/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */

#ifdef MOZ_X11
#include "mozilla/X11Util.h"
#endif
#include "nsIdleServiceQt.h"
#include "nsIServiceManager.h"
#include "nsDebug.h"
#include "prlink.h"

#if defined(MOZ_X11)
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 _XScreenSaverQueryExtension_fn _XSSQueryExtension = nullptr;
static _XScreenSaverAllocInfo_fn _XSSAllocInfo = nullptr;
static _XScreenSaverQueryInfo_fn _XSSQueryInfo = nullptr;
#endif

static bool sInitialized = false;

NS_IMPL_ISUPPORTS_INHERITED0(nsIdleServiceQt, nsIdleService)

nsIdleServiceQt::nsIdleServiceQt()
#if defined(MOZ_X11)
    : mXssInfo(nullptr)
#endif
{
}

static void Initialize()
{
    sInitialized = true;

#if defined(MOZ_X11)
    // This will leak - See comments in ~nsIdleServiceQt().
    PRLibrary* xsslib = PR_LoadLibrary("libXss.so.1");
    if (!xsslib) {
        return;
    }

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

nsIdleServiceQt::~nsIdleServiceQt()
{
#if defined(MOZ_X11)
    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
#endif
}

bool
nsIdleServiceQt::PollIdleTime(uint32_t *aIdleTime)
{
#if defined(MOZ_X11)
    // Ask xscreensaver about idle time:
    *aIdleTime = 0;

    // We might not have a display (cf. in xpcshell)
    Display *dplay = mozilla::DefaultXDisplay();
    if (!dplay) {
        return false;
    }

    if (!sInitialized) {
        Initialize();
    }
    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, RootWindowOfScreen(DefaultScreenOfDisplay(mozilla::DefaultXDisplay())), mXssInfo);
        *aIdleTime = mXssInfo->idle;
        return true;
    }
#endif

    return false;
}

bool
nsIdleServiceQt::UsePollMode()
{
#if defined(MOZ_X11)
    return false;
#endif
    return true;
}