#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x27, 20, 4);
/* Keypad setup */
const byte KEYPAD_ROWS = 4;
const byte KEYPAD_COLS = 4;
byte rowPins[KEYPAD_ROWS] = {5, 4, 3, 2};
byte colPins[KEYPAD_COLS] = {A3, A2, A1, A0};
char keys[KEYPAD_ROWS][KEYPAD_COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'.', '0', '#', 'D'}
};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, KEYPAD_ROWS, KEYPAD_COLS);

bool bolusMode = false;
float volume = 0.0;
float time = 0.0;

bool editMode = false;
char buffer[5];
int bufferIndex = 0;
char lastButton = ' ';
unsigned long blinks = 0;
unsigned long savedmillis = 0;
bool blinking = false;

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

  lcd.init();
  lcd.backlight();

  lcd.setCursor(8, 0);
  lcd.print("TEST");
}

void loop() {
  getKeys();
  if (editMode && millis() - blinks > 250) {
    lcd.setCursor(bufferIndex + 8, 2);
    lcd.blink();
    blinks = millis();
  }
  else if (!editMode) {
    if ( millis() - savedmillis == 2000)  {
      clearLCDLine(3);
    }
  }
}

void getKeys()  {
  char key = keypad.getKey();
  if (bufferIndex > 5) bufferIndex = 0;
  if (key != NO_KEY) {
    Serial.println(key);
    if (!editMode && key == 'A')
      MODES();
    if (key == 'B' || key == 'C') {
      lastButton = key;
      showValue(key);
    } else if (key == 'D' && (lastButton == 'B' || lastButton == 'C')) {
      enterEditMode(lastButton);
    } else if (key == '#') {
      saveAndExit();
    }
    else if (editMode && key == 'A') {
      bufferIndex--;
      lcd.setCursor(8 + bufferIndex, 2);
      lcd.print(' ');
    }
    else {
      if (editMode && (key >= '0' && key <= '9' || key == '.')) {
        buffer[bufferIndex++] = key;
        lcd.setCursor(8, 2);
        lcd.print(buffer);
        Serial.print("BUFFER: ");
        Serial.println(bufferIndex);
      }
    }
  }
}

void showValue(char key) {
  if (key == 'B') {
    buttonB();
  } else if (key == 'C') {
    buttonC();
  }
}

void enterEditMode(char key) {
  editMode = true;
  bufferIndex = 0;
  lcd.setCursor(8, 2);
}

void buttonB()  {
  clearLCDLine(1);
  clearLCDLine(2);
  clearLCDLine(3);
  if (bolusMode == false) {
    lcd.setCursor(0, 1);
    lcd.print("INFUSION MODE");
  }
  //  else if (bolusMode == true) {
  else  {
    lcd.setCursor(0, 1);
    lcd.print("BOLUS MODE");
  }
  lcd.setCursor(0, 2);
  lcd.print("VALUE:");
  lcd.setCursor(8, 2);
  lcd.print(formatFloat(volume));
}


void buttonC()  {
  clearLCDLine(1);
  clearLCDLine(2);
  clearLCDLine(3);
  if (bolusMode == false) {
    lcd.setCursor(0, 1);
    lcd.print("INFUSION MODE");
  }
  else {
    lcd.setCursor(0, 1);
    lcd.print("BOLUS MODE");
  }
  lcd.setCursor(0, 2);
  lcd.print("TIME:");
  lcd.setCursor(8, 2);
  lcd.print(formatFloat(time));
}

void saveAndExit() {
  if (editMode) {
    buffer[bufferIndex] = '\0';
    float newValue = atof(buffer);
    if (lastButton == 'B') {
      volume = newValue;
      showValue('B');
    } else if (lastButton == 'C') {
      time = newValue;
      showValue('C');
    }
    editMode = false;
    lcd.setCursor(5, 3);
    lcd.print("SAVED");
    lcd.noBlink();

    savedmillis = millis();

  }
}

String formatFloat(float value) {
  char temp[6];
  dtostrf(value, 5, 2, temp);
  return String(temp);
}

void MODES()  {
  //  Serial.println("key 1 is pressed");
  bolusMode = !bolusMode;
  clearLCDLine(1);
  clearLCDLine(2);
  clearLCDLine(3);


  if (bolusMode == true) {
    lcd.setCursor(0, 1);
    lcd.print("MODE : ");
    lcd.setCursor(7, 1);
    lcd.print("BOLUS");
  }
  else if (bolusMode == false)  {
    lcd.setCursor(0, 1);
    lcd.print("MODE : ");
    lcd.setCursor(7, 1);
    lcd.print("INFUSION");
  }
  lcd.setCursor(5, 3);
  lcd.print("test");
}

void clearLCDLine(int line)
{
  lcd.setCursor(0, line);
  for (int n = 0; n < 20; n++) // 20 indicates symbols in line. For 2x16 LCD write - 16
  {
    lcd.print(" ");
  }
}