#include <LiquidCrystal_I2C.h>

#define ENCODER_CLK 6
#define ENCODER_DT  7
#define ENCODER_SW  8

bool start = false;
uint8_t numstops = 50;
uint16_t pause = 250;
uint8_t pulse = 200;

typedef enum {
  SET_START,
  SET_NUMSTOPS,
  SET_PAUSE,
  SET_PULSE,
} Mode;

Mode mode = SET_NUMSTOPS;

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
//  Serial.begin(115200);

  pinMode(ENCODER_CLK, INPUT);
  pinMode(ENCODER_DT, INPUT);
  pinMode(ENCODER_SW, INPUT_PULLUP);

  lcd.begin(20, 4);
  // ------- Quick 2 blinks of backlight  -------------
  for (int i = 0; i < 2; i++)
  {
    lcd.backlight();
    delay(250);
    lcd.noBacklight();
    delay(250);
  }
  lcd.backlight(); // finish with backlight on
  // Print a message to the LCD.
  lcd.setCursor(0, 1);
  lcd.print("START");
  lcd.setCursor(1, 1);
  lcd.print("N. Stops: ");
  lcd.setCursor(1, 2);
  lcd.print("Pause ms: ");
  lcd.setCursor(1, 3);
  lcd.print("Pulse ms: ");

  updateDisplay();
}

long int modeLastChanged = 0;
int prevClk = HIGH;
void loop() {
  if (digitalRead(ENCODER_SW) == LOW && millis() - modeLastChanged > 300) {
    modeLastChanged = millis();
    nextMode();
    updateDisplay();
  }

  int clk = digitalRead(ENCODER_CLK);
  if (clk != prevClk && clk == LOW) {
    int dt = digitalRead(ENCODER_DT);
    int increment = dt == HIGH ? 1 : -1;
    updateValue(increment);
    updateDisplay();
/*
    Serial.print("Start");
    Serial.print(start);
    Serial.print(" Nº Stops:");
    Serial.print(degrees);
    Serial.print(" Pause:");
    Serial.print(pause);
    Serial.print(" Pulse:");
    Serial.println(pulse);
*/
  }
  prevClk = clk;
}

void nextMode() {
  if (!start) {
   switch (mode) {
     case SET_NUMSTOPS:
       mode = SET_PAUSE;
       break;

     case SET_PAUSE:
       mode = SET_PULSE;
       break;

     case SET_PULSE:
       mode = SET_START;
       break;

     case SET_START:
       mode = SET_NUMSTOPS;
       break;
   }
  }
}

void updateValue(int increment) {
  switch (mode) {
    case SET_NUMSTOPS:
      numstops = constrain(numstops + 2*increment, 2, 100);
      break;

    case SET_PAUSE:
      pause = constrain(pause + 50*increment, 100, 1000);
      break;

    case SET_PULSE:
      pulse = constrain(pulse + 10*increment, 100, 250);
      break;

    case SET_START:
      start = constrain(start + increment, 0, 1);
      break;
  }
}


void updateDisplay() {
  lcd.setCursor(10, 1);
  lcd.print("   ");
  lcd.setCursor(10, 1);
  lcd.print(numstops);
  if (mode == SET_NUMSTOPS) {
    lcd.setCursor(0, 0);
    lcd.print(" ");
    lcd.setCursor(0, 1);
    lcd.print(">");
  }

  lcd.setCursor(10, 2);
  lcd.print("    ");
  lcd.setCursor(10, 2);
  lcd.print(pause);
  if (mode == SET_PAUSE) {
    lcd.setCursor(0, 1);
    lcd.print(" ");
    lcd.setCursor(0, 2);
    lcd.print(">");
  }

  lcd.setCursor(10, 3);
  lcd.print("   ");
  lcd.setCursor(10, 3);
  lcd.print(pulse);
  if (mode == SET_PULSE) {
    lcd.setCursor(0, 2);
    lcd.print(" ");
    lcd.setCursor(0, 3);
    lcd.print(">");
  }

  lcd.setCursor(1, 0);
  if (start){
    lcd.print("STOP ");
  }
  else{
    lcd.print("START");
  }
  if (mode == SET_START) {
    lcd.setCursor(0, 3);
    lcd.print(" ");
    lcd.setCursor(0, 0);
    lcd.print(">");
  }
}