/********************************************************************
 KWin - the KDE window manager
 This file is part of the KDE project.

Copyright (C) 1999, 2000 Matthias Ettrich <ettrich@kde.org>
Copyright (C) 2003 Lubos Lunak <l.lunak@kde.org>

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.  If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/

#include "main.h"

//#define QT_CLEAN_NAMESPACE
#include <ksharedconfig.h>

#include <kglobal.h>
#include <klocale.h>
#include <stdlib.h>
#include <kcmdlineargs.h>
#include <kaboutdata.h>
#include <kcrash.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <QX11Info>
#include <stdio.h>
#include <fixx11h.h>
#include <kxerrorhandler.h>
#include <kdefakes.h>
#include <QtDBus/QtDBus>

#include <kdialog.h>
#include <kstandarddirs.h>
#include <kdebug.h>
#include <QLabel>
#include <QComboBox>
#include <QVBoxLayout>

#include "atoms.h"
#include "options.h"
#include "sm.h"
#include "utils.h"
#include "effects.h"

#define INT8 _X11INT8
#define INT32 _X11INT32
#include <X11/Xproto.h>
#undef INT8
#undef INT32

namespace KWin
{

Options* options;

Atoms* atoms;

int screen_number = -1;

static bool initting = false;

/**
 * Whether to run Xlib in synchronous mode and print backtraces for X errors.
 * Note that you most probably need to configure cmake with "-D__KDE_HAVE_GCC_VISIBILITY=0"
 * and -rdynamic in CXXFLAGS for kBacktrace() to work.
 */
static bool kwin_sync = false;

/**
 * Outputs: "Error: <error> (<value>), Request: <request>(<value>), Resource: <value>"
 */
// This is copied from KXErrorHandler and modified to explicitly use known extensions
static QByteArray errorMessage( const XErrorEvent& event, Display* dpy )
    {
    QByteArray ret;
    char tmp[256];
    char num[256];
    if( event.request_code < 128 )
        { // Core request
        XGetErrorText( dpy, event.error_code, tmp, 255 );
        // The explanation in parentheses just makes
        // it more verbose and is not really useful
        if( char* paren = strchr( tmp, '(' ))
            *paren = '\0';
        // The various casts are to get overloads non-ambiguous :-/
        ret = QByteArray( "error: " ) + (const char*)( tmp ) + '[' + QByteArray::number( event.error_code ) + ']';
        sprintf( num, "%d", event.request_code );
        XGetErrorDatabaseText( dpy, "XRequest", num, "<unknown>", tmp, 256 );
        ret += QByteArray( ", request: " ) + (const char*)( tmp ) + '[' + QByteArray::number( event.request_code ) + ']';
        if( event.resourceid != 0 )
            ret += QByteArray( ", resource: 0x" ) + QByteArray::number( qlonglong( event.resourceid ), 16 );
        }
    else // Extensions
        {
        // XGetErrorText() currently has a bug that makes it fail to find text
        // for some errors (when error==error_base), also XGetErrorDatabaseText()
        // requires the right extension name, so it is needed to get info about
        // all extensions. However that is almost impossible:
        // - Xlib itself has it, but in internal data.
        // - Opening another X connection now can cause deadlock with server grabs.
        // - Fetching it at startup means a bunch of roundtrips.

        // KWin here explicitly uses known extensions.
        int nextensions;
        const char** extensions;
        int* majors;
        int* error_bases;
        Extensions::fillExtensionsData( extensions, nextensions, majors, error_bases );
        XGetErrorText( dpy, event.error_code, tmp, 255 );
        int index = -1;
        int base = 0;
        for( int i = 0; i < nextensions; ++i )
            if( error_bases[i] != 0 &&
                event.error_code >= error_bases[i] && ( index == -1 || error_bases[i] > base ))
                {
                index = i;
                base = error_bases[i];
                }
        if( tmp == QString::number( event.error_code ))
            { // XGetErrorText() failed or it has a bug that causes not finding all errors, check ourselves
            if( index != -1 )
                {
                snprintf( num, 255, "%s.%d", extensions[index], event.error_code - base );
                XGetErrorDatabaseText( dpy, "XProtoError", num, "<unknown>", tmp, 255 );
                }
            else
                strcpy( tmp, "<unknown>" );
            }
        if( char* paren = strchr( tmp, '(' ))
            *paren = '\0';
        if( index != -1 )
            ret = QByteArray( "error: " ) + (const char*)( tmp ) + '[' + (const char*)( extensions[index] ) +
                '+' + QByteArray::number( event.error_code - base ) + ']';
        else
            ret = QByteArray( "error: " ) + (const char*)( tmp ) + '[' + QByteArray::number( event.error_code ) + ']';
        tmp[0] = '\0';
        for( int i = 0; i < nextensions; ++i )
            if( majors[i] == event.request_code )
                {
                snprintf( num, 255, "%s.%d", extensions[i], event.minor_code );
                XGetErrorDatabaseText( dpy, "XRequest", num, "<unknown>", tmp, 255 );
                ret += QByteArray( ", request: " ) + (const char*)( tmp ) + '[' +
                    (const char*)( extensions[i] ) + '+' + QByteArray::number( event.minor_code ) + ']';
                }
        if( tmp[0] == '\0' ) // Not found?
            ret += QByteArray( ", request <unknown> [" ) + QByteArray::number( event.request_code ) + ':'
                + QByteArray::number( event.minor_code ) + ']';
        if( event.resourceid != 0 )
            ret += QByteArray( ", resource: 0x" ) + QByteArray::number( qlonglong( event.resourceid ), 16 );
        }
    return ret;
    }

