/*
 *  OpenVPN-GUI -- A Windows GUI for OpenVPN.
 *
 *  Copyright (C) 2004 Mathias Sundman <mathias@nilings.se>
 *                2016 Selva Nair <selva.nair@gmail.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <windows.h>
#include <tchar.h>
#include <shlobj.h>

#include "main.h"
#include "options.h"
#include "openvpn-gui-res.h"
#include "registry.h"
#include "localization.h"

extern options_t o;

struct regkey_str {
    const WCHAR *name;
    WCHAR *var;
    int len;
    const WCHAR *value;
} regkey_str[] = {
      {L"config_dir", o.config_dir, _countof(o.config_dir), L"%USERPROFILE%\\OpenVPN\\config"},
      {L"config_ext", o.ext_string, _countof(o.ext_string), L"ovpn"},
      {L"log_dir", o.log_dir, _countof(o.log_dir), L"%USERPROFILE%\\OpenVPN\\log"}
    };

struct regkey_int {
    const WCHAR *name;
    DWORD *var;
    DWORD value;
} regkey_int[] = {
      {L"log_append", &o.log_append, 0},
      {L"iservice_admin", &o.iservice_admin, 1},
      {L"show_balloon", &o.show_balloon, 1},
      {L"silent_connection", &o.silent_connection, 0},
      {L"preconnectscript_timeout", &o.preconnectscript_timeout, 10},
      {L"connectscript_timeout", &o.connectscript_timeout, 30},
      {L"disconnectscript_timeout", &o.disconnectscript_timeout, 10},
      {L"show_script_window", &o.show_script_window, 0},
      {L"service_only", &o.service_only, 0},
      {L"config_menu_view", &o.config_menu_view, CONFIG_VIEW_AUTO}
    };

static int
RegValueExists (HKEY regkey, const WCHAR *name)
{
    return (RegQueryValueEx (regkey, name, NULL, NULL, NULL, NULL) == ERROR_SUCCESS);
}

static int
GetGlobalRegistryKeys()
{
  TCHAR windows_dir[MAX_PATH];
  TCHAR openvpn_path[MAX_PATH];
  HKEY regkey;

  if (!GetWindowsDirectory(windows_dir, _countof(windows_dir))) {
    /* can't get windows dir */
    ShowLocalizedMsg(IDS_ERR_GET_WINDOWS_DIR);
    /* Use a default value */
    _sntprintf_0(windows_dir, L"C:\\Windows");
  }

  /* set default editor and log_viewer as a fallback for opening config/log files */
  _sntprintf_0(o.editor, L"%s\\%s", windows_dir, L"System32\\notepad.exe");
  _sntprintf_0(o.log_viewer, L"%s", o.editor);

  /* Get path to OpenVPN installation. */
  if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, _T("SOFTWARE\\OpenVPN"), 0, KEY_READ, &regkey)
      != ERROR_SUCCESS)
    {
      /* registry key not found */
      regkey = NULL;
      ShowLocalizedMsg(IDS_ERR_OPEN_REGISTRY);
    }
  if (!regkey || !GetRegistryValue(regkey, _T(""), openvpn_path, _countof(openvpn_path))
      || _tcslen(openvpn_path) == 0)
    {
      /* error reading registry value */
      if (regkey)
          ShowLocalizedMsg(IDS_ERR_READING_REGISTRY);
      /* Use a sane default value */
      _sntprintf_0(openvpn_path, _T("%s"), _T("C:\\Program Files\\OpenVPN\\"));
    }
  if (openvpn_path[_tcslen(openvpn_path) - 1] != _T('\\'))
    _tcscat(openvpn_path, _T("\\"));

  /* an admin-defined global config dir defined in HKLM\OpenVPN\config_dir */
  if (!regkey || !GetRegistryValue(regkey, _T("config_dir"), o.global_config_dir, _countof(o.global_config_dir)))
    {
      /* use default = openvpnpath\config */
      _sntprintf_0(o.global_config_dir, _T("%sconfig"), openvpn_path);
    }

  if (!regkey || !GetRegistryValue(regkey, _T("ovpn_admin_group"), o.ovpn_admin_group, _countof(o.ovpn_admin_group)))
    {
      _tcsncpy(o.ovpn_admin_group, OVPN_ADMIN_GROUP, _countof(o.ovpn_admin_group)-1);
    }

