// Copyright 2014 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/surfaces/surface_aggregator.h"

#include <map>

#include "base/bind.h"
#include "base/containers/hash_tables.h"
#include "base/debug/trace_event.h"
#include "base/logging.h"
#include "cc/base/math_util.h"
#include "cc/output/compositor_frame.h"
#include "cc/output/delegated_frame_data.h"
#include "cc/quads/draw_quad.h"
#include "cc/quads/render_pass_draw_quad.h"
#include "cc/quads/shared_quad_state.h"
#include "cc/quads/surface_draw_quad.h"
#include "cc/surfaces/surface.h"
#include "cc/surfaces/surface_factory.h"
#include "cc/surfaces/surface_manager.h"
#include "cc/trees/blocking_task_runner.h"

namespace cc {
namespace {

void MoveMatchingRequests(
    RenderPassId id,
    std::multimap<RenderPassId, CopyOutputRequest*>* copy_requests,
    ScopedPtrVector<CopyOutputRequest>* output_requests) {
  auto request_range = copy_requests->equal_range(id);
  for (auto it = request_range.first; it != request_range.second; ++it) {
    DCHECK(it->second);
    output_requests->push_back(scoped_ptr<CopyOutputRequest>(it->second));
    it->second = nullptr;
  }
  copy_requests->erase(request_range.first, request_range.second);
}

}  // namespace

SurfaceAggregator::SurfaceAggregator(SurfaceManager* manager,
                                     ResourceProvider* provider)
    : manager_(manager), provider_(provider), next_render_pass_id_(1) {
  DCHECK(manager_);
}

SurfaceAggregator::~SurfaceAggregator() {}

class SurfaceAggregator::RenderPassIdAllocator {
 public:
  explicit RenderPassIdAllocator(int* next_index) : next_index_(next_index) {}
  ~RenderPassIdAllocator() {}

  void AddKnownPass(RenderPassId id) {
    if (id_to_index_map_.find(id) != id_to_index_map_.end())
      return;
    id_to_index_map_[id] = (*next_index_)++;
  }

  RenderPassId Remap(RenderPassId id) {
    DCHECK(id_to_index_map_.find(id) != id_to_index_map_.end());
    return RenderPassId(1, id_to_index_map_[id]);
  }

 private:
  base::hash_map<RenderPassId, int> id_to_index_map_;
  int* next_index_;

  DISALLOW_COPY_AND_ASSIGN(RenderPassIdAllocator);
};

static void UnrefHelper(base::WeakPtr<SurfaceFactory> surface_factory,
                        const ReturnedResourceArray& resources,
                        BlockingTaskRunner* main_thread_task_runner) {
  if (surface_factory)
    surface_factory->UnrefResources(resources);
}

RenderPassId SurfaceAggregator::RemapPassId(RenderPassId surface_local_pass_id,
                                            SurfaceId surface_id) {
  RenderPassIdAllocator* allocator = render_pass_allocator_map_.get(surface_id);
  if (!allocator) {
    allocator = new RenderPassIdAllocator(&next_render_pass_id_);
    render_pass_allocator_map_.set(surface_id, make_scoped_ptr(allocator));
  }
  allocator->AddKnownPass(surface_local_pass_id);
  return allocator->Remap(surface_local_pass_id);
}

int SurfaceAggregator::ChildIdForSurface(Surface* surface) {
  SurfaceToResourceChildIdMap::iterator it =
      surface_id_to_resource_child_id_.find(surface->surface_id());
  if (it == surface_id_to_resource_child_id_.end()) {
    int child_id =
        provider_->CreateChild(base::Bind(&UnrefHelper, surface->factory()));
    surface_id_to_resource_child_id_[surface->surface_id()] = child_id;
    return child_id;
  } else {
    return it->second;
  }
}

static ResourceProvider::ResourceId ResourceRemapHelper(
    bool* invalid_frame,
    const ResourceProvider::ResourceIdMap& child_to_parent_map,
    ResourceProvider::ResourceIdArray* resources_in_frame,
    ResourceProvider::ResourceId id) {
  ResourceProvider::ResourceIdMap::const_iterator it =
      child_to_parent_map.find(id);
  if (it == child_to_parent_map.end()) {
    *invalid_frame = true;
    return 0;
  }

