#include <gtest/gtest.h>

#include <memory_resource>
#include <stdexcept>

#include "renderive/scene/dependency/Dependency_Resolver.hpp"

namespace {

enum class Preparation {
    acquire_source,
    transform_vertices,
    upload_visual
};

using Resolver =
    renderive::scene::dependency::Dependency_Resolver<Preparation>;

TEST(dependency_resolver_test,
     resolves_declared_dependencies_in_deterministic_order) {
    std::pmr::unsynchronized_pool_resource memory;
    Resolver resolver(memory);
    resolver.attach(Preparation::upload_visual);
    resolver.attach(Preparation::acquire_source);
    resolver.attach(Preparation::transform_vertices);
    resolver.add_parent(Preparation::transform_vertices,
                        Preparation::acquire_source);
    resolver.add_parent(Preparation::upload_visual,
                        Preparation::transform_vertices);

    const auto resolution = resolver.resolve();
    EXPECT_EQ(resolution.order,
              (std::vector{Preparation::acquire_source,
                           Preparation::transform_vertices,
                           Preparation::upload_visual}));
}

TEST(dependency_resolver_test,
     rejected_cycle_preserves_the_previous_authoritative_relationships) {
    std::pmr::unsynchronized_pool_resource memory;
    Resolver resolver(memory);
    resolver.attach(Preparation::acquire_source);
    resolver.attach(Preparation::transform_vertices);
    resolver.attach(Preparation::upload_visual);
    resolver.add_parent(Preparation::transform_vertices,
                        Preparation::acquire_source);
    resolver.add_parent(Preparation::upload_visual,
                        Preparation::transform_vertices);

    EXPECT_EQ(resolver.add_parent(Preparation::acquire_source,
                                  Preparation::upload_visual).error,
              renderive::scene::dependency::Mutation_Error::cycle);

    EXPECT_TRUE(resolver.parents(Preparation::acquire_source).empty());
    EXPECT_EQ(resolver.resolve().order,
              (std::vector{Preparation::acquire_source,
                           Preparation::transform_vertices,
                           Preparation::upload_visual}));
}

} // namespace