/*****************************************************************************
 * cdg.c: CDG decoder module
 *****************************************************************************
 * Copyright (C) 2007 Laurent Aimar
 * $Id: 5a28a33799d1d96114577664f90372eb5baf98c0 $
 *
 * Authors: Laurent Aimar <fenrir # via.ecp.fr>
 *
 * 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_plugin.h>
#include <vlc_codec.h>

/*****************************************************************************
 * decoder_sys_t : decoder descriptor
 *****************************************************************************/

/* The screen size */
#define CDG_SCREEN_WIDTH 300u
#define CDG_SCREEN_HEIGHT 216u

/* The border of the screen size */
#define CDG_SCREEN_BORDER_WIDTH 6u
#define CDG_SCREEN_BORDER_HEIGHT 12u

/* The display part */
#define CDG_DISPLAY_WIDTH  (CDG_SCREEN_WIDTH-2*CDG_SCREEN_BORDER_WIDTH)
#define CDG_DISPLAY_HEIGHT (CDG_SCREEN_HEIGHT-2*CDG_SCREEN_BORDER_HEIGHT)

#define CDG_SCREEN_PITCH CDG_SCREEN_WIDTH

struct decoder_sys_t
{
    uint8_t  color[16][3];
    unsigned i_offseth;
    unsigned i_offsetv;
    uint8_t  screen[CDG_SCREEN_PITCH*CDG_SCREEN_HEIGHT];
    uint8_t  *p_screen;

    int      i_packet;
};

#define CDG_PACKET_SIZE 24u

#define CDG_COLOR_R_SHIFT  0
#define CDG_COLOR_G_SHIFT  8
#define CDG_COLOR_B_SHIFT 16

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );

static picture_t *Decode( decoder_t *, block_t ** );

static int DecodePacket( decoder_sys_t *p_cdg, uint8_t *p_buffer, int i_buffer );
static int Render( decoder_sys_t *p_cdg, picture_t *p_picture );

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin ()
    set_category( CAT_INPUT )
    set_subcategory( SUBCAT_INPUT_VCODEC )
    set_description( N_("CDG video decoder") )
    set_capability( "decoder", 1000 )
    set_callbacks( Open, Close )
    add_shortcut( "cdg" )
vlc_module_end ()

/*****************************************************************************
 * Open: probe the decoder and return score
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    decoder_t *p_dec = (decoder_t*)p_this;
    decoder_sys_t *p_sys;

    if( p_dec->fmt_in.i_codec != VLC_CODEC_CDG )
        return VLC_EGENERIC;

    /* Allocate the memory needed to store the decoder's structure */
    p_dec->p_sys = p_sys = calloc( 1, sizeof(decoder_sys_t) );
    if( !p_sys )
        return VLC_ENOMEM;

    /* Init */
    p_sys->p_screen = p_sys->screen;
    p_sys->i_packet = 0;

    /* Set output properties
     * TODO maybe it would be better to use RV16 or RV24 ? */
    p_dec->fmt_out.i_cat = VIDEO_ES;
    p_dec->fmt_out.i_codec = VLC_CODEC_RGB32;
    p_dec->fmt_out.video.i_width = CDG_DISPLAY_WIDTH;
    p_dec->fmt_out.video.i_height = CDG_DISPLAY_HEIGHT;
    p_dec->fmt_out.video.i_sar_num = 1;
    p_dec->fmt_out.video.i_sar_den = 1;
    p_dec->fmt_out.video.i_rmask = 0xff << CDG_COLOR_R_SHIFT;
    p_dec->fmt_out.video.i_gmask = 0xff << CDG_COLOR_G_SHIFT;
    p_dec->fmt_out.video.i_bmask = 0xff << CDG_COLOR_B_SHIFT;

    /* Set callbacks */
    p_dec->pf_decode_video = Decode;

    return VLC_SUCCESS;
}

/****************************************************************************
 * Decode: the whole thing
 ****************************************************************************
 * This function must be fed with a complete compressed frame.
 ****************************************************************************/
static picture_t *Decode( decoder_t *p_dec, block_t **pp_block )
{
    decoder_sys_t *p_sys = p_dec->p_sys;
    block_t *p_block;
    picture_t *p_pic = NULL;

    if( !pp_block || !*pp_block )
        return NULL;
    p_block = *pp_block;

    if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) )
    {
        p_sys->i_packet = 0;
        goto exit;
    }

    /* Decode packet */
    while( p_block->i_buffer >= CDG_PACKET_SIZE )
    {
        DecodePacket( p_sys, p_block->p_buffer, CDG_PACKET_SIZE );
        p_block->i_buffer -= CDG_PACKET_SIZE;
        p_block->p_buffer += CDG_PACKET_SIZE;
    }

    /* Only display 25 frame per second (there is 75 packets per second) */
    if( (p_sys->i_packet%3) == 1 )
    {
        /* Get a new picture */
        p_pic = decoder_NewPicture( p_dec );
        if( !p_pic )
            goto exit;

