/* GStreamer
 * Copyright (C) 2019 Seungha Yang <seungha.yang@navercorp.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 <string.h>
#include "gstd3d11memory.h"
#include "gstd3d11device.h"
#include "gstd3d11utils.h"

GST_DEBUG_CATEGORY_STATIC (gst_d3d11_allocator_debug);
#define GST_CAT_DEFAULT gst_d3d11_allocator_debug

GstD3D11AllocationParams *
gst_d3d11_allocation_params_new (GstVideoInfo * info,
    GstD3D11AllocationFlags flags)
{
  GstD3D11AllocationParams *ret;
  const GstD3D11Format *d3d11_format;
  gint i;

  g_return_val_if_fail (info != NULL, NULL);

  d3d11_format = gst_d3d11_format_from_gst (GST_VIDEO_INFO_FORMAT (info));
  if (!d3d11_format) {
    GST_WARNING ("Couldn't get d3d11 format");
    return NULL;
  }

  ret = g_new0 (GstD3D11AllocationParams, 1);

  ret->info = *info;
  ret->d3d11_format = d3d11_format;

  /* Usage Flag
   * https://docs.microsoft.com/en-us/windows/win32/api/d3d11/ne-d3d11-d3d11_usage
   *
   * +----------------------------------------------------------+
   * | Resource Usage | Default | Dynamic | Immutable | Staging |
   * +----------------+---------+---------+-----------+---------+
   * | GPU-Read       | Yes     | Yes     | Yes       | Yes     |
   * | GPU-Write      | Yes     |         |           | Yes     |
   * | CPU-Read       |         |         |           | Yes     |
   * | CPU-Write      |         | Yes     |           | Yes     |
   * +----------------------------------------------------------+
   */

  /* If corresponding dxgi format is undefined, use resource format instead */
  if (d3d11_format->dxgi_format == DXGI_FORMAT_UNKNOWN ||
      (flags & GST_D3D11_ALLOCATION_FLAG_USE_RESOURCE_FORMAT) ==
      GST_D3D11_ALLOCATION_FLAG_USE_RESOURCE_FORMAT) {
    flags |= GST_D3D11_ALLOCATION_FLAG_USE_RESOURCE_FORMAT;

    for (i = 0; i < GST_VIDEO_INFO_N_PLANES (info); i++) {
      g_assert (d3d11_format->resource_format[i] != DXGI_FORMAT_UNKNOWN);

      ret->desc[i].Width = GST_VIDEO_INFO_COMP_WIDTH (info, i);
      ret->desc[i].Height = GST_VIDEO_INFO_COMP_HEIGHT (info, i);
      ret->desc[i].MipLevels = 1;
      ret->desc[i].ArraySize = 1;
      ret->desc[i].Format = d3d11_format->resource_format[i];
      ret->desc[i].SampleDesc.Count = 1;
      ret->desc[i].SampleDesc.Quality = 0;
      ret->desc[i].Usage = D3D11_USAGE_DEFAULT;
      /* User must set proper BindFlags and MiscFlags manually */
    }
  } else {
    g_assert (d3d11_format->dxgi_format != DXGI_FORMAT_UNKNOWN);

    ret->desc[0].Width = GST_VIDEO_INFO_WIDTH (info);
    ret->desc[0].Height = GST_VIDEO_INFO_HEIGHT (info);
    ret->desc[0].MipLevels = 1;
    ret->desc[0].ArraySize = 1;
    ret->desc[0].Format = d3d11_format->dxgi_format;
    ret->desc[0].SampleDesc.Count = 1;
    ret->desc[0].SampleDesc.Quality = 0;
    ret->desc[0].Usage = D3D11_USAGE_DEFAULT;
  }

  ret->flags = flags;

  return ret;
}

GstD3D11AllocationParams *
gst_d3d11_allocation_params_copy (GstD3D11AllocationParams * src)
{
  GstD3D11AllocationParams *dst;

  g_return_val_if_fail (src != NULL, NULL);

  dst = g_new0 (GstD3D11AllocationParams, 1);
  memcpy (dst, src, sizeof (GstD3D11AllocationParams));

  return dst;
}

void
gst_d3d11_allocation_params_free (GstD3D11AllocationParams * params)
{
  g_free (params);
}

G_DEFINE_BOXED_TYPE (GstD3D11AllocationParams, gst_d3d11_allocation_params,
    (GBoxedCopyFunc) gst_d3d11_allocation_params_copy,
    (GBoxedFreeFunc) gst_d3d11_allocation_params_free);

