#include <TinyWireM.h>
#include <Tiny4kOLED.h>

#define BUTPIN PB3
#define DATAPIN PB1

uint8_t width = 128;
uint8_t height = 32;
uint8_t menlen = 4;

bool but = false;

int cnt = 0;

uint16_t adc_value;

int8_t curmen = 0;

String option;

int8_t rpts = 50;

void updateDisplay() {
  // Clear whatever random data has been left in memory.
  oled.clear();
  oled.print(F("MENU:    "));
  if (but) oled.println(F("SENDING"));
  else oled.println(F("       "));
  oled.println(option);
}

void setup() {
  // put your setup code here, to run once:
  pinMode(BUTPIN, INPUT_PULLUP);
  pinMode(DATAPIN, OUTPUT);

  oled.begin(width, height, sizeof(tiny4koled_init_128x32br), tiny4koled_init_128x32br);
  
  oled.setFont(FONT8X16);
  // Setup the first half of memory.
  updateDisplay();
  // Switch the half of RAM that we are writing to, to be the half that is non currently displayed.
  oled.switchRenderFrame();
  // Setup the second half of memory.
  updateDisplay();
  // Switch back to being ready to render on the first frame while displaying the second frame.
  oled.switchFrame();
  // Turn on the display.
  oled.on();


  // ADC Left Shift Result
  ADMUX |= 1<<ADLAR;

  // ADC Voltage Referrence
  ADMUX |= 0<<REFS2|0<<REFS1|0<<REFS0;        // Vcc is used as Voltage Referrence

  // ADC Input Channel/s
  ADMUX |= 0<<MUX3|0<<MUX2|1<<MUX1|0<<MUX0;   // Use ADC1 on pin PB4 as ADC input

  // ADC clock prescaler
  ADCSRA |= 0<<ADPS2|1<<ADPS1|1<<ADPS0;       // Use a divide by 8 Prescaler.
                                              // Sysclock = 8MHz, ADCclk = 1MHz (max)

  ADCSRA |= 1<<ADEN;                          // Enable the ADC

}

void loop() {
  //delay(50);
  updateDisplay();

  oled.switchFrame();

  ADCSRA |= 1<<ADSC;                          // Start the ADC conversion                                            // a 0 on ADCSRA means conversion is complete
  adc_value = ADCL|(ADCH << 8);               // ADC value is left justified. Use operand precedence rules
                                              // left to right precedence, so ADCL is read first
  curmen = map(adc_value, 0, 65472, 0, menlen);

  switch (curmen)
  {
  case 0:
    option = "FIRST OPTION   ";

    break;

  case 1:
    option = "SECOND OPTION  ";

    break;

  case 2:
    option = "THIRD OPTION   ";

    break;

  case 3:
    option = "FOURTH OPTION  ";

    break;
  
  default:
    break;
  }

  if (digitalRead(BUTPIN) == LOW){
    
    if (!but){
      
     
      for (int i = 0; i < rpts; i++){
        digitalWrite(DATAPIN, HIGH);
        delay(curmen+1);
        digitalWrite(DATAPIN, LOW);
        delay(curmen+1);
        option = "SENT";
      }

      but = true;
      cnt = 0;
    }
  }

  if (but && cnt > 5){
    but = false;
  }
  cnt++;

  delay(50);

}