/*
  * KMS/DRM input device
  *
  * 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 <fcntl.h>
 #include <unistd.h>
 
 #include <drm.h>
 #include <drm_fourcc.h>
 #include <drm_mode.h>
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
 #include "libavutil/hwcontext.h"
 #include "libavutil/hwcontext_drm.h"
 #include "libavutil/internal.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixfmt.h"
 #include "libavutil/pixdesc.h"
 #include "libavutil/time.h"
 
 #include "libavformat/avformat.h"
 #include "libavformat/internal.h"
 
 typedef struct KMSGrabContext {
     const AVClass *class;
 
     AVBufferRef *device_ref;
     AVHWDeviceContext *device;
     AVDRMDeviceContext *hwctx;
 
     AVBufferRef *frames_ref;
     AVHWFramesContext *frames;
 
     uint32_t plane_id;
     uint32_t drm_format;
     unsigned int width;
     unsigned int height;
 
     int64_t frame_delay;
     int64_t frame_last;
 
     const char *device_path;
     enum AVPixelFormat format;
     int64_t drm_format_modifier;
     int64_t source_plane;
     int64_t source_crtc;
     AVRational framerate;
 } KMSGrabContext;
 
 static void kmsgrab_free_desc(void *opaque, uint8_t *data)
 {
     AVDRMFrameDescriptor *desc = (AVDRMFrameDescriptor*)data;
 
     close(desc->objects[0].fd);
 
     av_free(desc);
 }
 
 static void kmsgrab_free_frame(void *opaque, uint8_t *data)
 {
     AVFrame *frame = (AVFrame*)data;
 
     av_frame_free(&frame);
 }
 
 static int kmsgrab_read_packet(AVFormatContext *avctx, AVPacket *pkt)
 {
     KMSGrabContext *ctx = avctx->priv_data;
     drmModePlane *plane;
     drmModeFB *fb;
     AVDRMFrameDescriptor *desc;
     AVFrame *frame;
     int64_t now;
     int err, fd;
 
     now = av_gettime();
     if (ctx->frame_last) {
         int64_t delay;
         while (1) {
             delay = ctx->frame_last + ctx->frame_delay - now;
             if (delay <= 0)
                 break;
             av_usleep(delay);
             now = av_gettime();
         }
     }
     ctx->frame_last = now;
 
     plane = drmModeGetPlane(ctx->hwctx->fd, ctx->plane_id);
     if (!plane) {
         av_log(avctx, AV_LOG_ERROR, "Failed to get plane "
                "%"PRIu32".\n", ctx->plane_id);
         return AVERROR(EIO);
     }
     if (!plane->fb_id) {
         av_log(avctx, AV_LOG_ERROR, "Plane %"PRIu32" no longer has "
                "an associated framebuffer.\n", ctx->plane_id);
         return AVERROR(EIO);
     }
 
     fb = drmModeGetFB(ctx->hwctx->fd, plane->fb_id);
     if (!fb) {
         av_log(avctx, AV_LOG_ERROR, "Failed to get framebuffer "
                "%"PRIu32".\n", plane->fb_id);
         return AVERROR(EIO);
     }
     if (fb->width != ctx->width || fb->height != ctx->height) {
         av_log(avctx, AV_LOG_ERROR, "Plane %"PRIu32" framebuffer "
                "dimensions changed: now %"PRIu32"x%"PRIu32".\n",
                ctx->plane_id, fb->width, fb->height);
         return AVERROR(EIO);
     }
     if (!fb->handle) {
         av_log(avctx, AV_LOG_ERROR, "No handle set on framebuffer.\n");
         return AVERROR(EIO);
     }
 
     err = drmPrimeHandleToFD(ctx->hwctx->fd, fb->handle, O_RDONLY, &fd);
     if (err < 0) {
         err = errno;
         av_log(avctx, AV_LOG_ERROR, "Failed to get PRIME fd from "
                "framebuffer handle: %s.\n", strerror(errno));
         return AVERROR(err);
     }
 
     desc = av_mallocz(sizeof(*desc));
     if (!desc)
         return AVERROR(ENOMEM);
 
