//https://iq.opengenus.org/ls-command-in-c/

//Used for basic input/output stream
#include <stdio.h>
//Used for handling directory files
#include <dirent.h>
//For EXIT codes and error handling
#include <errno.h>
#include <stdlib.h>

void _ls(const char *dir,int op_a,int op_l)
{
    //Here we will list the directory
    struct dirent *d;
    DIR *dh = opendir(dir);
    if (!dh)
    {
        if (errno = ENOENT)
        {
            //If the directory is not found
            perror("Directory doesn't exist");
        }
        else
        {
            //If the directory is not readable then throw error and exit
            perror("Unable to read directory");
        }
        exit(EXIT_FAILURE);
    }
    //While the next entry is not readable we will print directory files
    while ((d = readdir(dh)) != NULL)
    {
        //If hidden files are found we continue
        if (!op_a && d->d_name[0] == '.')
            continue;
        printf("%s  ", d->d_name);
        if(op_l) printf("\n");
    }
    if(!op_l)
    printf("\n");
}
int main(int argc, const char *argv[])
{
    if (argc == 1)
    {
        _ls(".",0,0);
    }
    else if (argc == 2)
    {
        if (argv[1][0] == '-')
        {
            //Checking if option is passed
            //Options supporting: a, l
            int op_a = 0, op_l = 0;
            char *p = (char*)(argv[1] + 1);
            while(*p){
                if(*p == 'a') op_a = 1;
                else if(*p == 'l') op_l = 1;
                else{
                    perror("Option not available");
                    exit(EXIT_FAILURE);
                }
                p++;
            }
            _ls(".",op_a,op_l);
        }
    }
    return 0;
}