#include <limits.h>
#include <errno.h>
#include<stdio.h>
#include <stdlib.h>
#include<unistd.h>
#include<getopt.h>


static struct option option_args[] = {
    {"help", no_argument, 0, 'h' },
    {"verbose", no_argument, 0, 'v' },
    {"output", required_argument, 0, 'o' },
    {"max", required_argument, 0, 'm' },
    {0,0,0,0}
};

void print_usage(char* arg){
    fprintf(stdout, "Uso: %s\n", arg);
    fprintf(stdout, "[--help]\n");
    fprintf(stdout, "[--verbose]\n");
    fprintf(stdout, "[--output <archivo>]\n");
    fprintf(stdout, "[--max <num>]\n");
    fprintf(stdout, "[posicionales...]\n");
}

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

    printf("argv[0]: %s\n", argv[0]);

    int opt;
    int opt_index = 0;

    while((opt = getopt_long(argc, argv, "hvo:m:", option_args, &opt_index)) != -1){
        switch (opt){
            case 'h':
                print_usage(argv[0]);
                exit(0);
                break;
            case 'v':
                fprintf(stdout, "Modo verbose: ON\n");
                break;
            case 'o':
                fprintf(stdout, "Output: %s\n", optarg);
                break;
            case 'm':
                errno = 0;
                char* errorptr = NULL;
                long maximo = strtol(optarg, &errorptr, 10);
                if(    (errno == EINVAL) 
                    || (errno == ERANGE) 
                    || (*errorptr != 0)
                    || (maximo < INT_MIN)
                    || (maximo > INT_MAX)
                ){
                    fprintf(stderr, "--max debe ser un numero entero valido.\n");
                    exit(1);
                }
                printf("Maximo:%ld\n", maximo);
                break;
            case '?':
                print_usage(argv[0]);
                exit(1);
                break;
        }
    }

    fprintf(stdout, "Posicionales:\n");
    for(int i = optind; i < argc; i++){
        fprintf(stdout, "%s\n", argv[i]);
    }

    return 0;
}