/*
* Copyright (c) 2012-2015 Christian Surlykke, Petr Vanek
*
* This file is part of qt-lightdm-greeter 
* It is distributed under the LGPL 2.1 or later license.
* Please refer to the LICENSE file for a copy of the license.
*/
#include <QtWidgets/QApplication>
#include <QDesktopWidget>
#include <QtGlobal>
#include <QtDebug>
#include <QSettings>
#include <QIcon>
#include <QPainter>
#include <QMap>
#include <QSocketNotifier>

#include <fcntl.h>              /* Obtain O_* constant definitions */
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>

#include <iostream>

#include "settings.h"
#include "mainwindow.h"
#include "x11util.h"
#include "global.h"

Settings *s_settings = new Settings();

static int sockets[2];

static void createSimpleBackground();

static void sigUsr1(int);

static void messageHandler(QtMsgType type, const QMessageLogContext&, const QString& msg)
{
    std::cerr << type << ": " << msg.toUtf8().constData() << '\n';
}

static inline int size(const QRect& r)
{
	return r.width() * r.height();
}

int main(int argc, char *argv[])
{
	if (argc > 1 && QString(argv[1]) == QString("--test")) {
		Global::enableTestMode();
	}

	QApplication a(argc, argv);

    // I have no idea why, but Qt's stock qWarning() output never makes it
    // to /var/log/lightdm/x-0-greeter.log, so we use std::cerr instead..
    qInstallMessageHandler(messageHandler);

    if (!Settings::iconThemeName().isEmpty()) {
        QIcon::setThemeName(Settings::iconThemeName());
    }

    if (!Global::testMode() && !Settings::autoLoginCheckCmd().isEmpty()) {
    	QProcess p;
        int ret = QProcess::execute(Settings::autoLoginCheckCmd());
    	if (ret == 0) {
    		if (Global::autoLoginGuest()) {
    			qWarning() << "Guest login ok";
                createSimpleBackground();
                return a.exec();
    		} else {
    			qWarning() << "Guest login failed";
    			// TODO: Set error message, display somewhere
    		}
    	}
    }

    // Build background for X server, in case we start a session that
	// doesn't set one on its own this will make sure it's not simply
	// black
	QImage entire;

	// Get a list of non-overlapping screens, as this might lead to a broken
	// greeter with main windows covering other login forms
	QMap<int, QRect> screens;
    if (Global::testMode()) {
        screens.insert(0, QRect(0, 0, 1024, 768));
    } else {
    	QSize desktopSize = QApplication::desktop()->size();
    	qWarning() << "Desktop full size is " << desktopSize;
    	entire = QImage(desktopSize, QImage::Format_RGB32);
        for (int i = 0; i < QApplication::desktop()->screenCount(); ++i) {
            QRect r = QApplication::desktop()->screenGeometry(i);
            QMutableMapIterator<int, QRect>it(screens);
            while (it.hasNext()) {
                it.next();
                if (!it.value().intersects(r))
                    continue;
                // Overlap, bigger wins
                if (size(it.value()) >= size(r)) {
                    // Existing is bigger
                    goto skip_rect;
                }
                // New is bigger, remove existing and keep going
                it.remove();
            }
            // We reached here, so add new window
            screens.insert(i, r);
            skip_rect: ; // Do nothing
        }
    }

	// Determine primary screen
	int primary;
	if (screens.contains(QApplication::desktop()->primaryScreen())) {
		// Primary screen still in selection
		primary = QApplication::desktop()->primaryScreen();
	} else {
		// Fallback to first one
		primary = screens.begin().key();
	}

	struct sigaction usr1;

	usr1.sa_handler = &sigUsr1;
	sigemptyset(&usr1.sa_mask);
	usr1.sa_flags = SA_RESTART;

	QSocketNotifier *sn = NULL;
	if (sigaction(SIGUSR1, &usr1, 0) == 0 && ::socketpair(AF_UNIX, SOCK_STREAM, 0, sockets) == 0) {
		sn = new QSocketNotifier(sockets[1], QSocketNotifier::Read);
		QObject::connect(sn, &QSocketNotifier::activated, [](int fd) {
			char tmp[1000];
			read(fd, tmp, sizeof tmp);
		});
	}

    // Now set up all the screens
	QPainter painter(&entire);
    MainWindow *focusWindow = 0;
    QMapIterator<int, QRect> it(screens);
    while (it.hasNext()) {
    	it.next();
        MainWindow *w = new MainWindow(primary == it.key(), it.key(), it.value());
        w->show();
		if (sn != NULL) {
			QObject::connect(sn, SIGNAL(activated(int)), w, SLOT(showStandby()));
		}
        if (w->showLoginForm()) {
            focusWindow = w;
        }
        if (!entire.isNull()) {
        	QPoint p = it.value().topLeft();
        	painter.drawImage(p, w->getBackground());
        }
    }

    if (!entire.isNull()) {
        qWarning() << "Setting x background";
    	AddPixmapToBackground(entire.constBits(), entire.width(), entire.height(), 24, entire.bytesPerLine(), entire.byteCount());
    }

    // Ensure we set the primary screen's widget as active when there
    // are more screens
    if (focusWindow) {
        focusWindow->setFocus(Qt::OtherFocusReason);
        focusWindow->activateWindow();
    }

    return a.exec();
}

static void createSimpleBackground()
{
    QImage img = Global::getConfigGradient();
    if (img.isNull())
        return;
    img = img.scaled(QApplication::desktop()->size(), Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
    AddPixmapToBackground(img.constBits(), img.width(), img.height(), 24, img.bytesPerLine(), img.byteCount());
}

static void sigUsr1(int)
{
	char a = 1;
	::write(sockets[0], &a, sizeof(a));
}