  if (!regkey || !GetRegistryValue(regkey, _T("exe_path"), o.exe_path, _countof(o.exe_path)))
    {
      _sntprintf_0(o.exe_path, _T("%sbin\\openvpn.exe"), openvpn_path);
    }

  if (!regkey || !GetRegistryValue(regkey, _T("priority"), o.priority_string, _countof(o.priority_string)))
    {
      _tcsncpy(o.priority_string, _T("NORMAL_PRIORITY_CLASS"), _countof(o.priority_string)-1);
    }
  if (!regkey || !GetRegistryValueNumeric(regkey, _T("disable_save_passwords"), &o.disable_save_passwords))
  {
      o.disable_save_passwords = 0;
  }
  if (regkey)
      RegCloseKey(regkey);
  return true;
}

int
GetRegistryKeys ()
{
    HKEY regkey;
    DWORD status;
    int i;

    if (!GetGlobalRegistryKeys())
        return false;

    status = RegOpenKeyEx(HKEY_CURRENT_USER, GUI_REGKEY_HKCU, 0, KEY_READ, &regkey);

    for (i = 0 ; i < (int) _countof (regkey_str); ++i)
    {
        if ( status != ERROR_SUCCESS ||
            !GetRegistryValue (regkey, regkey_str[i].name, regkey_str[i].var, regkey_str[i].len))
        {
            /* no value found in registry, use the default */
            wcsncpy (regkey_str[i].var, regkey_str[i].value, regkey_str[i].len);
            regkey_str[i].var[regkey_str[i].len-1] = L'\0';
            PrintDebug(L"default: %s = %s", regkey_str[i].name, regkey_str[i].var);
        }
        else
            PrintDebug(L"from registry: %s = %s", regkey_str[i].name, regkey_str[i].var);
    }

    for (i = 0 ; i < (int) _countof (regkey_int); ++i)
    {
        if ( status != ERROR_SUCCESS ||
             !GetRegistryValueNumeric (regkey, regkey_int[i].name, regkey_int[i].var))
        {
            /* no value found in registry, use the default */
            *regkey_int[i].var = regkey_int[i].value;
            PrintDebug(L"default: %s = %lu", regkey_int[i].name, *regkey_int[i].var);
        }
        else
            PrintDebug(L"from registry: %s = %lu", regkey_int[i].name, *regkey_int[i].var);
    }

    if ( status == ERROR_SUCCESS)
        RegCloseKey (regkey);

    if ((o.disconnectscript_timeout == 0))
    {
        ShowLocalizedMsg(IDS_ERR_DISCONN_SCRIPT_TIMEOUT);
        o.disconnectscript_timeout = 10;
    }
    if ((o.preconnectscript_timeout == 0))
    {
        ShowLocalizedMsg(IDS_ERR_PRECONN_SCRIPT_TIMEOUT);
        o.preconnectscript_timeout = 10;
    }

    ExpandOptions ();
    return true;
}

int
SaveRegistryKeys ()
{
    HKEY regkey;
    DWORD status;
    int i;
    int ret = false;

    status = RegCreateKeyEx(HKEY_CURRENT_USER, GUI_REGKEY_HKCU, 0, NULL, REG_OPTION_NON_VOLATILE,
                            KEY_WRITE|KEY_READ, NULL, &regkey, NULL);
    if (status != ERROR_SUCCESS)
    {
        ShowLocalizedMsg (IDS_ERR_CREATE_REG_HKCU_KEY, GUI_REGKEY_HKCU);
        goto out;
    }
    for (i = 0 ; i < (int) _countof (regkey_str); ++i)
    {
        /* save only if the value differs from default or already present in registry */
        if ( CompareStringExpanded (regkey_str[i].var, regkey_str[i].value) != 0 ||
             RegValueExists(regkey, regkey_str[i].name) )
        {
            if (!SetRegistryValue (regkey, regkey_str[i].name, regkey_str[i].var))
                goto out;
        }
    }

    for (i = 0 ; i < (int) _countof (regkey_int); ++i)
    {
        if ( *regkey_int[i].var != regkey_int[i].value ||
             RegValueExists(regkey, regkey_int[i].name) )
        {
            if (!SetRegistryValueNumeric (regkey, regkey_int[i].name, *regkey_int[i].var))
                goto out;
        }
    }
    ret = true;

out:

    if (status == ERROR_SUCCESS)
        RegCloseKey(regkey);
    return ret;
}

static BOOL
GetRegistryVersion (version_t *v)
{
    HKEY regkey;
    CLEAR (*v);
    DWORD len = sizeof(*v);

