#include "Explicit_Renderable_Runtime.h"
#include "../../architecture/Renderable.h"
#include "../../base/Memory.h"
#include <mutex>
#include <system_error>
#include <utility>

namespace renderive {

namespace {

struct Explicit_Input_Slot {
    Input_Data* data{};
    std::uint64_t version = 0;
    bool pending = false;
    std::shared_ptr<Update_State> completion_state;
};

} // namespace

struct Explicit_Renderable_Runtime_Data {
    Renderable* owner{};
    mutable std::mutex state_mutex;
    mutable std::mutex input_mutex;
    Render_Object_Owner state_owner;
    Render_State* state{};
    Render_Object_Owner input_owner;
    Explicit_Input_Slot input;
    std::uint64_t input_version = 0;
    std::pmr::vector<std::shared_ptr<Update_State>> committed_update_states{memory_resource(Memory_Domain::Update_Completion)};

    void initialize(Renderable& renderable) {
        clear();
        state_owner = renderable.create_render_state();
        state = state_owner.get<Render_State>();
        if (state)
            state->version = 1;
        input_owner = renderable.create_input_data();
        input.data = input_owner.get<Input_Data>();
        input.version = 0;
        input.pending = false;
        input.completion_state.reset();
    }

    void cancel_pending_completions() {
        std::lock_guard<std::mutex> lock(input_mutex);
        if (input.completion_state) {
            input.completion_state->complete_all(std::make_error_code(std::errc::operation_canceled), Update_Outcome::Cancelled);
            input.completion_state.reset();
        }
        cancel_update_states(committed_update_states);
    }

    void clear() {
        {
            std::lock_guard<std::mutex> input_lock(input_mutex);
            if (input.completion_state) {
                input.completion_state->complete_all(std::make_error_code(std::errc::operation_canceled), Update_Outcome::Cancelled);
                input.completion_state.reset();
            }
            input.data = nullptr;
            input.version = 0;
            input.pending = false;
            input_owner.reset();
            input_version = 0;
        }
        {
            std::lock_guard<std::mutex> state_lock(state_mutex);
            state = nullptr;
            state_owner.reset();
        }
    }
};

namespace {

struct Explicit_State_Read_Handle final : Render_State_Read_Handle {
    explicit Explicit_State_Read_Handle(std::unique_lock<std::mutex> lock)
        : lock(std::move(lock)) {}
    std::unique_lock<std::mutex> lock;
};

struct Explicit_Input_Frame_Handle final : Render_Input_Frame_Handle {
    Explicit_Input_Frame_Handle(Explicit_Renderable_Runtime_Data* runtime, std::unique_lock<std::mutex> lock)
        : runtime(runtime), lock(std::move(lock)) {}
    void consume_input(Input_Data* input) override {
        if (consumed || !runtime)
            return;
        consumed = true;
        if (runtime->input.completion_state) {
            runtime->input.completion_state->complete_until(Update_Stage::Committed);
            runtime->committed_update_states.push_back(std::move(runtime->input.completion_state));
        }
        if (input)
            input->consume();
        runtime->input.pending = false;
    }
    Explicit_Renderable_Runtime_Data* runtime{};
    std::unique_lock<std::mutex> lock;
    bool consumed = false;
};

struct Explicit_State_Write_Handle final : Render_State_Write_Handle {
    Explicit_State_Write_Handle(Explicit_Renderable_Runtime_Data* runtime, std::unique_lock<std::mutex> lock)
        : runtime(runtime), lock(std::move(lock)) {}
    ~Explicit_State_Write_Handle() override {
        if (!runtime || !runtime->state)
            return;
        ++runtime->state->version;
        lock.unlock();
        if (runtime->owner)
            runtime->owner->mark_render_dirty(Dirty_Reason::Config);
    }
    Explicit_Renderable_Runtime_Data* runtime{};
    std::unique_lock<std::mutex> lock;
};

struct Explicit_Input_Write_Handle final : Render_Input_Write_Handle {
    Explicit_Input_Write_Handle(Explicit_Renderable_Runtime_Data* runtime, std::unique_lock<std::mutex> lock, bool notify_render)
        : runtime(runtime), lock(std::move(lock)), notify_render(notify_render) {}
    ~Explicit_Input_Write_Handle() override {
        if (!runtime)
            return;
        runtime->input.version = ++runtime->input_version;
        runtime->input.pending = true;
        lock.unlock();
        if (notify_render && runtime->owner)
            runtime->owner->mark_render_dirty();
    }
    void set_completion(std::shared_ptr<Update_State> state) override {
        if (!runtime)
            return;
        if (runtime->input.completion_state && runtime->input.completion_state != state)
            runtime->input.completion_state->complete_all(std::make_error_code(std::errc::operation_canceled), Update_Outcome::Cancelled);
        runtime->input.completion_state = std::move(state);
    }
    Explicit_Renderable_Runtime_Data* runtime{};
    std::unique_lock<std::mutex> lock;
    bool notify_render{};
};

