/* 
 * Copyright (C) 2013 Sebastian Dröge <sebastian@centricular.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "gstopenexrdec.h"

#include <gst/base/base.h>
#include <string.h>

#include <ImfRgbaFile.h>
#include <ImfIO.h>
using namespace Imf;
using namespace Imath;

/* Memory stream reader */
class MemIStream:public IStream
{
public:
  MemIStream (const char *file_name, const guint8 * data,
      gsize size):IStream (file_name), data (data), offset (0), size (size)
  {
  }

  virtual bool read (char c[], int n);
  virtual Int64 tellg ();
  virtual void seekg (Int64 pos);
  virtual void clear ();

private:
  const guint8 *data;
  gsize offset, size;
};

bool MemIStream::read (char c[], int n)
{
  if (offset + n > size)
    throw
    Iex::InputExc ("Unexpected end of file");

  memcpy (c, data + offset, n);
  offset += n;

  return (offset == size);
}

Int64 MemIStream::tellg ()
{
  return offset;
}

void
MemIStream::seekg (Int64 pos)
{
  offset = pos;
  if (offset > size)
    offset = size;
}

void
MemIStream::clear ()
{

}

GST_DEBUG_CATEGORY_STATIC (gst_openexr_dec_debug);
#define GST_CAT_DEFAULT gst_openexr_dec_debug

static gboolean gst_openexr_dec_start (GstVideoDecoder * decoder);
static gboolean gst_openexr_dec_stop (GstVideoDecoder * decoder);
static GstFlowReturn gst_openexr_dec_parse (GstVideoDecoder * decoder,
    GstVideoCodecFrame * frame, GstAdapter * adapter, gboolean at_eos);
static gboolean gst_openexr_dec_set_format (GstVideoDecoder * decoder,
    GstVideoCodecState * state);
static GstFlowReturn gst_openexr_dec_handle_frame (GstVideoDecoder * decoder,
    GstVideoCodecFrame * frame);
static gboolean gst_openexr_dec_decide_allocation (GstVideoDecoder * decoder,
    GstQuery * query);

static GstStaticPadTemplate gst_openexr_dec_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("image/x-exr")
    );

static GstStaticPadTemplate gst_openexr_dec_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE ("ARGB64"))
    );

#define parent_class gst_openexr_dec_parent_class
G_DEFINE_TYPE (GstOpenEXRDec, gst_openexr_dec, GST_TYPE_VIDEO_DECODER);

static void
gst_openexr_dec_class_init (GstOpenEXRDecClass * klass)
{
  GstElementClass *element_class;
  GstVideoDecoderClass *video_decoder_class;

  element_class = (GstElementClass *) klass;
  video_decoder_class = (GstVideoDecoderClass *) klass;

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_openexr_dec_src_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_openexr_dec_sink_template));

  gst_element_class_set_static_metadata (element_class,
      "OpenEXR decoder",
      "Codec/Decoder/Video",
      "Decode EXR streams", "Sebastian Dröge <sebastian@centricular.com>");

  video_decoder_class->start = GST_DEBUG_FUNCPTR (gst_openexr_dec_start);
  video_decoder_class->stop = GST_DEBUG_FUNCPTR (gst_openexr_dec_stop);
  video_decoder_class->parse = GST_DEBUG_FUNCPTR (gst_openexr_dec_parse);
  video_decoder_class->set_format =
      GST_DEBUG_FUNCPTR (gst_openexr_dec_set_format);
  video_decoder_class->handle_frame =
      GST_DEBUG_FUNCPTR (gst_openexr_dec_handle_frame);
  video_decoder_class->decide_allocation = gst_openexr_dec_decide_allocation;

  GST_DEBUG_CATEGORY_INIT (gst_openexr_dec_debug, "openexrdec", 0,
      "OpenEXR Decoder");
}

static void
gst_openexr_dec_init (GstOpenEXRDec * self)
{
  GstVideoDecoder *decoder = (GstVideoDecoder *) self;

  gst_video_decoder_set_packetized (decoder, FALSE);
}

static gboolean
gst_openexr_dec_start (GstVideoDecoder * decoder)
{
  GstOpenEXRDec *self = GST_OPENEXR_DEC (decoder);

  GST_DEBUG_OBJECT (self, "Starting");

  return TRUE;
}

static gboolean
gst_openexr_dec_stop (GstVideoDecoder * video_decoder)
{
  GstOpenEXRDec *self = GST_OPENEXR_DEC (video_decoder);

