/*
GST_PLUGIN_PATH=. GST_REGISTRY=./registry.xml GST_DEBUG=*:5 \
                gst-launch-0.10 videotestsrc ! ffmpegcolorspace  name=precsp ! \
                                cvbgsubtraction ! \
                                ffmpegcolorspace name=postcsp ! ximagesink \
                2>debug.log
ERROR: from element /pipeline0/videotestsrc0: Internal data flow error.
Additional debug info:
gstbasesrc.c(1614): gst_base_src_loop (): /pipeline0/videotestsrc0:
streaming task paused, reason not-negotiated (-4)
*/

/* ex:set ts=2 et: */

#ifndef __GST_BGSUBTRACTION_H__
#define __GST_BGSUBTRACTION_H__

#include <glib-object.h>
#include <gst/gst.h>
#include <gst/base/gstbasetransform.h>
#include <cv.h>
#include <cvaux.h>

G_BEGIN_DECLS

#define GST_TYPE_BGSUBTRACTION             (gst_bgsubtraction_get_type())
#define GST_BGSUBTRACTION(obj)             (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_BGSUBTRACTION,GstBgSubtraction))
#define GST_BGSUBTRACTION_CLASS(klass)     (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_BGSUBTRACTION,GstBgSubtractionClass))
#define GST_IS_BGSUBTRACTION(obj)          (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_BGSUBTRACTION))
#define GST_IS_BGSUBTRACTION_CLASS(klass)  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_BGSUBTRACTION))

#define GST_TYPE_BGSUBTRACTION_OP          (gst_bgsubtraction_op_get_type())


typedef struct _GstBgSubtraction      GstBgSubtraction;
typedef struct _GstBgSubtractionClass GstBgSubtractionClass;

struct _GstBgSubtraction
{
  GstBaseTransform parent;

  /*< private >*/
  CvBGStatModel *model;
  IplImage *srcimage;
  IplImage *dstimage; /* gray levels */
  CvSize size;
  int channels;
  int step;
};

struct _GstBgSubtractionClass 
{
  GstBaseTransformClass parent_class;
};

GType gst_bgsubtraction_get_type (void);

G_END_DECLS

#endif /* __GST_BGSUBTRACTION_H__ */


/* ex:set ts=2 et: */

#include "gstbgsubtraction.h"

GST_DEBUG_CATEGORY_STATIC (gst_bgsubtraction_debug);
#define GST_CAT_DEFAULT gst_bgsubtraction_debug

static const GstElementDetails bgsubtraction_details = 
  GST_ELEMENT_DETAILS (
    "Background subtraction",
    "Filter/Vision",
    "Extracts the background from a video sequence",
    "Steve Frécinaux <code@istique.net>"
  );

static GstStaticPadTemplate sink_factory =
  GST_STATIC_PAD_TEMPLATE (
    "sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-raw-gray")
//    GST_STATIC_CAPS ("video/x-raw-gray ; video/x-raw-rgb ; video/x-raw-yuv")
  );

static GstStaticPadTemplate src_factory =
  GST_STATIC_PAD_TEMPLATE (
    "src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-raw-gray")
  );

enum
{
  PROP_0
};

GST_BOILERPLATE (GstBgSubtraction, gst_bgsubtraction, GstBaseTransform,
                 GST_TYPE_BASE_TRANSFORM);

static void
gst_bgsubtraction_set_property (GObject *object, guint prop_id,
                                const GValue *value, GParamSpec *pspec)
{
  GstBgSubtraction *filter = GST_BGSUBTRACTION (object);

  switch (prop_id) {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_bgsubtraction_get_property (GObject *object, guint prop_id,
                                GValue *value, GParamSpec *pspec)
{
  GstBgSubtraction *filter = GST_BGSUBTRACTION (object);

  switch (prop_id) {
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static GstCaps *
gst_bgsubtraction_transform_caps (GstBaseTransform *base, 
                                  GstPadDirection direction, GstCaps *caps)
{
  GstBgSubtraction *filter = GST_BGSUBTRACTION (base);
  GstCaps *tcaps;
  GstStructure *structure;
  int i, n;
  const GValue *width, *height, *framerate, *par;

  /* informations that should be conserved */
  structure = gst_caps_get_structure (caps, 0);
  width = gst_structure_get_value (structure, "width");
  height = gst_structure_get_value (structure, "height");
  framerate = gst_structure_get_value (structure, "framerate");
  par = gst_structure_get_value (structure, "pixel-aspect-ratio");

  if (direction == GST_PAD_SINK) {
    tcaps = gst_static_pad_template_get_caps (&src_factory);
  } else if (direction == GST_PAD_SRC) {
    tcaps = gst_static_pad_template_get_caps (&sink_factory);
  } else {
    g_return_val_if_reached (NULL);
  }

  tcaps = gst_caps_make_writable (tcaps);
  n = gst_caps_get_size (tcaps);
  for (i = 0; i < n; i++) {
    structure = gst_caps_get_structure (tcaps, i);

    if (width != NULL)
      gst_structure_set_value (structure, "width", width);
    if (height != NULL)
      gst_structure_set_value (structure, "height", height);
    if (framerate != NULL)
      gst_structure_set_value (structure, "framerate", framerate);
    if (par != NULL)
      gst_structure_set_value (structure, "pixel-aspect-ratio", par);
  }

