/*****************************************************************************
 * bluescreen.c : Bluescreen (weather channel like) video filter for vlc
 *****************************************************************************
 * Copyright (C) 2005-2007 VLC authors and VideoLAN
 *
 * Authors: Antoine Cellerier <dionoea at videolan tod org>
 *
 * 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 implied 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.
 *****************************************************************************/

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

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

#include <vlc_common.h>
#include <vlc_configuration.h>
#include <vlc_plugin.h>
#include <vlc_filter.h>
#include <vlc_picture.h>

#define BLUESCREEN_HELP N_( \
    "This effect, also known as \"greenscreen\" or \"chroma key\" blends " \
    "the \"blue parts\" of the foreground image of the mosaic on the " \
    "background (like weather forecasts). You can choose the \"key\" " \
    "color for blending (blue by default)." )

#define BLUESCREENU_TEXT N_("Bluescreen U value")
#define BLUESCREENU_LONGTEXT N_( \
        "\"U\" value for the bluescreen key color " \
        "(in YUV values). From 0 to 255. Defaults to 120 for blue." )
#define BLUESCREENV_TEXT N_("Bluescreen V value")
#define BLUESCREENV_LONGTEXT N_( \
        "\"V\" value for the bluescreen key color " \
        "(in YUV values). From 0 to 255. Defaults to 90 for blue." )
#define BLUESCREENUTOL_TEXT N_("Bluescreen U tolerance")
#define BLUESCREENUTOL_LONGTEXT N_( \
        "Tolerance of the bluescreen blender " \
        "on color variations for the U plane. A value between 10 and 20 " \
        "seems sensible." )
#define BLUESCREENVTOL_TEXT N_("Bluescreen V tolerance")
#define BLUESCREENVTOL_LONGTEXT N_( \
        "Tolerance of the bluescreen blender " \
        "on color variations for the V plane. A value between 10 and 20 " \
        "seems sensible." )

#define CFG_PREFIX "bluescreen-"

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  Create      ( filter_t * );
static void Destroy     ( filter_t * );

static picture_t *Filter( filter_t *, picture_t * );
static int BluescreenCallback( vlc_object_t *, char const *,
                               vlc_value_t, vlc_value_t, void * );

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin ()
    set_description( N_("Bluescreen video filter") )
    set_shortname( N_("Bluescreen" ))
    set_help( BLUESCREEN_HELP )
    set_subcategory( SUBCAT_VIDEO_VFILTER )
    add_shortcut( "bluescreen" )
    set_callback_video_filter( Create )

    add_integer_with_range( CFG_PREFIX "u", 120, 0, 255,
                            BLUESCREENU_TEXT, BLUESCREENU_LONGTEXT )
    add_integer_with_range( CFG_PREFIX "v", 90, 0, 255,
                            BLUESCREENV_TEXT, BLUESCREENV_LONGTEXT )
    add_integer_with_range( CFG_PREFIX "ut", 17, 0, 255,
                            BLUESCREENUTOL_TEXT, BLUESCREENUTOL_LONGTEXT )
    add_integer_with_range( CFG_PREFIX "vt", 17, 0, 255,
                            BLUESCREENVTOL_TEXT, BLUESCREENVTOL_LONGTEXT )
vlc_module_end ()

static const char *const ppsz_filter_options[] = {
    "u", "v", "ut", "vt", NULL
};

typedef struct
{
    vlc_mutex_t lock;
    int i_u, i_v, i_ut, i_vt;
    uint8_t *p_at;
} filter_sys_t;

static const struct vlc_filter_operations filter_ops =
{
    .filter_video = Filter, .close = Destroy,
};

static int Create( filter_t *p_filter )
{
    filter_sys_t *p_sys;

    if( p_filter->fmt_in.video.i_chroma != VLC_CODEC_YUVA )
    {
        msg_Err( p_filter,
                 "Unsupported input chroma \"%4.4s\". "
                 "Bluescreen can only use \"YUVA\".",
                 (char*)&p_filter->fmt_in.video.i_chroma );
        return VLC_EGENERIC;
    }

    /* Allocate structure */
    p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
    if( p_filter->p_sys == NULL )
        return VLC_ENOMEM;
    p_sys = p_filter->p_sys;

    config_ChainParse( p_filter, CFG_PREFIX, ppsz_filter_options,
                       p_filter->p_cfg );

    int val;
    vlc_mutex_init( &p_sys->lock );
#define GET_VAR( name, min, max )                                           \
    val = var_CreateGetIntegerCommand( p_filter, CFG_PREFIX #name );        \
    p_sys->i_##name = VLC_CLIP( val, min, max );                                \
    var_AddCallback( p_filter, CFG_PREFIX #name, BluescreenCallback, p_sys );

    GET_VAR( u, 0x00, 0xff );
    GET_VAR( v, 0x00, 0xff );
    GET_VAR( ut, 0x00, 0xff );
    GET_VAR( vt, 0x00, 0xff );
    p_sys->p_at = NULL;
#undef GET_VAR

    p_filter->ops = &filter_ops;

    return VLC_SUCCESS;
}

static void Destroy( filter_t *p_filter )
{
    filter_sys_t *p_sys = p_filter->p_sys;

    var_DelCallback( p_filter, CFG_PREFIX "u", BluescreenCallback, p_sys );
    var_DelCallback( p_filter, CFG_PREFIX "v", BluescreenCallback, p_sys );
    var_DelCallback( p_filter, CFG_PREFIX "ut", BluescreenCallback, p_sys );
    var_DelCallback( p_filter, CFG_PREFIX "vt", BluescreenCallback, p_sys );

