/* SPDX-License-Identifier: GPL-3.0-or-later

 * Copyright © 2016-2018 The TokTok team.

 * Copyright © 2013 Tox project.

 */

/*

 * Miscellaneous functions and data structures for doing random things.

 */

#ifndef _POSIX_C_SOURCE

// For nanosleep().

#define _POSIX_C_SOURCE 200112L

#endif

#include "misc_tools.h"

#include <assert.h>

#include <ctype.h>

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sodium.h>

#if defined(_WIN32) || defined(__WIN32__) || defined(WIN32)

#include <windows.h>

#else

#include <time.h>

#endif

#include "../toxcore/ccompat.h"

#include "../toxcore/tox.h"

void c_sleep(uint32_t x)

{

#if defined(_WIN32) || defined(__WIN32__) || defined(WIN32)

    Sleep(x);

#else

    struct timespec req;

    req.tv_sec = x / 1000;

    req.tv_nsec = (long)x % 1000 * 1000 * 1000;

    nanosleep(&req, nullptr);

#endif

}

// You are responsible for freeing the return value!

uint8_t *hex_string_to_bin(const char *hex_string)

{

    // byte is represented by exactly 2 hex digits, so length of binary string

    // is half of that of the hex one. only hex string with even length

    // valid. the more proper implementation would be to check if strlen(hex_string)

    // is odd and return error code if it is. we assume strlen is even. if it's not

    // then the last byte just won't be written in 'ret'.

    size_t i, len = strlen(hex_string) / 2;

    uint8_t *ret = (uint8_t *)malloc(len);

    const char *pos = hex_string;

    if (ret == nullptr) {

        return nullptr;

    }

    for (i = 0; i < len; ++i, pos += 2) {

        unsigned int val;

        sscanf(pos, "%02x", &val);

        ret[i] = val;

    }

    return ret;

}

void to_hex(char *out, uint8_t *in, int size)

{

    while (size--) {

        if (*in >> 4 < 0xA) {

            *out++ = '0' + (*in >> 4);

        } else {

            *out++ = 'A' + (*in >> 4) - 0xA;

        }

        if ((*in & 0xf) < 0xA) {

            *out++ = '0' + (*in & 0xF);

        } else {

            *out++ = 'A' + (*in & 0xF) - 0xA;

        }

        in++;

    }

}

/* Reimplementation of strncasecmp() function from strings.h, as strings.h is

 * POSIX and not portable. Specifically it doesn't exist on MSVC.

 */

int tox_strncasecmp(const char *s1, const char *s2, size_t n)

{

    while (n--) {

        int c1 = tolower(*(s1++));

        int c2 = tolower(*(s2++));

        if (c1 == '\0' || c2 == '\0' || c1 != c2) {

            return c1 - c2;

        }

    }

    return 0;

}

int cmdline_parsefor_ipv46(int argc, char **argv, bool *ipv6enabled)

{

    int argvoffset = 0, argi;

    for (argi = 1; argi < argc; argi++) {

        if (!tox_strncasecmp(argv[argi], "--ipv", 5)) {

            if (argv[argi][5] && !argv[argi][6]) {

                char c = argv[argi][5];

                if (c == '4') {

                    *ipv6enabled = false;

                } else if (c == '6') {

                    *ipv6enabled = true;

                } else {

                    printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);

                    return -1;

                }

            } else {

                printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);

                return -1;

            }

            if (argvoffset != argi - 1) {

                printf("Argument must come first: %s.\n", argv[argi]);

                return -1;

            }

            argvoffset++;

        }

    }

    return argvoffset;

}

static const char *test_rng_name(void)

{

    return "test_rng";

}

static uint32_t rng_state;

static uint32_t test_rng_random(void)

{

    rng_state = 2624534371 * rng_state + 1;

    return rng_state;

}

static void test_rng_buf(void *const buf, const size_t size)

{

    uint8_t *p = (uint8_t *)buf;

    uint32_t r = 0;

    for (size_t i = 0; i < size; i++) {

        if ((i % 4) == 0) {

            r = test_rng_random();

        }

        *p = (r >> ((i % 4) * 8)) & 0xff;

        ++p;

    }

}

static uint32_t test_rng_uniform(const uint32_t upper_bound)

{

    // XXX: Not uniform! But that's ok for testing purposes.

    return test_rng_random() % upper_bound;

}

static void test_rng_stir(void) { }

static int test_rng_close(void)

{

    return 0;

}

static randombytes_implementation test_rng = {

    test_rng_name,

    test_rng_random,

    test_rng_stir,

    test_rng_uniform,

    test_rng_buf,

    test_rng_close

};

/* Simple insecure PRNG for testing purposes */

int use_test_rng(uint32_t seed)

{

    rng_state = seed;

    return randombytes_set_implementation(&test_rng);

}