#include <stdlib.h>
#include <stdio.h>
#include <string.h>	// Mainly for strtok
#include <unistd.h>
#include <errno.h>

#define MAX_ARGS 4

char * PATH = "MyShell$ ";

char *path; //for the command path

typedef struct{
	char *cmd_path;	//path of command
	int argc;	//number of args for the cmd
	char *argv[MAX_ARGS];
	//char cmd_suffix;
}commandStruct;

void runCommand(commandStruct *command1);

void cdr(int argc, char *argv[]);

int main() {
	
	system("clear");

	while(1) {
                int flag = 0; //gia tin entoli cd
		char buffer[100], *input;
		pid_t child;
		int childstatus, status;	//For Fork
	
		char *cmd;			//For strtok

		char *command;			//The command
		int cmdlen;

		commandStruct *command1 = (commandStruct*) malloc(sizeof(commandStruct));	
		command1->argc = 1;
		
		printf("%s", PATH);
		fflush(stdout);
                input=fgets(buffer, 100, stdin);
		
                
                while(input[0]=='\n')
                {
                    printf("%s", PATH);
                    fflush(stdout);
                    input = fgets(buffer, 256, stdin);
                }
                
                

		cmdlen = strlen(input);		//Take out new line char
		if (input[cmdlen-1] == '\n') {	//
			input[cmdlen-1] = '\0';	//
		}				//

		//Get first token (the command) from input
       		cmd = strtok(input, " ");
		command = cmd;
                
               
		if (strcmp(command, "exit") == 0){
                    break;
		}
                
               
		command1->cmd_path = command;
		command1->argv[0] = command1->cmd_path;
	
		//Loop thru until whole command is tokenized
	        while (1)
	        {
	               	//Check command has no more than 4 args
			if (command1->argc > 4) {
				printf("\nError! Too many command arguements!\n");
				break;
			}

			//Extract next part of command
	                cmd = strtok(NULL, " ");

	                //Check that there is nothing else to extract
	                if (cmd == NULL)
	                {
	                        //printf("Command Tokenised");
				break;
			}

			command1->argv[command1->argc] = cmd;	//put arg into arg array
			command1->argc = command1->argc+1;	//increase count of args
		         	
	        }

		printf("Number of args: %d\n", command1->argc);
	
                if(strcmp(command, "cd") == 0){
                                cdr(command1->argc, command1->argv);
                                flag=1;
                }
                if(flag==0){
                    childstatus = fork();
                    if (childstatus != 0) { //if parent process is running
			wait(&status);
		} 
                else {
		/* This area is child process */
                        runCommand(command1);
			return(0);
		}
                }

	}
	return 0;
	exit(0);
}

void cdr(int argc, char *argv[]){
    
    if(argc==1){
        const char* home=getenv("HOME");
        chdir(home);
        return;
    }
    int result=chdir(argv[1]);
    if (result!=0){
        switch(result){
            case EACCES: perror("Permission denied");
            break;
            case EIO:	perror("An input output error occured");
            break;
            case ENAMETOOLONG: perror("Path is to long");
            break;
            case ENOTDIR: perror("A component of path not a directory");
            break;
            case ENOENT: perror("No such file or directory"); printf("enoent\n");
            break;
            default: printf("Couldn't change directory to %s\n", argv[1] );
        }
   }
}

void runCommand(commandStruct *command1) {
	
	printf("Command: %s\n", command1->cmd_path);
        int i=0;
	i=execvp(command1->cmd_path, command1->argv);
        if (i==-1){
            printf("Λανθασμένη ή μη υποστηριζόμενη εντολή\n");
        }

}