/*
 * GStreamer
 * Copyright (C) 2015 Matthew Waters <matthew@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 <string.h>

#include <gst/gl/gstglbasememory.h>

/**
 * SECTION:gstglbasememory
 * @short_description: memory subclass for GL buffers
 * @see_also: #GstMemory, #GstAllocator
 *
 * GstGLBaseMemory is a #GstMemory subclass providing the basis of support
 * for the mapping of GL buffers.
 *
 * Data is uploaded or downloaded from the GPU as is necessary.
 */

#define USING_OPENGL(context) (gst_gl_context_check_gl_version (context, GST_GL_API_OPENGL, 1, 0))
#define USING_OPENGL3(context) (gst_gl_context_check_gl_version (context, GST_GL_API_OPENGL3, 3, 1))
#define USING_GLES(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES, 1, 0))
#define USING_GLES2(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES2, 2, 0))
#define USING_GLES3(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES2, 3, 0))

GST_DEBUG_CATEGORY_STATIC (GST_CAT_GL_BASE_MEMORY);
#define GST_CAT_DEFUALT GST_CAT_GL_BASE_MEMORY

GQuark
gst_gl_base_memory_error_quark (void)
{
  return g_quark_from_static_string ("gst-gl-base-buffer-error-quark");
}

static gboolean
_default_create (GstGLBaseMemory * mem, GError ** error)
{
  g_set_error (error, GST_GL_BASE_MEMORY_ERROR, GST_GL_BASE_MEMORY_ERROR_FAILED,
      "subclass should define create() vfunc");

  g_critical ("subclass should override "
      "GstGLBaseMemoryAllocatorClass::create() function");

  return FALSE;
}

struct create_data
{
  GstGLBaseMemory *mem;
  gboolean result;
};

static void
_mem_create_gl (GstGLContext * context, struct create_data *transfer)
{
  GstGLBaseMemoryAllocatorClass *alloc_class;
  GError *error = NULL;

  alloc_class =
      GST_GL_BASE_MEMORY_ALLOCATOR_GET_CLASS (transfer->mem->mem.allocator);

  g_return_if_fail (alloc_class->create != NULL);

  if ((transfer->result = alloc_class->create (transfer->mem, &error)))
    return;

  g_assert (error != NULL);

  GST_CAT_ERROR (GST_CAT_GL_BASE_MEMORY, "Failed to create GL buffer: %s",
      error->message);
  g_clear_error (&error);
}

void
gst_gl_base_memory_init (GstGLBaseMemory * mem, GstAllocator * allocator,
    GstMemory * parent, GstGLContext * context, GstAllocationParams * params,
    gsize size, GDestroyNotify notify, gpointer user_data)
{
  gsize align = gst_memory_alignment, offset = 0, maxsize = size;
  GstMemoryFlags flags = 0;
  struct create_data data;

  if (params) {
    flags = params->flags;
    align |= params->align;
    offset = params->prefix;
    maxsize += params->prefix + params->padding + align;
  }

  gst_memory_init (GST_MEMORY_CAST (mem), flags, allocator, parent, maxsize,
      align, offset, size);

  mem->context = gst_object_ref (context);
  mem->notify = notify;
  mem->user_data = user_data;

  g_mutex_init (&mem->lock);

  data.mem = mem;

  gst_gl_context_thread_add (context,
      (GstGLContextThreadFunc) _mem_create_gl, &data);
  if (!data.result) {
    GST_CAT_ERROR (GST_CAT_GL_BASE_MEMORY,
        "Could not create GL buffer with context:%p", context);
  }

  GST_CAT_DEBUG (GST_CAT_GL_BASE_MEMORY, "new GL buffer memory:%p size:%"
      G_GSIZE_FORMAT, mem, maxsize);
}

static gpointer
_align_data (gpointer data, gsize align, gsize * maxsize)
{
  guint8 *ret = data;
  gsize aoffset;

