#define _CRT_SECURE_NO_WARNINGS

#include <Arduino.h>
#include <LiquidCrystal_I2C.h>

typedef void (func_t)();

namespace LcdUi {
    enum class EleType : uint8_t {
	NONE,
	OPT,
	TEXT
    };

    template <uint8_t COL, uint8_t ROW>
    class LcdUi_I2C : public LiquidCrystal_I2C {
	public:
	    LcdUi_I2C(uint8_t addr) :
		LiquidCrystal_I2C(addr, COL, ROW)
	    {
		for (uint8_t i = 0; i < ROW; i++) {
		    memset(this->ele[i], 0, ROW);
		}
		memset(this->ele_type, 0, sizeof(EleType) * ROW);
	    }

	    ~LcdUi_I2C() = default;

	private:
	    char ele[ROW][COL];
	    EleType ele_type[ROW];
	    // which OPT element type is being select
	    uint8_t sel_opt;
	    func_t *opt_comm[ROW];
	    
	public:
	    uint8_t set_ele(const char* opt, uint8_t ind, EleType type) {
		if (strlen(opt) >= COL || ind >= ROW) return 1;
		strncpy(ele[ind], opt, COL - 1);  
		ele_type[ind] = type;
		return 0;
	    }
	    
	    void set_opt_comm(func_t command, uint8_t ind) {
		opt_comm[ind] = command;	
	    }

	    void update_ui() {
		// set sel_opt to the first OPT element type
		for (uint8_t i = 0; i < ROW; i++) {
		    if (ele_type[i] == EleType::OPT) {
			sel_opt = i;
			break;
		    }
		}
	    }

	    void show_ele() {
		// a string buffer use to indicate opt 
		// that is being select
		char sel_opt_str[COL + 1];

		for (int8_t i = 0; i < ROW; i++) {
		    setCursor(0, i);
		    if (i == sel_opt) {
			sprintf(sel_opt_str, ">%s", ele[i]);
			print(sel_opt_str);
		    } else {
			print(ele[i]);
		    }
		}
	    }

	    void move_up_opt() {
		// move up to the closest OPT element type and 
		// skip other types
		for (int8_t i = sel_opt; i >= 0; i--) {
		    if (ele_type[i] == EleType::OPT) {
			sel_opt = i;
		    }
		}
	    }

	    void move_down_opt() {
		// move down to the closest OPT element type and
		// skip other types
		for (uint8_t i = sel_opt; i < ROW; i++) {
		    if (ele_type[i] == EleType::OPT) {
			sel_opt = i;
		    }
		}
	    }
       
	    void select_ui_opt() {
		opt_comm[sel_opt]();     
	    } 
    };

}


LcdUi::LcdUi_I2C<20, 4> lcd_ui(0x27);

void command_test() {
    Serial.println("Hello");
}

void setup() {
    Serial.begin(9600);
    lcd_ui.init();
    lcd_ui.clear();         
    lcd_ui.backlight();
    lcd_ui.set_ele("Text", 0, LcdUi::EleType::TEXT);
    lcd_ui.set_ele("First", 1, LcdUi::EleType::OPT);
    lcd_ui.set_opt_comm(command_test, 1);
    lcd_ui.set_ele("Second", 2, LcdUi::EleType::OPT);
    lcd_ui.update_ui();
    lcd_ui.show_ele();
}

void loop() {
    delay(1000);
    lcd_ui.select_ui_opt();
    delay(1000);
    lcd_ui.move_down_opt();
    lcd_ui.show_ele();
    delay(1000);
    lcd_ui.move_up_opt();
    lcd_ui.show_ele();
}