/*****************************************************************************
 * remoteosd.c: remote osd over vnc filter module
 *****************************************************************************
 * Copyright (C) 2007-2008 Matthias Bauer
 * $Id: d01812c4b1e0e11f1256eaba81e85cfdbf6a8706 $
 *
 * Authors: Matthias Bauer <matthias dot bauer #_at_# gmx dot ch>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 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 implid warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * RemoteOSD uses the RFB-Protocol of VNC to display an On-Screen-Display
 * menu generated by a streaming server as overlay for the streamed video.
 *
 * The streaming server that implements this is the ffnetdev plugin for VDR.
 * VDR (VideoDiskRecorder) is an Linux based OpenSource harddisk recorder
 * software.
 * The VDR ffnetdev plugin emulates the hardware MPEG decoder and streams the
 * video over the network instead of hardware video outputs.
 * The OSD menu of VDR is offered with the RFB protocol to a VNC client.
 *
 * In fact this video-filter is a simple VNC client that could be also used to
 * connect to a real VNC host.
 * Only 8-bit color is supported at the moment.
 * Using password protected VNC hosts is supported but not recommended, because
 * you need to insert the used password in the plugin configuration page of
 * VLC configuration in plain text and it's saved in plain text.
 *****************************************************************************/

//#define VNC_DEBUG

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_filter.h>
#include <vlc_mouse.h>
#include <vlc_subpicture.h>
#include <vlc_actions.h>               /* KEY_MODIFIER_CTRL */

#include <vlc_network.h>               /* net_*, htonl */
#include <gcrypt.h>                    /* to encrypt password */
#include <vlc_gcrypt.h>

#include "remoteosd_rfbproto.h" /* type definitions of the RFB protocol for VNC */

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
#define READ_BUFFER_SIZE 1000000

#define RMTOSD_HOST_TEXT N_("VNC Host")
#define RMTOSD_HOST_LONGTEXT N_( \
    "VNC hostname or IP address." )

#define RMTOSD_PORT_TEXT N_("VNC Port")
#define RMTOSD_PORT_LONGTEXT N_( \
    "VNC port number." )

#define RMTOSD_PASSWORD_TEXT N_("VNC Password")
#define RMTOSD_PASSWORD_LONGTEXT N_( \
    "VNC password." )

#define RMTOSD_UPDATE_TEXT N_("VNC poll interval" )
#define RMTOSD_UPDATE_LONGTEXT N_( \
    "In this interval an update from VNC is requested, default every 300 ms.")

#define RMTOSD_POLL_TEXT N_("VNC polling")
#define RMTOSD_POLL_LONGTEXT N_( \
    "Activate VNC polling. Do NOT activate for use as VDR ffnetdev client." )

#define RMTOSD_MOUSE_TEXT N_("Mouse events")
#define RMTOSD_MOUSE_LONGTEXT N_( \
    "Send mouse events to VNC host. Not needed for use as VDR ffnetdev client." )

#define RMTOSD_KEYS_TEXT N_("Key events")
#define RMTOSD_KEYS_LONGTEXT N_( \
    "Send key events to VNC host." )

#define RMTOSD_ALPHA_TEXT N_("Alpha transparency value (default 255)")
#define RMTOSD_ALPHA_LONGTEXT N_( \
    "The transparency of the OSD VNC can be changed by giving a value " \
    "between 0 and 255. A lower value specifies more transparency a higher " \
    "means less transparency. The default is being not transparent " \
    "(value 255) the minimum is fully transparent (value 0)." )

#define RMTOSD_CFG "rmtosd-"

#define RMTOSD_UPDATE_MIN     200
#define RMTOSD_UPDATE_DEFAULT 1000
#define RMTOSD_UPDATE_MAX     300

static int  CreateFilter ( vlc_object_t * );
static void DestroyFilter( vlc_object_t * );

vlc_module_begin ()
    set_description( N_("Remote-OSD over VNC") )
    set_capability( "sub source", 100 )
    set_shortname( N_("Remote-OSD") )
    set_category( CAT_VIDEO )
    set_subcategory( SUBCAT_VIDEO_SUBPIC )
    add_shortcut( "rmtosd" )
    set_callbacks( CreateFilter, DestroyFilter )

    add_string( RMTOSD_CFG "host", "myvdr", RMTOSD_HOST_TEXT,
        RMTOSD_HOST_LONGTEXT, false )
    add_integer_with_range( RMTOSD_CFG "port", 20001, 1, 0xFFFF,
        RMTOSD_PORT_TEXT, RMTOSD_PORT_LONGTEXT, false )
    add_password( RMTOSD_CFG "password", "", RMTOSD_PASSWORD_TEXT,
        RMTOSD_PASSWORD_LONGTEXT, false )
    add_integer_with_range( RMTOSD_CFG "update", RMTOSD_UPDATE_DEFAULT,
        RMTOSD_UPDATE_MIN, RMTOSD_UPDATE_MAX, RMTOSD_UPDATE_TEXT,
        RMTOSD_UPDATE_LONGTEXT, true )
    add_bool( RMTOSD_CFG "vnc-polling", false,
              RMTOSD_POLL_TEXT , RMTOSD_POLL_LONGTEXT, false )
    add_bool( RMTOSD_CFG "mouse-events", false,
              RMTOSD_MOUSE_TEXT , RMTOSD_MOUSE_LONGTEXT, false )
    add_bool( RMTOSD_CFG "key-events", false,
              RMTOSD_KEYS_TEXT , RMTOSD_KEYS_LONGTEXT, false )
    add_integer_with_range( RMTOSD_CFG "alpha", 255, 0, 255,
        RMTOSD_ALPHA_TEXT, RMTOSD_ALPHA_LONGTEXT, true )

vlc_module_end ()


/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
#define CHALLENGESIZE 16
#define MAX_VNC_SERVER_NAME_LENGTH 255