#define gst_d3d11_allocator_parent_class parent_class
G_DEFINE_TYPE (GstD3D11Allocator, gst_d3d11_allocator, GST_TYPE_ALLOCATOR);

static inline D3D11_MAP
gst_map_flags_to_d3d11 (GstMapFlags flags)
{
  if ((flags & GST_MAP_READWRITE) == GST_MAP_READWRITE)
    return D3D11_MAP_READ_WRITE;
  else if ((flags & GST_MAP_WRITE) == GST_MAP_WRITE)
    return D3D11_MAP_WRITE;
  else if ((flags & GST_MAP_READ) == GST_MAP_READ)
    return D3D11_MAP_READ;
  else
    g_assert_not_reached ();

  return D3D11_MAP_READ;
}

static ID3D11Texture2D *
create_staging_texture (GstD3D11Device * device,
    const D3D11_TEXTURE2D_DESC * ref)
{
  D3D11_TEXTURE2D_DESC desc = { 0, };

  desc.Width = ref->Width;
  desc.Height = ref->Height;
  desc.MipLevels = 1;
  desc.Format = ref->Format;
  desc.SampleDesc.Count = 1;
  desc.ArraySize = 1;
  desc.Usage = D3D11_USAGE_STAGING;
  desc.CPUAccessFlags = (D3D11_CPU_ACCESS_READ | D3D11_CPU_ACCESS_WRITE);

  return gst_d3d11_device_create_texture (device, &desc, NULL);
}

typedef struct
{
  ID3D11Resource *dst;
  ID3D11Resource *src;
} D3D11CopyTextureData;

static void
copy_texture (GstD3D11Device * device, D3D11CopyTextureData * data)
{
  ID3D11DeviceContext *device_context =
      gst_d3d11_device_get_device_context_handle (device);

  ID3D11DeviceContext_CopySubresourceRegion (device_context,
      data->dst, 0, 0, 0, 0, data->src, 0, NULL);
}

typedef struct
{
  GstD3D11Memory *mem;
  D3D11_MAP map_type;

  gboolean ret;
} D3D11MapData;

static void
map_cpu_access_data (GstD3D11Device * device, D3D11MapData * map_data)
{
  GstD3D11Memory *dmem = map_data->mem;
  HRESULT hr;
  ID3D11Resource *texture = (ID3D11Resource *) dmem->texture;
  ID3D11Resource *staging = (ID3D11Resource *) dmem->staging;
  ID3D11DeviceContext *device_context =
      gst_d3d11_device_get_device_context_handle (device);

  if (GST_MEMORY_FLAG_IS_SET (dmem, GST_D3D11_MEMORY_TRANSFER_NEED_DOWNLOAD)) {
    ID3D11DeviceContext_CopySubresourceRegion (device_context,
        staging, 0, 0, 0, 0, texture, 0, NULL);
  }

  hr = ID3D11DeviceContext_Map (device_context,
      staging, 0, map_data->map_type, 0, &dmem->map);

  if (FAILED (hr)) {
    GST_ERROR_OBJECT (GST_MEMORY_CAST (dmem)->allocator,
        "Failed to map staging texture (0x%x)", (guint) hr);
    map_data->ret = FALSE;
  }

  map_data->ret = TRUE;
}

static gpointer
gst_d3d11_memory_map (GstMemory * mem, gsize maxsize, GstMapFlags flags)
{
  GstD3D11Memory *dmem = (GstD3D11Memory *) mem;

  g_mutex_lock (&dmem->lock);

  if ((flags & GST_MAP_D3D11) == GST_MAP_D3D11) {
    if (dmem->staging &&
        GST_MEMORY_FLAG_IS_SET (dmem, GST_D3D11_MEMORY_TRANSFER_NEED_UPLOAD)) {
      D3D11CopyTextureData data;

      data.dst = (ID3D11Resource *) dmem->texture;
      data.src = (ID3D11Resource *) dmem->staging;

      gst_d3d11_device_thread_add (dmem->device,
          (GstD3D11DeviceThreadFunc) copy_texture, &data);
    }

    GST_MEMORY_FLAG_UNSET (dmem, GST_D3D11_MEMORY_TRANSFER_NEED_UPLOAD);

    if ((flags & GST_MAP_WRITE) == GST_MAP_WRITE)
      GST_MINI_OBJECT_FLAG_SET (dmem, GST_D3D11_MEMORY_TRANSFER_NEED_DOWNLOAD);

    g_assert (dmem->texture != NULL);
    g_mutex_unlock (&dmem->lock);

    return dmem->texture;
  }

  if (dmem->cpu_map_count == 0) {
    D3D11MapData map_data;

