/*
  * Microsoft Windows ICO muxer

  * Copyright (c) 2012 Michael Bradshaw <mjbshaw gmail com>

  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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.
  *
  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * Microsoft Windows ICO muxer
  */
 
 #include "libavutil/intreadwrite.h"
 #include "libavutil/pixdesc.h"
 #include "avformat.h"
 
 typedef struct {
     int offset;
     int size;
     unsigned char width;
     unsigned char height;
     short bits;
 } IcoImage;
 
 typedef struct {
     int current_image;
     int nb_images;
     IcoImage *images;
 } IcoMuxContext;
 
 static int ico_check_attributes(AVFormatContext *s, const AVCodecContext *c)
 {

     if (c->codec_id == AV_CODEC_ID_BMP) {

         if (c->pix_fmt == AV_PIX_FMT_PAL8 && AV_PIX_FMT_RGB32 != AV_PIX_FMT_BGRA) {

             av_log(s, AV_LOG_ERROR, "Wrong endianness for bmp pixel format\n");
             return AVERROR(EINVAL);

         } else if (c->pix_fmt != AV_PIX_FMT_PAL8 &&
                    c->pix_fmt != AV_PIX_FMT_RGB555LE &&
                    c->pix_fmt != AV_PIX_FMT_BGR24 &&
                    c->pix_fmt != AV_PIX_FMT_BGRA) {

             av_log(s, AV_LOG_ERROR, "BMP must be 1bit, 4bit, 8bit, 16bit, 24bit, or 32bit\n");
             return AVERROR(EINVAL);
         }

     } else if (c->codec_id == AV_CODEC_ID_PNG) {

         if (c->pix_fmt != AV_PIX_FMT_RGBA) {

             av_log(s, AV_LOG_ERROR, "PNG in ico requires pixel format to be rgba\n");
             return AVERROR(EINVAL);
         }
     } else {
         av_log(s, AV_LOG_ERROR, "Unsupported codec %s\n", c->codec_name);
         return AVERROR(EINVAL);
     }
 
     if (c->width > 256 ||
         c->height > 256) {
         av_log(s, AV_LOG_ERROR, "Unsupported dimensions %dx%d (dimensions cannot exceed 256x256)\n", c->width, c->height);
         return AVERROR(EINVAL);
     }
 
     return 0;
 }
 
 static int ico_write_header(AVFormatContext *s)
 {
     IcoMuxContext *ico = s->priv_data;
     AVIOContext *pb = s->pb;
     int ret;
     int i;
 
     if (!pb->seekable) {
         av_log(s, AV_LOG_ERROR, "Output is not seekable\n");
         return AVERROR(EINVAL);
     }
 
     ico->current_image = 0;
     ico->nb_images = s->nb_streams;
 
     avio_wl16(pb, 0); // reserved
     avio_wl16(pb, 1); // 1 == icon
     avio_skip(pb, 2); // skip the number of images
 
     for (i = 0; i < s->nb_streams; i++) {
         if (ret = ico_check_attributes(s, s->streams[i]->codec))
             return ret;
 
         // Fill in later when writing trailer...
         avio_skip(pb, 16);
     }
 
     ico->images = av_mallocz(ico->nb_images * sizeof(IcoMuxContext));
     if (!ico->images)
         return AVERROR(ENOMEM);
 
     avio_flush(pb);
 
     return 0;
 }
 
 static int ico_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     IcoMuxContext *ico = s->priv_data;
     IcoImage *image;
     AVIOContext *pb = s->pb;
     AVCodecContext *c = s->streams[pkt->stream_index]->codec;
     int i;
 
     if (ico->current_image >= ico->nb_images) {
         av_log(s, AV_LOG_ERROR, "ICO already contains %d images\n", ico->current_image);
         return AVERROR(EIO);
     }
 
     image = &ico->images[ico->current_image++];
 
     image->offset = avio_tell(pb);
     image->width = (c->width == 256) ? 0 : c->width;
     image->height = (c->height == 256) ? 0 : c->height;
 

     if (c->codec_id == AV_CODEC_ID_PNG) {

         image->bits = c->bits_per_coded_sample;
         image->size = pkt->size;
 
         avio_write(pb, pkt->data, pkt->size);
     } else { // BMP
         if (AV_RL32(pkt->data + 14) != 40) { // must be BITMAPINFOHEADER
             av_log(s, AV_LOG_ERROR, "Invalid BMP\n");
             return AVERROR(EINVAL);
         }
 
         image->bits = AV_RL16(pkt->data + 28); // allows things like 1bit and 4bit images to be preserved
         image->size = pkt->size - 14 + c->height * (c->width + 7) / 8;
 
         avio_write(pb, pkt->data + 14, 8); // Skip the BITMAPFILEHEADER header
         avio_wl32(pb, AV_RL32(pkt->data + 22) * 2); // rewrite height as 2 * height
         avio_write(pb, pkt->data + 26, pkt->size - 26);
 
         for (i = 0; i < c->height * (c->width + 7) / 8; ++i)
             avio_w8(pb, 0x00); // Write bitmask (opaque)
     }
 
     avio_flush(pb);
 
     return 0;
 }
 
 static int ico_write_trailer(AVFormatContext *s)
 {
     IcoMuxContext *ico = s->priv_data;
     AVIOContext *pb = s->pb;
     int i;
 
     avio_seek(pb, 4, SEEK_SET);
 
     avio_wl16(pb, ico->current_image);
 
     for (i = 0; i < ico->nb_images; i++) {
         avio_w8(pb, ico->images[i].width);
         avio_w8(pb, ico->images[i].height);
 

         if (s->streams[i]->codec->codec_id == AV_CODEC_ID_BMP &&

             s->streams[i]->codec->pix_fmt == AV_PIX_FMT_PAL8) {

             avio_w8(pb, (ico->images[i].bits >= 8) ? 0 : 1 << ico->images[i].bits);
         } else {
             avio_w8(pb, 0);
         }
 
         avio_w8(pb, 0); // reserved
         avio_wl16(pb, 1); // color planes
         avio_wl16(pb, ico->images[i].bits);
         avio_wl32(pb, ico->images[i].size);
         avio_wl32(pb, ico->images[i].offset);
     }
 
     av_freep(&ico->images);
 
     return 0;
 }
 
 AVOutputFormat ff_ico_muxer = {
     .name           = "ico",
     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Windows ICO"),
     .priv_data_size = sizeof(IcoMuxContext),
     .mime_type      = "image/vnd.microsoft.icon",
     .extensions     = "ico",

     .audio_codec    = AV_CODEC_ID_NONE,
     .video_codec    = AV_CODEC_ID_BMP,

     .write_header   = ico_write_header,
     .write_packet   = ico_write_packet,
     .write_trailer  = ico_write_trailer,
     .flags          = AVFMT_NOTIMESTAMPS,
 };