/* subsource functions */
static subpicture_t *Filter( filter_t *, mtime_t );

static int MouseEvent( filter_t *,
                       const vlc_mouse_t *,
                       const vlc_mouse_t *,
                       const video_format_t * );

static int KeyEvent( vlc_object_t *p_this, char const *psz_var,
                     vlc_value_t oldval, vlc_value_t newval, void *p_data );

static void* vnc_worker_thread ( void * );

static void* update_request_thread( void * );

static bool process_server_message ( filter_t *p_filter,
                                     rfbServerToClientMsg *msg );

static inline void rgb_to_yuv( uint8_t *y, uint8_t *u, uint8_t *v,
                               int r, int g, int b );

static inline bool fill_rect( filter_sys_t* p_sys,
                              uint16_t i_x, uint16_t i_y,
                              uint16_t i_w, uint16_t i_h,
                              uint8_t i_color );
static inline bool copy_rect( filter_sys_t* p_sys,
                              uint16_t i_x, uint16_t i_y,
                              uint16_t i_w, uint16_t i_h,
                              uint16_t i_sx, uint16_t i_sy );


static inline bool raw_line(  filter_sys_t* p_sys,
                              uint16_t i_x, uint16_t i_y,
                              uint16_t i_w );

static void vnc_encrypt_bytes( unsigned char *bytes, char *passwd );


/*****************************************************************************
 * Sub source code
 *****************************************************************************/

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
struct filter_sys_t
{
    vlc_mutex_t   lock;                /* To lock for read/write on picture */

    bool          b_need_update;       /* VNC picture is updated, do update the OSD*/
    uint8_t       i_alpha;             /* alpha transparency value */

    char          *psz_host;           /* VNC host */

    char          *psz_passwd;         /* VNC password */

    picture_t     *p_pic;              /* The picture with OSD data from VNC */

    int           i_socket;            /* Socket used for VNC */

    uint16_t      i_vnc_width;          /* The with of the VNC screen */
    uint16_t      i_vnc_height;         /* The height of the VNC screen */

    bool          b_vnc_key_events;    /* Send KeyEvents ? */
    bool    b_alpha_from_vnc;    /* Special ffnetdev alpha feature enabled ? */

    char          read_buffer[READ_BUFFER_SIZE];

    vlc_thread_t  worker_thread;

    uint8_t       ar_color_table_yuv[256][4];
};

/*****************************************************************************
 * CreateFilter: Create the filter and open the definition file
 *****************************************************************************/
static int CreateFilter ( vlc_object_t *p_this )
{
    filter_t *p_filter = (filter_t *)p_this;

    filter_sys_t *p_sys = malloc( sizeof (*p_sys) );
    if( unlikely(p_sys == NULL) )
        return VLC_ENOMEM;

    /* Populating struct */
    vlc_mutex_init( &p_sys->lock );
    p_sys->b_need_update = false;
    p_sys->psz_host = var_InheritString( p_this, RMTOSD_CFG "host" );
    p_sys->psz_passwd = var_InheritString( p_this, RMTOSD_CFG "password" );
    p_sys->i_alpha = var_InheritInteger( p_this, RMTOSD_CFG "alpha" );
    p_sys->p_pic = NULL;
    p_sys->i_socket = -1;

    memset( p_sys->ar_color_table_yuv, 255,
            sizeof( p_sys->ar_color_table_yuv ) );

    if( p_sys->psz_host == NULL )
    {
        msg_Err( p_filter, "unable to get vnc host" );
        goto error;
    }

    if( p_sys->psz_passwd == NULL )
    {
        msg_Err( p_filter, "unable to get vnc password" );
        goto error;
    }

    p_filter->p_sys = p_sys;

    vlc_gcrypt_init();

    /* create the vnc worker thread */
    if( vlc_clone( &p_sys->worker_thread,
                   vnc_worker_thread, p_filter, VLC_THREAD_PRIORITY_LOW ) )
    {
        msg_Err( p_filter, "cannot spawn vnc message reader thread" );
        goto error;
    }

    /* Attach subpicture source callback */
    p_filter->pf_sub_source = Filter;

    es_format_Init( &p_filter->fmt_out, SPU_ES, VLC_CODEC_SPU );
    p_filter->fmt_out.i_priority = ES_PRIORITY_SELECTABLE_MIN;

    if( var_InheritBool( p_this, RMTOSD_CFG "mouse-events" ) )
        p_filter->pf_sub_mouse = MouseEvent;

    p_sys->b_vnc_key_events = var_InheritBool( p_this,
                                               RMTOSD_CFG "key-events" );
    if( p_sys->b_vnc_key_events )
        var_AddCallback( p_filter->obj.libvlc, "key-pressed", KeyEvent, p_this );

    msg_Dbg( p_filter, "osdvnc filter started" );

    return VLC_SUCCESS;

error:
    msg_Err( p_filter, "osdvnc filter discarded" );

    vlc_mutex_destroy( &p_sys->lock );
    free( p_sys->psz_host );
    free( p_sys->psz_passwd );
    free( p_sys );

    return VLC_EGENERIC;
}

/*****************************************************************************
 * DestroyFilter: Make a clean exit of this plugin
 *****************************************************************************/
static void DestroyFilter( vlc_object_t *p_this )
{
    filter_t     *p_filter = (filter_t*)p_this;
    filter_sys_t *p_sys = p_filter->p_sys;

    msg_Dbg( p_filter, "DestroyFilter called." );

    if( p_sys->b_vnc_key_events )
        var_DelCallback( p_filter->obj.libvlc, "key-pressed", KeyEvent, p_this );

    vlc_cancel( p_sys->worker_thread );
    vlc_join( p_sys->worker_thread, NULL );

    if( p_sys->p_pic != NULL )
        picture_Release( p_sys->p_pic );
    if( p_sys->i_socket >= 0 )
        net_Close( p_sys->i_socket );

    vlc_mutex_destroy( &p_sys->lock );
    free( p_sys->psz_host );
    free( p_sys->psz_passwd );
    free( p_sys );
}