    /* Allocate staging texture for CPU access */
    if (!dmem->staging) {
      dmem->staging = create_staging_texture (dmem->device, &dmem->desc);
      if (!dmem->staging) {
        GST_ERROR_OBJECT (mem->allocator, "Couldn't create staging texture");
        g_mutex_unlock (&dmem->lock);

        return NULL;
      }

      /* first memory, always need download to staging */
      GST_MINI_OBJECT_FLAG_SET (mem, GST_D3D11_MEMORY_TRANSFER_NEED_DOWNLOAD);
    }

    map_data.mem = dmem;
    map_data.map_type = gst_map_flags_to_d3d11 (flags);

    gst_d3d11_device_thread_add (dmem->device, (GstD3D11DeviceThreadFunc)
        map_cpu_access_data, &map_data);

    if (!map_data.ret) {
      GST_ERROR_OBJECT (mem->allocator, "Couldn't map staging texture");
      g_mutex_unlock (&dmem->lock);

      return NULL;
    }
  }

  if ((flags & GST_MAP_WRITE) == GST_MAP_WRITE)
    GST_MINI_OBJECT_FLAG_SET (mem, GST_D3D11_MEMORY_TRANSFER_NEED_UPLOAD);

  GST_MEMORY_FLAG_UNSET (mem, GST_D3D11_MEMORY_TRANSFER_NEED_DOWNLOAD);

  dmem->cpu_map_count++;
  g_mutex_unlock (&dmem->lock);

  return dmem->map.pData;
}

static void
unmap_cpu_access_data (GstD3D11Device * device, gpointer data)
{
  GstD3D11Memory *dmem = (GstD3D11Memory *) data;
  ID3D11Resource *staging = (ID3D11Resource *) dmem->staging;
  ID3D11DeviceContext *device_context =
      gst_d3d11_device_get_device_context_handle (device);

  ID3D11DeviceContext_Unmap (device_context, staging, 0);
}

static void
gst_d3d11_memory_unmap_full (GstMemory * mem, GstMapInfo * info)
{
  GstD3D11Memory *dmem = (GstD3D11Memory *) mem;

  g_mutex_lock (&dmem->lock);
  if ((info->flags & GST_MAP_D3D11) == GST_MAP_D3D11) {
    if ((info->flags & GST_MAP_WRITE) == GST_MAP_WRITE)
      GST_MINI_OBJECT_FLAG_SET (mem, GST_D3D11_MEMORY_TRANSFER_NEED_DOWNLOAD);

    g_mutex_unlock (&dmem->lock);
    return;
  }

  if ((info->flags & GST_MAP_WRITE))
    GST_MINI_OBJECT_FLAG_SET (mem, GST_D3D11_MEMORY_TRANSFER_NEED_UPLOAD);

  dmem->cpu_map_count--;
  if (dmem->cpu_map_count > 0) {
    g_mutex_unlock (&dmem->lock);
    return;
  }

  gst_d3d11_device_thread_add (dmem->device, (GstD3D11DeviceThreadFunc)
      unmap_cpu_access_data, dmem);

  g_mutex_unlock (&dmem->lock);
}

static GstMemory *
gst_d3d11_memory_share (GstMemory * mem, gssize offset, gssize size)
{
  /* TODO: impl. */
  return NULL;
}

static GstMemory *
gst_d3d11_allocator_dummy_alloc (GstAllocator * allocator, gsize size,
    GstAllocationParams * params)
{
  g_return_val_if_reached (NULL);
}

static void
release_texture (GstD3D11Device * device, GstD3D11Memory * mem)
{
  if (mem->texture)
    ID3D11Texture2D_Release (mem->texture);

  if (mem->staging)
    ID3D11Texture2D_Release (mem->staging);
}

static void
gst_d3d11_allocator_free (GstAllocator * allocator, GstMemory * mem)
{
  GstD3D11Memory *dmem = (GstD3D11Memory *) mem;
  GstD3D11Device *device = dmem->device;

  if (dmem->texture || dmem->staging)
    gst_d3d11_device_thread_add (device,
        (GstD3D11DeviceThreadFunc) release_texture, dmem);

  gst_object_unref (device);
  g_mutex_clear (&dmem->lock);

  g_free (dmem);
}

static void
gst_d3d11_allocator_dispose (GObject * object)
{
  GstD3D11Allocator *alloc = GST_D3D11_ALLOCATOR (object);

  gst_clear_object (&alloc->device);

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

static void
gst_d3d11_allocator_class_init (GstD3D11AllocatorClass * klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
  GstAllocatorClass *allocator_class = GST_ALLOCATOR_CLASS (klass);

  gobject_class->dispose = gst_d3d11_allocator_dispose;

  allocator_class->alloc = gst_d3d11_allocator_dummy_alloc;
  allocator_class->free = gst_d3d11_allocator_free;

  GST_DEBUG_CATEGORY_INIT (gst_d3d11_allocator_debug, "d3d11allocator", 0,
      "d3d11allocator object");
}

static void
gst_d3d11_allocator_init (GstD3D11Allocator * allocator)
{
  GstAllocator *alloc = GST_ALLOCATOR_CAST (allocator);

  alloc->mem_type = GST_D3D11_MEMORY_NAME;
  alloc->mem_map = gst_d3d11_memory_map;
  alloc->mem_unmap_full = gst_d3d11_memory_unmap_full;
  alloc->mem_share = gst_d3d11_memory_share;
  /* fallback copy */