     *desc = (AVDRMFrameDescriptor) {
         .nb_objects = 1,
         .objects[0] = {
             .fd               = fd,
             .size             = fb->height * fb->pitch,
             .format_modifier  = ctx->drm_format_modifier,
         },
         .nb_layers = 1,
         .layers[0] = {
             .format           = ctx->drm_format,
             .nb_planes        = 1,
             .planes[0] = {
                 .object_index = 0,
                 .offset       = 0,
                 .pitch        = fb->pitch,
             },
         },
     };
 
     frame = av_frame_alloc();
     if (!frame)
         return AVERROR(ENOMEM);
 
     frame->hw_frames_ctx = av_buffer_ref(ctx->frames_ref);
     if (!frame->hw_frames_ctx)
         return AVERROR(ENOMEM);
 
     frame->buf[0] = av_buffer_create((uint8_t*)desc, sizeof(*desc),
                                      &kmsgrab_free_desc, avctx, 0);
     if (!frame->buf[0])
         return AVERROR(ENOMEM);
 
     frame->data[0] = (uint8_t*)desc;
     frame->format  = AV_PIX_FMT_DRM_PRIME;
     frame->width   = fb->width;
     frame->height  = fb->height;
 
     drmModeFreeFB(fb);
     drmModeFreePlane(plane);
 
     pkt->buf = av_buffer_create((uint8_t*)frame, sizeof(*frame),
                                 &kmsgrab_free_frame, avctx, 0);
     if (!pkt->buf)
         return AVERROR(ENOMEM);
 

     pkt->data   = (uint8_t*)frame;
     pkt->size   = sizeof(*frame);
     pkt->pts    = now;
     pkt->flags |= AV_PKT_FLAG_TRUSTED;

 
     return 0;
 }
 
 static const struct {
     enum AVPixelFormat pixfmt;
     uint32_t drm_format;
 } kmsgrab_formats[] = {

 #ifdef DRM_FORMAT_R8

     { AV_PIX_FMT_GRAY8,    DRM_FORMAT_R8       },

 #endif
 #ifdef DRM_FORMAT_R16

     { AV_PIX_FMT_GRAY16LE, DRM_FORMAT_R16      },

     { AV_PIX_FMT_GRAY16BE, DRM_FORMAT_R16      | DRM_FORMAT_BIG_ENDIAN },

 #endif

     { AV_PIX_FMT_BGR8,     DRM_FORMAT_BGR233   },
     { AV_PIX_FMT_RGB555LE, DRM_FORMAT_XRGB1555 },
     { AV_PIX_FMT_RGB555BE, DRM_FORMAT_XRGB1555 | DRM_FORMAT_BIG_ENDIAN },
     { AV_PIX_FMT_BGR555LE, DRM_FORMAT_XBGR1555 },
     { AV_PIX_FMT_BGR555BE, DRM_FORMAT_XBGR1555 | DRM_FORMAT_BIG_ENDIAN },
     { AV_PIX_FMT_RGB565LE, DRM_FORMAT_RGB565   },
     { AV_PIX_FMT_RGB565BE, DRM_FORMAT_RGB565   | DRM_FORMAT_BIG_ENDIAN },
     { AV_PIX_FMT_BGR565LE, DRM_FORMAT_BGR565   },
     { AV_PIX_FMT_BGR565BE, DRM_FORMAT_BGR565   | DRM_FORMAT_BIG_ENDIAN },

     { AV_PIX_FMT_RGB24,    DRM_FORMAT_RGB888   },
     { AV_PIX_FMT_BGR24,    DRM_FORMAT_BGR888   },

     { AV_PIX_FMT_0RGB,     DRM_FORMAT_BGRX8888 },
     { AV_PIX_FMT_0BGR,     DRM_FORMAT_RGBX8888 },
     { AV_PIX_FMT_RGB0,     DRM_FORMAT_XBGR8888 },
     { AV_PIX_FMT_BGR0,     DRM_FORMAT_XRGB8888 },
     { AV_PIX_FMT_ARGB,     DRM_FORMAT_BGRA8888 },
     { AV_PIX_FMT_ABGR,     DRM_FORMAT_RGBA8888 },
     { AV_PIX_FMT_RGBA,     DRM_FORMAT_ABGR8888 },
     { AV_PIX_FMT_BGRA,     DRM_FORMAT_ARGB8888 },