  DCHECK_EQ(it->first, id);
  ResourceProvider::ResourceId remapped_id = it->second;
  resources_in_frame->push_back(id);
  return remapped_id;
}

bool SurfaceAggregator::TakeResources(Surface* surface,
                                      const DelegatedFrameData* frame_data,
                                      RenderPassList* render_pass_list) {
  RenderPass::CopyAll(frame_data->render_pass_list, render_pass_list);
  if (!provider_)  // TODO(jamesr): hack for unit tests that don't set up rp
    return false;

  int child_id = ChildIdForSurface(surface);
  provider_->ReceiveFromChild(child_id, frame_data->resource_list);
  if (surface->factory())
    surface->factory()->RefResources(frame_data->resource_list);

  typedef ResourceProvider::ResourceIdArray IdArray;
  IdArray referenced_resources;

  bool invalid_frame = false;
  DrawQuad::ResourceIteratorCallback remap =
      base::Bind(&ResourceRemapHelper,
                 &invalid_frame,
                 provider_->GetChildToParentMap(child_id),
                 &referenced_resources);
  for (const auto& render_pass : *render_pass_list) {
    for (const auto& quad : render_pass->quad_list)
      quad->IterateResources(remap);
  }

  if (!invalid_frame)
    provider_->DeclareUsedResourcesFromChild(child_id, referenced_resources);

  return invalid_frame;
}

gfx::Rect SurfaceAggregator::DamageRectForSurface(const Surface* surface,
                                                  const RenderPass& source) {
  int previous_index = previous_contained_surfaces_[surface->surface_id()];
  if (previous_index == surface->frame_index())
    return gfx::Rect();
  else if (previous_index == surface->frame_index() - 1)
    return source.damage_rect;
  return gfx::Rect(surface->size());
}

void SurfaceAggregator::HandleSurfaceQuad(const SurfaceDrawQuad* surface_quad,
                                          float opacity,
                                          RenderPass* dest_pass) {
  SurfaceId surface_id = surface_quad->surface_id;
  // If this surface's id is already in our referenced set then it creates
  // a cycle in the graph and should be dropped.
  if (referenced_surfaces_.count(surface_id))
    return;
  Surface* surface = manager_->GetSurfaceForId(surface_id);
  if (!surface) {
    contained_surfaces_[surface_id] = 0;
    return;
  }
  contained_surfaces_[surface_id] = surface->frame_index();
  const CompositorFrame* frame = surface->GetEligibleFrame();
  if (!frame)
    return;
  const DelegatedFrameData* frame_data = frame->delegated_frame_data.get();
  if (!frame_data)
    return;

  std::multimap<RenderPassId, CopyOutputRequest*> copy_requests;
  surface->TakeCopyOutputRequests(&copy_requests);

  RenderPassList render_pass_list;
  bool invalid_frame = TakeResources(surface, frame_data, &render_pass_list);
  if (invalid_frame) {
    for (auto& request : copy_requests) {
      request.second->SendEmptyResult();
      delete request.second;
    }
    return;
  }

  SurfaceSet::iterator it = referenced_surfaces_.insert(surface_id).first;

  bool merge_pass = copy_requests.empty();

  const RenderPassList& referenced_passes = render_pass_list;
  size_t passes_to_copy =
      merge_pass ? referenced_passes.size() - 1 : referenced_passes.size();
  for (size_t j = 0; j < passes_to_copy; ++j) {
    const RenderPass& source = *referenced_passes[j];

    size_t sqs_size = source.shared_quad_state_list.size();
    size_t dq_size = source.quad_list.size();
    scoped_ptr<RenderPass> copy_pass(RenderPass::Create(sqs_size, dq_size));

    RenderPassId remapped_pass_id = RemapPassId(source.id, surface_id);

    copy_pass->SetAll(remapped_pass_id,
                      source.output_rect,
                      source.damage_rect,
                      source.transform_to_root_target,
                      source.has_transparent_background);

    MoveMatchingRequests(source.id, &copy_requests, &copy_pass->copy_requests);

    // Contributing passes aggregated in to the pass list need to take the
    // transform of the surface quad into account to update their transform to
    // the root surface.
    // TODO(jamesr): Make sure this is sufficient for surfaces nested several
    // levels deep and add tests.
    copy_pass->transform_to_root_target.ConcatTransform(
        surface_quad->quadTransform());