static int x11ErrorHandler( Display* d, XErrorEvent* e )
    {
    bool ignore_badwindow = true; // Might be temporary

    if( initting && ( e->request_code == X_ChangeWindowAttributes || e->request_code == X_GrabKey ) &&
        e->error_code == BadAccess )
        {
        fputs( i18n( "kwin: it looks like there's already a window manager running. kwin not started.\n" ).toLocal8Bit(), stderr );
        exit(1);
        }

    if( ignore_badwindow && ( e->error_code == BadWindow || e->error_code == BadColor ))
        return 0;

    //fprintf( stderr, "kwin: X Error (%s)\n", KXErrorHandler::errorMessage( *e, d ).data());
    fprintf( stderr, "kwin: X Error (%s)\n", errorMessage( *e, d ).data() );

    if( kwin_sync )
    fprintf( stderr, "%s\n", kBacktrace().toLocal8Bit().data() );

    if( initting )
        {
        fputs( i18n( "kwin: failure during initialization; aborting").toLocal8Bit(), stderr );
        exit( 1 );
        }
    return 0;
    }

class AlternativeWMDialog : public KDialog
{
    public:
        AlternativeWMDialog()
            : KDialog()
            {
            setButtons( KDialog::Ok | KDialog::Cancel );

            QWidget* mainWidget = new QWidget( this );
            QVBoxLayout* layout = new QVBoxLayout( mainWidget );
            QString text = i18n(
                "KWin is unstable.\n"
                "It seems to have crashed several times in a row.\n"
                "You can select another window manager to run:" );
            QLabel* textLabel = new QLabel( text, mainWidget );
            layout->addWidget( textLabel );
            wmList = new QComboBox( mainWidget );
            wmList->setEditable( true );
            layout->addWidget( wmList );

            addWM( "metacity" );
            addWM( "openbox" );
            addWM( "fvwm2" );
            addWM( "kwin" );

            setMainWidget( mainWidget );

            raise();
            centerOnScreen( this );
            }

        void addWM( const QString& wm )
            {
            // TODO: Check if WM is installed
            if( !KStandardDirs::findExe( wm ).isEmpty() )
                wmList->addItem( wm );
            }
        QString selectedWM() const
            { return wmList->currentText(); }

    private:
        QComboBox* wmList;
};

int Application::crashes = 0;

Application::Application()
    : KApplication()
    , owner( screen_number )
    {
    if( KCmdLineArgs::parsedArgs( "qt" )->isSet( "sync" ))
        {
        kwin_sync = true;
        XSynchronize( display(), True );
        kDebug( 1212 ) << "Running KWin in sync mode";
        }
    KCmdLineArgs* args = KCmdLineArgs::parsedArgs();
    KSharedConfig::Ptr config = KGlobal::config();
    if( !config->isImmutable() && args->isSet( "lock" ))
        {
#ifdef __GNUC__
#warning this shouldn not be necessary
#endif
        //config->setReadOnly( true );
        config->reparseConfiguration();
        }

    if( screen_number == -1 )
        screen_number = DefaultScreen( display() );

    if( !owner.claim( args->isSet( "replace" ), true ))
        {
        fputs( i18n( "kwin: unable to claim manager selection, another wm running? (try using --replace)\n" ).toLocal8Bit(), stderr );
        ::exit( 1 );
        }
    connect( &owner, SIGNAL( lostOwnership() ), SLOT( lostSelection() ));

