#include "render_2D/scene/Render_Scene_2D.h"
#include <renderive/renderable/Renderable_Build.hpp>
#include <gtest/gtest.h>
#include <memory>

namespace renderive {
namespace {

std::unique_ptr<Render_Scene_2D> make_scene(
    Render_Scene_2D::State state = {}) {
    auto strategy =
        std::make_shared<Low_Latency_Render_Scene_2D_Strategy>();
    return Render_Scene_2D::Builder(std::move(strategy))
        .configure([&](Render_Scene_2D::Properties& properties) {
            properties = state;
        })
        .build().value();
}

TEST(RenderScene2DFramePipeline, BuilderOwnsConstructionAndState) {
    Render_Scene_2D::State state;
    state.viewport = {96, 54};
    state.background = Color{8, 16, 24, 255};
    auto scene = make_scene(state);
    ASSERT_TRUE(scene);
    EXPECT_EQ(scene->root_renderable()->object_name(), "root");
}


TEST(RenderScene2DFramePipeline, SceneBuilderOwnsRenderableGroupAndObjectNames) {
    auto builder = Render_Scene_2D::Builder(
        std::make_shared<Manual_Render_Scene_2D_Strategy>());
    const auto root = builder.root_renderable();
    auto child = detail::make_renderable_group(false, "child");
    Renderable_Build_Topology topology;
    topology.dependency.push_back(
        detail::build_relationship(child, root));
    topology.display.push_back(
        detail::build_relationship(child, root));
    detail::Renderable_Build_Access::set_topology(*child, std::move(topology));
    builder.add_renderable(child);

    auto built_scene = builder.build();
    ASSERT_TRUE(built_scene);
    ASSERT_TRUE(*built_scene);
    EXPECT_EQ(child->object_name(), "child");
    EXPECT_EQ((*built_scene)->observer().renderable_count, 2U);
}

TEST(RenderScene2DFramePipeline, SceneBuilderRejectsMissingDependencyEndpoint) {
    auto builder = Render_Scene_2D::Builder(
        std::make_shared<Manual_Render_Scene_2D_Strategy>());
    const auto root = builder.root_renderable();
    auto external = detail::make_renderable_group(false, "external");
    auto child = detail::make_renderable_group(false, "child");
    Renderable_Build_Topology topology;
    topology.dependency.push_back(
        detail::build_relationship(child, external));
    topology.display.push_back(
        detail::build_relationship(child, root));
    detail::Renderable_Build_Access::set_topology(*child, std::move(topology));
    builder.add_renderable(child);

    auto built_scene = builder.build();
    ASSERT_FALSE(built_scene);
    EXPECT_EQ(built_scene.error(),
              Scene_Build_Result::dependency_endpoint_missing);
}

TEST(RenderScene2DFramePipeline, SceneBuilderRejectsDependencyCycle) {
    auto builder = Render_Scene_2D::Builder(
        std::make_shared<Manual_Render_Scene_2D_Strategy>());
    auto first = detail::make_renderable_group(false, "first");
    auto second = detail::make_renderable_group(false, "second");

    Renderable_Build_Topology first_topology;
    first_topology.dependency.push_back(
        detail::build_relationship(first, second));
    detail::Renderable_Build_Access::set_topology(
        *first, std::move(first_topology));

    Renderable_Build_Topology second_topology;
    second_topology.dependency.push_back(
        detail::build_relationship(second, first));
    detail::Renderable_Build_Access::set_topology(
        *second, std::move(second_topology));

    builder.add_renderable(first);
    builder.add_renderable(second);
    auto built_scene = builder.build();
    ASSERT_FALSE(built_scene);
    EXPECT_EQ(built_scene.error(), Scene_Build_Result::dependency_cycle);
}

TEST(RenderScene2DFramePipeline, SceneValidityDoesNotGateStrategyProgress) {
    Render_Scene_2D::State state;
    state.viewport = {80, 45};
    auto scene = make_scene(state);
    scene->publish_frame_state();
    EXPECT_EQ(scene->observer().state, state);
    EXPECT_EQ(scene->render_frame().value(), Plot_Render_Status::view_inactive);
    scene->activate_view();
    EXPECT_EQ(scene->render_frame().value(), Plot_Render_Status::rendered);
    EXPECT_EQ(scene->render_frame().value(), Plot_Render_Status::rendered);
    EXPECT_EQ(scene->wait_for_render(), Scene_Render_Result::none);
}

TEST(RenderScene2DFramePipeline, ObserverReadsPublishedDoubleBufferedState) {
    Render_Scene_2D::State state;
    state.viewport = {32, 24};
    auto scene = make_scene(state);
    scene->activate_view();
    ASSERT_EQ(scene->render_frame().value(), Plot_Render_Status::rendered);
    ASSERT_EQ(scene->wait_for_render(), Scene_Render_Result::none);
    const auto observation = scene->observer();
    EXPECT_EQ(observation.state, state);
    EXPECT_EQ(observation.renderable_count, 1U);
    EXPECT_TRUE(observation.view_active);
    EXPECT_GT(observation.frequency_hz, 0.0);
}

} // namespace
} // namespace renderive