        Render( p_sys, p_pic );
        p_pic->date = p_block->i_pts > VLC_TS_INVALID ? p_block->i_pts : p_block->i_dts;
    }

exit:
    block_Release( p_block ); *pp_block = NULL;
    return p_pic;
}

/*****************************************************************************
 * Close: decoder destruction
 *****************************************************************************/
static void Close( vlc_object_t *p_this )
{
    decoder_t *p_dec = (decoder_t *)p_this;
    decoder_sys_t *p_sys = p_dec->p_sys;

    free( p_sys );
}

/*****************************************************************************
 * Decoder
 *****************************************************************************/
static void ScreenFill( decoder_sys_t *p_cdg, int sx, int sy, int dx, int dy, int c )
{
    int x, y;
    for( y = sy; y < sy+dy; y++ )
        for( x = sx; x < sx+dx; x++ )
            p_cdg->p_screen[y*CDG_SCREEN_PITCH+x] = c;
}
static int DecodeMemoryPreset( decoder_sys_t *p_cdg, const uint8_t *p_data )
{
    const int i_color = p_data[0]&0x0f;
#if 0
    const int i_repeat= p_data[1]&0x0f;
#endif
    /* if i_repeat > 0 we could ignore it if we have a reliable stream */
    ScreenFill( p_cdg, 0, 0, CDG_SCREEN_WIDTH, CDG_SCREEN_HEIGHT, i_color );
    return 0;
}
static int DecodeBorderPreset( decoder_sys_t *p_cdg, const uint8_t *p_data )
{
    const int i_color = p_data[0]&0x0f;

    /* */
    ScreenFill( p_cdg,   0,   0,
                CDG_SCREEN_WIDTH, CDG_SCREEN_BORDER_HEIGHT, i_color );
    ScreenFill( p_cdg,   0, CDG_SCREEN_HEIGHT-CDG_SCREEN_BORDER_HEIGHT,
                CDG_SCREEN_WIDTH, CDG_SCREEN_BORDER_HEIGHT, i_color );
    ScreenFill( p_cdg,   0, CDG_SCREEN_BORDER_HEIGHT,
                CDG_SCREEN_BORDER_WIDTH, CDG_SCREEN_HEIGHT-CDG_SCREEN_BORDER_HEIGHT, i_color );
    ScreenFill( p_cdg,   CDG_SCREEN_WIDTH-CDG_SCREEN_BORDER_WIDTH, CDG_SCREEN_BORDER_HEIGHT,
                CDG_SCREEN_BORDER_WIDTH, CDG_SCREEN_HEIGHT-CDG_SCREEN_BORDER_HEIGHT, i_color );
    return 0;
}

static int DecodeLoadColorTable( decoder_sys_t *p_cdg, const uint8_t *p_data, int i_base )
{
    int n;
    for( n = 0; n < 8; n++ )
    {
        const int c = ((p_data[2*n+0] << 8) | p_data[2*n+1]);
        const int r = (c >> 10)&0x0f;
        const int g = ((c >> 6)&0x0c) | ((c >> 4)&0x03);
        const int b = c &0x0f;

        p_cdg->color[i_base+n][0] = r << 4;
        p_cdg->color[i_base+n][1] = g << 4;
        p_cdg->color[i_base+n][2] = b << 4;
    }
    return 0;
}
static int DecodeTileBlock( decoder_sys_t *p_cdg, const uint8_t *p_data, int doXor )
{
    int p_color[2];
    int sx, sy;
    int x, y;

    p_color[0] = p_data[0] & 0x0f;
    p_color[1] = p_data[1] & 0x0f;

    sy = (p_data[2] & 0x1f)*12;
    sx = (p_data[3] & 0x3f)*6;

    for( y = 0; y < 12; y++ )
    {
        for( x = 0; x < 6; x++ )
        {
            const int idx = ( p_data[4+y] >> (5-x) ) & 0x01;

            unsigned index = (sy+y)*CDG_SCREEN_PITCH+(sx+x);
            if( index >= CDG_SCREEN_PITCH*CDG_SCREEN_HEIGHT )
                return 0;

            uint8_t *p = &p_cdg->p_screen[index];

            if( doXor )
                *p ^= p_color[idx];
            else
                *p = p_color[idx];
        }
    }
    return 0;
}

static int DecodeScroll( decoder_sys_t *p_cdg, const uint8_t *p_data, int b_copy )
{
    uint8_t copy[CDG_SCREEN_PITCH*CDG_SCREEN_HEIGHT];

    uint8_t color = p_data[0]&0x0f;
    int i_shifth;
    int i_shiftv;

    /* */
    p_cdg->i_offseth = p_data[1]&0x7;
    if( p_cdg->i_offseth >= CDG_SCREEN_BORDER_WIDTH )
        p_cdg->i_offseth = CDG_SCREEN_BORDER_WIDTH-1;

    p_cdg->i_offsetv = p_data[2]&0xf;
    if( p_cdg->i_offsetv >= CDG_SCREEN_BORDER_HEIGHT )
        p_cdg->i_offsetv = CDG_SCREEN_BORDER_HEIGHT-1;