  /* do alignment */
  if ((aoffset = ((guintptr) ret & align))) {
    aoffset = (align + 1) - aoffset;
    ret += aoffset;
    *maxsize -= aoffset;
  }

  return ret;
}

/* subclass usage only */
gboolean
gst_gl_base_memory_alloc_data (GstGLBaseMemory * gl_mem)
{
  GstMemory *mem = (GstMemory *) gl_mem;

  if (gl_mem->data)
    return TRUE;

  GST_CAT_LOG (GST_CAT_GL_BASE_MEMORY, "%p attempting allocation of data "
      "pointer of size %" G_GSIZE_FORMAT, gl_mem, mem->maxsize);
  gl_mem->alloc_data = g_try_malloc (mem->maxsize);

  if (gl_mem->alloc_data == NULL)
    return FALSE;

  gl_mem->data = _align_data (gl_mem->alloc_data, mem->align, &mem->maxsize);

  GST_CAT_DEBUG (GST_CAT_GL_BASE_MEMORY, "%p allocated data pointer alloc %p, "
      "data %p", gl_mem, gl_mem->alloc_data, gl_mem->data);

  return TRUE;
}

struct map_data
{
  GstGLBaseMemory *mem;
  GstMapInfo *info;
  gsize size;
  gpointer data;
};

static void
_map_data_gl (GstGLContext * context, struct map_data *transfer)
{
  GstGLBaseMemoryAllocatorClass *alloc_class;
  GstGLBaseMemory *mem = transfer->mem;
  GstMapInfo *info = transfer->info;

  alloc_class =
      GST_GL_BASE_MEMORY_ALLOCATOR_GET_CLASS (transfer->mem->mem.allocator);

  g_return_if_fail (alloc_class->map != NULL);

  g_mutex_lock (&mem->lock);

  GST_CAT_LOG (GST_CAT_GL_BASE_MEMORY, "mapping mem %p flags %04x", mem,
      info->flags);

  /* FIXME: validate map flags based on the memory domain */
  if (mem->map_count++ == 0)
    mem->map_flags = info->flags;
  else {
    /* assert that the flags are a subset of the first map flags */
    g_assert ((((GST_MAP_GL - 1) & info->flags) & mem->map_flags) != 0);
    GST_CAT_LOG (GST_CAT_GL_BASE_MEMORY, "multiple map no %d flags %04x "
        "all flags %04x", mem->map_count, info->flags, mem->map_flags);
  }

  if ((info->flags & GST_MAP_GL) != (mem->map_flags & GST_MAP_GL))
    mem->map_flags |= GST_MAP_GL;

  if (info->flags & GST_MAP_GL)
    mem->gl_map_count++;

  transfer->data = alloc_class->map (transfer->mem, transfer->info,
      transfer->size);

  if (transfer->data) {
    if (info->flags & GST_MAP_GL) {
      if (info->flags & GST_MAP_WRITE)
        GST_MINI_OBJECT_FLAG_SET (mem,
            GST_GL_BASE_MEMORY_TRANSFER_NEED_DOWNLOAD);
      GST_MEMORY_FLAG_UNSET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_UPLOAD);
    } else {
      if (info->flags & GST_MAP_WRITE)
        GST_MINI_OBJECT_FLAG_SET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_UPLOAD);
      GST_MEMORY_FLAG_UNSET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_DOWNLOAD);
    }
  }

  g_mutex_unlock (&mem->lock);
}

static gpointer
_mem_map_full (GstGLBaseMemory * mem, GstMapInfo * info, gsize size)
{
  struct map_data transfer;

  transfer.mem = mem;
  transfer.info = info;
  transfer.size = size;
  transfer.data = NULL;

  gst_gl_context_thread_add (mem->context,
      (GstGLContextThreadFunc) _map_data_gl, &transfer);

  return transfer.data;
}

struct unmap_data
{
  GstGLBaseMemory *mem;
  GstMapInfo *info;
};

static void
_unmap_data_gl (GstGLContext * context, struct unmap_data *transfer)
{
  GstGLBaseMemoryAllocatorClass *alloc_class;
  GstGLBaseMemory *mem = transfer->mem;
  GstMapInfo *info = transfer->info;

  alloc_class =
      GST_GL_BASE_MEMORY_ALLOCATOR_GET_CLASS (transfer->mem->mem.allocator);

  g_return_if_fail (alloc_class->unmap != NULL);

  g_mutex_lock (&mem->lock);

