#include <iconv.h>

#include "ziconv.hpp"
using namespace iflytop;

string ZIconv::utf8_to_gb2312(const std::string& utf8_str) {
  // 打开转换描述符
  iconv_t cd = iconv_open("GB2312", "UTF-8");
  if (cd == (iconv_t)-1) {
    perror("iconv_open failed");
    exit(EXIT_FAILURE);
  }

  // 输入字符串
  const char* in_str  = utf8_str.c_str();
  size_t      in_size = utf8_str.size();

  // 输出缓冲区
  size_t out_size = in_size * 2;  // 假设输出的字节数不会超过输入的两倍
  char*  out_buf  = new char[out_size];
  char*  out_str  = out_buf;

  // 进行转换
  if (iconv(cd, const_cast<char**>(&in_str), &in_size, &out_str, &out_size) == (size_t)-1) {
    perror("iconv failed");
    iconv_close(cd);
    delete[] out_buf;
    exit(EXIT_FAILURE);
  }

  // 关闭转换描述符
  iconv_close(cd);

  // 获取转换后的字符串
  std::string gb2312_str(out_buf, out_str - out_buf);

  // 释放内存
  delete[] out_buf;

  return gb2312_str;
}