/* Put any symbolic constants (defines) here */
#define True 1 
#define False 0
char lastcommand[80]="";
/* This is the start of the shell. In here we will be able to run commands and as of 2 it is running basic commands from execvp*/
int main(int argc, char *argv[])
{

  while(1){
    //Initilization up here
    int showpid[5];
    pid_t pid;
    char inputstr[80];
    char * arguments[10];
    int argnumber = 0;
    int i;
    char lastcommand[80];
    char * brokenString = NULL;
    printf("UNIShell$ ");
    fgets(inputstr, 80, stdin);
    inputstr[strcspn(inputstr, "\n")] = 0;
    //This mess is for Ryan as he types all four to quit out lol
    if (strncmp(inputstr, "quit", 4) == 0 || strncmp(inputstr, "Exit", 4) == 0 || strncmp(inputstr, "exit", 4) == 0 || strncmp(inputstr, "Quit", 4) == 0){
      printf("Exiting!\n");
      exit(0);
    }
    if (strncmp(inputstr,"lc",2)!=0){
      strcpy(lastcommand,inputstr);
    }
    else {
      strcpy(inputstr,lastcommand);
    }
    // This will make BrokenString and split the input on whitespaces
    brokenString = strtok(inputstr, " " );
    //printf(brokenString);
    //^^ Print for testing

    /* while (brokenString != NULL){
        printf ("%s\n", brokenString);
	brokenString = strtok (NULL, " ");
	}*/
    //^ Was an attempt at a check that did not respond the way I wanted to
    //Sets the memory to 0's when starting as it does not trash collect
    memset(arguments, 0, sizeof(arguments));
    memset(showpid, 0, sizeof(showpid));
    //This while loop will send the BrokenString and store it as an array so that we can call it later
    while(brokenString != NULL){
      arguments[argnumber] = brokenString;
      brokenString = strtok(NULL, " ");
      argnumber++;
    }
    if (strncmp(inputstr, "cd", 2) == 0){
      chdir(arguments[1]);
      setenv("PWD", arguments[1], 1);
    }
    /*if (strncmp(inputstr, "showpid", 7) == 0){
      for (i=0; i<5; i++){
	printf("%d \n", showpid[i]);
      }
      continue;
      }*/
    /*arguments[0] = "ps";
    arguments[1] = "-aux";
    arguments[2] = NULL;*/

    //^Some hardcoded arguments

    //Printing for test
    // printf("%s", arguments[0]);

    //This is a the fork that will find the child function and execute commands given there
    if ((pid = fork()) == 0){
      execvp(arguments[0], arguments);
      if(strncmp(inputstr, "showpid", 7) != 0 || strncmp(inputstr, "cd", 2) != 0 || strncmp(inputstr, "..", 2) != 0 || strncmp(inputstr,"lc",2) != 0){
	printf("Error: Command Not Found\n");
	//Do we still need this print statement now that we have showpid and cd functionality??
      }
      exit(0);
    }
    //Else will wait for the child to finish then go back to the start
    else{
      showpid[0] = showpid[1];
      showpid[1] = showpid[2];
      showpid[2] = showpid[3];
      showpid[3] = showpid[4];
      showpid[4] = pid;
      waitpid(-1, NULL, 0);
    }
    if (strncmp(inputstr, "showpid", 7) == 0){
      for (i=0; i<5; i++){
	printf("%d \n", showpid[i]);
      }
      continue;
    }
  }
}