#include <gtest/gtest.h>

#include "renderive/renderable/Inheritance.hpp"

#include <type_traits>
#include <vector>

namespace {

namespace renderable_chain = renderive::renderable_inheritance;

enum class Visit {
    parent,
    child
};

struct Event {};

struct Impl_Base : renderive::inheritance::Type_Root {
    explicit Impl_Base(std::vector<Visit>& visits) : visits(&visits) {}
    std::vector<Visit>* visits;
};

struct Parent_Impl
    : renderable_chain::Impl_Root<Parent_Impl, Impl_Base, Event> {
    using Impl_Root::Impl_Root;

    struct Observer : renderable_chain::Observer_Root<Parent_Impl> {
        static void handle(Parent_Impl& impl, const Event&) {
            impl.visits->push_back(Visit::parent);
        }
    };
};

struct Child_Impl : renderable_chain::Impl_Node<Child_Impl, Parent_Impl> {
    using Impl_Node::Impl_Node;

    struct Observer
        : renderable_chain::Observer_Node<Child_Impl,
                                          Parent_Impl::Observer> {
        static void handle(Child_Impl& impl, const Event&) {
            impl.visits->push_back(Visit::child);
        }
    };
};

struct Parent_State : renderable_chain::State_Root<Parent_State> {};
struct Child_State
    : renderable_chain::State_Node<Child_State, Parent_State> {};

struct Parent_Builder_Layer
    : renderable_chain::Builder_Root<Parent_Builder_Layer> {};
struct Child_Builder_Layer
    : renderable_chain::Builder_Node<Child_Builder_Layer,
                                     Parent_Builder_Layer> {};

struct Business_Builder {
    explicit Business_Builder(bool& initialized) : initialized(&initialized) {}
    void build() const { *initialized = true; }
    bool* initialized;
};

struct Final_Builder
    : renderable_chain::Builder<Final_Builder, Child_Builder_Layer,
                                Business_Builder> {
    using Builder::Builder;
};

struct Root_Base {
public:
    explicit Root_Base(bool& constructed) : constructed(&constructed) {
        constructed = true;
    }

    bool* constructed;
};

struct Renderable_Root
    : renderive::renderable::render_base<Renderable_Root, Root_Base, true> {
    using render_base::render_base;
    struct Impl {};
};

struct Product_Properties {
    bool enabled{};
};

template <class Product_Type, class Properties_Type>
struct Product_Business_Builder {
    using Product = Product_Type;
    using Properties = Properties_Type;

    explicit Product_Business_Builder(bool& initialized)
        : initialized(&initialized) {}

    void build() const { *initialized = true; }

    bool* initialized;
};

struct Visual_Control
    : renderive::renderable::render_base<Visual_Control, Renderable_Root> {
    using State = Product_Properties;

    template <class Product, class Properties>
    using Business_Builder = Product_Business_Builder<Product, Properties>;

    using render_base::render_base;

protected:
    template <class, auto Member, class Value>
    void set_state(Value&& value) {
        state.*Member = std::forward<Value>(value);
    }

    template <class, auto Member>
    auto get_state() const {
        return state.*Member;
    }

private:
    State state;
};

using Renderable_Product = renderive::renderable::attach<Visual_Control>;

TEST(renderable_inheritance_test, dispatches_nested_observers_parent_first) {
    std::vector<Visit> visits;
    Child_Impl impl(visits);

    impl.dispatch(Event{});

    EXPECT_EQ(visits, (std::vector{Visit::parent, Visit::child}));
}

TEST(renderable_inheritance_test, preserves_business_builder_capabilities) {
    bool initialized{};
    Final_Builder builder(initialized);

    builder.build();

    EXPECT_TRUE(initialized);
    static_assert(std::same_as<
                  renderive::inheritance::Type_At_Position_T<
                      typename Final_Builder::Inheritance_Registry,
                      renderable_chain::Builder_Chain,
                      Final_Builder::Inheritance_Position>,
                  Final_Builder>);
    static_assert(std::same_as<
                  renderive::inheritance::Type_At_Position_T<
                      typename Child_State::Inheritance_Registry,
                      renderable_chain::State_Chain,
                      Child_State::Inheritance_Position>,
                  Child_State>);
}

TEST(renderable_inheritance_test,
     composes_root_control_and_product_without_business_boilerplate) {
    bool constructed{};
    Renderable_Product product(constructed);
    EXPECT_TRUE(constructed);

    bool initialized{};
    Renderable_Product::Builder builder(initialized);
    builder.build();
    EXPECT_TRUE(initialized);

    static_assert(std::same_as<Renderable_Product::Properties,
                               Product_Properties>);
    static_assert(std::same_as<
                  typename Renderable_Product::Builder::Product,
                  Renderable_Product>);
}

} // namespace