    CopyQuadsToPass(source.quad_list, source.shared_quad_state_list,
                    gfx::Transform(), 1.f, copy_pass.get(), surface_id);

    dest_pass_list_->push_back(copy_pass.Pass());
  }

  const RenderPass& last_pass = *render_pass_list.back();
  if (merge_pass) {
    // TODO(jamesr): Clean up last pass special casing.
    const QuadList& quads = last_pass.quad_list;

    // TODO(jamesr): Make sure clipping is enforced.
    CopyQuadsToPass(quads, last_pass.shared_quad_state_list,
                    surface_quad->quadTransform(),
                    surface_quad->opacity() * opacity, dest_pass, surface_id);
  } else {
    RenderPassId remapped_pass_id = RemapPassId(last_pass.id, surface_id);

    SharedQuadState* shared_quad_state =
        dest_pass->CreateAndAppendSharedQuadState();
    shared_quad_state->CopyFrom(surface_quad->shared_quad_state);
    shared_quad_state->opacity *= opacity;
    RenderPassDrawQuad* quad =
        dest_pass->CreateAndAppendDrawQuad<RenderPassDrawQuad>();
    quad->SetNew(shared_quad_state,
                 surface_quad->rect,
                 surface_quad->visible_rect,
                 remapped_pass_id,
                 0,
                 gfx::Vector2dF(),
                 gfx::Size(),
                 FilterOperations(),
                 gfx::Vector2dF(),
                 FilterOperations());
  }
  dest_pass->damage_rect =
      gfx::UnionRects(dest_pass->damage_rect,
                      MathUtil::MapEnclosingClippedRect(
                          surface_quad->quadTransform(),
                          DamageRectForSurface(surface, last_pass)));

  referenced_surfaces_.erase(it);
}

void SurfaceAggregator::CopySharedQuadState(
    const SharedQuadState* source_sqs,
    const gfx::Transform& content_to_target_transform,
    RenderPass* dest_render_pass) {
  SharedQuadState* copy_shared_quad_state =
      dest_render_pass->CreateAndAppendSharedQuadState();
  copy_shared_quad_state->CopyFrom(source_sqs);
  // content_to_target_transform contains any transformation that may exist
  // between the context that these quads are being copied from (i.e. the
  // surface's draw transform when aggregated from within a surface) to the
  // target space of the pass. This will be identity except when copying the
  // root draw pass from a surface into a pass when the surface draw quad's
  // transform is not identity.
  copy_shared_quad_state->content_to_target_transform.ConcatTransform(
      content_to_target_transform);
  if (copy_shared_quad_state->is_clipped) {
    copy_shared_quad_state->clip_rect = MathUtil::MapEnclosingClippedRect(
        content_to_target_transform, copy_shared_quad_state->clip_rect);
  }
}

void SurfaceAggregator::CopyQuadsToPass(
    const QuadList& source_quad_list,
    const SharedQuadStateList& source_shared_quad_state_list,
    const gfx::Transform& content_to_target_transform,
    float opacity,
    RenderPass* dest_pass,
    SurfaceId surface_id) {
  const SharedQuadState* last_copied_source_shared_quad_state = NULL;

  SharedQuadStateList::ConstIterator sqs_iter =
      source_shared_quad_state_list.begin();
  for (const auto& quad : source_quad_list) {
    while (quad->shared_quad_state != *sqs_iter) {
      ++sqs_iter;
      DCHECK(sqs_iter != source_shared_quad_state_list.end());
    }
    DCHECK_EQ(quad->shared_quad_state, *sqs_iter);

    if (quad->material == DrawQuad::SURFACE_CONTENT) {
      const SurfaceDrawQuad* surface_quad = SurfaceDrawQuad::MaterialCast(quad);
      HandleSurfaceQuad(surface_quad, opacity, dest_pass);
    } else {
      if (quad->shared_quad_state != last_copied_source_shared_quad_state) {
        CopySharedQuadState(
            quad->shared_quad_state, content_to_target_transform, dest_pass);
        dest_pass->shared_quad_state_list.back()->opacity *= opacity;
        last_copied_source_shared_quad_state = quad->shared_quad_state;
      }
      if (quad->material == DrawQuad::RENDER_PASS) {
        const RenderPassDrawQuad* pass_quad =
            RenderPassDrawQuad::MaterialCast(quad);
        RenderPassId original_pass_id = pass_quad->render_pass_id;
        RenderPassId remapped_pass_id =
            RemapPassId(original_pass_id, surface_id);