    KCrash::setEmergencySaveFunction( Application::crashHandler );
    crashes = args->getOption( "crashes" ).toInt();
    if( crashes >= 4 )
        { // Something has gone seriously wrong
        AlternativeWMDialog dialog;
        QString cmd = "kwin";
        if( dialog.exec() == QDialog::Accepted )
            cmd = dialog.selectedWM();
        else
            ::exit( 1 );
        if( cmd.length() > 500 )
            {
            kDebug( 1212 ) << "Command is too long, truncating";
            cmd = cmd.left( 500 );
            }
        kDebug( 1212 ) << "Starting" << cmd << "and exiting";
        char buf[1024];
        sprintf( buf, "%s &", cmd.toAscii().data() );
        system( buf );
        ::exit( 1 );
        }
    if( crashes >= 2 )
        { // Disable compositing if we have had too many crashes
        kDebug( 1212 ) << "Too many crashes recently, disabling compositing";
        KConfigGroup compgroup( config, "Compositing" );
        compgroup.writeEntry( "Enabled", false );
        }
    // Reset crashes count if we stay up for more that 15 seconds
    QTimer::singleShot( 15*1000, this, SLOT( resetCrashesCount() ));

    // If KWin was already running it saved its configuration after loosing the selection -> Reread
    config->reparseConfiguration();

    initting = true; // Startup...

    // Install X11 error handler
    XSetErrorHandler( x11ErrorHandler );

    // Check  whether another windowmanager is running
    XSelectInput( display(), rootWindow(), SubstructureRedirectMask );
    syncX(); // Trigger error now

    atoms = new Atoms;

    initting = false; // TODO

    // This tries to detect compositing options and can use GLX. GLX problems
    // (X errors) shouldn't cause kwin to abort, so this is out of the
    // critical startup section where x errors cause kwin to abort.
    options = new Options;

    // create workspace.
    (void) new Workspace( isSessionRestored() );

    syncX(); // Trigger possible errors, there's still a chance to abort

    initting = false; // Startup done, we are up and running now.

    XEvent e;
    e.xclient.type = ClientMessage;
    e.xclient.message_type = XInternAtom( display(), "_KDE_SPLASH_PROGRESS", False );
    e.xclient.display = display();
    e.xclient.window = rootWindow();
    e.xclient.format = 8;
    strcpy( e.xclient.data.b, "wm" );
    XSendEvent( display(), rootWindow(), False, SubstructureNotifyMask, &e );
    }

Application::~Application()
    {
    delete Workspace::self();
    if( owner.ownerWindow() != None ) // If there was no --replace (no new WM)
        XSetInputFocus( display(), PointerRoot, RevertToPointerRoot, xTime() );
    delete options;
    delete effects;
    delete atoms;
    }

void Application::lostSelection()
    {
    sendPostedEvents();
    delete Workspace::self();
    // Remove windowmanager privileges
    XSelectInput( display(), rootWindow(), PropertyChangeMask );
    quit();
    }

bool Application::x11EventFilter( XEvent* e )
    {
    if( Workspace::self() && Workspace::self()->workspaceEvent( e ))
        return true;
    return KApplication::x11EventFilter( e );
    }

bool Application::notify( QObject* o, QEvent* e )
    {
    if( Workspace::self()->workspaceEvent( e ))
        return true;
    return KApplication::notify( o, e );
    }

static void sighandler( int )
    {
    QApplication::exit();
    }

void Application::crashHandler( int signal )
    {
    crashes++;

    fprintf( stderr, "Application::crashHandler() called with signal %d; recent crashes: %d\n", signal, crashes );
    char cmd[1024];
    sprintf( cmd, "kwin --crashes %d &", crashes );

    sleep( 1 );
    system( cmd );
    }

void Application::resetCrashesCount()
    {
    crashes = 0;
    }

} // namespace

static const char version[] = KDE_VERSION_STRING;
static const char description[] = I18N_NOOP( "KDE window manager" );

extern "C"
KDE_EXPORT int kdemain( int argc, char * argv[] )
    {
    bool restored = false;
    for( int arg = 1; arg < argc; arg++ )
        {
        if( !qstrcmp( argv[arg], "-session" ))
            {
            restored = true;
            break;
            }
        }

    if( !restored )
        { // We only do the multihead fork if we are not restored by the session
          // manager, since the session manager will register multiple kwins,
          // one for each screen...
        QByteArray multiHead = getenv( "KDE_MULTIHEAD" );
        if( multiHead.toLower() == "true" )
            {
            Display* dpy = XOpenDisplay( NULL );
            if( !dpy )
                {
                fprintf( stderr, "%s: FATAL ERROR while trying to open display %s\n",
                    argv[0], XDisplayName( NULL ));
                exit( 1 );
                }

            int number_of_screens = ScreenCount( dpy );
            KWin::screen_number = DefaultScreen( dpy );
            int pos; // Temporarily needed to reconstruct DISPLAY var if multi-head
            QByteArray display_name = XDisplayString( dpy );
            XCloseDisplay( dpy );
            dpy = 0;

            if(( pos = display_name.lastIndexOf( '.' )) != -1 )
                display_name.remove( pos, 10 ); // 10 is enough to be sure we removed ".s"

