/* GStreamer
 * Copyright (C) 2023 Seungha Yang <seungha@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 "gstd3d12.h"
#include <wrl.h>
#include <queue>
#include <mutex>

GST_DEBUG_CATEGORY_STATIC (gst_d3d12_command_allocator_pool_debug);
#define GST_CAT_DEFAULT gst_d3d12_command_allocator_pool_debug

/* *INDENT-OFF* */
using namespace Microsoft::WRL;

struct _GstD3D12CommandAllocator : public GstMiniObject
{
  ~_GstD3D12CommandAllocator ()
  {
    if (notify)
      notify (user_data);
  }

  GstD3D12CommandAllocatorPool *pool = nullptr;
  D3D12_COMMAND_LIST_TYPE type;
  ComPtr < ID3D12CommandAllocator > ca;
  gpointer user_data = nullptr;
  GDestroyNotify notify = nullptr;
};

struct GstD3D12CommandAllocatorPoolPrivate
{
  ~GstD3D12CommandAllocatorPoolPrivate ()
  {
    while (!cmd_pool.empty ()) {
      auto cmd = cmd_pool.front ();
      cmd_pool.pop ();
      gst_mini_object_unref (cmd);
    }
  }

  ComPtr<ID3D12Device> device;

  std::mutex lock;
  std::queue<GstD3D12CommandAllocator *>cmd_pool;
  D3D12_COMMAND_LIST_TYPE cmd_type;
};
/* *INDENT-ON* */

struct _GstD3D12CommandAllocatorPool
{
  GstObject parent;

  GstD3D12CommandAllocatorPoolPrivate *priv;
};

GST_DEFINE_MINI_OBJECT_TYPE (GstD3D12CommandAllocator,
    gst_d3d12_command_allocator);

static void gst_d3d12_command_allocator_pool_finalize (GObject * object);

#define gst_d3d12_command_allocator_pool_parent_class parent_class
G_DEFINE_TYPE (GstD3D12CommandAllocatorPool,
    gst_d3d12_command_allocator_pool, GST_TYPE_OBJECT);

static void
gst_d3d12_command_allocator_pool_class_init (GstD3D12CommandAllocatorPoolClass *
    klass)
{
  auto object_class = G_OBJECT_CLASS (klass);

  object_class->finalize = gst_d3d12_command_allocator_pool_finalize;

  GST_DEBUG_CATEGORY_INIT (gst_d3d12_command_allocator_pool_debug,
      "d3d12commandallocatorpool", 0, "d3d12commandallocatorpool");
}

static void
gst_d3d12_command_allocator_pool_init (GstD3D12CommandAllocatorPool * self)
{
  self->priv = new GstD3D12CommandAllocatorPoolPrivate ();
}

static void
gst_d3d12_command_allocator_pool_finalize (GObject * object)
{
  auto self = GST_D3D12_COMMAND_ALLOCATOR_POOL (object);

  delete self->priv;

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

GstD3D12CommandAllocatorPool *
gst_d3d12_command_allocator_pool_new (GstD3D12Device * device,
    D3D12_COMMAND_LIST_TYPE type)
{
  g_return_val_if_fail (GST_IS_D3D12_DEVICE (device), nullptr);

  auto self = (GstD3D12CommandAllocatorPool *)
      g_object_new (GST_TYPE_D3D12_COMMAND_ALLOCATOR_POOL, nullptr);
  gst_object_ref_sink (self);

  auto priv = self->priv;
  priv->device = gst_d3d12_device_get_device_handle (device);
  priv->cmd_type = type;

  return self;
}

static void
gst_d3d12_command_allocator_pool_release (GstD3D12CommandAllocatorPool * pool,
    GstD3D12CommandAllocator * cmd)
{
  auto priv = pool->priv;
  {
    std::lock_guard < std::mutex > lk (priv->lock);
    cmd->dispose = nullptr;
    cmd->pool = nullptr;
    priv->cmd_pool.push (cmd);
  }

  gst_object_unref (pool);
}

static gboolean
gst_d3d12_command_allocator_dispose (GstD3D12CommandAllocator * cmd)
{
  if (!cmd->pool)
    return TRUE;