     { AV_PIX_FMT_YUYV422,  DRM_FORMAT_YUYV     },
     { AV_PIX_FMT_YVYU422,  DRM_FORMAT_YVYU     },
     { AV_PIX_FMT_UYVY422,  DRM_FORMAT_UYVY     },
 };
 
 static av_cold int kmsgrab_read_header(AVFormatContext *avctx)
 {
     KMSGrabContext *ctx = avctx->priv_data;
     drmModePlaneRes *plane_res = NULL;
     drmModePlane *plane = NULL;
     drmModeFB *fb = NULL;
     AVStream *stream;
     int err, i;
 
     for (i = 0; i < FF_ARRAY_ELEMS(kmsgrab_formats); i++) {
         if (kmsgrab_formats[i].pixfmt == ctx->format) {
             ctx->drm_format = kmsgrab_formats[i].drm_format;
             break;
         }
     }
     if (i >= FF_ARRAY_ELEMS(kmsgrab_formats)) {
         av_log(avctx, AV_LOG_ERROR, "Unsupported format %s.\n",
                av_get_pix_fmt_name(ctx->format));
         return AVERROR(EINVAL);
     }
 
     err = av_hwdevice_ctx_create(&ctx->device_ref, AV_HWDEVICE_TYPE_DRM,
                                  ctx->device_path, NULL, 0);
     if (err < 0) {
         av_log(avctx, AV_LOG_ERROR, "Failed to open DRM device.\n");
         return err;
     }
     ctx->device = (AVHWDeviceContext*) ctx->device_ref->data;
     ctx->hwctx  = (AVDRMDeviceContext*)ctx->device->hwctx;
 
     err = drmSetClientCap(ctx->hwctx->fd,
                           DRM_CLIENT_CAP_UNIVERSAL_PLANES, 1);
     if (err < 0) {
         av_log(avctx, AV_LOG_WARNING, "Failed to set universal planes "
                "capability: primary planes will not be usable.\n");
     }
 
     if (ctx->source_plane > 0) {
         plane = drmModeGetPlane(ctx->hwctx->fd, ctx->source_plane);
         if (!plane) {
             err = errno;
             av_log(avctx, AV_LOG_ERROR, "Failed to get plane %"PRId64": "
                    "%s.\n", ctx->source_plane, strerror(err));
             err = AVERROR(err);
             goto fail;
         }
 
         if (plane->fb_id == 0) {
             av_log(avctx, AV_LOG_ERROR, "Plane %"PRId64" does not have "
                    "an attached framebuffer.\n", ctx->source_plane);
             err = AVERROR(EINVAL);
             goto fail;
         }
     } else {
         plane_res = drmModeGetPlaneResources(ctx->hwctx->fd);
         if (!plane_res) {
             av_log(avctx, AV_LOG_ERROR, "Failed to get plane "
                    "resources: %s.\n", strerror(errno));
             err = AVERROR(EINVAL);
             goto fail;
         }
 
         for (i = 0; i < plane_res->count_planes; i++) {
             plane = drmModeGetPlane(ctx->hwctx->fd,
                                     plane_res->planes[i]);
             if (!plane) {
                 err = errno;
                 av_log(avctx, AV_LOG_VERBOSE, "Failed to get "
                        "plane %"PRIu32": %s.\n",
                        plane_res->planes[i], strerror(err));
                 continue;
             }
 
             av_log(avctx, AV_LOG_DEBUG, "Plane %"PRIu32": "
                    "CRTC %"PRIu32" FB %"PRIu32".\n",
                    plane->plane_id, plane->crtc_id, plane->fb_id);
 
             if ((ctx->source_crtc > 0 &&
                  plane->crtc_id != ctx->source_crtc) ||
                 plane->fb_id == 0) {
                 // Either not connected to the target source CRTC
                 // or not active.
                 drmModeFreePlane(plane);
                 plane = NULL;
                 continue;
             }
 
             break;
         }
 
         if (i == plane_res->count_planes) {
             if (ctx->source_crtc > 0) {
                 av_log(avctx, AV_LOG_ERROR, "No usable planes found on "
                        "CRTC %"PRId64".\n", ctx->source_crtc);
             } else {
                 av_log(avctx, AV_LOG_ERROR, "No usable planes found.\n");
             }
             err = AVERROR(EINVAL);
             goto fail;
         }
 
         av_log(avctx, AV_LOG_INFO, "Using plane %"PRIu32" to "
                "locate framebuffers.\n", plane->plane_id);
     }
 
     ctx->plane_id = plane->plane_id;
 
     fb = drmModeGetFB(ctx->hwctx->fd, plane->fb_id);
     if (!fb) {
         err = errno;
         av_log(avctx, AV_LOG_ERROR, "Failed to get "
                "framebuffer %"PRIu32": %s.\n",
                plane->fb_id, strerror(err));
         err = AVERROR(err);
         goto fail;
     }
 
     av_log(avctx, AV_LOG_INFO, "Template framebuffer is %"PRIu32": "
            "%"PRIu32"x%"PRIu32" %"PRIu32"bpp %"PRIu32"b depth.\n",
            fb->fb_id, fb->width, fb->height, fb->bpp, fb->depth);
 