//  gst_caps_do_simplify (tcaps);

  return tcaps;
}

static gboolean
gst_bgsubtraction_get_unit_size (GstBaseTransform *base, GstCaps *caps,
                                 guint *size)
{
  GstBgSubtraction *filter = GST_BGSUBTRACTION (base);
  GstStructure *structure;
  gint width, height, bpp = 8;

  structure = gst_caps_get_structure (caps, 0);

  if (gst_structure_get_int (structure, "width", &width) &&
      gst_structure_get_int (structure, "height", &height)) {
    *size = width * height; /* because the output image is gray-level */
    return TRUE;
  }
  
  return FALSE;
}


static gboolean
gst_bgsubtraction_set_caps (GstBaseTransform *base, GstCaps *incaps, 
                            GstCaps *outcaps)
{
  GstBgSubtraction *filter = GST_BGSUBTRACTION (base);
  GstStructure *structure;
  int bpp = 8;
  gboolean ret;

  structure = gst_caps_get_structure (incaps, 0);

  /* Update the image header so it can contain the new image */
  gst_structure_get_int (structure, "width", &(filter->size.width));
  gst_structure_get_int (structure, "height", &(filter->size.height));
  gst_structure_get_int (structure, "bpp", &bpp);

  filter->channels = bpp / 8;

  filter->step = filter->channels * filter->size.width;

  if (filter->srcimage != NULL)
    cvReleaseImageHeader (&(filter->srcimage));
  filter->srcimage = cvCreateImageHeader (filter->size, IPL_DEPTH_8U, filter->channels);

  if (filter->dstimage != NULL)
    cvReleaseImageHeader (&(filter->dstimage));
  filter->dstimage = cvCreateImageHeader (filter->size, IPL_DEPTH_8U, 1);

  if (filter->model != NULL) {
    cvReleaseBGStatModel (&(filter->model));
    filter->model = NULL;
  }

  return TRUE;
}

static GstFlowReturn
gst_bgsubtraction_transform (GstBaseTransform *base, GstBuffer *inbuf,
                             GstBuffer *outbuf)
{
  GstBgSubtraction *filter = GST_BGSUBTRACTION (base);

  gst_buffer_stamp (outbuf, inbuf);

  cvSetData (filter->srcimage, GST_BUFFER_DATA (inbuf), filter->step);
  cvSetData (filter->dstimage, GST_BUFFER_DATA (outbuf), filter->size.width);

  if (filter->model == NULL) {
    /* initialize the model with the first frame (ie the current one) */
    filter->model = cvCreateGaussianBGModel (filter->srcimage, NULL);
  } else {
    /* update the current model */
    cvUpdateBGStatModel (filter->srcimage, filter->model);
  }

  cvCopy (filter->model->foreground, filter->dstimage, NULL);

  return GST_FLOW_OK;
}


static void
gst_bgsubtraction_init (GstBgSubtraction *filter, GstBgSubtractionClass *klass)
{
  filter->model = NULL;
  
  filter->step = 0;
  filter->srcimage = NULL;
  filter->dstimage = NULL;
}

static void
gst_bgsubtraction_finalize (GObject *object)
{
  GstBgSubtraction *filter = GST_BGSUBTRACTION (object);

  if (filter->srcimage != NULL)
    cvReleaseImageHeader (&(filter->srcimage));
  
  if (filter->dstimage != NULL)
    cvReleaseImageHeader (&(filter->dstimage));

  if (filter->model != NULL)
    cvReleaseBGStatModel (&(filter->model));

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static void
gst_bgsubtraction_base_init (gpointer klass)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

  gst_element_class_add_pad_template (element_class,
                                      gst_static_pad_template_get (&src_factory));
  gst_element_class_add_pad_template (element_class,
                                      gst_static_pad_template_get (&sink_factory));
  gst_element_class_set_details (element_class, &bgsubtraction_details);
}

static void
gst_bgsubtraction_class_init (GstBgSubtractionClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
  GstBaseTransformClass *transform_class = GST_BASE_TRANSFORM_CLASS (klass);

  object_class->set_property = gst_bgsubtraction_set_property;
  object_class->get_property = gst_bgsubtraction_get_property;
  object_class->finalize = gst_bgsubtraction_finalize;
#if 1
  transform_class->transform_caps = GST_DEBUG_FUNCPTR (gst_bgsubtraction_transform_caps);
#endif
  transform_class->get_unit_size = GST_DEBUG_FUNCPTR (gst_bgsubtraction_get_unit_size);
  transform_class->set_caps = GST_DEBUG_FUNCPTR (gst_bgsubtraction_set_caps);
  transform_class->transform = GST_DEBUG_FUNCPTR (gst_bgsubtraction_transform);

  GST_DEBUG_CATEGORY_INIT (gst_bgsubtraction_debug, "bgsubtraction",
                           0, "Background Subtraction");
}