        dest_pass->CopyFromAndAppendRenderPassDrawQuad(
            pass_quad,
            dest_pass->shared_quad_state_list.back(),
            remapped_pass_id);
      } else {
        dest_pass->CopyFromAndAppendDrawQuad(
            quad, dest_pass->shared_quad_state_list.back());
      }
    }
  }
}

void SurfaceAggregator::CopyPasses(const DelegatedFrameData* frame_data,
                                   Surface* surface) {
  RenderPassList source_pass_list;

  // The root surface is allowed to have copy output requests, so grab them
  // off its render passes.
  std::multimap<RenderPassId, CopyOutputRequest*> copy_requests;
  surface->TakeCopyOutputRequests(&copy_requests);

  bool invalid_frame = TakeResources(surface, frame_data, &source_pass_list);
  DCHECK(!invalid_frame);

  for (size_t i = 0; i < source_pass_list.size(); ++i) {
    const RenderPass& source = *source_pass_list[i];

    size_t sqs_size = source.shared_quad_state_list.size();
    size_t dq_size = source.quad_list.size();
    scoped_ptr<RenderPass> copy_pass(RenderPass::Create(sqs_size, dq_size));

    MoveMatchingRequests(source.id, &copy_requests, &copy_pass->copy_requests);

    RenderPassId remapped_pass_id =
        RemapPassId(source.id, surface->surface_id());

    copy_pass->SetAll(remapped_pass_id,
                      source.output_rect,
                      DamageRectForSurface(surface, source),
                      source.transform_to_root_target,
                      source.has_transparent_background);

    CopyQuadsToPass(source.quad_list, source.shared_quad_state_list,
                    gfx::Transform(), 1.f, copy_pass.get(),
                    surface->surface_id());

    dest_pass_list_->push_back(copy_pass.Pass());
  }
}

void SurfaceAggregator::RemoveUnreferencedChildren() {
  for (const auto& surface : previous_contained_surfaces_) {
    if (!contained_surfaces_.count(surface.first)) {
      SurfaceToResourceChildIdMap::iterator it =
          surface_id_to_resource_child_id_.find(surface.first);
      if (it != surface_id_to_resource_child_id_.end()) {
        provider_->DestroyChild(it->second);
        surface_id_to_resource_child_id_.erase(it);
      }
    }
  }
}

scoped_ptr<CompositorFrame> SurfaceAggregator::Aggregate(SurfaceId surface_id) {
  Surface* surface = manager_->GetSurfaceForId(surface_id);
  DCHECK(surface);
  contained_surfaces_[surface_id] = surface->frame_index();
  const CompositorFrame* root_surface_frame = surface->GetEligibleFrame();
  if (!root_surface_frame)
    return nullptr;
  TRACE_EVENT0("cc", "SurfaceAggregator::Aggregate");

  scoped_ptr<CompositorFrame> frame(new CompositorFrame);
  frame->delegated_frame_data = make_scoped_ptr(new DelegatedFrameData);

  DCHECK(root_surface_frame->delegated_frame_data);

  SurfaceSet::iterator it = referenced_surfaces_.insert(surface_id).first;

  dest_resource_list_ = &frame->delegated_frame_data->resource_list;
  dest_pass_list_ = &frame->delegated_frame_data->render_pass_list;

  CopyPasses(root_surface_frame->delegated_frame_data.get(), surface);

  referenced_surfaces_.erase(it);
  DCHECK(referenced_surfaces_.empty());

  dest_pass_list_ = NULL;
  RemoveUnreferencedChildren();
  contained_surfaces_.swap(previous_contained_surfaces_);
  contained_surfaces_.clear();

  for (SurfaceIndexMap::iterator it = previous_contained_surfaces_.begin();
       it != previous_contained_surfaces_.end();
       ++it) {
    Surface* surface = manager_->GetSurfaceForId(it->first);
    if (surface)
      surface->TakeLatencyInfo(&frame->metadata.latency_info);
  }

  // TODO(jamesr): Aggregate all resource references into the returned frame's
  // resource list.

  return frame.Pass();
}

}  // namespace cc