/* SPDX-License-Identifier: Apache-2.0
 * Copyright 2011-2022 Blender Foundation */

#include "scene/tables.h"
#include "device/device.h"
#include "scene/scene.h"
#include "scene/stats.h"

#include "util/log.h"
#include "util/time.h"

CCL_NAMESPACE_BEGIN

/* Lookup Tables */

LookupTables::LookupTables()
{
  need_update_ = true;
}

LookupTables::~LookupTables()
{
  assert(lookup_tables.size() == 0);
}

void LookupTables::device_update(Device *, DeviceScene *dscene, Scene *scene)
{
  if (!need_update())
    return;

  scoped_callback_timer timer([scene](double time) {
    if (scene->update_stats) {
      scene->update_stats->tables.times.add_entry({"device_update", time});
    }
  });

  VLOG_INFO << "Total " << lookup_tables.size() << " lookup tables.";

  if (lookup_tables.size() > 0)
    dscene->lookup_table.copy_to_device();

  need_update_ = false;
}

void LookupTables::device_free(Device *, DeviceScene *dscene)
{
  dscene->lookup_table.free();
}

bool LookupTables::need_update() const
{
  return need_update_;
}

static size_t round_up_to_multiple(size_t size, size_t chunk)
{
  return ((size + chunk - 1) / chunk) * chunk;
}

size_t LookupTables::add_table(DeviceScene *dscene, vector<float> &data)
{
  assert(data.size() > 0);

  need_update_ = true;

  Table new_table;
  new_table.offset = 0;
  new_table.size = round_up_to_multiple(data.size(), TABLE_CHUNK_SIZE);

  /* find space to put lookup table */
  list<Table>::iterator table;

  for (table = lookup_tables.begin(); table != lookup_tables.end(); table++) {
    if (new_table.offset + new_table.size <= table->offset) {
      lookup_tables.insert(table, new_table);
      break;
    }
    else
      new_table.offset = table->offset + table->size;
  }

  if (table == lookup_tables.end()) {
    /* add at the end */
    lookup_tables.push_back(new_table);
    dscene->lookup_table.resize(new_table.offset + new_table.size);
  }

  /* copy table data and return offset */
  float *dtable = dscene->lookup_table.data();
  memcpy(dtable + new_table.offset, &data[0], sizeof(float) * data.size());

  return new_table.offset;
}

void LookupTables::remove_table(size_t *offset)
{
  if (*offset == TABLE_OFFSET_INVALID) {
    /* The table isn't even allocated, so just return here. */
    return;
  }

  need_update_ = true;

  list<Table>::iterator table;

  for (table = lookup_tables.begin(); table != lookup_tables.end(); table++) {
    if (table->offset == *offset) {
      lookup_tables.erase(table);
      *offset = TABLE_OFFSET_INVALID;
      return;
    }
  }

  assert(table != lookup_tables.end());
}

CCL_NAMESPACE_END