static bool read_exact( filter_t *obj, int fd, void *buf, size_t len )
{
    return (ssize_t)len == net_Read( obj, fd, buf, len );
}


static bool write_exact( filter_t *obj, int fd, const void *buf, size_t len )
{
    return (ssize_t)len == net_Write( obj, fd, buf, len );
}

static int vnc_connect( filter_t *p_filter )
{
    filter_sys_t *p_sys = p_filter->p_sys;

    int port = var_InheritInteger( p_filter, RMTOSD_CFG "port" );

    int fd = net_ConnectTCP( p_filter, p_sys->psz_host, port );
    if( fd == -1 )
    {
        msg_Err( p_filter, "Could not connect to VNC host" );
        return -1;
    }

    msg_Dbg( p_filter, "Reading protocol version" );

    rfbProtocolVersionMsg pv;
    if ( !read_exact( p_filter, fd, pv, sz_rfbProtocolVersionMsg ) )
    {
        msg_Err( p_filter, "Could not read version message" );
        goto error;
    }
    pv[sz_rfbProtocolVersionMsg] = '\0'; /* pv size is sz_rfbProtocolVersionMsg+1 */

    msg_Dbg( p_filter, "Server version is %s", pv );

    strncpy(pv, "RFB 003.003\n", sz_rfbProtocolVersionMsg);

    if( !write_exact(p_filter, fd, pv, sz_rfbProtocolVersionMsg) )
    {
        msg_Err( p_filter, "Could not write version message" );
        goto error;
    }

    msg_Dbg( p_filter, "Reading authentication scheme" );
    uint32_t i_authScheme;
    if( !read_exact( p_filter, fd, &i_authScheme, 4 ) )
    {
        msg_Err( p_filter, "Could not read authentication scheme" );
        goto error;
    }
    i_authScheme = htonl(i_authScheme);

    msg_Dbg( p_filter, "Authentication scheme = %x", i_authScheme );
    if ( i_authScheme == rfbConnFailed )
    {
        msg_Err( p_filter, "Connection rejected by server" );
        goto error;
    }
    if (i_authScheme == rfbVncAuth)
    {
        unsigned char challenge[CHALLENGESIZE];
        if ( !read_exact( p_filter, fd, challenge, CHALLENGESIZE ) )
        {
            msg_Err( p_filter, "Could not read password challenge" );
            goto error;
        }

        vnc_encrypt_bytes( challenge, p_sys->psz_passwd );

        if( !write_exact(p_filter, fd, challenge, CHALLENGESIZE ) )
        {
            msg_Err( p_filter, "Could not write password" );
            goto error;
        }
        uint32_t i_authResult;
        if( !read_exact( p_filter, fd, &i_authResult, 4 ) )
        {
            msg_Err( p_filter, "Could not read authentication result" );
            goto error;
        }
        i_authResult = htonl(i_authResult);
        if (i_authResult != rfbVncAuthOK)
        {
            msg_Err( p_filter, "VNC authentication failed" );
            goto error;
        }
    }

    msg_Dbg( p_filter, "Writing client init message" );
    rfbClientInitMsg ci;
    ci.shared = 1;
    if( !write_exact( p_filter, fd, &ci, sz_rfbClientInitMsg ) )
    {
        msg_Err( p_filter, "Could not write client init message" );
        goto error;
    }

    msg_Dbg( p_filter, "Reading server init message" );
    rfbServerInitMsg si;
    if( !read_exact( p_filter, fd, &si, sz_rfbServerInitMsg ) )
    {
        msg_Err( p_filter, "Could not read server init message" );
        goto error;
    }
    si.framebufferWidth = htons(si.framebufferWidth);
    si.framebufferHeight = htons(si.framebufferHeight);
    si.format.redMax = htons(si.format.redMax);
    si.format.greenMax = htons(si.format.greenMax);
    si.format.blueMax = htons(si.format.blueMax);

    p_sys->i_vnc_width = si.framebufferWidth;
    p_sys->i_vnc_height = si.framebufferHeight;

    msg_Dbg( p_filter, "Servers preferred pixelformat: "
                        "%ux%u, R(%u),G(%u),B(%u), %u bit, depht=%u, %s",
                        si.framebufferWidth,
                        si.framebufferHeight,
                        si.format.redMax,
                        si.format.greenMax,
                        si.format.blueMax,
                        si.format.bitsPerPixel,
                        si.format.depth,
                        si.format.trueColour ? "TrueColor" : "Not-TrueColor");

    uint32_t i_nameLength = htonl(si.nameLength);
    if( i_nameLength > MAX_VNC_SERVER_NAME_LENGTH )
    {
        msg_Err( p_filter, "Server name too long" );
        goto error;
    }
    char s_ServerName[MAX_VNC_SERVER_NAME_LENGTH+1];

    msg_Dbg( p_filter, "Reading server name with size = %u", i_nameLength );
    if( !read_exact( p_filter, fd, s_ServerName, i_nameLength ) )
    {
        msg_Err( p_filter, "Could not read server name" );
        goto error;
    }
    s_ServerName[i_nameLength] = '\0';

    if( strcmp( s_ServerName, "VDR-OSD") == 0 )
    {
        msg_Dbg( p_filter, "Server is a VDR" );
        p_sys->b_alpha_from_vnc = true;
    }
    else
    {
        msg_Dbg( p_filter, "Server is a normal VNC" );
        p_sys->b_alpha_from_vnc = false;
    }


    msg_Dbg( p_filter, "Server init message read properly" );
    msg_Dbg( p_filter, "Server name is %s", s_ServerName );

    msg_Dbg( p_filter, "Writing SetPixelFormat message" );

    rfbSetPixelFormatMsg sp;
    sp.type = rfbSetPixelFormat;
    sp.pad1 = sp.pad2 = 0;
    sp.format.bitsPerPixel = 8;
    sp.format.depth = 8 ;
    sp.format.bigEndian = 1;
    sp.format.trueColour = 0;
    sp.format.redMax = htons(31);
    sp.format.greenMax = htons(31);
    sp.format.blueMax = htons(31);
    sp.format.redShift = 10;
    sp.format.greenShift = 5;
    sp.format.blueShift = 0;
    sp.format.pad1 = sp.format.pad2 = 0;