} // namespace

Explicit_Renderable_Runtime::Explicit_Renderable_Runtime(Renderable& owner)
    : d(std::make_unique<Explicit_Renderable_Runtime_Data>()) {
    d->owner = &owner;
    d->initialize(owner);
}

Explicit_Renderable_Runtime::~Explicit_Renderable_Runtime() {
    d->clear();
}

void Explicit_Renderable_Runtime::set_render_state_copier(Copy_Render_State_Function) {}

void Explicit_Renderable_Runtime::cancel_pending_completions() {
    d->cancel_pending_completions();
}

void Explicit_Renderable_Runtime::drain_committed_update_states(std::pmr::vector<std::shared_ptr<Update_State>>& output) {
    for (auto& state : d->committed_update_states)
        output.push_back(std::move(state));
    d->committed_update_states.clear();
}

Render_State_Read_Guard Explicit_Renderable_Runtime::acquire_state_read(Renderable_State_Role) {
    return acquire_render_state_read();
}

Render_State_Read_Guard Explicit_Renderable_Runtime::acquire_render_state_read() {
    std::unique_lock<std::mutex> lock(d->state_mutex);
    if (!d->state)
        return {};
    return Render_State_Read_Guard(d->state, std::make_unique<Explicit_State_Read_Handle>(std::move(lock)));
}

Render_State_Read_Guard Explicit_Renderable_Runtime::acquire_edit_state_read() {
    return acquire_render_state_read();
}

Render_State_Write_Guard Explicit_Renderable_Runtime::acquire_edit_state() {
    std::unique_lock<std::mutex> lock(d->state_mutex);
    if (!d->state)
        return {};
    return Render_State_Write_Guard(d->state, std::make_unique<Explicit_State_Write_Handle>(d.get(), std::move(lock)));
}

Render_Input_Write_Guard Explicit_Renderable_Runtime::acquire_edit_input(bool notify_render) {
    std::unique_lock<std::mutex> lock(d->input_mutex);
    if (!d->input.data)
        return {};
    return Render_Input_Write_Guard(d->input.data, std::make_unique<Explicit_Input_Write_Handle>(d.get(), std::move(lock), notify_render));
}

Render_Input_Frame_Guard Explicit_Renderable_Runtime::acquire_input_read(Renderable_Input_Role) {
    std::unique_lock<std::mutex> lock(d->input_mutex, std::try_to_lock);
    if (!lock || !d->input.data)
        return {};
    return Render_Input_Frame_Guard(d->input.data, std::make_unique<Explicit_Input_Frame_Handle>(d.get(), std::move(lock)));
}

Renderable_Frame_View Explicit_Renderable_Runtime::capture_frame_view() {
    std::unique_lock<std::mutex> state_lock(d->state_mutex);
    if (!d->state)
        return {};
    auto state_guard = Render_State_Read_Guard(
        d->state,
        std::make_unique<Explicit_State_Read_Handle>(std::move(state_lock)));

    Render_Input_Frame_Guard input_guard;
    std::unique_lock<std::mutex> input_lock(d->input_mutex);
    if (d->input.data) {
        input_guard = Render_Input_Frame_Guard(
            d->input.data,
            std::make_unique<Explicit_Input_Frame_Handle>(d.get(), std::move(input_lock)));
    }
    return Renderable_Frame_View(std::move(state_guard), std::move(input_guard));
}

Render_State* Explicit_Renderable_Runtime::state(Renderable_State_Role) {
    return d->state;
}

Input_Data* Explicit_Renderable_Runtime::input_data(Renderable_Input_Role) {
    return d->input.data;
}

void Explicit_Renderable_Runtime::clear_render_input() {
    std::lock_guard<std::mutex> lock(d->input_mutex);
    if (d->input.completion_state) {
        d->input.completion_state->complete_until(Update_Stage::Committed);
        d->committed_update_states.push_back(std::move(d->input.completion_state));
    }
    if (d->input.data)
        d->input.data->clear();
    d->input.pending = false;
}

std::unique_ptr<Renderable_Runtime> make_explicit_renderable_runtime(Renderable& owner) {
    return std::make_unique<Explicit_Renderable_Runtime>(owner);
}

} // namespace renderive