/*
  * Copyright (c) 2013 Lukasz Marek
  *
  * 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
  */
 
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <linux/fb.h>
 #include "libavutil/pixdesc.h"
 #include "libavutil/log.h"
 #include "libavutil/mem.h"
 #include "libavutil/opt.h"
 #include "libavformat/avformat.h"

 #include "fbdev_common.h"

 
 typedef struct {
     AVClass *class;                   ///< class for private options
     int xoffset;                      ///< x coordinate of top left corner
     int yoffset;                      ///< y coordinate of top left corner
     struct fb_var_screeninfo varinfo; ///< framebuffer variable info
     struct fb_fix_screeninfo fixinfo; ///< framebuffer fixed info
     int fd;                           ///< framebuffer device file descriptor
     uint8_t *data;                    ///< framebuffer data
 } FBDevContext;
 
 static av_cold int fbdev_write_header(AVFormatContext *h)
 {
     FBDevContext *fbdev = h->priv_data;
     enum AVPixelFormat pix_fmt;
     int ret, flags = O_RDWR;

     const char* device;

     if (h->nb_streams != 1 || h->streams[0]->codec->codec_type != AVMEDIA_TYPE_VIDEO) {
         av_log(fbdev, AV_LOG_ERROR, "Only a single video stream is supported.\n");

         return AVERROR(EINVAL);
     }
 

     if (h->filename[0])
         device = h->filename;
     else
         device = ff_fbdev_default_device();
 
     if ((fbdev->fd = avpriv_open(device, flags)) == -1) {

         ret = AVERROR(errno);
         av_log(h, AV_LOG_ERROR,
                "Could not open framebuffer device '%s': %s\n",

                device, av_err2str(ret));

         return ret;
     }
 
     if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
         ret = AVERROR(errno);
         av_log(h, AV_LOG_ERROR, "FBIOGET_VSCREENINFO: %s\n", av_err2str(ret));
         goto fail;
     }
 
     if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
         ret = AVERROR(errno);
         av_log(h, AV_LOG_ERROR, "FBIOGET_FSCREENINFO: %s\n", av_err2str(ret));
         goto fail;
     }
 

     pix_fmt = ff_get_pixfmt_from_fb_varinfo(&fbdev->varinfo);

     if (pix_fmt == AV_PIX_FMT_NONE) {
         ret = AVERROR(EINVAL);
         av_log(h, AV_LOG_ERROR, "Framebuffer pixel format not supported.\n");
         goto fail;
     }
 
     fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_WRITE, MAP_SHARED, fbdev->fd, 0);
     if (fbdev->data == MAP_FAILED) {
         ret = AVERROR(errno);
         av_log(h, AV_LOG_ERROR, "Error in mmap(): %s\n", av_err2str(ret));
         goto fail;
     }
 
     return 0;
   fail:
     close(fbdev->fd);
     return ret;
 }
 
 static int fbdev_write_packet(AVFormatContext *h, AVPacket *pkt)
 {
     FBDevContext *fbdev = h->priv_data;
     uint8_t *pin, *pout;
     enum AVPixelFormat fb_pix_fmt;
     int disp_height;
     int bytes_to_copy;

     AVCodecContext *codec_ctx = h->streams[0]->codec;

     enum AVPixelFormat video_pix_fmt = codec_ctx->pix_fmt;
     int video_width = codec_ctx->width;
     int video_height = codec_ctx->height;
     int bytes_per_pixel = ((codec_ctx->bits_per_coded_sample + 7) >> 3);
     int src_line_size = video_width * bytes_per_pixel;

     int i;

 
     if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)
         av_log(h, AV_LOG_WARNING,
                "Error refreshing variable info: %s\n", av_err2str(AVERROR(errno)));
 

     fb_pix_fmt = ff_get_pixfmt_from_fb_varinfo(&fbdev->varinfo);

 
     if (fb_pix_fmt != video_pix_fmt) {
         av_log(h, AV_LOG_ERROR, "Pixel format %s is not supported, use %s\n",
                av_get_pix_fmt_name(video_pix_fmt), av_get_pix_fmt_name(fb_pix_fmt));
         return AVERROR(EINVAL);
     }
 
     disp_height = FFMIN(fbdev->varinfo.yres, video_height);
     bytes_to_copy = FFMIN(fbdev->varinfo.xres, video_width) * bytes_per_pixel;
 
     pin  = pkt->data;
     pout = fbdev->data +
            bytes_per_pixel * fbdev->varinfo.xoffset +
            fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
 
     if (fbdev->xoffset) {
         if (fbdev->xoffset < 0) {
             if (-fbdev->xoffset >= video_width) //nothing to display
                 return 0;
             bytes_to_copy += fbdev->xoffset * bytes_per_pixel;
             pin -= fbdev->xoffset * bytes_per_pixel;
         } else {
             int diff = (video_width + fbdev->xoffset) - fbdev->varinfo.xres;
             if (diff > 0) {
                 if (diff >= video_width) //nothing to display
                     return 0;
                 bytes_to_copy -= diff * bytes_per_pixel;
             }
             pout += bytes_per_pixel * fbdev->xoffset;
         }
     }
 
     if (fbdev->yoffset) {
         if (fbdev->yoffset < 0) {
             if (-fbdev->yoffset >= video_height) //nothing to display
                 return 0;
             disp_height += fbdev->yoffset;
             pin -= fbdev->yoffset * src_line_size;
         } else {
             int diff = (video_height + fbdev->yoffset) - fbdev->varinfo.yres;
             if (diff > 0) {
                 if (diff >= video_height) //nothing to display
                     return 0;
                 disp_height -= diff;
             }
             pout += fbdev->yoffset * fbdev->fixinfo.line_length;
         }
     }
 

     for (i = 0; i < disp_height; i++) {

         memcpy(pout, pin, bytes_to_copy);
         pout += fbdev->fixinfo.line_length;
         pin  += src_line_size;
     }
 
     return 0;
 }
 
 static av_cold int fbdev_write_trailer(AVFormatContext *h)
 {
     FBDevContext *fbdev = h->priv_data;
     munmap(fbdev->data, fbdev->fixinfo.smem_len);
     close(fbdev->fd);
     return 0;
 }
 
 #define OFFSET(x) offsetof(FBDevContext, x)
 #define ENC AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
     { "xoffset", "set x coordinate of top left corner", OFFSET(xoffset), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, ENC },
     { "yoffset", "set y coordinate of top left corner", OFFSET(yoffset), AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, ENC },
     { NULL }
 };
 
 static const AVClass fbdev_class = {
     .class_name = "fbdev outdev",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 AVOutputFormat ff_fbdev_muxer = {
     .name           = "fbdev",
     .long_name      = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
     .priv_data_size = sizeof(FBDevContext),
     .audio_codec    = AV_CODEC_ID_NONE,
     .video_codec    = AV_CODEC_ID_RAWVIDEO,
     .write_header   = fbdev_write_header,
     .write_packet   = fbdev_write_packet,
     .write_trailer  = fbdev_write_trailer,
     .flags          = AVFMT_NOFILE | AVFMT_VARIABLE_FPS | AVFMT_NOTIMESTAMPS,
     .priv_class     = &fbdev_class,
 };