    if( !write_exact( p_filter, fd, &sp, sz_rfbSetPixelFormatMsg) )
    {
        msg_Err( p_filter, "Could not write SetPixelFormat message" );
        goto error;
    }

    msg_Dbg( p_filter, "Writing SetEncodings message" );

    rfbSetEncodingsMsg se;
    se.type = rfbSetEncodings;
    se.pad = 0;
    se.nEncodings = htons( p_sys->b_alpha_from_vnc ? 3 : 2 );

    if( !write_exact( p_filter, fd, &se, sz_rfbSetEncodingsMsg) )
    {
        msg_Err( p_filter, "Could not write SetEncodings message begin" );
        goto error;
    }

    uint32_t i_encoding;

    msg_Dbg( p_filter, "Writing SetEncodings rfbEncodingCopyRect" );
    i_encoding = htonl(rfbEncodingCopyRect);
    if( !write_exact( p_filter, fd, &i_encoding, 4) )
    {
        msg_Err( p_filter, "Could not write encoding type rfbEncodingCopyRect." );
        goto error;
    }

    msg_Dbg( p_filter, "Writing SetEncodings rfbEncodingRRE" );
    i_encoding = htonl(rfbEncodingRRE);
    if( !write_exact(p_filter, fd, &i_encoding, 4) )
    {
        msg_Err( p_filter, "Could not write encoding type rfbEncodingRRE." );
        goto error;
    }

    if( p_sys->b_alpha_from_vnc )
    {
        msg_Dbg( p_filter, "Writing SetEncodings rfbEncSpecialUseAlpha" );
        i_encoding = 0x00F0FFFF; /* rfbEncSpecialUseAlpha is 0xFFFFF000
                                  * before we swap it */
        if( !write_exact(p_filter, fd, &i_encoding, 4) )
        {
            msg_Err( p_filter, "Could not write encoding type rfbEncSpecialUseAlpha." );
            goto error;
        }
    }

    return fd;
error:
    net_Close( fd );
    return -1;
}

static int write_update_request(filter_t *p_filter, bool incremental)
{
    filter_sys_t *p_sys = p_filter->p_sys;
    rfbFramebufferUpdateRequestMsg udr;

    udr.type = rfbFramebufferUpdateRequest;
    udr.incremental = incremental;
    udr.x = 0;
    udr.y = 0;
    udr.w = htons(p_sys->i_vnc_width);
    udr.h = htons(p_sys->i_vnc_height);

    int w = write_exact(p_filter, p_sys->i_socket, &udr,
                        sz_rfbFramebufferUpdateRequestMsg);
    if( !w )
        msg_Err( p_filter, "Could not write rfbFramebufferUpdateRequestMsg." );
    return w;
}

static void update_thread_cleanup( void *p )
{
    vlc_thread_t *th = p;

    vlc_cancel( *th );
    vlc_join( *th, NULL );
}

static void dummy_cleanup( void *p )
{
    (void) p;
}

static void* vnc_worker_thread( void *obj )
{
    filter_t* p_filter = (filter_t*)obj;
    filter_sys_t *p_sys = p_filter->p_sys;
    vlc_thread_t update_thread;
    int canc = vlc_savecancel ();

    msg_Dbg( p_filter, "VNC worker thread started" );

    int fd = vnc_connect( p_filter );
    if( fd == -1 )
    {
        msg_Err( p_filter, "Error occurred while handshaking VNC host" );
        return NULL;
    }

    /* Create an empty picture for VNC the data */
    picture_t *pic =  picture_New( VLC_CODEC_YUVA, p_sys->i_vnc_width,
                                   p_sys->i_vnc_height, 1, 1 );
    if( likely(pic != NULL) )
    {
        vlc_mutex_lock( &p_sys->lock );
        p_sys->i_socket = fd;
        p_sys->p_pic = pic;
        vlc_mutex_unlock( &p_sys->lock );
    }
    else
    {
        net_Close( fd );
        return NULL;
    }

    write_update_request( p_filter, false );

    /* create the update request thread */
    bool polling = var_InheritBool( p_filter, RMTOSD_CFG "vnc-polling" );
    if( polling
     && vlc_clone( &update_thread, update_request_thread,
                   p_filter, VLC_THREAD_PRIORITY_LOW ) )
    {
        msg_Err( p_filter, "cannot spawn VNC update request thread" );
        polling = false;
    }

    vlc_cleanup_push( polling ? update_thread_cleanup : dummy_cleanup,
                      &update_thread );

    /* connection is initialized, now read and handle server messages */
    for( ;; )
    {
        rfbServerToClientMsg msg;
        int i_msgSize;

        memset( &msg, 0, sizeof(msg) );
        vlc_restorecancel (canc);

        if( !read_exact(p_filter, fd, &msg, 1 ) )
        {
            msg_Err( p_filter, "Error while waiting for next server message");
            break;
        }
        switch (msg.type)
        {
        case rfbFramebufferUpdate:
            i_msgSize = sz_rfbFramebufferUpdateMsg;
            break;
        case rfbSetColourMapEntries:
            i_msgSize = sz_rfbSetColourMapEntriesMsg;
            break;
        case rfbBell:
            i_msgSize = sz_rfbBellMsg;
            break;
        case rfbServerCutText:
            i_msgSize = sz_rfbServerCutTextMsg;
            break;
        case rfbReSizeFrameBuffer:
            i_msgSize = sz_rfbReSizeFrameBufferMsg;
            break;
        default:
            i_msgSize = 0;
            msg_Err( p_filter, "Invalid message %u received", msg.type );
            break;
        }

        if( i_msgSize <= 0 )
            break;

        if( --i_msgSize > 0 )
        {
            if ( !read_exact( p_filter, fd, ((char *)&msg) + 1, i_msgSize ) )
            {
                msg_Err( p_filter, "Error while reading message of type %u",
                         msg.type );
                break;
            }
        }