  gst_mini_object_ref (cmd);
  gst_d3d12_command_allocator_pool_release (cmd->pool, cmd);

  return FALSE;
}

static void
gst_d3d12_command_allocator_free (GstD3D12CommandAllocator * cmd)
{
  delete cmd;
}

static GstD3D12CommandAllocator *
gst_d3d12_command_allocator_new (ID3D12CommandAllocator * ca,
    D3D12_COMMAND_LIST_TYPE type)
{
  auto cmd = new GstD3D12CommandAllocator ();
  cmd->ca = ca;
  cmd->type = type;

  gst_mini_object_init (cmd, 0, gst_d3d12_command_allocator_get_type (),
      nullptr, nullptr,
      (GstMiniObjectFreeFunction) gst_d3d12_command_allocator_free);

  return cmd;
}

gboolean
gst_d3d12_command_allocator_pool_acquire (GstD3D12CommandAllocatorPool * pool,
    GstD3D12CommandAllocator ** cmd)
{
  g_return_val_if_fail (GST_IS_D3D12_COMMAND_ALLOCATOR_POOL (pool), FALSE);
  g_return_val_if_fail (cmd, FALSE);

  *cmd = nullptr;

  auto priv = pool->priv;
  GstD3D12CommandAllocator *new_cmd = nullptr;
  HRESULT hr;

  {
    std::lock_guard < std::mutex > lk (priv->lock);
    if (!priv->cmd_pool.empty ()) {
      new_cmd = priv->cmd_pool.front ();
      priv->cmd_pool.pop ();
    }
  }

  if (!new_cmd) {
    ComPtr < ID3D12CommandAllocator > ca;
    hr = priv->device->CreateCommandAllocator (priv->cmd_type,
        IID_PPV_ARGS (&ca));
    if (FAILED (hr)) {
      GST_ERROR_OBJECT (pool, "Couldn't create command allocator, hr: 0x%x",
          (guint) hr);
      return FALSE;
    }

    new_cmd = gst_d3d12_command_allocator_new (ca.Get (), priv->cmd_type);
  }

  new_cmd->pool = (GstD3D12CommandAllocatorPool *) gst_object_ref (pool);
  new_cmd->dispose =
      (GstMiniObjectDisposeFunction) gst_d3d12_command_allocator_dispose;

  *cmd = new_cmd;

  return TRUE;
}

GstD3D12CommandAllocator *
gst_d3d12_command_allocator_ref (GstD3D12CommandAllocator * cmd)
{
  return (GstD3D12CommandAllocator *) gst_mini_object_ref (cmd);
}

void
gst_d3d12_command_allocator_unref (GstD3D12CommandAllocator * cmd)
{
  gst_mini_object_unref (cmd);
}

void
gst_clear_d3d12_command_allocator (GstD3D12CommandAllocator ** cmd)
{
  gst_clear_mini_object (cmd);
}

D3D12_COMMAND_LIST_TYPE
gst_d3d12_command_allocator_get_command_type (GstD3D12CommandAllocator * cmd)
{
  g_return_val_if_fail (cmd, D3D12_COMMAND_LIST_TYPE_NONE);

  return cmd->type;
}

gboolean
gst_d3d12_command_allocator_get_handle (GstD3D12CommandAllocator * cmd,
    ID3D12CommandAllocator ** ca)
{
  g_return_val_if_fail (cmd, FALSE);
  g_return_val_if_fail (ca, FALSE);

  *ca = cmd->ca.Get ();
  (*ca)->AddRef ();

  return TRUE;
}

void
gst_d3d12_command_allocator_set_user_data (GstD3D12CommandAllocator * cmd,
    gpointer user_data, GDestroyNotify notify)
{
  g_return_if_fail (cmd);

  if (cmd->notify)
    cmd->notify (cmd->user_data);

  cmd->user_data = user_data;
  cmd->notify = notify;
}

gpointer
gst_d3d12_command_allocator_get_user_data (GstD3D12CommandAllocator * cmd)
{
  g_return_val_if_fail (cmd, nullptr);

  return cmd->user_data;
}