//
// HierarchyPanel.cpp：实体列表实现。
//

#include "HierarchyPanel.h"
#include "Engine/ECS/Components.h"
#include "Engine/ECS/EntityHandle.h"   // CreateEntity 返回完整 EntityHandle

#include <imgui.h>

using namespace Engine;

namespace {
    struct ScopedID {
        explicit ScopedID(const u64 uuid) {
                ImGui::PushID(reinterpret_cast<const void*>(uuid));
        }
        ~ScopedID() {ImGui::PopID(); }
    };
}

void HierarchyPanel::Draw(const EditorContext& ctx, entt::entity& selected)
{
    ImGui::Begin("Hierarchy");

    // 工具栏：创建实体（在遍历之前，不修改遍历中的注册表结构）
    if (ImGui::Button("+ Create Entity"))
    {
        const auto e = ctx.scene->CreateEntity("Entity");
        selected = e;
    }
    ImGui::Separator();

    auto& reg = ctx.scene->GetRegistry();

    reg.view<Engine::ECS::NameComponent>().each(
        [&](const entt::entity e, const Engine::ECS::NameComponent& name)
        {
            const bool isSelected = (selected == e);

            u64 rowId = static_cast < uint64_t >( static_cast < uint32_t >(e));
            if (const auto * id = reg.try_get<Engine::ECS::IdComponent>(e)) {
                rowId = id->uuid.Value();
            }
            const ScopedID scope (rowId);

            const std::string label = name.name.empty() ? "(unnamed)" : name.name;
            if (ImGui::Selectable(label.c_str(), isSelected))
            {
                selected = e;
            }

            // 右键菜单：删除（延迟销毁，帧尾统一 flush）
            if (ImGui::BeginPopupContextItem("entity_ctx"))
            {
                if (ImGui::MenuItem("Delete"))
                {
                    ctx.scene->DestroyEntity(e);
                    if (selected == e)
                    {
                        selected = entt::null;
                    }
                }
                ImGui::EndPopup();
            }

            // 组件徽标 + 悬停清单
            std::string badge;
            if (reg.all_of<Engine::ECS::MeshRendererComponent>(e)) badge += "[M]";
            if (reg.all_of<Engine::ECS::AnimationComponent>(e))    badge += "[A]";
            if (reg.all_of<Engine::ECS::CameraComponent>(e))       badge += "[C]";
            if (reg.all_of<Engine::ECS::LightComponent>(e))        badge += "[L]";
            if (!badge.empty())
            {
                ImGui::SameLine();
                ImGui::TextDisabled("%s", badge.c_str());
                if (ImGui::IsItemHovered())
                {
                    ImGui::SetTooltip(
                        "M=Mesh  A=Animation  C=Camera  L=Light");
                }
            }
        });

    ImGui::End();
}