        canc = vlc_savecancel ();
        process_server_message( p_filter, &msg);
    }

    vlc_cleanup_pop();
    if( polling )
        update_thread_cleanup( &update_thread );

    msg_Dbg( p_filter, "VNC message reader thread ended" );
    vlc_restorecancel (canc);
    return NULL;
}

static void* update_request_thread( void *obj )
{
    filter_t* p_filter = (filter_t*)obj;
    int canc = vlc_savecancel();
    mtime_t interval = var_InheritInteger( p_filter, RMTOSD_CFG "update" );
    vlc_restorecancel(canc);

    if( interval < 100 )
        interval = 100;
    interval *= 1000; /* ms -> µs */

    do
        msleep( interval );
    while( write_update_request( p_filter, true ) );

    return NULL;
}

static bool process_server_message ( filter_t *p_filter,
                                     rfbServerToClientMsg *msg )
{
    filter_sys_t *p_sys = p_filter->p_sys;

    switch (msg->type)
    {
    case rfbFramebufferUpdate:
        {
            msg->fu.nRects = htons(msg->fu.nRects);
            rfbFramebufferUpdateRectHeader hdr;

            for (int i_rect = 0; i_rect < msg->fu.nRects; i_rect++)
            {
                if (!read_exact(p_filter, p_sys->i_socket, &hdr,
                                sz_rfbFramebufferUpdateRectHeader ) )
                {
                    msg_Err( p_filter, "Could not read FrameBufferUpdate header" );
                    return false;
                }
                hdr.r.x = htons(hdr.r.x);
                hdr.r.y = htons(hdr.r.y);
                hdr.r.w = htons(hdr.r.w);
                hdr.r.h = htons(hdr.r.h);
                hdr.encoding = htonl(hdr.encoding);

                switch (hdr.encoding)
                {
                case rfbEncodingRaw:
                    {
                        int i_line;
                        for (i_line = 0; i_line < hdr.r.h; i_line++)
                        {
                            if ( !read_exact( p_filter, p_sys->i_socket,
                                    p_sys->read_buffer, hdr.r.w ) )
                            {
                                msg_Err( p_filter,
                                 "Could not read FrameBufferUpdate line data" );
                               return false;
                            }
                            vlc_mutex_lock( &p_sys->lock );
                            if ( !raw_line( p_sys, hdr.r.x,
                                            hdr.r.y + i_line,
                                            hdr.r.w ) )
                            {
                                msg_Err( p_filter, "raw_line failed." );
                                vlc_mutex_unlock( &p_sys->lock );
                                return false;
                            }
                            vlc_mutex_unlock( &p_sys->lock );
                        }
                    }
                    break;

                case rfbEncodingCopyRect:
                    {
                        rfbCopyRect rect;

                        if ( !read_exact( p_filter, p_sys->i_socket,
                                          &rect, sz_rfbCopyRect ) )
                        {
                            msg_Err( p_filter, "Could not read rfbCopyRect" );
                            return false;
                        }
                        rect.srcX = htons( rect.srcX );
                        rect.srcY = htons( rect.srcY );

                        vlc_mutex_lock( &p_sys->lock );
                        if ( !copy_rect( p_sys,
                                         hdr.r.x,   hdr.r.y,
                                         hdr.r.w,   hdr.r.h,
                                         rect.srcX, rect.srcY ) )
                        {
                            msg_Err( p_filter, "copy_rect failed." );
                            vlc_mutex_unlock( &p_sys->lock );
                            return false;
                        }
                        vlc_mutex_unlock( &p_sys->lock );
                    }
                    break;

                case rfbEncodingRRE:
                    {
                        rfbRREHeader rrehdr;
                        if ( !read_exact( p_filter, p_sys->i_socket,
                                          &rrehdr, sz_rfbRREHeader ) )
                        {
                            msg_Err( p_filter, "Could not read rfbRREHeader" );
                            return false;
                        }
                        uint8_t i_pixcolor;
                        if ( !read_exact( p_filter, p_sys->i_socket,
                                          &i_pixcolor, 1 ) )
                        {
                            msg_Err( p_filter, "Could not read RRE pixcolor" );
                            return false;
                        }

                        vlc_mutex_lock( &p_sys->lock );
                        if ( !fill_rect( p_sys,
                                        hdr.r.x, hdr.r.y,
                                        hdr.r.w, hdr.r.h,
                                        i_pixcolor) )
                        {
                            msg_Err( p_filter, "main fill_rect failed." );
                            vlc_mutex_unlock( &p_sys->lock );
                            return false;
                        }
                        vlc_mutex_unlock( &p_sys->lock );

                        rrehdr.nSubrects = htonl(rrehdr.nSubrects);

                        int i_datasize = rrehdr.nSubrects *
                                     ( sizeof(i_pixcolor) + sz_rfbRectangle ) ;
                        if ( i_datasize > READ_BUFFER_SIZE )
                        {
                            msg_Err( p_filter, "Buffer too small, "
                                     "need %u bytes", i_datasize );
                            return false;
                        }
                        if ( !read_exact( p_filter, p_sys->i_socket,
                                          p_sys->read_buffer, i_datasize ) )
                        {
                            msg_Err( p_filter,
                                     "Could not read RRE subrect data" );
                            return false;
                        }

                        uint32_t i_subrect;
                        rfbRectangle* p_subrect;
                        int i_offset = 0;
                        vlc_mutex_lock( &p_sys->lock );
                        for ( i_subrect = 0;
                              i_subrect < rrehdr.nSubrects; i_subrect++)
                        {
                            i_pixcolor = p_sys->read_buffer[i_offset];
                            i_offset += sizeof(i_pixcolor);
                            p_subrect =
                               (rfbRectangle*)(p_sys->read_buffer + i_offset);
                            i_offset += sz_rfbRectangle;

