// This is a personal academic project. Dear PVS-Studio, please check it.
// PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <errno.h>
#include <getopt.h>

#include "args.h"

static unsigned short port(const char *s) {
     char *end = 0;
     const long sl = strtol(s, &end, 10);

     if (end == s || '\0' != *end || ((LONG_MIN == sl || LONG_MAX == sl) && ERANGE == errno) || sl < 0 || sl > USHRT_MAX) {
         fprintf(stderr, "Port should be in the range of 1-65536: %s\n", s);
         exit(1);
         return 1;
     }
     return (unsigned short) sl;
}

static void user(char *s, struct users *user) {
    char *p = strchr(s, ':');
    if (p == NULL) {
        fprintf(stderr, "Password not found\n");
        exit(1);
    } else {
        *p = 0;
        p++;
        user->name = s;
        user->pass = p;
    }
}

static void version(void) {
    fprintf(stderr, "BProxy v0.0\nITBA Protocolos de Comunicación 2021/1 -- Grupo 7\nVer LICENSE.md\n");
}

static void usage(const char *progname) {
    fprintf(stderr,
        "Usage: %s [OPTION]\n\n"
        "   -h               Imprime la ayuda y termina.\n"
        "   -l <SOCKS addr>  Dirección donde servirá el proxy SOCKS.\n"
        "   -L <conf addr>  Dirección donde servirá el servicio de management.\n"
        "   -p <SOCKS port>  Puerto entrante conexiones SOCKS.\n"
        "   -P <conf port>   Puerto entrante conexiones configuracion.\n"
        "   -u <name>:<pass> Usuario y contraseña de usuario que puede usar el proxy. Hasta 500.\n"
        "   -v               Imprime información sobre la versión y termina.\n\n",
        progname);
    exit(1);
}

void parse_args(const int argc, char **argv, struct socks5args *args) {
    memset(args, 0, sizeof(*args));

    args->socks_addr = "0.0.0.0";
    args->socks_port = 1080;

    args->mng_addr   = "127.0.0.1";
    args->mng_port   = 8080;

    args->disectors_enabled = true;

    int c;
    int nusers = 0;

    while (true) {
        c = getopt(argc, argv, "hl:L:Np:P:u:v");
        if (c == -1)
            break;

        switch (c) {
            case 'h':
                usage(argv[0]);
                break;
            case 'l':
                args->socks_addr = optarg;
                break;
            case 'L':
                args->mng_addr = optarg;
                break;
            case 'N':
                args->disectors_enabled = false;
                break;
            case 'p':
                args->socks_port = port(optarg);
                break;
            case 'P':
                args->mng_port   = port(optarg);
                break;
            case 'u':
                if (nusers >= MAX_USERS) {
                    fprintf(stderr, "Maximun number of command line users reached: %d.\n", MAX_USERS);
                    exit(1);
                } else {
                    user(optarg, args->users + nusers);
                    nusers++;
                }
                break;
            case 'v':
                version();
                exit(0);
                break;
            default:
                fprintf(stderr, "unknown argument %d.\n", c);
                exit(1);
        }

    }

    if (optind < argc) {
        fprintf(stderr, "Argument not accepted: ");
        while (optind < argc) {
            fprintf(stderr, "%s ", argv[optind++]);
        }
        fprintf(stderr, "\n");
        exit(1);
    }
}