     ctx->width  = fb->width;
     ctx->height = fb->height;
 
     if (!fb->handle) {
         av_log(avctx, AV_LOG_ERROR, "No handle set on framebuffer: "
                "maybe you need some additional capabilities?\n");
         err = AVERROR(EINVAL);
         goto fail;
     }
 
     stream = avformat_new_stream(avctx, NULL);
     if (!stream) {
         err = AVERROR(ENOMEM);
         goto fail;
     }
 
     stream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
     stream->codecpar->codec_id   = AV_CODEC_ID_WRAPPED_AVFRAME;
     stream->codecpar->width      = fb->width;
     stream->codecpar->height     = fb->height;
     stream->codecpar->format     = AV_PIX_FMT_DRM_PRIME;
 
     avpriv_set_pts_info(stream, 64, 1, 1000000);
 
     ctx->frames_ref = av_hwframe_ctx_alloc(ctx->device_ref);
     if (!ctx->frames_ref) {
         err = AVERROR(ENOMEM);
         goto fail;
     }
     ctx->frames = (AVHWFramesContext*)ctx->frames_ref->data;
 
     ctx->frames->format    = AV_PIX_FMT_DRM_PRIME;
     ctx->frames->sw_format = ctx->format,
     ctx->frames->width     = fb->width;
     ctx->frames->height    = fb->height;
 
     err = av_hwframe_ctx_init(ctx->frames_ref);
     if (err < 0) {
         av_log(avctx, AV_LOG_ERROR, "Failed to initialise "
                "hardware frames context: %d.\n", err);
         goto fail;
     }
 
     ctx->frame_delay = av_rescale_q(1, (AVRational) { ctx->framerate.den,
                 ctx->framerate.num }, AV_TIME_BASE_Q);
 
     err = 0;
 fail:
     if (plane_res)
         drmModeFreePlaneResources(plane_res);
     if (plane)
         drmModeFreePlane(plane);
     if (fb)
         drmModeFreeFB(fb);
 
     return err;
 }
 
 static av_cold int kmsgrab_read_close(AVFormatContext *avctx)
 {
     KMSGrabContext *ctx = avctx->priv_data;
 
     av_buffer_unref(&ctx->frames_ref);
     av_buffer_unref(&ctx->device_ref);
 
     return 0;
 }
 
 #define OFFSET(x) offsetof(KMSGrabContext, x)
 #define FLAGS AV_OPT_FLAG_DECODING_PARAM
 static const AVOption options[] = {
     { "device", "DRM device path",
       OFFSET(device_path), AV_OPT_TYPE_STRING,
       { .str = "/dev/dri/card0" }, 0, 0, FLAGS },
     { "format", "Pixel format for framebuffer",
       OFFSET(format), AV_OPT_TYPE_PIXEL_FMT,
       { .i64 = AV_PIX_FMT_BGR0 }, 0, UINT32_MAX, FLAGS },
     { "format_modifier", "DRM format modifier for framebuffer",
       OFFSET(drm_format_modifier), AV_OPT_TYPE_INT64,
       { .i64 = DRM_FORMAT_MOD_NONE }, 0, INT64_MAX, FLAGS },
     { "crtc_id", "CRTC ID to define capture source",
       OFFSET(source_crtc), AV_OPT_TYPE_INT64,
       { .i64 = 0 }, 0, UINT32_MAX, FLAGS },
     { "plane_id", "Plane ID to define capture source",
       OFFSET(source_plane), AV_OPT_TYPE_INT64,
       { .i64 = 0 }, 0, UINT32_MAX, FLAGS },
     { "framerate", "Framerate to capture at",
       OFFSET(framerate), AV_OPT_TYPE_RATIONAL,
       { .dbl = 30.0 }, 0, 1000, FLAGS },
     { NULL },
 };
 
 static const AVClass kmsgrab_class = {
     .class_name = "kmsgrab indev",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,

     .category   = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,

 };
 
 AVInputFormat ff_kmsgrab_demuxer = {
     .name           = "kmsgrab",
     .long_name      = NULL_IF_CONFIG_SMALL("KMS screen capture"),
     .priv_data_size = sizeof(KMSGrabContext),
     .read_header    = &kmsgrab_read_header,
     .read_packet    = &kmsgrab_read_packet,
     .read_close     = &kmsgrab_read_close,
     .flags          = AVFMT_NOFILE,
     .priv_class     = &kmsgrab_class,
 };