    if (RegOpenKeyEx(HKEY_CURRENT_USER, GUI_REGKEY_HKCU, 0, KEY_READ, &regkey) == ERROR_SUCCESS)
    {
        if (RegGetValueW (regkey, NULL, L"version", RRF_RT_REG_BINARY, NULL, v, &len)
              != ERROR_SUCCESS)
            CLEAR (*v);
        RegCloseKey(regkey);
    }
    return true;
}

static BOOL
SetRegistryVersion (const version_t *v)
{
    HKEY regkey;
    DWORD status;
    BOOL ret = false;

    status = RegCreateKeyEx(HKEY_CURRENT_USER, GUI_REGKEY_HKCU, 0, NULL, REG_OPTION_NON_VOLATILE,
                            KEY_WRITE, NULL, &regkey, NULL);
    if (status == ERROR_SUCCESS)
    {
        if (RegSetValueEx(regkey, L"version", 0, REG_BINARY, (const BYTE*) v, sizeof(*v)) == ERROR_SUCCESS)
            ret = true;
        RegCloseKey(regkey);
    }
    else
       PrintDebug (L"Eror opening/creating 'HKCU\\%s' registry key", GUI_REGKEY_HKCU);
    return ret;
}

static int
MigrateNilingsKeys()
{
    DWORD status;
    BOOL ret = false;
    HKEY regkey, regkey_proxy, regkey_nilings;

    status = RegOpenKeyEx(HKEY_CURRENT_USER, L"Software\\Nilings\\OpenVPN-GUI", 0,
                             KEY_READ, &regkey_nilings);
    if (status != ERROR_SUCCESS)
        return true; /* No old keys to migrate */

    status = RegCreateKeyEx(HKEY_CURRENT_USER, GUI_REGKEY_HKCU, 0, NULL, REG_OPTION_NON_VOLATILE,
                                    KEY_ALL_ACCESS, NULL, &regkey, NULL);
    if (status != ERROR_SUCCESS)
    {
        ShowLocalizedMsg (IDS_ERR_CREATE_REG_HKCU_KEY, GUI_REGKEY_HKCU);
        RegCloseKey (regkey_nilings);
        return false;
    }

    /* For some reason this needs ALL_ACCESS for the CopyTree below to work */
    status = RegCreateKeyEx(regkey, L"proxy", 0, NULL, REG_OPTION_NON_VOLATILE,
                            KEY_ALL_ACCESS, NULL, &regkey_proxy, NULL);
    if (status == ERROR_SUCCESS)
    {
        DWORD ui_lang;
        /* Move language setting from Nilings to GUI_REGKEY_HKCU */
        if (GetRegistryValueNumeric(regkey_nilings, L"ui_language", &ui_lang))
            SetRegistryValueNumeric (regkey, L"ui_language", ui_lang);

        status = RegCopyTree (regkey_nilings, NULL, regkey_proxy);
        if (status == ERROR_SUCCESS)
        {
            RegDeleteValue (regkey_proxy, L"ui_language"); /* in case copied here */
            ret = true;
        }
        RegCloseKey (regkey_proxy);
    }
    else
        PrintDebug (L"Error creating key 'proxy' in HKCU\\%s", GUI_REGKEY_HKCU);

    RegCloseKey (regkey);
    RegCloseKey (regkey_nilings);

    return ret;
}

int
UpdateRegistry (void)
{
    version_t v;

    GetRegistryVersion (&v);

    if (memcmp(&v, &o.version, sizeof(v)) == 0)
        return true;

    switch (v.major)
    {
        case 0: /* Cleanup GUI_REGKEY_HKCU and migrate any values under Nilings */

            RegDeleteTree (HKEY_CURRENT_USER, GUI_REGKEY_HKCU); /* delete all values and subkeys */

            if (!MigrateNilingsKeys())
                return false;
        /* fall through to handle further updates */
        case 11:
            /* current version -- nothing to do */
            break;
        default:
            break;
    }

    SetRegistryVersion (&o.version);
    PrintDebug (L"Registry updated to version %hu.%hu", o.version.major, o.version.minor);

    return true;
}

LONG GetRegistryValue(HKEY regkey, const TCHAR *name, TCHAR *data, DWORD len)
{
  LONG status;
  DWORD type;
  DWORD data_len;

  data_len = len * sizeof(*data);