  GST_DEBUG_OBJECT (self, "Stopping");

  if (self->output_state) {
    gst_video_codec_state_unref (self->output_state);
    self->output_state = NULL;
  }

  if (self->input_state) {
    gst_video_codec_state_unref (self->input_state);
    self->input_state = NULL;
  }

  GST_DEBUG_OBJECT (self, "Stopped");

  return TRUE;
}

static GstFlowReturn
gst_openexr_dec_parse (GstVideoDecoder * decoder,
    GstVideoCodecFrame * frame, GstAdapter * adapter, gboolean at_eos)
{
  GstByteReader reader;
  const guint8 *data;
  gsize size;
  guint32 u32;
  guint64 u64;
  guint8 version;
  gboolean single_tile, long_name;
  gboolean non_image, multipart;
  /* *INDENT-OFF * */
  struct
  {
    guint32 x1, y1, x2, y2;
  } data_window = {
  (guint32) - 1, (guint32) - 1, (guint32) - 1, (guint32) - 1};
  struct
  {
    guint32 w, h;
    guint8 mode;
  } tile_desc = {
  (guint32) - 1, (guint32) - 1, (guint8) - 1};
  guint8 compression = (guint8) - 1;
  guint32 chunk_count = (guint32) - 1;
  /* *INDENT-ON * */

  size = gst_adapter_available (adapter);

  GST_DEBUG_OBJECT (decoder, "Parsing OpenEXR image data %" G_GSIZE_FORMAT,
      size);

  if (size < 8)
    goto need_more_data;

  data = (const guint8 *) gst_adapter_map (adapter, size);

  gst_byte_reader_init (&reader, data, size);

  /* Must start with the OpenEXR magic number */
  if (!gst_byte_reader_peek_uint32_le (&reader, &u32))
    goto need_more_data;

  if (u32 != 0x01312f76) {
    for (;;) {
      guint offset;

      offset = gst_byte_reader_masked_scan_uint32 (&reader, 0xffffffff,
          0x762f3101, 0, gst_byte_reader_get_remaining (&reader));

      if (offset == (guint) - 1) {
        gst_adapter_flush (adapter,
            gst_byte_reader_get_remaining (&reader) - 4);
        goto need_more_data;
      }

      if (!gst_byte_reader_skip (&reader, offset))
        goto need_more_data;

      if (!gst_byte_reader_peek_uint32_le (&reader, &u32))
        goto need_more_data;

      if (u32 == 0x01312f76) {
        /* We're skipping, go out, we'll be back */
        gst_adapter_flush (adapter, gst_byte_reader_get_pos (&reader));
        goto need_more_data;
      }
      if (!gst_byte_reader_skip (&reader, 4))
        goto need_more_data;
    }
  }

  /* Now we're at the magic number */
  if (!gst_byte_reader_skip (&reader, 4))
    goto need_more_data;

  /* version and flags */
  if (!gst_byte_reader_get_uint32_le (&reader, &u32))
    goto need_more_data;

  version = (u32 & 0xff);
  if (version != 1 && version != 2) {
    GST_ERROR_OBJECT (decoder, "Unsupported OpenEXR version %d", version);
    return GST_FLOW_NOT_NEGOTIATED;
  }
  single_tile = ! !(u32 & 0x200);
  long_name = ! !(u32 & 0x400);
  non_image = ! !(u32 & 0x800);
  multipart = ! !(u32 & 0x1000);
  GST_DEBUG_OBJECT (decoder,
      "OpenEXR image version %d, single tile %d, long name %d, non-image %d, multipart %d",
      version, single_tile, long_name, non_image, multipart);

  /* attributes */
  if (multipart) {
    GST_WARNING_OBJECT (decoder, "Multipart files not supported");
    return GST_FLOW_NOT_NEGOTIATED;
  }
  if (non_image) {
    GST_WARNING_OBJECT (decoder, "Deep-data images not supported");
    return GST_FLOW_NOT_NEGOTIATED;
  }