    free( p_sys->p_at );
    free( p_sys );
}

static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
{
    filter_sys_t *p_sys = p_filter->p_sys;

    int i_lines = p_pic->p[ A_PLANE ].i_lines;
    int i_pitch = p_pic->p[ A_PLANE ].i_pitch;
    uint8_t *p_a = p_pic->p[ A_PLANE ].p_pixels;
    uint8_t *p_at;
    uint8_t *p_u = p_pic->p[ U_PLANE ].p_pixels;
    uint8_t *p_v = p_pic->p[ V_PLANE ].p_pixels;
    uint8_t umin, umax, vmin, vmax;

    if( p_pic->format.i_chroma != VLC_CODEC_YUVA )
    {
        msg_Err( p_filter,
                 "Unsupported input chroma \"%4.4s\". "
                 "Bluescreen can only use \"YUVA\".",
                 (char*)&p_pic->format.i_chroma );
        return NULL;
    }

    p_sys->p_at = xrealloc( p_sys->p_at, i_lines * i_pitch );
    p_at = p_sys->p_at;

    vlc_mutex_lock( &p_sys->lock );
    umin = p_sys->i_u - p_sys->i_ut >= 0x00 ? p_sys->i_u - p_sys->i_ut : 0x00;
    umax = p_sys->i_u + p_sys->i_ut <= 0xff ? p_sys->i_u + p_sys->i_ut : 0xff;
    vmin = p_sys->i_v - p_sys->i_vt >= 0x00 ? p_sys->i_v - p_sys->i_vt : 0x00;
    vmax = p_sys->i_v + p_sys->i_vt <= 0xff ? p_sys->i_v + p_sys->i_vt : 0xff;
    vlc_mutex_unlock( &p_sys->lock );

    for( int i = 0; i < i_lines*i_pitch; i++ )
    {
        if(    p_u[i] < umax && p_u[i] > umin
            && p_v[i] < vmax && p_v[i] > vmin )
        {
            p_at[i] = 0x00;
        }
        else
        {
            p_at[i] = 0xff;
        }
    }
    /* Gaussian convolution to make it look cleaner */
    memset( p_a, 0, 2 * i_pitch );
    for( int i = 2; i < i_lines - 2; i++ )
    {
        p_a[i*i_pitch] = 0x00;
        p_a[i*i_pitch+1] = 0x00;
        for( int j = 2; j < i_pitch - 2; j++ )
        {
            p_a[i*i_pitch+j] = (uint8_t)((
              /* 2 rows up */
                ( p_at[(i-2)*i_pitch+j-2]<<1 )
              + ( p_at[(i-2)*i_pitch+j-1]<<2 )
              + ( p_at[(i-2)*i_pitch+j]<<2 )
              + ( p_at[(i-2)*i_pitch+j+1]<<2 )
              + ( p_at[(i-2)*i_pitch+j+2]<<1 )
              /* 1 row up */
              + ( p_at[(i-1)*i_pitch+j-2]<<2 )
              + ( p_at[(i-1)*i_pitch+j-1]<<3 )
              + ( p_at[(i-1)*i_pitch+j]*12 )
              + ( p_at[(i-1)*i_pitch+j+1]<<3 )
              + ( p_at[(i-1)*i_pitch+j+2]<<2 )
              /* */
              + ( p_at[i*i_pitch+j-2]<<2 )
              + ( p_at[i*i_pitch+j-1]*12 )
              + ( p_at[i*i_pitch+j]<<4 )
              + ( p_at[i*i_pitch+j+1]*12 )
              + ( p_at[i*i_pitch+j+2]<<2 )
              /* 1 row down */
              + ( p_at[(i+1)*i_pitch+j-2]<<2 )
              + ( p_at[(i+1)*i_pitch+j-1]<<3 )
              + ( p_at[(i+1)*i_pitch+j]*12 )
              + ( p_at[(i+1)*i_pitch+j+1]<<3 )
              + ( p_at[(i+1)*i_pitch+j+2]<<2 )
              /* 2 rows down */
              + ( p_at[(i+2)*i_pitch+j-2]<<1 )
              + ( p_at[(i+2)*i_pitch+j-1]<<2 )
              + ( p_at[(i+2)*i_pitch+j]<<2 )
              + ( p_at[(i+2)*i_pitch+j+1]<<2 )
              + ( p_at[(i+2)*i_pitch+j+2]<<1 )
              )/152);
              if( p_a[i*i_pitch+j] < 0xbf ) p_a[i*i_pitch+j] = 0x00;
        }
    }
    return p_pic;
}

/*****************************************************************************
* Callback to update params on the fly
*****************************************************************************/
static int BluescreenCallback( vlc_object_t *p_this, char const *psz_var,
                               vlc_value_t oldval, vlc_value_t newval,
                               void *p_data )
{
    VLC_UNUSED(p_this); VLC_UNUSED(oldval);
    filter_sys_t *p_sys = p_data;

    vlc_mutex_lock( &p_sys->lock );
#define VAR_IS( a ) !strcmp( psz_var, CFG_PREFIX a )
    if( VAR_IS( "u" ) )
        p_sys->i_u = VLC_CLIP( newval.i_int, 0, 255 );
    else if( VAR_IS( "v" ) )
        p_sys->i_v = VLC_CLIP( newval.i_int, 0, 255 );
    else if( VAR_IS( "ut" ) )
        p_sys->i_ut = VLC_CLIP( newval.i_int, 0, 255 );
    else if( VAR_IS( "vt" ) )
        p_sys->i_vt = VLC_CLIP( newval.i_int, 0, 255 );
    vlc_mutex_unlock( &p_sys->lock );

    return VLC_SUCCESS;
}
