/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <assert.h>
#include <direct.h>
#include <malloc.h>
#include <string.h>

#include "uv.h"
#include "internal.h"
#include "tlhelp32.h"


int uv_utf16_to_utf8(const wchar_t* utf16Buffer, size_t utf16Size,
    char* utf8Buffer, size_t utf8Size) {
  return WideCharToMultiByte(CP_UTF8,
                             0,
                             utf16Buffer,
                             utf16Size,
                             utf8Buffer,
                             utf8Size,
                             NULL,
                             NULL);
}


int uv_utf8_to_utf16(const char* utf8Buffer, wchar_t* utf16Buffer,
    size_t utf16Size) {
  return MultiByteToWideChar(CP_UTF8,
                             0,
                             utf8Buffer,
                             -1,
                             utf16Buffer,
                             utf16Size);
}


int uv_exepath(char* buffer, size_t* size) {
  int retVal;
  size_t utf16Size;
  wchar_t* utf16Buffer;

  if (!buffer || !size) {
    return -1;
  }

  utf16Buffer = (wchar_t*)malloc(sizeof(wchar_t) * *size);
  if (!utf16Buffer) {
    retVal = -1;
    goto done;
  }

  /* Get the path as UTF-16 */
  utf16Size = GetModuleFileNameW(NULL, utf16Buffer, *size - 1);
  if (utf16Size <= 0) {
    /* uv__set_sys_error(loop, GetLastError()); */
    retVal = -1;
    goto done;
  }

  utf16Buffer[utf16Size] = L'\0';

  /* Convert to UTF-8 */
  *size = uv_utf16_to_utf8(utf16Buffer, utf16Size, buffer, *size);
  if (!*size) {
    /* uv__set_sys_error(loop, GetLastError()); */
    retVal = -1;
    goto done;
  }

  buffer[*size] = '\0';
  retVal = 0;

done:
  if (utf16Buffer) {
    free(utf16Buffer);
  }

  return retVal;
}


uv_err_t uv_cwd(char* buffer, size_t size) {
  uv_err_t err;
  size_t utf8Size;
  wchar_t* utf16Buffer = NULL;

  if (!buffer || !size) {
    err.code = UV_EINVAL;
    goto done;
  }

  utf16Buffer = (wchar_t*)malloc(sizeof(wchar_t) * size);
  if (!utf16Buffer) {
    err.code = UV_ENOMEM;
    goto done;
  }

  if (!_wgetcwd(utf16Buffer, size - 1)) {
    err = uv__new_sys_error(_doserrno);
    goto done;
  }

  utf16Buffer[size - 1] = L'\0';

  /* Convert to UTF-8 */
  utf8Size = uv_utf16_to_utf8(utf16Buffer, -1, buffer, size);
  if (utf8Size == 0) {
    err = uv__new_sys_error(GetLastError());
    goto done;
  }

  buffer[utf8Size] = '\0';
  err = uv_ok_;

done:
  if (utf16Buffer) {
    free(utf16Buffer);
  }

  return err;
}


uv_err_t uv_chdir(const char* dir) {
  uv_err_t err;
  wchar_t* utf16Buffer = NULL;
  size_t utf16Size;

  if (!dir) {
    err.code = UV_EINVAL;
    goto done;
  }

  utf16Size = uv_utf8_to_utf16(dir, NULL, 0);
  if (!utf16Size) {
    err = uv__new_sys_error(GetLastError());
    goto done;
  }

  utf16Buffer = (wchar_t*)malloc(sizeof(wchar_t) * utf16Size);
  if (!utf16Buffer) {
    err.code = UV_ENOMEM;
    goto done;
  }

  if (!uv_utf8_to_utf16(dir, utf16Buffer, utf16Size)) {
    err = uv__new_sys_error(GetLastError());
    goto done;
  }

  if (_wchdir(utf16Buffer) == -1) {
    err = uv__new_sys_error(_doserrno);
    goto done;
  }

  err = uv_ok_;

done:
  if (utf16Buffer) {
    free(utf16Buffer);
  }

  return err;
}


void uv_loadavg(double avg[3]) {
  /* Can't be implemented */
  avg[0] = avg[1] = avg[2] = 0;
}


uint64_t uv_get_free_memory(void) {
  MEMORYSTATUSEX memory_status;
  memory_status.dwLength = sizeof(memory_status);

  if(!GlobalMemoryStatusEx(&memory_status))
  {
     return -1;
  }

  return (uint64_t)memory_status.ullAvailPhys;
}


uint64_t uv_get_total_memory(void) {
  MEMORYSTATUSEX memory_status;
  memory_status.dwLength = sizeof(memory_status);

  if(!GlobalMemoryStatusEx(&memory_status))
  {
    return -1;
  }

  return (uint64_t)memory_status.ullTotalPhys;
}


int uv_parent_pid() {
  int parent_pid = -1;
  HANDLE handle;
  PROCESSENTRY32 pe;
  int current_pid = GetCurrentProcessId();

  pe.dwSize = sizeof(PROCESSENTRY32);
  handle = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);

  if (Process32First(handle, &pe)) {
    do {
      if (pe.th32ProcessID == current_pid) {
        parent_pid = pe.th32ParentProcessID;
        break;
      }
    } while( Process32Next(handle, &pe));
  }

  CloseHandle(handle);
  return parent_pid;
}