  /* get a registry string */
  status = RegQueryValueEx(regkey, name, NULL, &type, (byte *) data, &data_len);
  if (status != ERROR_SUCCESS || type != REG_SZ)
    return(0);

  data_len /= sizeof(*data);
  if (data_len > 0)
      data[data_len - 1] = L'\0'; /* REG_SZ strings are not guaranteed to be null-terminated */
  else
      data[0] = L'\0';

  return(data_len);

}

LONG
GetRegistryValueNumeric(HKEY regkey, const TCHAR *name, DWORD *data)
{
  DWORD type;
  DWORD size = sizeof(*data);
  LONG status = RegQueryValueEx(regkey, name, NULL, &type, (PBYTE) data, &size);
  return (type == REG_DWORD && status == ERROR_SUCCESS) ? 1 : 0;
}

int SetRegistryValue(HKEY regkey, const TCHAR *name, const TCHAR *data)
{
  /* set a registry string */
  DWORD size = (_tcslen(data) + 1) * sizeof(*data);
  if(RegSetValueEx(regkey, name, 0, REG_SZ, (PBYTE) data, size) != ERROR_SUCCESS)
    {
      /* Error writing registry value */
      ShowLocalizedMsg(IDS_ERR_WRITE_REGVALUE, GUI_REGKEY_HKCU, name);
      return(0);
    }

  return(1);
}

int
SetRegistryValueNumeric(HKEY regkey, const TCHAR *name, DWORD data)
{
  LONG status = RegSetValueEx(regkey, name, 0, REG_DWORD, (PBYTE) &data, sizeof(data));
  if (status == ERROR_SUCCESS)
    return 1;

  ShowLocalizedMsg(IDS_ERR_WRITE_REGVALUE, GUI_REGKEY_HKCU, name);
  return 0;
}

/*
 * Open HKCU\Software\OpenVPN-GUI\configs\config-name.
 * The caller must close the key. Returns 1 on success.
 */
static int
OpenConfigRegistryKey(const WCHAR *config_name, HKEY *regkey, BOOL create)
{
    DWORD status;
    const WCHAR fmt[] = L"SOFTWARE\\OpenVPN-GUI\\configs\\%s";
    int count = (wcslen(config_name) + wcslen(fmt) + 1);
    WCHAR *name = malloc(count * sizeof(WCHAR));

    if (!name)
        return 0;

    _snwprintf(name, count, fmt, config_name);
    name[count-1] = L'\0';

    if (!create)
       status = RegOpenKeyEx (HKEY_CURRENT_USER, name, 0, KEY_READ | KEY_WRITE, regkey);
    else
    /* create if key doesn't exist */
       status = RegCreateKeyEx(HKEY_CURRENT_USER, name, 0, NULL,
               REG_OPTION_NON_VOLATILE, KEY_READ | KEY_WRITE, NULL, regkey, NULL);
    free (name);

    return (status == ERROR_SUCCESS);
}

int
SetConfigRegistryValueBinary(const WCHAR *config_name, const WCHAR *name, const BYTE *data, DWORD len)
{
    HKEY regkey;
    DWORD status;

    if (!OpenConfigRegistryKey(config_name, &regkey, TRUE))
        return 0;
    status = RegSetValueEx(regkey, name, 0, REG_BINARY, data, len);
    RegCloseKey(regkey);

    return (status == ERROR_SUCCESS);
}

/*
 * Read registry value into the user supplied buffer data that can hold
 * up to len bytes. Returns the actual number of bytes read or zero on error.
 * If data is NULL returns the required buffer size, and no data is read.
 */
DWORD
GetConfigRegistryValue(const WCHAR *config_name, const WCHAR *name, BYTE *data, DWORD len)
{
    DWORD status;
    DWORD type;
    HKEY regkey;

    if (!OpenConfigRegistryKey(config_name, &regkey, FALSE))
        return 0;
    status = RegQueryValueEx(regkey, name, NULL, &type, data, &len);
    RegCloseKey(regkey);
    if (status == ERROR_SUCCESS)
        return len;
    else
        return 0;
}

int
DeleteConfigRegistryValue(const WCHAR *config_name, const WCHAR *name)
{
    DWORD status;
    HKEY regkey;

    if (!OpenConfigRegistryKey(config_name, &regkey, FALSE))
        return 0;
    status = RegDeleteValue(regkey, name);
    RegCloseKey(regkey);

    return (status == ERROR_SUCCESS);
}