#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

void enc_device_info(uint8_t *puParm1, uint8_t *pbParm2)

{
  int iVar1;
  uint32_t uVar2;
  uint32_t uVar3;

  uVar2 = (((((pbParm2[0] << 8) + pbParm2[1]) << 8) + pbParm2[2]) << 8) + pbParm2[3];
  uVar3 = (((((pbParm2[4] << 8) + pbParm2[5]) << 8) + pbParm2[6]) << 8) + pbParm2[7];
  iVar1 = 0;
  do
  {
    iVar1 = iVar1 + 0x9E3779B9;
    uVar2 = uVar2 + (((uVar3 * 0x10) + 0xB7FAE432) ^ (iVar1 + uVar3) ^ ((uVar3 >> 5) + 0x76B9DAF5));
    uVar3 = uVar3 + (((uVar2 >> 5) + 0x659D0001) ^ (uVar2 * 0x10 + 0xAC540F39) ^ (uVar2 + iVar1));
  } while (iVar1 != 0xC6EF3720);
  *puParm1 = (char)(uVar2 >> 0x18);
  puParm1[1] = (char)(uVar2 >> 0x10);
  puParm1[2] = (char)(uVar2 >> 8);
  puParm1[3] = (char)uVar2;
  puParm1[4] = (char)(uVar3 >> 0x18);
  puParm1[5] = (char)(uVar3 >> 0x10);
  puParm1[6] = (char)(uVar3 >> 8);
  puParm1[7] = (char)uVar3;
  return;
}

/**
   @brief 解密由 enc_device_info 加密的数据。
 * * @param out 指向存放解密后明文的8字节缓冲区。
   @param in 指向待解密的8字节密文。
*/
void dec_device_info(uint8_t *out, uint8_t *in)
{
  uint32_t uVar2; // 数据块的前32位
  uint32_t uVar3; // 数据块的后32位
  uint32_t iVar1; // 轮密钥

  // 1. 从输入密文中加载数据到两个32位变量 (大端模式)
  uVar2 = ((uint32_t)in[0] << 24) | ((uint32_t)in[1] << 16) | ((uint32_t)in[2] << 8) | (uint32_t)in[3];
  uVar3 = ((uint32_t)in[4] << 24) | ((uint32_t)in[5] << 16) | ((uint32_t)in[6] << 8) | (uint32_t)in[7];

  // 2. 初始化轮密钥为加密过程的最终值
  iVar1 = 0xC6EF3720;

  // 3. 执行32轮逆向运算
  for (int i = 0; i < 32; i++)
  {
    // 逆向更新 uVar3, 使用 enc_device_info 中 uVar3 更新的常量
    uVar3 = uVar3 - (((uVar2 >> 5) + 0x659D0001) ^ ((uVar2 << 4) + 0xAC540F39) ^ (uVar2 + iVar1));

    // 逆向更新 uVar2, 使用 enc_device_info 中 uVar2 更新的常量
    uVar2 = uVar2 - (((uVar3 << 4) + 0xB7FAE432) ^ (iVar1 + uVar3) ^ ((uVar3 >> 5) + 0x76B9DAF5));

    // 更新轮密钥到上一轮的值
    iVar1 = iVar1 - 0x9E3779B9;
  }

  // 4. 将解密后的32位变量写回输出缓冲区 (大端模式)
  out[0] = (uint8_t)(uVar2 >> 24);
  out[1] = (uint8_t)(uVar2 >> 16);
  out[2] = (uint8_t)(uVar2 >> 8);
  out[3] = (uint8_t)uVar2;
  out[4] = (uint8_t)(uVar3 >> 24);
  out[5] = (uint8_t)(uVar3 >> 16);
  out[6] = (uint8_t)(uVar3 >> 8);
  out[7] = (uint8_t)uVar3;
}

void enc_device_data(uint8_t *puParm1, uint8_t *pbParm2)

