#pragma once

#include <bitset>
#include <memory>
#include <optional>
#include <string>
#include <unordered_map>

#include <raylib.h>

#include "TextRenderer.hpp"

constexpr float DEFAULT_FONT_SIZE { 24 };

struct TextInputOptions {
	bool multiline { false };
	float font_size { DEFAULT_FONT_SIZE };
};

struct ImGui {
	ImGui(std::shared_ptr<TextRenderer> text_renderer);

	ImGui(ImGui const &) = delete;
	auto operator=(ImGui const &) -> ImGui & = delete;
	ImGui(ImGui &&) = default;
	auto operator=(ImGui &&) -> ImGui & = default;

	void begin(u32 const rune, bool ctrl, bool shift);
	void end();

	// Bit 0 -> Submitted
	// Bit 1 -> String changed
	auto text_input(std::size_t id, std::pmr::string &str, Rectangle rec,
	    TextInputOptions options = {}) -> std::bitset<2>;

	struct TextInputSurrounding {
		std::string text;
		int cursor { 0 };
		int anchor { 0 };
		std::size_t caret_byte { 0 };
	};

	struct TextInputCursor {
		Rectangle rect {};
		bool visible { true };
	};

	auto focused_text_input() const -> std::optional<std::size_t>;
	auto text_input_surrounding(
	    std::size_t id, std::pmr::string const &str) const
	    -> std::optional<TextInputSurrounding>;
	auto text_input_cursor(std::size_t id) const
	    -> std::optional<TextInputCursor>;
	void ime_commit_text(std::pmr::string &str, std::string_view text);
	void ime_delete_surrounding(
	    std::pmr::string &str, std::size_t before, std::size_t after);
	void ime_set_preedit(std::string text, int cursor_begin, int cursor_end);
	void ime_clear_preedit();

	void set_font(FontHandle font);

	[[nodiscard]] inline auto id(std::string_view const str) -> std::size_t
	{
		std::hash<std::string_view> hasher;
		return hasher(str);
	}

private:
	struct TextInputState {
		int current_rune_idx { 0 };
		Vector2 scroll_offset;   // y not used if multiline == false
		Vector2 cursor_position; // y not used if multiline == false
		bool caret_visible { true };
		double caret_timer { 0.0 };
		std::string preedit_text;
		int preedit_cursor_begin { 0 };
		int preedit_cursor_end { 0 };
		bool preedit_active { false };
		bool preedit_cursor_hidden { false };
		std::size_t caret_byte { 0 };
		Rectangle caret_rect {};
		bool external_change { false };
	};

	std::unordered_map<std::size_t, TextInputState> m_ti_states;
	std::size_t m_focused_id {};
	u32 m_rune {}; // 1234 <-> hjkl arrow keys
	bool m_ctrl {};
	bool m_shift {};

	std::optional<FontHandle> m_font {};
	std::shared_ptr<TextRenderer> m_text_renderer {};
};

struct ImGuiGuard {
	ImGuiGuard(std::shared_ptr<ImGui> imgui, u32 const rune, bool const ctrl,
	    bool const shift)
	    : m_imgui(imgui)
	{
		m_imgui->begin(rune, ctrl, shift);
	}
	~ImGuiGuard() { m_imgui->end(); }

private:
	std::shared_ptr<ImGui> m_imgui { nullptr };
};