    /* */
    switch( (p_data[1] >> 4)&0x3 )
    {
    case 0x01: i_shifth =  6; break;
    case 0x02: i_shifth = -6; break;
    default:
        i_shifth = 0;
        break;
    }
    switch( (p_data[2] >> 4)&0x3 )
    {
    case 0x01: i_shiftv = 12; break;
    case 0x02: i_shiftv =-12; break;
    default:
        i_shiftv = 0;
        break;
    }

    if( i_shifth == 0 && i_shiftv == 0 )
        return 0;

    /* Make a copy of the screen */
    memcpy( copy, p_cdg->screen, sizeof(p_cdg->screen) );

    /* Fill the uncovered part XXX way too much */
    ScreenFill( p_cdg, 0, 0, CDG_SCREEN_WIDTH, CDG_SCREEN_HEIGHT, color );

    /* Copy back */
    for( unsigned y = 0; y < CDG_SCREEN_HEIGHT; y++ )
    {
        int dy = i_shiftv + y;
        for( unsigned x = 0; x < CDG_SCREEN_WIDTH; x++ )
        {
            int dx = i_shifth + x;

            if( b_copy )
            {
                dy = (dy + CDG_SCREEN_HEIGHT) % CDG_SCREEN_HEIGHT;
                dx = (dx + CDG_SCREEN_WIDTH ) % CDG_SCREEN_WIDTH;
            }
            else
            {
                if( dy < 0 || (unsigned)dy >= CDG_SCREEN_HEIGHT ||
                    dx < 0 || (unsigned)dx >= CDG_SCREEN_WIDTH )
                    continue;
            }
            p_cdg->screen[dy*CDG_SCREEN_PITCH+dx] = copy[y*CDG_SCREEN_PITCH+x];
        }
    }
    /* */
    //CdgDebug( CDG_LOG_WARNING, "DecodeScroll: color=%d ch=%d oh=%d cv=%d ov=%d\n copy=%d\n", color, i_shifth, p_cdg->i_offseth, i_shiftv, p_cdg->i_offsetv, b_copy );
    return 0;
}

static int DecodePacket( decoder_sys_t *p_cdg, uint8_t *p_buffer, int i_buffer )
{
    const int i_cmd = p_buffer[0] & 0x3f;
    const int i_instruction = p_buffer[1] & 0x3f;
    const uint8_t *p_data = &p_buffer[4];

    if( i_buffer != CDG_PACKET_SIZE )
        return -1;

    p_cdg->i_packet++;

    /* Handle CDG command only */
    if( i_cmd != 0x09 )
        return 0;

    switch( i_instruction )
    {
        case 1:
            DecodeMemoryPreset( p_cdg, p_data );
            break;
        case 2:
            DecodeBorderPreset( p_cdg, p_data );
            break;
        case 6:
            DecodeTileBlock( p_cdg, p_data, 0 );
            break;
        case 20:
            DecodeScroll( p_cdg, p_data, 0 );
            break;
        case 24:
            DecodeScroll( p_cdg, p_data, 1 );
            break;
        case 28:
            /* FIXME what to do about that one ? */
            //CdgDebug( CDG_LOG_WARNING, "DecodeDefineTransparentColor not implemented\n" );
            //DecodeDefineTransparentColor( p_cdg, p_data );
            break;
        case 30:
            DecodeLoadColorTable( p_cdg, p_data, 0 );
            break;
        case 31:
            DecodeLoadColorTable( p_cdg, p_data, 8 );
            break;
        case 38:
            DecodeTileBlock( p_cdg, p_data, 1 );
            break;
        default:
            break;
    }
    return 0;
}

static void RenderPixel( picture_t *p_picture, int x, int y, uint32_t c )
{
    const int i_plane = 0;
    const int i_pitch = p_picture->p[i_plane].i_pitch;
    uint32_t *s = (uint32_t*)&p_picture->p[i_plane].p_pixels[y*i_pitch + x*sizeof(uint32_t)];
    *s = c;
}
static uint32_t RenderRGB( int r, int g, int b )
{
    return ( r << CDG_COLOR_R_SHIFT ) | ( g << CDG_COLOR_G_SHIFT ) | ( b << CDG_COLOR_B_SHIFT );
}

static int Render( decoder_sys_t *p_cdg, picture_t *p_picture )
{
    for( unsigned y = 0; y < CDG_DISPLAY_HEIGHT; y++ )
    {
        for( unsigned x = 0; x < CDG_DISPLAY_WIDTH; x++ )
        {
            const int sx = x + p_cdg->i_offseth + CDG_SCREEN_BORDER_WIDTH;
            const int sy = y + p_cdg->i_offsetv + CDG_SCREEN_BORDER_HEIGHT;
            uint8_t cidx = p_cdg->p_screen[sy*CDG_SCREEN_PITCH +sx];
            uint8_t r = p_cdg->color[cidx][0];
            uint8_t g = p_cdg->color[cidx][1];
            uint8_t b = p_cdg->color[cidx][2];

            RenderPixel( p_picture, x, y, RenderRGB( r, g, b ) );
        }
    }
    return 0;
}