                            if (!fill_rect( p_sys,
                                            htons(p_subrect->x) + hdr.r.x,
                                            htons(p_subrect->y) + hdr.r.y,
                                            htons(p_subrect->w),
                                            htons(p_subrect->h),
                                            i_pixcolor) )
                            {
                                msg_Err( p_filter,
                                    "subrect %u fill_rect failed.", i_subrect );
                                vlc_mutex_unlock( &p_sys->lock );
                                return false;
                            }
                        }
                        vlc_mutex_unlock( &p_sys->lock );
                    }
                    break;

                }

            }
            vlc_mutex_lock( &p_sys->lock );
            p_sys->b_need_update = true;
            vlc_mutex_unlock( &p_sys->lock );
        }
        return true;

    case rfbSetColourMapEntries:
        {
            msg->scme.nColours = htons(msg->scme.nColours);
            msg->scme.firstColour = htons(msg->scme.firstColour);
            int i_datasize;
            if ( p_sys->b_alpha_from_vnc )
            {
                i_datasize = 2 * msg->scme.nColours * 4;
            }
            else
            {
                i_datasize = 2 * msg->scme.nColours * 3;
            }
            if ( i_datasize > READ_BUFFER_SIZE )
            {
                msg_Err( p_filter, "Buffer too small, need %u bytes",
                                   i_datasize );
                return false;
            }

            if ( !read_exact( p_filter, p_sys->i_socket,
                              p_sys->read_buffer, i_datasize ) )
            {
                msg_Err( p_filter, "Could not read color map data" );
                return false;
            }

            uint8_t i_red, i_green, i_blue, i_alpha, i_color_index;
            uint16_t i_offset = 0;
            i_alpha = 255;

            for (int i = 0; i < msg->scme.nColours; i++)
            {
                i_color_index = i+msg->scme.firstColour;
                if ( p_sys->b_alpha_from_vnc )
                {
                    i_alpha = p_sys->read_buffer[i_offset];
                    i_offset += 2;
                }
                i_red   = p_sys->read_buffer[i_offset];
                i_offset += 2;
                i_green = p_sys->read_buffer[i_offset];
                i_offset += 2;
                i_blue  = p_sys->read_buffer[i_offset];
                i_offset += 2;
                rgb_to_yuv( &p_sys->ar_color_table_yuv[i_color_index][0],
                            &p_sys->ar_color_table_yuv[i_color_index][1],
                            &p_sys->ar_color_table_yuv[i_color_index][2],
                            i_red,
                            i_green,
                            i_blue );
                p_sys->ar_color_table_yuv[i][3] = i_alpha;
            }
        }
        return true;

    case rfbBell:
        msg_Err( p_filter, "rfbBell received" );
        return true;

    case rfbServerCutText:
        msg->sct.length = htons(msg->sct.length);
        if ( msg->sct.length > READ_BUFFER_SIZE )
        {
            msg_Err( p_filter, "Buffer too small, need %u bytes", msg->sct.length );
            return false;
        }
        if ( !read_exact( p_filter, p_sys->i_socket,
                          p_sys->read_buffer, msg->sct.length ) )
        {
            msg_Err( p_filter, "Could not read Reading rfbServerCutText data" );
            return false;
        }
        return true;

    case rfbReSizeFrameBuffer:
        msg_Err( p_filter, "Reading rfbReSizeFrameBuffer not implemented" );
        return false;

    default:
        msg_Err( p_filter, "Invalid message %u received", msg->type );
        return false;
    }
    return false;
}

/****************************************************************************
 * Filter: the whole thing
 ****************************************************************************
 * This function outputs subpictures at regular time intervals.
 ****************************************************************************/
static subpicture_t *Filter( filter_t *p_filter, mtime_t date )
{
    filter_sys_t *p_sys = p_filter->p_sys;
    subpicture_t *p_spu;
    subpicture_region_t *p_region;
    video_format_t fmt;
    picture_t *p_pic = NULL;

    vlc_mutex_lock( &p_sys->lock );

    if( p_sys->b_need_update )
        p_pic = p_sys->p_pic;

    if( p_pic == NULL )
    {
        vlc_mutex_unlock( &p_sys->lock );
        return NULL;
    }

    /* Allocate the subpicture internal data. */
    p_spu = filter_NewSubpicture( p_filter );
    if( !p_spu )
    {
        vlc_mutex_unlock( &p_sys->lock );
        return NULL;
    }

    p_spu->b_absolute = false;
    p_spu->i_start = date;
    p_spu->i_stop = 0;
    p_spu->b_ephemer = true;

    /* Create new SPU region */
    memset( &fmt, 0, sizeof(video_format_t) );
    fmt.i_chroma = VLC_CODEC_YUVA;
    fmt.i_sar_num = fmt.i_sar_den = 1;
    fmt.i_width = fmt.i_visible_width = p_pic->p[Y_PLANE].i_visible_pitch;
    fmt.i_height = fmt.i_visible_height = p_pic->p[Y_PLANE].i_visible_lines;
    fmt.i_x_offset = fmt.i_y_offset = 0;
    p_region = subpicture_region_New( &fmt );
    if( !p_region )
    {
        msg_Err( p_filter, "cannot allocate SPU region" );
        subpicture_Delete( p_spu );
        vlc_mutex_unlock( &p_sys->lock );
        return NULL;
    }

    /* FIXME the copy is probably not needed anymore */
    picture_Copy( p_region->p_picture, p_pic );

    p_sys->b_need_update = false;

    vlc_mutex_unlock( &p_sys->lock );

