#pragma once

#include "Renderer.h"
#include "TextureManager.h"
#include "Environment.h"
#include "external/nlohmann/json.hpp"
#include <string>
#include <vector>
#include <memory>
#include <functional>

namespace ZL {

	using json = nlohmann::json;

	struct UiRect {
		float x = 0;
		float y = 0;
		float w = 0;
		float h = 0;
		bool contains(float px, float py) const {
			return px >= x && px <= x + w && py >= y && py <= y + h;
		}
	};

	enum class ButtonState {
		Normal,
		Hover,
		Pressed
	};

	struct UiButton {
		std::string name;
		UiRect rect;
		std::shared_ptr<Texture> texNormal;
		std::shared_ptr<Texture> texHover;
		std::shared_ptr<Texture> texPressed;
		ButtonState state = ButtonState::Normal;

		VertexRenderStruct mesh;

		std::function<void(const std::string&)> onClick;

		void buildMesh();
		void draw(Renderer& renderer) const;
	};

	struct UiNode {
		std::string type;
		UiRect rect;
		std::string name;
		std::vector<std::shared_ptr<UiNode>> children;
		std::shared_ptr<UiButton> button;
		std::string orientation = "vertical";
		float spacing = 0.0f;
	};

	class UiManager {
	public:
		UiManager() = default;

		void loadFromFile(const std::string& path, Renderer& renderer, const std::string& zipFile = "");

		void draw(Renderer& renderer);

		void onMouseMove(int x, int y);
		void onMouseDown(int x, int y);
		void onMouseUp(int x, int y);

		std::shared_ptr<UiButton> findButton(const std::string& name);

		bool setButtonCallback(const std::string& name, std::function<void(const std::string&)> cb);

		bool pushMenuFromFile(const std::string& path, Renderer& renderer, const std::string& zipFile = "");
		bool popMenu();
		void clearMenuStack();

	private:
		std::shared_ptr<UiNode> parseNode(const json& j, Renderer& renderer, const std::string& zipFile);
		void layoutNode(const std::shared_ptr<UiNode>& node);
		void collectButtons(const std::shared_ptr<UiNode>& node);

		std::shared_ptr<UiNode> root;
		std::vector<std::shared_ptr<UiButton>> buttons;

		std::shared_ptr<UiButton> pressedButton;

		struct MenuState {
			std::shared_ptr<UiNode> root;
			std::vector<std::shared_ptr<UiButton>> buttons;
			std::shared_ptr<UiButton> pressedButton;
			std::string path;
		};

		std::vector<MenuState> menuStack;
	};

} // namespace ZL