{
  int iVar1;
  uint32_t uVar2;
  uint32_t uVar3;

  uVar2 = (((((pbParm2[0] << 8) + pbParm2[1]) << 8) + pbParm2[2]) << 8) + pbParm2[3];
  uVar3 = (((((pbParm2[4] << 8) + pbParm2[5]) << 8) + pbParm2[6]) << 8) + pbParm2[7];
  iVar1 = 0;
  do
  {
    iVar1 = iVar1 + 0x9E3779B9;
    uVar2 = uVar2 + (((uVar3 * 0x10) + 0x659D0001) ^ (iVar1 + uVar3) ^ ((uVar3 >> 5) + 0xAC540F39));
    uVar3 = uVar3 + (((uVar2 >> 5) + 0xB7FAE432) ^ (uVar2 * 0x10 + 0x76B9DAF5) ^ (uVar2 + iVar1));
  } while (iVar1 != 0xC6EF3720);
  *puParm1 = (char)(uVar2 >> 0x18);
  puParm1[1] = (char)(uVar2 >> 0x10);
  puParm1[2] = (char)(uVar2 >> 8);
  puParm1[3] = (char)uVar2;
  puParm1[4] = (char)(uVar3 >> 0x18);
  puParm1[5] = (char)(uVar3 >> 0x10);
  puParm1[6] = (char)(uVar3 >> 8);
  puParm1[7] = (char)uVar3;
  return;
}

// 传入参数：out - 用于存放解密后明文的缓冲区(8字节), in - 待解密的密文(8字节)
void dec_device_data(uint8_t *out, uint8_t *in)
{
  uint32_t uVar2; // 对应加密函数的 uVar2 (数据块的前32位)
  uint32_t uVar3; // 对应加密函数的 uVar3 (数据块的后32位)
  uint32_t iVar1; // 对应加密函数的 iVar1 (轮密钥)

  // 1. 从输入密文中加载数据到两个32位变量 (大端模式)
  uVar2 = ((uint32_t)in[0] << 24) | ((uint32_t)in[1] << 16) | ((uint32_t)in[2] << 8) | (uint32_t)in[3];
  uVar3 = ((uint32_t)in[4] << 24) | ((uint32_t)in[5] << 16) | ((uint32_t)in[6] << 8) | (uint32_t)in[7];

  // 2. 初始化轮密钥为加密过程的最终值
  // 0xC6EF3720 = 32 * 0x9E3779B9
  iVar1 = 0xC6EF3720;

  // 3. 执行32轮逆向运算
  // 使用 for 循环代替 do-while，逻辑更清晰
  for (int i = 0; i < 32; i++)
  {
    // 逆向更新 uVar3
    uVar3 = uVar3 - (((uVar2 >> 5) + 0xB7FAE432) ^ ((uVar2 << 4) + 0x76B9DAF5) ^ (uVar2 + iVar1));

    // 逆向更新 uVar2
    // 注意: 原加密代码中的 uVar3 * 0x10 等价于 uVar3 << 4
    uVar2 = uVar2 - (((uVar3 << 4) + 0x659D0001) ^ (iVar1 + uVar3) ^ ((uVar3 >> 5) + 0xAC540F39));

    // 更新轮密钥到上一轮的值
    iVar1 = iVar1 - 0x9E3779B9;
  }

  // 4. 将解密后的32位变量写回输出缓冲区 (大端模式)
  out[0] = (uint8_t)(uVar2 >> 24);
  out[1] = (uint8_t)(uVar2 >> 16);
  out[2] = (uint8_t)(uVar2 >> 8);
  out[3] = (uint8_t)uVar2;
  out[4] = (uint8_t)(uVar3 >> 24);
  out[5] = (uint8_t)(uVar3 >> 16);
  out[6] = (uint8_t)(uVar3 >> 8);
  out[7] = (uint8_t)uVar3;
}

const uint8_t test_data[][8] = {
  {0, 1, 2, 3, 4, 5, 6, 7},
  {1, 2, 3, 4, 5, 6, 7, 8},
};
void app_main() {
  printf("Hello, Wokwi!\n");
  uint8_t tmp_buf[8];
  for (int i = 0; i < sizeof(test_data) / sizeof(test_data[0]); i++)
  {
    printf("=======================\r\n");
    printf("test data:");
    for (int str_i = 0; str_i < 8; str_i++)
    {
      printf("%02x ", test_data[i][str_i]);
    }
    printf("\r\n");
    enc_device_data(tmp_buf, (uint8_t *)&test_data[i]);
    printf("enc data:");
    for (int str_i = 0; str_i < 8; str_i++)
    {
      printf("%02x ", tmp_buf[str_i]);
    }
    printf("\r\n");

    dec_device_data(tmp_buf, tmp_buf);
    printf("dec data:");
    for (int str_i = 0; str_i < 8; str_i++)
    {
      printf("%02x ", tmp_buf[str_i]);
    }
    printf("\r\n");
  }
  while (true) {

    vTaskDelay(1000 / portTICK_PERIOD_MS);
  }
}