    /* set to one of the 9 relative locations */
    p_region->i_align = 0; /* Center */
    p_spu->b_absolute = false;


    p_spu->i_original_picture_width = 0; /*Let vout core do the horizontal scaling */
    p_spu->i_original_picture_height = fmt.i_height;

    p_spu->p_region = p_region;

    p_spu->i_alpha = ( p_sys->i_alpha );

    return p_spu;
}


static inline void rgb_to_yuv( uint8_t *y, uint8_t *u, uint8_t *v,
                               int r, int g, int b )
{
    *y = ( ( (  66 * r + 129 * g +  25 * b + 128 ) >> 8 ) + 16 );
    *u =   ( ( -38 * r -  74 * g + 112 * b + 128 ) >> 8 ) + 128 ;
    *v =   ( ( 112 * r -  94 * g -  18 * b + 128 ) >> 8 ) + 128 ;
}

static inline bool fill_rect( filter_sys_t* p_sys,
                              uint16_t i_x, uint16_t i_y,
                              uint16_t i_w, uint16_t i_h,
                              uint8_t i_color)
{
    plane_t *p_outY = p_sys->p_pic->p+Y_PLANE;
    plane_t *p_outU = p_sys->p_pic->p+U_PLANE;
    plane_t *p_outV = p_sys->p_pic->p+V_PLANE;
    plane_t *p_outA = p_sys->p_pic->p+A_PLANE;
    int i_pitch = p_outY->i_pitch;
    int i_lines = p_outY->i_lines;
    if ( i_x + i_w > i_pitch)
        return false;
    if ( i_y + i_h > i_lines)
        return false;
    int i_line_offset = i_y * i_pitch;
    uint8_t i_yuv_y = p_sys->ar_color_table_yuv[i_color][0];
    uint8_t i_yuv_u = p_sys->ar_color_table_yuv[i_color][1];
    uint8_t i_yuv_v = p_sys->ar_color_table_yuv[i_color][2];
    uint8_t i_alpha = p_sys->ar_color_table_yuv[i_color][3];
    for( int i_line = 0; i_line < i_h; i_line++ )
    {
        for( int i_column = 0; i_column < i_w; i_column++ )
        {
            int i_total_offset = i_line_offset + i_x + i_column;
            p_outY->p_pixels[ i_total_offset ] = i_yuv_y;
            p_outU->p_pixels[ i_total_offset ] = i_yuv_u;
            p_outV->p_pixels[ i_total_offset ] = i_yuv_v;
            p_outA->p_pixels[ i_total_offset ] = i_alpha;
        }
        i_line_offset += i_pitch;
    }
    return true;
}

static inline bool copy_rect( filter_sys_t* p_sys,
                              uint16_t i_x, uint16_t i_y,
                              uint16_t i_w, uint16_t i_h,
                              uint16_t i_sx, uint16_t i_sy )
{
    plane_t *p_Y = p_sys->p_pic->p+Y_PLANE;
    plane_t *p_U = p_sys->p_pic->p+U_PLANE;
    plane_t *p_V = p_sys->p_pic->p+V_PLANE;
    plane_t *p_A = p_sys->p_pic->p+A_PLANE;

    int i_pitch = p_Y->i_pitch;
    int i_lines = p_Y->i_lines;

    fprintf( stderr, "copy_rect: (%d,%d)+(%d,%d) -> (%d,%d)\n", i_x, i_y, i_w, i_h, i_sx, i_sy );

    if( i_x + i_w > i_pitch || i_sx + i_w > i_pitch )
        return false;
    if( i_y + i_h > i_lines || i_sy + i_h > i_lines)
        return false;

    if( i_w <= 0 || i_h <= 0 )
        return true;

    uint8_t *pb_buffer = calloc( i_w * i_h, 4 );
    if( !pb_buffer )
        return false;

    for( int i_line = 0; i_line < i_h; i_line++ )
    {
        for( int i_column = 0; i_column < i_w; i_column++ )
        {
            const int i_src_offset = ( i_sy + i_line ) * i_pitch + i_sx + i_column;
            const int i_tmp_offset = (    0 + i_line ) *     i_w +    0 + i_column;

            pb_buffer[4*i_tmp_offset + 0] = p_Y->p_pixels[i_src_offset];
            pb_buffer[4*i_tmp_offset + 1] = p_U->p_pixels[i_src_offset];
            pb_buffer[4*i_tmp_offset + 2] = p_V->p_pixels[i_src_offset];
            pb_buffer[4*i_tmp_offset + 3] = p_A->p_pixels[i_src_offset];
        }
    }

    for( int i_line = 0; i_line < i_h; i_line++ )
    {
        for( int i_column = 0; i_column < i_w; i_column++ )
        {
            const int i_tmp_offset = (   0 + i_line ) *     i_w +   0 + i_column;
            const int i_dst_offset = ( i_y + i_line ) * i_pitch + i_x + i_column;

            p_Y->p_pixels[i_dst_offset] = pb_buffer[4*i_tmp_offset + 0];
            p_U->p_pixels[i_dst_offset] = pb_buffer[4*i_tmp_offset + 1];
            p_V->p_pixels[i_dst_offset] = pb_buffer[4*i_tmp_offset + 2];
            p_A->p_pixels[i_dst_offset] = pb_buffer[4*i_tmp_offset + 3];
        }
    }
    free( pb_buffer );
    return true;

}

static inline bool raw_line(  filter_sys_t* p_sys,
                              uint16_t i_x, uint16_t i_y,
                              uint16_t i_w )
{
    plane_t *p_outY = p_sys->p_pic->p+Y_PLANE;
    plane_t *p_outU = p_sys->p_pic->p+U_PLANE;
    plane_t *p_outV = p_sys->p_pic->p+V_PLANE;
    plane_t *p_outA = p_sys->p_pic->p+A_PLANE;
    int i_pitch = p_outY->i_pitch;
    int i_lines = p_outY->i_lines;
    if ( i_x + i_w > i_pitch)
        return false;
    if ( i_y > i_lines)
        return false;

    int i_line_offset = i_y * i_pitch + i_x;

    for( int i_column = 0; i_column < i_w; i_column++ )
    {
        int i_offset = i_line_offset + i_column;
        uint8_t i_color = p_sys->read_buffer[i_column];
        p_outY->p_pixels[ i_offset ] = p_sys->ar_color_table_yuv[i_color][0];
        p_outU->p_pixels[ i_offset ] = p_sys->ar_color_table_yuv[i_color][1];
        p_outV->p_pixels[ i_offset ] = p_sys->ar_color_table_yuv[i_color][2];
        p_outA->p_pixels[ i_offset ] = p_sys->ar_color_table_yuv[i_color][3];
    }

