// Copyright 2013 The Flutter 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 <memory>

#include "flutter/testing/testing.h"
#include "impeller/base/validation.h"
#include "impeller/core/allocator.h"
#include "impeller/core/texture_descriptor.h"
#include "impeller/entity/entity_playground.h"
#include "impeller/entity/render_target_cache.h"
#include "impeller/playground/playground_test.h"
#include "impeller/renderer/testing/mocks.h"

namespace impeller {
namespace testing {

using RenderTargetCacheTest = EntityPlayground;
INSTANTIATE_PLAYGROUND_SUITE(RenderTargetCacheTest);

class TestAllocator : public Allocator {
 public:
  TestAllocator() = default;

  ~TestAllocator() = default;

  ISize GetMaxTextureSizeSupported() const override {
    return ISize(1024, 1024);
  };

  std::shared_ptr<DeviceBuffer> OnCreateBuffer(
      const DeviceBufferDescriptor& desc) override {
    if (should_fail) {
      return nullptr;
    }
    return std::make_shared<MockDeviceBuffer>(desc);
  };

  virtual std::shared_ptr<Texture> OnCreateTexture(
      const TextureDescriptor& desc) override {
    if (should_fail) {
      return nullptr;
    }
    return std::make_shared<MockTexture>(desc);
  };

  bool should_fail = false;
};

TEST_P(RenderTargetCacheTest, CachesUsedTexturesAcrossFrames) {
  auto render_target_cache =
      RenderTargetCache(GetContext()->GetResourceAllocator());

  render_target_cache.Start();
  // Create two render targets of the same exact size/shape. Both should be
  // marked as used this frame, so the cached data set will contain two.
  render_target_cache.CreateOffscreen(*GetContext(), {100, 100}, 1);
  render_target_cache.CreateOffscreen(*GetContext(), {100, 100}, 1);

  EXPECT_EQ(render_target_cache.CachedTextureCount(), 2u);

  render_target_cache.End();
  render_target_cache.Start();

  // Next frame, only create one texture. The set will still contain two,
  // but one will be removed at the end of the frame.
  render_target_cache.CreateOffscreen(*GetContext(), {100, 100}, 1);
  EXPECT_EQ(render_target_cache.CachedTextureCount(), 2u);

  render_target_cache.End();
  EXPECT_EQ(render_target_cache.CachedTextureCount(), 1u);
}

TEST_P(RenderTargetCacheTest, DoesNotPersistFailedAllocations) {
  ScopedValidationDisable disable;
  auto allocator = std::make_shared<TestAllocator>();
  auto render_target_cache = RenderTargetCache(allocator);

  render_target_cache.Start();
  allocator->should_fail = true;

  auto render_target =
      render_target_cache.CreateOffscreen(*GetContext(), {100, 100}, 1);

  EXPECT_FALSE(render_target.IsValid());
  EXPECT_EQ(render_target_cache.CachedTextureCount(), 0u);
}

TEST_P(RenderTargetCacheTest, CachedTextureGetsNewAttachmentConfig) {
  auto render_target_cache =
      RenderTargetCache(GetContext()->GetResourceAllocator());

  render_target_cache.Start();
  RenderTarget::AttachmentConfig color_attachment_config =
      RenderTarget::kDefaultColorAttachmentConfig;
  RenderTarget target1 = render_target_cache.CreateOffscreen(
      *GetContext(), {100, 100}, 1, "Offscreen1", color_attachment_config);
  render_target_cache.End();

  render_target_cache.Start();
  color_attachment_config.clear_color = Color::Red();
  RenderTarget target2 = render_target_cache.CreateOffscreen(
      *GetContext(), {100, 100}, 1, "Offscreen2", color_attachment_config);
  render_target_cache.End();

  auto color1 = target1.GetColorAttachments().find(0)->second;
  auto color2 = target2.GetColorAttachments().find(0)->second;
  // The second color attachment should reuse the first attachment's texture
  // but with attributes from the second AttachmentConfig.
  EXPECT_EQ(color2.texture, color1.texture);
  EXPECT_EQ(color2.clear_color, Color::Red());
}

}  // namespace testing
}  // namespace impeller