  /* Read attributes */
  for (;;) {
    const gchar *name, *type;
    guint8 u8;

    if (!gst_byte_reader_peek_uint8 (&reader, &u8))
      goto need_more_data;
    if (u8 == 0) {
      gst_byte_reader_skip (&reader, 1);
      break;
    }

    if (!gst_byte_reader_get_string_utf8 (&reader, &name))
      goto need_more_data;
    if (!gst_byte_reader_get_string_utf8 (&reader, &type))
      goto need_more_data;
    if (!gst_byte_reader_get_uint32_le (&reader, &u32))
      goto need_more_data;
    if (gst_byte_reader_get_remaining (&reader) < u32)
      goto need_more_data;

    if (strcmp (name, "dataWindow") == 0) {
      if (strcmp (type, "box2i") != 0 || u32 != 16)
        return GST_FLOW_ERROR;

      data_window.x1 = gst_byte_reader_get_uint32_le_unchecked (&reader);
      data_window.y1 = gst_byte_reader_get_uint32_le_unchecked (&reader);
      data_window.x2 = gst_byte_reader_get_uint32_le_unchecked (&reader);
      data_window.y2 = gst_byte_reader_get_uint32_le_unchecked (&reader);
    } else if (strcmp (name, "tiles") == 0) {
      if (strcmp (type, "tiledesc") != 0 || u32 != 9)
        return GST_FLOW_ERROR;
      tile_desc.w = gst_byte_reader_get_uint32_le_unchecked (&reader);
      tile_desc.h = gst_byte_reader_get_uint32_le_unchecked (&reader);
      tile_desc.mode = gst_byte_reader_get_uint8_unchecked (&reader);
    } else if (strcmp (name, "compression") == 0) {
      if (strcmp (type, "compression") != 0 || u32 != 1)
        return GST_FLOW_ERROR;
      compression = gst_byte_reader_get_uint8_unchecked (&reader);
    } else if (strcmp (name, "chunkCount") == 0) {
      if (strcmp (type, "int") != 0 || u32 != 4)
        return GST_FLOW_ERROR;
      chunk_count = gst_byte_reader_get_uint32_le_unchecked (&reader);
    } else {
      gst_byte_reader_skip_unchecked (&reader, u32);
    }
  }

  if (data_window.x1 == (guint32) - 1)
    return GST_FLOW_ERROR;
  if (data_window.x2 < data_window.x1)
    return GST_FLOW_ERROR;
  if (data_window.y2 < data_window.y1)
    return GST_FLOW_ERROR;
  if (compression == (guint8) - 1)
    return GST_FLOW_ERROR;
  if (single_tile && tile_desc.w == (guint32) - 1)
    return GST_FLOW_ERROR;

  GST_DEBUG_OBJECT (decoder, "Have data window (%u, %u)x(%u, %u)",
      data_window.x1, data_window.y1, data_window.x2, data_window.y2);
  GST_DEBUG_OBJECT (decoder, "Have compression %u", compression);
  if (single_tile)
    GST_DEBUG_OBJECT (decoder, "Have tiles (%u, %u), mode %u", tile_desc.w,
        tile_desc.h, tile_desc.mode);

  /* offset table */
  if (chunk_count == (guint32) - 1) {
    if (single_tile) {
      guint xt, yt;

      xt = data_window.x2 - data_window.x1 + 1;
      xt = (xt + tile_desc.w - 1) / tile_desc.w;

      yt = data_window.y2 - data_window.y1 + 1;
      yt = (yt + tile_desc.h - 1) / tile_desc.h;

      chunk_count = xt * yt;
      GST_DEBUG_OBJECT (decoder, "Have %ux%u tiles", xt, yt);
    } else {
      chunk_count = data_window.y2 - data_window.y1 + 1;

      switch (compression) {
        case 0:                /* NO */
        case 1:                /* RLE */
        case 2:                /* ZIPS */
          break;
        case 3:                /* ZIP */
        case 5:                /* PXR24 */
          chunk_count = (chunk_count + 15) / 16;
          break;
        case 4:                /* PIZ */
        case 6:                /* B44 */
        case 7:                /* B44A */
          chunk_count = (chunk_count + 31) / 32;
          break;
        default:
          GST_WARNING_OBJECT (decoder, "Unsupported compression %u",
              compression);
          return GST_FLOW_NOT_NEGOTIATED;
      }
    }
  } else {
    GST_WARNING_OBJECT (decoder, "Chunk data not supported");
    return GST_FLOW_NOT_NEGOTIATED;
  }

  if (gst_byte_reader_get_remaining (&reader) < chunk_count * 8)
    goto need_more_data;

  gst_byte_reader_skip_unchecked (&reader, (chunk_count - 1) * 8);
  u64 = gst_byte_reader_get_uint64_le_unchecked (&reader);

  GST_DEBUG_OBJECT (decoder, "Offset of last chunk %" G_GUINT64_FORMAT, u64);

  /* pixel data */

  /* go to the last pixel data chunk */
  if (!gst_byte_reader_set_pos (&reader, u64))
    goto need_more_data;