  GST_CAT_LOG (GST_CAT_GL_BASE_MEMORY, "unmapping mem %p flags %04x", mem,
      info->flags);

  alloc_class->unmap (transfer->mem, transfer->info);

  if (info->flags & GST_MAP_GL && --mem->gl_map_count)
    /* unset the gl flag */
    mem->map_flags &= ~GST_MAP_GL;

  if (--mem->map_count <= 0) {
    mem->map_flags = 0;
  }

  if (info->flags & GST_MAP_GL) {
    if (info->flags & GST_MAP_WRITE)
      GST_MINI_OBJECT_FLAG_SET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_DOWNLOAD);
  } else {
    if (info->flags & GST_MAP_WRITE)
      GST_MINI_OBJECT_FLAG_SET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_UPLOAD);
  }

  g_mutex_unlock (&mem->lock);
}

static void
_mem_unmap_full (GstGLBaseMemory * mem, GstMapInfo * info)
{
  struct unmap_data transfer;

  transfer.mem = mem;
  transfer.info = info;

  gst_gl_context_thread_add (mem->context,
      (GstGLContextThreadFunc) _unmap_data_gl, &transfer);
}

static GstGLBaseMemory *
_default_copy (GstGLBaseMemory * src, gssize offset, gssize size)
{
  return NULL;
}

struct copy_params
{
  GstGLBaseMemory *src;
  GstGLBaseMemory *dest;
  gssize offset;
  gssize size;
  gboolean result;
};

static void
_mem_copy_gl (GstGLContext * context, struct copy_params *transfer)
{
  GstGLBaseMemoryAllocatorClass *alloc_class;

  alloc_class =
      GST_GL_BASE_MEMORY_ALLOCATOR_GET_CLASS (transfer->src->mem.allocator);

  g_return_if_fail (alloc_class->copy != NULL);

  transfer->dest =
      alloc_class->copy (transfer->src, transfer->offset, transfer->size);
}

static GstMemory *
_mem_copy (GstGLBaseMemory * src, gssize offset, gssize size)
{
  struct copy_params transfer;

  transfer.dest = NULL;
  transfer.src = src;
  transfer.offset = offset;
  transfer.size = size;
  if (size == -1 || size > 0)
    gst_gl_context_thread_add (src->context,
        (GstGLContextThreadFunc) _mem_copy_gl, &transfer);

  return (GstMemory *) transfer.dest;
}

static GstMemory *
_mem_share (GstGLBaseMemory * mem, gssize offset, gssize size)
{
  return NULL;
}

static gboolean
_mem_is_span (GstGLBaseMemory * mem1, GstGLBaseMemory * mem2, gsize * offset)
{
  return FALSE;
}

static GstMemory *
_mem_alloc (GstAllocator * allocator, gsize size, GstAllocationParams * params)
{
  g_critical ("Subclass should override GstAllocatorClass::alloc() function");

  return NULL;
}

static void
_default_destroy (GstGLBaseMemory * mem)
{
}

static void
_destroy_gl_objects (GstGLContext * context, GstGLBaseMemory * mem)
{
  GstGLBaseMemoryAllocatorClass *alloc_class;

  alloc_class = GST_GL_BASE_MEMORY_ALLOCATOR_GET_CLASS (mem->mem.allocator);

  g_return_if_fail (alloc_class->destroy != NULL);

  alloc_class->destroy (mem);
}

static void
_mem_free (GstAllocator * allocator, GstMemory * memory)
{
  GstGLBaseMemory *mem = (GstGLBaseMemory *) memory;

  GST_CAT_TRACE (GST_CAT_GL_BASE_MEMORY, "freeing buffer memory:%p", mem);

  gst_gl_context_thread_add (mem->context,
      (GstGLContextThreadFunc) _destroy_gl_objects, mem);

  g_mutex_clear (&mem->lock);

  if (mem->alloc_data) {
    g_free (mem->alloc_data);
    mem->alloc_data = NULL;
  }
  mem->data = NULL;