  GST_OBJECT_FLAG_SET (alloc, GST_ALLOCATOR_FLAG_CUSTOM_ALLOC);
}

GstD3D11Allocator *
gst_d3d11_allocator_new (GstD3D11Device * device)
{
  GstD3D11Allocator *allocator;

  g_return_val_if_fail (GST_IS_D3D11_DEVICE (device), NULL);

  allocator = g_object_new (GST_TYPE_D3D11_ALLOCATOR, NULL);
  allocator->device = gst_object_ref (device);

  return allocator;
}

typedef struct
{
  ID3D11Resource *staging;
  D3D11_TEXTURE2D_DESC *desc;

  gint stride[GST_VIDEO_MAX_PLANES];
  gsize size;

  gboolean ret;
} CalSizeData;

static void
calculate_mem_size (GstD3D11Device * device, CalSizeData * data)
{
  HRESULT hr;
  D3D11_MAPPED_SUBRESOURCE map;
  gsize offset[GST_VIDEO_MAX_PLANES];
  ID3D11DeviceContext *device_context =
      gst_d3d11_device_get_device_context_handle (device);

  hr = ID3D11DeviceContext_Map (device_context,
      data->staging, 0, D3D11_MAP_READ, 0, &map);

  if (FAILED (hr)) {
    GST_ERROR_OBJECT (device,
        "Failed to map staging texture (0x%x)", (guint) hr);
    data->ret = FALSE;
  }

  data->ret = gst_d3d11_dxgi_format_get_size (data->desc->Format,
      data->desc->Width, data->desc->Height, map.RowPitch,
      offset, data->stride, &data->size);

  ID3D11DeviceContext_Unmap (device_context, data->staging, 0);
}

GstMemory *
gst_d3d11_allocator_alloc (GstD3D11Allocator * allocator,
    GstD3D11AllocationParams * params)
{
  GstD3D11Memory *mem;
  GstD3D11Device *device;
  ID3D11Texture2D *texture = NULL;
  ID3D11Texture2D *staging = NULL;
  D3D11_TEXTURE2D_DESC *desc;
  gsize *size;
  gboolean is_first = FALSE;

  g_return_val_if_fail (GST_IS_D3D11_ALLOCATOR (allocator), NULL);
  g_return_val_if_fail (params != NULL, NULL);

  device = allocator->device;
  desc = &params->desc[params->plane];
  size = &params->size[params->plane];

  if (*size == 0)
    is_first = TRUE;

  texture = gst_d3d11_device_create_texture (device, desc, NULL);
  if (!texture) {
    GST_ERROR_OBJECT (allocator, "Couldn't create texture");
    goto error;
  }

  /* per plane, allocated staging texture to calculate actual size,
   * stride, and offset */
  if (is_first) {
    CalSizeData data;
    gint num_plane;
    gint i;

    staging = create_staging_texture (device, desc);
    if (!staging) {
      GST_ERROR_OBJECT (allocator, "Couldn't create staging texture");
      goto error;
    }

    data.staging = (ID3D11Resource *) staging;
    data.desc = desc;

    gst_d3d11_device_thread_add (device,
        (GstD3D11DeviceThreadFunc) calculate_mem_size, &data);

    num_plane = gst_d3d11_dxgi_format_n_planes (desc->Format);

    for (i = 0; i < num_plane; i++) {
      params->stride[params->plane + i] = data.stride[i];
    }

    *size = data.size;
  }

  mem = g_new0 (GstD3D11Memory, 1);

  gst_memory_init (GST_MEMORY_CAST (mem),
      0, GST_ALLOCATOR_CAST (allocator), NULL, *size, 0, 0, *size);

  g_mutex_init (&mem->lock);
  mem->info = params->info;
  mem->plane = params->plane;
  mem->desc = *desc;
  mem->texture = texture;
  mem->staging = staging;
  mem->device = gst_object_ref (device);

  if (staging)
    GST_MINI_OBJECT_FLAG_SET (mem, GST_D3D11_MEMORY_TRANSFER_NEED_DOWNLOAD);

  return GST_MEMORY_CAST (mem);

error:
  if (texture)
    gst_d3d11_device_release_texture (device, texture);

  if (staging)
    gst_d3d11_device_release_texture (device, texture);

  return NULL;
}

gboolean
gst_is_d3d11_memory (GstMemory * mem)
{
  return mem != NULL && mem->allocator != NULL &&
      GST_IS_D3D11_ALLOCATOR (mem->allocator);
}