  /* and read its size and skip it */
  if (single_tile) {
    if (!gst_byte_reader_skip (&reader, 4 * 4))
      goto need_more_data;
    if (!gst_byte_reader_get_uint32_le (&reader, &u32))
      goto need_more_data;
    if (!gst_byte_reader_skip (&reader, u32))
      goto need_more_data;
  } else {
    if (!gst_byte_reader_skip (&reader, 4))
      goto need_more_data;
    if (!gst_byte_reader_get_uint32_le (&reader, &u32))
      goto need_more_data;
    if (!gst_byte_reader_skip (&reader, u32))
      goto need_more_data;
  }

  GST_DEBUG_OBJECT (decoder, "Have complete image of size %u",
      gst_byte_reader_get_pos (&reader));

  gst_video_decoder_add_to_frame (decoder, gst_byte_reader_get_pos (&reader));

  return gst_video_decoder_have_frame (decoder);

need_more_data:
  GST_DEBUG_OBJECT (decoder, "Need more data");
  return GST_VIDEO_DECODER_FLOW_NEED_DATA;
}

static gboolean
gst_openexr_dec_set_format (GstVideoDecoder * decoder,
    GstVideoCodecState * state)
{
  GstOpenEXRDec *self = GST_OPENEXR_DEC (decoder);

  GST_DEBUG_OBJECT (self, "Setting format: %" GST_PTR_FORMAT, state->caps);

  if (self->input_state)
    gst_video_codec_state_unref (self->input_state);
  self->input_state = gst_video_codec_state_ref (state);

  return TRUE;
}

static GstFlowReturn
gst_openexr_dec_negotiate (GstOpenEXRDec * self, RgbaInputFile * file)
{
  GstVideoFormat format;
  gint width, height;
  gfloat par;

  /* TODO: Use displayWindow here and also support output of ARGB_F16 */
  format = GST_VIDEO_FORMAT_ARGB64;
  Box2i dw = file->dataWindow ();
  width = dw.max.x - dw.min.x + 1;
  height = dw.max.y - dw.min.y + 1;
  par = file->pixelAspectRatio ();

  if (!self->output_state ||
      self->output_state->info.finfo->format != format ||
      self->output_state->info.width != width ||
      self->output_state->info.height != height) {
    if (self->output_state)
      gst_video_codec_state_unref (self->output_state);
    self->output_state =
        gst_video_decoder_set_output_state (GST_VIDEO_DECODER (self), format,
        width, height, self->input_state);

    GST_DEBUG_OBJECT (self, "Have image of size %dx%d (par %f)", width, height, par);
    gst_util_double_to_fraction (par, &self->output_state->info.par_n, &self->output_state->info.par_d);

    if (!gst_video_decoder_negotiate (GST_VIDEO_DECODER (self)))
      return GST_FLOW_NOT_NEGOTIATED;
  }

  return GST_FLOW_OK;
}

static GstFlowReturn
gst_openexr_dec_handle_frame (GstVideoDecoder * decoder,
    GstVideoCodecFrame * frame)
{
  GstOpenEXRDec *self = GST_OPENEXR_DEC (decoder);
  GstFlowReturn ret = GST_FLOW_OK;
  gint64 deadline;
  GstMapInfo map;
  GstVideoFrame vframe;

  GST_DEBUG_OBJECT (self, "Handling frame");

  deadline = gst_video_decoder_get_max_decode_time (decoder, frame);
  if (deadline < 0) {
    GST_LOG_OBJECT (self, "Dropping too late frame: deadline %" G_GINT64_FORMAT,
        deadline);
    ret = gst_video_decoder_drop_frame (decoder, frame);
    return ret;
  }

  if (!gst_buffer_map (frame->input_buffer, &map, GST_MAP_READ)) {
    gst_video_codec_frame_unref (frame);

    GST_ELEMENT_ERROR (self, CORE, FAILED,
        ("Failed to map input buffer"), (NULL));
    return GST_FLOW_ERROR;
  }

  /* Now read the file and catch any exceptions */
  MemIStream *istr;
  RgbaInputFile *file;
  try {
    istr =
        new
        MemIStream (gst_pad_get_stream_id (GST_VIDEO_DECODER_SINK_PAD
            (decoder)), map.data, map.size);
  }
  catch (Iex::BaseExc e) {
    gst_video_codec_frame_unref (frame);

    GST_ELEMENT_ERROR (self, CORE, FAILED,
        ("Failed to create input stream"), (NULL));
    return GST_FLOW_ERROR;
  }
  try {
    file = new RgbaInputFile (*istr);
  }
  catch (Iex::BaseExc e) {
    delete istr;
    gst_video_codec_frame_unref (frame);