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

  gst_object_unref (mem->context);
}


void
gst_gl_base_memory_init_once (void)
{
  static volatile gsize _init = 0;

  if (g_once_init_enter (&_init)) {
    GST_DEBUG_CATEGORY_INIT (GST_CAT_GL_BASE_MEMORY, "glbasememory", 0,
        "OpenGL BaseMemory");

    g_once_init_leave (&_init, 1);
  }
}

G_DEFINE_ABSTRACT_TYPE (GstGLBaseMemoryAllocator, gst_gl_base_memory_allocator,
    GST_TYPE_ALLOCATOR);

static void
gst_gl_base_memory_allocator_class_init (GstGLBaseMemoryAllocatorClass * klass)
{
  GstAllocatorClass *allocator_class = (GstAllocatorClass *) klass;

  allocator_class->alloc = _mem_alloc;
  allocator_class->free = _mem_free;

  klass->create = _default_create;
  klass->copy = _default_copy;
  klass->destroy = _default_destroy;
}

static void
gst_gl_base_memory_allocator_init (GstGLBaseMemoryAllocator * allocator)
{
  GstAllocator *alloc = GST_ALLOCATOR_CAST (allocator);

  /* Keep the fallback copy function around, we will need it when copying with
   * at an offset or smaller size */
  allocator->fallback_mem_copy = alloc->mem_copy;

  alloc->mem_map_full = (GstMemoryMapFullFunction) _mem_map_full;
  alloc->mem_unmap_full = (GstMemoryUnmapFullFunction) _mem_unmap_full;
  alloc->mem_copy = (GstMemoryCopyFunction) _mem_copy;
  alloc->mem_share = (GstMemoryShareFunction) _mem_share;
  alloc->mem_is_span = (GstMemoryIsSpanFunction) _mem_is_span;
}

/**
 * gst_is_gl_base_memory:
 * @mem:a #GstMemory
 * 
 * Returns: whether the memory at @mem is a #GstGLBaseMemory
 */
gboolean
gst_is_gl_base_memory (GstMemory * mem)
{
  return mem != NULL && mem->allocator != NULL &&
      g_type_is_a (G_OBJECT_TYPE (mem->allocator),
      GST_TYPE_GL_BASE_MEMORY_ALLOCATOR);
}

gboolean
gst_gl_base_memory_memcpy (GstGLBaseMemory * src, GstGLBaseMemory * dest,
    gssize offset, gssize size)
{
  GstMapInfo sinfo, dinfo;

  if (!gst_gl_base_memory_alloc_data (GST_GL_BASE_MEMORY_CAST (dest)))
    return FALSE;

  if (dest == NULL) {
    GST_CAT_WARNING (GST_CAT_GL_BASE_MEMORY, "Could not copy GL Buffer");
    return FALSE;
  }

  if (!gst_memory_map ((GstMemory *) src, &sinfo, GST_MAP_READ)) {
    GST_CAT_WARNING (GST_CAT_GL_BASE_MEMORY,
        "could not read map source memory %p", src);
    return FALSE;
  }

  if (!gst_memory_map ((GstMemory *) dest, &dinfo, GST_MAP_WRITE)) {
    GST_CAT_WARNING (GST_CAT_GL_BASE_MEMORY,
        "could not write map dest memory %p", dest);
    gst_memory_unmap ((GstMemory *) src, &sinfo);
    return FALSE;
  }

  if (size == -1)
    size = sinfo.size > offset ? sinfo.size - offset : 0;

  GST_CAT_DEBUG (GST_CAT_GL_BASE_MEMORY,
      "memcpy %" G_GSSIZE_FORMAT " memory %p -> %p", size, src, dest);
  memcpy (dinfo.data, sinfo.data + offset, size);
  gst_memory_unmap ((GstMemory *) dest, &dinfo);
  gst_memory_unmap ((GstMemory *) src, &sinfo);

  return TRUE;
}