/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:expandtab:shiftwidth=4:tabstop=4:
 */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <gtk/gtk.h>

#include "nsUserIdleServiceGTK.h"
#include "nsDebug.h"
#include "prlink.h"
#include "mozilla/Logging.h"

using mozilla::LogLevel;

static mozilla::LazyLogModule sIdleLog("nsIUserIdleService");

typedef bool (*_XScreenSaverQueryExtension_fn)(Display* dpy, int* event_base,
                                               int* error_base);

typedef XScreenSaverInfo* (*_XScreenSaverAllocInfo_fn)(void);

typedef void (*_XScreenSaverQueryInfo_fn)(Display* dpy, Drawable drw,
                                          XScreenSaverInfo* info);

static bool sInitialized = false;
static _XScreenSaverQueryExtension_fn _XSSQueryExtension = nullptr;
static _XScreenSaverAllocInfo_fn _XSSAllocInfo = nullptr;
static _XScreenSaverQueryInfo_fn _XSSQueryInfo = nullptr;

static void Initialize() {
  if (!gdk_display_get_default() ||
      !GDK_IS_X11_DISPLAY(gdk_display_get_default())) {
    return;
  }

  // This will leak - See comments in ~nsUserIdleServiceGTK().
  PRLibrary* xsslib = PR_LoadLibrary("libXss.so.1");
  if (!xsslib)  // ouch.
  {
    MOZ_LOG(sIdleLog, LogLevel::Warning, ("Failed to find libXss.so!\n"));
    return;
  }

  _XSSQueryExtension = (_XScreenSaverQueryExtension_fn)PR_FindFunctionSymbol(
      xsslib, "XScreenSaverQueryExtension");
  _XSSAllocInfo = (_XScreenSaverAllocInfo_fn)PR_FindFunctionSymbol(
      xsslib, "XScreenSaverAllocInfo");
  _XSSQueryInfo = (_XScreenSaverQueryInfo_fn)PR_FindFunctionSymbol(
      xsslib, "XScreenSaverQueryInfo");

  if (!_XSSQueryExtension)
    MOZ_LOG(sIdleLog, LogLevel::Warning,
            ("Failed to get XSSQueryExtension!\n"));
  if (!_XSSAllocInfo)
    MOZ_LOG(sIdleLog, LogLevel::Warning, ("Failed to get XSSAllocInfo!\n"));
  if (!_XSSQueryInfo)
    MOZ_LOG(sIdleLog, LogLevel::Warning, ("Failed to get XSSQueryInfo!\n"));

  sInitialized = true;
}

nsUserIdleServiceGTK::nsUserIdleServiceGTK() : mXssInfo(nullptr) {
  Initialize();
}

nsUserIdleServiceGTK::~nsUserIdleServiceGTK() {
  if (mXssInfo) XFree(mXssInfo);

// It is not safe to unload libXScrnSaver until each display is closed because
// the library registers callbacks through XESetCloseDisplay (Bug 397607).
// (Also the library and its functions are scoped for the file not the object.)
#if 0
    if (xsslib) {
        PR_UnloadLibrary(xsslib);
        xsslib = nullptr;
    }
#endif
}

bool nsUserIdleServiceGTK::PollIdleTime(uint32_t* aIdleTime) {
  if (!sInitialized) {
    // For some reason, we could not find xscreensaver.
    return false;
  }

  // Ask xscreensaver about idle time:
  *aIdleTime = 0;

  // We might not have a display (cf. in xpcshell)
  Display* dplay = GDK_DISPLAY_XDISPLAY(gdk_display_get_default());
  if (!dplay) {
    MOZ_LOG(sIdleLog, LogLevel::Warning, ("No display found!\n"));
    return false;
  }

  if (!_XSSQueryExtension || !_XSSAllocInfo || !_XSSQueryInfo) {
    return false;
  }

  int event_base, error_base;
  if (_XSSQueryExtension(dplay, &event_base, &error_base)) {
    if (!mXssInfo) mXssInfo = _XSSAllocInfo();
    if (!mXssInfo) return false;
    _XSSQueryInfo(dplay, GDK_ROOT_WINDOW(), mXssInfo);
    *aIdleTime = mXssInfo->idle;
    return true;
  }
  // If we get here, we couldn't get to XScreenSaver:
  MOZ_LOG(sIdleLog, LogLevel::Warning, ("XSSQueryExtension returned false!\n"));
  return false;
}

bool nsUserIdleServiceGTK::UsePollMode() { return sInitialized; }