    return true;
}


/*****************************************************************************
 * MouseEvent: callback for mouse events
 *****************************************************************************/
static int MouseEvent( filter_t *p_filter,
                       const vlc_mouse_t *p_old,
                       const vlc_mouse_t *p_new,
                       const video_format_t *p_fmt )
{
    filter_sys_t *p_sys = p_filter->p_sys;
    VLC_UNUSED(p_old);

    int i_v = p_new->i_pressed;
    int i_x = p_new->i_x;
    int i_y = p_new->i_y;

    vlc_mutex_lock( &p_sys->lock );

    const int v_h = p_fmt->i_visible_height;
    const int v_w = p_sys->i_vnc_width * v_h / p_sys->i_vnc_height;
    const int v_x = (p_fmt->i_visible_width-v_w)/2;

    i_x -= v_x;

    if( i_y < 0 || i_x < 0 || i_y >= v_h || i_x >= v_w )
    {
        vlc_mutex_unlock( &p_sys->lock );
        msg_Dbg( p_filter, "invalid mouse event? x=%d y=%d btn=%x", i_x, i_y, i_v );
        return VLC_SUCCESS;
    }

    if( p_sys->i_socket == -1 )
    {
        vlc_mutex_unlock( &p_sys->lock );
        return VLC_SUCCESS;
    }

#ifdef VNC_DEBUG
    msg_Dbg( p_filter, "mouse event x=%d y=%d btn=%x", i_x, i_y, i_v );
#endif

    /* */
    i_x = i_x * p_sys->i_vnc_width / v_w;
    i_y = i_y * p_sys->i_vnc_height / v_h;

    /* buttonMask bits 0-7 are buttons 1-8, 0=up, 1=down */
    rfbPointerEventMsg ev;
    ev.type = rfbPointerEvent;
    ev.buttonMask = i_v;
    ev.x = htons(i_x);
    ev.y = htons(i_y);

    write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbPointerEventMsg);
    vlc_mutex_unlock( &p_sys->lock );

    return VLC_EGENERIC;
}

/*****************************************************************************
 * KeyEvent: callback for keyboard events
 *****************************************************************************/
static int KeyEvent( vlc_object_t *p_this, char const *psz_var,
                     vlc_value_t oldval, vlc_value_t newval, void *p_data )
{
    VLC_UNUSED(psz_var); VLC_UNUSED(oldval);

    filter_t *p_filter = (filter_t *)p_data;
    filter_sys_t *p_sys = p_filter->p_sys;

    msg_Dbg( p_this, "key pressed (%"PRId64") ", newval.i_int );

    if ( !newval.i_int )
    {
        msg_Err( p_this, "Received invalid key event 0" );
        return VLC_EGENERIC;
    }

    vlc_mutex_lock( &p_sys->lock );
    if( p_sys->i_socket == -1 )
    {
        vlc_mutex_unlock( &p_sys->lock );
        return VLC_SUCCESS;
    }

    uint32_t i_key32 = newval.i_int;
    i_key32 = htonl(i_key32);
    rfbKeyEventMsg ev;

    ev.type = rfbKeyEvent;
    ev.down = 1;
    ev.pad = 0;

    /* first key-down for modifier-keys */
    if (newval.i_int & KEY_MODIFIER_CTRL)
    {
        ev.key = 0xffe3;
        write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbKeyEventMsg );
    }
    if (newval.i_int & KEY_MODIFIER_SHIFT)
    {
        ev.key = 0xffe1;
        write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbKeyEventMsg );
    }
    if (newval.i_int & KEY_MODIFIER_ALT)
    {
        ev.key = 0xffe9;
        write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbKeyEventMsg );
    }

    /* then key-down for the pressed key */
    ev.key = i_key32;
    write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbKeyEventMsg );

    ev.down = 0;

    /* then key-up for the pressed key */
    write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbKeyEventMsg );

    /* last key-down for modifier-keys */
    if (newval.i_int & KEY_MODIFIER_CTRL)
    {
        ev.key = 0xffe3;
        write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbKeyEventMsg );
    }
    if (newval.i_int & KEY_MODIFIER_SHIFT)
    {
        ev.key = 0xffe1;
        write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbKeyEventMsg );
    }
    if (newval.i_int & KEY_MODIFIER_ALT)
    {
       ev.key = 0xffe9;
       write_exact( p_filter, p_sys->i_socket, &ev, sz_rfbKeyEventMsg );
    }
    vlc_mutex_unlock( &p_sys->lock );

    return VLC_SUCCESS;
}

static void vnc_encrypt_bytes( unsigned char *bytes, char *passwd )
{
    unsigned char key[8];

    for( unsigned i = 0; i < 8; i++ )
        key[i] = i < strlen( passwd ) ? passwd[i] : '\0';

    gcry_cipher_hd_t ctx;
    gcry_cipher_open( &ctx, GCRY_CIPHER_DES, GCRY_CIPHER_MODE_ECB,0);

    /* reverse bits of the key */
    for( unsigned i = 0 ; i < 8 ; i++ )
        key[i] =
            (key[i] >> 7) +
            (((key[i] >> 6) & 0x01 ) << 1 ) +
            (((key[i] >> 5) & 0x01 ) << 2 ) +
            (((key[i] >> 4) & 0x01 ) << 3 ) +
            (((key[i] >> 3) & 0x01 ) << 4 ) +
            (((key[i] >> 2) & 0x01 ) << 5 ) +
            (((key[i] >> 1) & 0x01 ) << 6 ) +
            ((key[i] & 0x01) << 7 );

    gcry_cipher_setkey( ctx, key, 8 );
    gcry_cipher_encrypt( ctx, bytes, CHALLENGESIZE, bytes, CHALLENGESIZE );
    gcry_cipher_close( ctx );
}