    GST_ELEMENT_ERROR (self, CORE, FAILED,
        ("Failed to read OpenEXR stream"), (NULL));
    return GST_FLOW_ERROR;
  }

  ret = gst_openexr_dec_negotiate (self, file);
  if (ret != GST_FLOW_OK) {
    delete file;
    delete istr;
    gst_buffer_unmap (frame->input_buffer, &map);
    gst_video_codec_frame_unref (frame);

    GST_ELEMENT_ERROR (self, CORE, NEGOTIATION,
        ("Failed to negotiate"), (NULL));
    return ret;
  }

  ret = gst_video_decoder_allocate_output_frame (decoder, frame);
  if (ret != GST_FLOW_OK) {
    delete file;
    delete istr;
    gst_buffer_unmap (frame->input_buffer, &map);
    gst_video_codec_frame_unref (frame);

    GST_ELEMENT_ERROR (self, CORE, FAILED,
        ("Failed to allocate output buffer"), (NULL));
    return ret;
  }

  if (!gst_video_frame_map (&vframe, &self->output_state->info,
          frame->output_buffer, GST_MAP_WRITE)) {
    delete file;
    delete istr;
    gst_buffer_unmap (frame->input_buffer, &map);
    gst_video_codec_frame_unref (frame);

    GST_ELEMENT_ERROR (self, CORE, FAILED,
        ("Failed to map output buffer"), (NULL));
    return GST_FLOW_ERROR;
  }

  /* Decode the file */
  Box2i dw = file->dataWindow ();
  int width = dw.max.x - dw.min.x + 1;
  int height = dw.max.y - dw.min.y + 1;
  Rgba *fb = new Rgba[width * height];

  try {
    file->setFrameBuffer (fb - dw.min.x - dw.min.y * width, 1, width);
    file->readPixels (dw.min.y, dw.max.y);
  } catch (Iex::BaseExc e) {
    delete[](fb);
    delete file;
    delete istr;
    gst_buffer_unmap (frame->input_buffer, &map);
    gst_video_frame_unmap (&vframe);

    GST_ELEMENT_ERROR (self, CORE, FAILED, ("Failed to read pixels"), (NULL));
    return GST_FLOW_ERROR;
  }

  /* And convert from ARGB64_F16 to ARGB64 */
  gint i, j;
  guint16 *dest = (guint16 *) GST_VIDEO_FRAME_PLANE_DATA (&vframe, 0);
  guint dstride = GST_VIDEO_FRAME_PLANE_STRIDE (&vframe, 0);
  Rgba *ptr = fb;

  /* TODO: Use displayWindow here and also support output of ARGB_F16
   * and add a conversion filter element that can change exposure and
   * other things */
  for (i = 0; i < height; i++) {
    for (j = 0; j < width; j++) {
      dest[4 * j + 0] = CLAMP (((float) ptr->a) * 65536, 0, 65535);
      dest[4 * j + 1] = CLAMP (((float) ptr->r) * 65536, 0, 65535);
      dest[4 * j + 2] = CLAMP (((float) ptr->g) * 65536, 0, 65535);
      dest[4 * j + 3] = CLAMP (((float) ptr->b) * 65536, 0, 65535);
      ptr++;
    }
    dest += dstride / 2;
  }

  delete[](fb);
  delete file;
  delete istr;
  gst_buffer_unmap (frame->input_buffer, &map);
  gst_video_frame_unmap (&vframe);

  ret = gst_video_decoder_finish_frame (decoder, frame);

  return ret;
}

static gboolean
gst_openexr_dec_decide_allocation (GstVideoDecoder * decoder, GstQuery * query)
{
  GstBufferPool *pool;
  GstStructure *config;

  if (!GST_VIDEO_DECODER_CLASS (parent_class)->decide_allocation (decoder,
          query))
    return FALSE;

  g_assert (gst_query_get_n_allocation_pools (query) > 0);
  gst_query_parse_nth_allocation_pool (query, 0, &pool, NULL, NULL, NULL);
  g_assert (pool != NULL);

  config = gst_buffer_pool_get_config (pool);
  if (gst_query_find_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL)) {
    gst_buffer_pool_config_add_option (config,
        GST_BUFFER_POOL_OPTION_VIDEO_META);
  }
  gst_buffer_pool_set_config (pool, config);
  gst_object_unref (pool);

  return TRUE;
}