            QString envir;
            if( number_of_screens != 1 )
                {
                for( int i = 0; i < number_of_screens; i++ )
                    {
                    // If execution doesn't pass by here, then kwin
                    // acts exactly as previously
                    if( i != KWin::screen_number && fork() == 0 )
                        {
                        KWin::screen_number = i;
                        // Break here because we are the child process, we don't
                        // want to fork() anymore
                        break;
                        }
                    }
                // In the next statement, display_name shouldn't contain a screen
                // number. If it had it, it was removed at the "pos" check
                envir.sprintf( "DISPLAY=%s.%d", display_name.data(), KWin::screen_number );

                if( putenv( strdup( envir.toAscii() )))
                    {
                    fprintf( stderr, "%s: WARNING: unable to set DISPLAY environment variable\n", argv[0] );
                    perror("putenv()");
                    }
                }
            }
        }

    KAboutData aboutData(
        "kwin",                     // The program name used internally
        0,                          // The message catalog name. If null, program name is used instead
        ki18n( "KWin" ),            // A displayable program name string
        version,                    // The program version string
        ki18n( description ),       // Short description of what the app does
        KAboutData::License_GPL,    // The license this code is released under
        ki18n( "(c) 1999-2008, The KDE Developers" )); // Copyright Statement
    aboutData.addAuthor( ki18n( "Matthias Ettrich" ),KLocalizedString(), "ettrich@kde.org" );
    aboutData.addAuthor( ki18n( "Cristian Tibirna" ),KLocalizedString(), "tibirna@kde.org" );
    aboutData.addAuthor( ki18n( "Daniel M. Duley" ),KLocalizedString(), "mosfet@kde.org" );
    aboutData.addAuthor( ki18n( "Luboš Luňák" ), ki18n( "Maintainer" ), "l.lunak@kde.org" );

    KCmdLineArgs::init( argc, argv, &aboutData );

    KCmdLineOptions args;
    args.add( "lock", ki18n( "Disable configuration options" ));
    args.add( "replace", ki18n( "Replace already-running ICCCM2.0-compliant window manager" ));
    args.add( "crashes <n>", ki18n( "Indicate that KWin has recently crashed n times" ));
    KCmdLineArgs::addCmdLineOptions( args );

    if( signal( SIGTERM, KWin::sighandler ) == SIG_IGN )
        signal( SIGTERM, SIG_IGN );
    if( signal( SIGINT, KWin::sighandler ) == SIG_IGN )
        signal( SIGINT, SIG_IGN );
    if( signal( SIGHUP, KWin::sighandler ) == SIG_IGN )
        signal( SIGHUP, SIG_IGN );

    // HACK: This is needed for AIGLX
    if( qstrcmp( getenv( "KWIN_DIRECT_GL" ), "1" ) != 0 )
        setenv( "LIBGL_ALWAYS_INDIRECT","1", true );

    // HACK: this is needed to work around a Qt4.4.0RC1 bug (#157659)
    setenv( "QT_SLOW_TOPLEVEL_RESIZE", "1", true );

    KWin::Application a;
    KWin::SessionManager weAreIndeed;
    KWin::SessionSaveDoneHelper helper;
    KGlobal::locale()->insertCatalog( "kwin_effects" );

    // Announce when KWIN_DIRECT_GL is set for above HACK
    if( qstrcmp( getenv( "KWIN_DIRECT_GL" ), "1" ) == 0 )
        kDebug( 1212 ) << "KWIN_DIRECT_GL set, not forcing LIBGL_ALWAYS_INDIRECT=1";

    fcntl( XConnectionNumber( KWin::display() ), F_SETFD, 1 );

    QString appname;
    if( KWin::screen_number == 0 )
        appname = "org.kde.kwin";
    else
        appname.sprintf( "org.kde.kwin-screen-%d", KWin::screen_number );

    QDBusConnection::sessionBus().interface()->registerService(
        appname, QDBusConnectionInterface::DontQueueService );

    return a.exec();
    }

#include "main.moc"
