// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/layers/layer_proto_converter.h"

#include "base/stl_util.h"
#include "cc/layers/empty_content_layer_client.h"
#include "cc/layers/heads_up_display_layer.h"
#include "cc/layers/layer.h"
#include "cc/layers/layer_settings.h"
#include "cc/layers/picture_layer.h"
#include "cc/proto/layer.pb.h"
#include "cc/trees/layer_tree_host_common.h"
#include "cc/trees/layer_tree_settings.h"

namespace cc {

LayerProtoConverter::LayerProtoConverter() {}

LayerProtoConverter::~LayerProtoConverter() {}

// static
void LayerProtoConverter::SerializeLayerHierarchy(
    const scoped_refptr<Layer> root_layer,
    proto::LayerNode* root_node) {
  root_layer->ToLayerNodeProto(root_node);
}

// static
scoped_refptr<Layer> LayerProtoConverter::DeserializeLayerHierarchy(
    scoped_refptr<Layer> existing_root,
    const proto::LayerNode& root_node) {
  LayerIdMap layer_id_map;
  if (existing_root)
    RecursivelyFindAllLayers(existing_root, &layer_id_map);

  scoped_refptr<Layer> new_root = existing_root;
  if (!existing_root ||
      (root_node.has_id() && root_node.id() != existing_root->id())) {
    // The root node has changed or there was no root node,
    // so find or create the new root.
    new_root = FindOrAllocateAndConstruct(root_node, layer_id_map);
  }
  new_root->FromLayerNodeProto(root_node, layer_id_map);
  return new_root;
}

// static
void LayerProtoConverter::SerializeLayerProperties(
    Layer* root_layer,
    proto::LayerUpdate* layer_update) {
  RecursivelySerializeLayerProperties(root_layer, layer_update);
}

// static
void LayerProtoConverter::DeserializeLayerProperties(
    Layer* existing_root,
    const proto::LayerUpdate& layer_update) {
  DCHECK(existing_root);
  LayerIdMap layer_id_map;
  RecursivelyFindAllLayers(existing_root, &layer_id_map);

  for (int i = 0; i < layer_update.layers_size(); ++i) {
    const proto::LayerProperties& layer_properties = layer_update.layers(i);

    Layer::LayerIdMap::const_iterator iter =
        layer_id_map.find(layer_properties.id());
    DCHECK(iter != layer_id_map.end());

    iter->second->FromLayerPropertiesProto(layer_properties);
  }
}

// static
void LayerProtoConverter::RecursivelySerializeLayerProperties(
    Layer* layer,
    proto::LayerUpdate* layer_update) {
  bool serialize_descendants = layer->ToLayerPropertiesProto(layer_update);
  if (!serialize_descendants)
    return;

  for (const auto& child : layer->children()) {
    RecursivelySerializeLayerProperties(child.get(), layer_update);
  }
  if (layer->mask_layer())
    RecursivelySerializeLayerProperties(layer->mask_layer(), layer_update);
  if (layer->replica_layer())
    RecursivelySerializeLayerProperties(layer->replica_layer(), layer_update);
}

// static
void LayerProtoConverter::RecursivelyFindAllLayers(
    const scoped_refptr<Layer>& layer,
    LayerIdMap* layer_id_map) {
  LayerTreeHostCommon::CallFunctionForSubtree(
      layer.get(),
      [layer_id_map](Layer* layer) { (*layer_id_map)[layer->id()] = layer; });
}

// static
scoped_refptr<Layer> LayerProtoConverter::FindOrAllocateAndConstruct(
    const proto::LayerNode& proto,
    const Layer::LayerIdMap& layer_id_map) {
  DCHECK(proto.has_id());
  Layer::LayerIdMap::const_iterator iter = layer_id_map.find(proto.id());
  if (iter != layer_id_map.end())
    return iter->second;
  DCHECK(proto.has_type());
  switch (proto.type()) {
    // Fall through and build a base layer.  This won't have any special layer
    // properties but still maintains the layer hierarchy if we run into a
    // layer type we don't support.
    case proto::LayerNode::UNKNOWN:
    case proto::LayerNode::LAYER:
      return Layer::Create(LayerSettings()).get();
    case proto::LayerNode::PICTURE_LAYER:
      return PictureLayer::Create(LayerSettings(),
                                  EmptyContentLayerClient::GetInstance());
    case proto::LayerNode::HEADS_UP_DISPLAY_LAYER:
      return HeadsUpDisplayLayer::Create(LayerSettings());
  }
  // TODO(nyquist): Add the rest of the necessary LayerTypes. This function
  // should not return null.
  NOTREACHED();
  return nullptr;
}

}  // namespace cc