#include <LiquidCrystal.h>
#include <Wire.h>
#include "SparkFunHTU21D.h"
 
#define TRIGGER_PIN 5
#define ECHO_PIN 6
 
HTU21D myHumidity;
 
int pinA = 2; // Rotary encoder CLK
int pinB = 3; // Rotary encoder DT
int pinC = 4; // Rotary encoder button
float encoderPosCount = 76.0;
int pinALast;
bool buttonPressed = false;
int mode = -1; // 0 for frequency, 1 for temperature/humidity, 2 for RTC, 3 for IR Receiver, 4 for Distance Sensor
LiquidCrystal lcd(12,11,10,9,8,7);
 
// Initial functions
void initialiseSystem() {
  Serial.begin(9600);
  lcd.begin(16, 2);
  pinMode(pinA, INPUT);
  pinMode(pinB, INPUT);
  pinMode(pinC, INPUT_PULLUP);
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);    
  pinALast = digitalRead(pinA);
  myHumidity.begin();
  lcd.print("System Initialising");
  delay(1000);
  lcd.clear();
  Serial.println("System Initialising");
}
 
void setup() {
  initialiseSystem();
}
 
void loop() {
  static unsigned long lastButtonPressTime = 0;
  static unsigned long lastUpdateTime = 0;
  if (millis() - lastButtonPressTime > 200) {
    if (digitalRead(pinC) == LOW) {
      handleRotaryPress();
      lastButtonPressTime = millis();
    } else {
      buttonPressed = false;
    }
  }
  handleRotaryRotate();
}
 
//Print functions for conciseness
void printLCD(String line1, String line2 = "") {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(line1);
  lcd.setCursor(0, 1);
  lcd.print(line2);
}
 
void printSerial(String line1, String line2 = "") {
  Serial.print(line1);
  Serial.println(line2);
}
 
// Placeholder functions for additional modules
void RTC() {
  // Implement RTC functionality to show time/date, and set an alarm.
  printLCD("RTC Mode");
  delay(400);
  lcd.clear();
}
 
void IRReceiver() {
  // Implement IR receiver functionality to represent each button as a function.
  printLCD("IR Mode");
  delay(400);
  lcd.clear();
}
 
float measureDistance() {
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);
  long duration = pulseIn(ECHO_PIN, HIGH);
  return (duration * 0.034) / 2; // Speed of sound wave divided by 2 (go and return)
}
 
float calculateVolumeFromDistance(float distance) {
  float volume;
  if (distance > 0 && distance < 30) {
    volume = map(distance, 5, 30, 0, 100);
  } else {
    volume = 100;
  }
  return volume;
}
 
void DistanceSensor() {
  // Implement distance sensor functionality to show distance and gesture control to turn the radio on/off.
  printLCD("Distance Mode");
  delay(400);
  lcd.clear();
  float distance = measureDistance();
  float volume = calculateVolumeFromDistance(distance);
  // Display volume if in the correct mode
  printLCD("Distance: " + String(distance), "Volume: " + String(volume));
}
 
void FMModule(int frequency) {
  // Implement FM module functionality here
  printSerial("Frequency: ", String(frequency, 1) + " MHz");
}
 
void updateTemperatureAndHumidity() {
  printLCD("Temp/Humd Mode");
  delay(400);
  lcd.clear();
  float humd = myHumidity.readHumidity();
  float temp = myHumidity.readTemperature();
 
  printLCD("Temp: " + String(temp, 1) + (char)223 + "C", "Humidity: " + String(humd, 1) + "%");
  printSerial("Temp: ", String(temp, 1) + "C");
  printSerial("Humidity: ", String(humd, 1) + "%");
}
 
void handleRotaryPress() {
  // Function to handle rotary encoder button press
  buttonPressed = true;
 
  if (mode >= 4) {
    mode = 0; // Wrap around to 0 if it exceeds 3
  } else {
    mode++;
  }
 
  switch (mode) {
    case 0:
      updateTemperatureAndHumidity();
      break;
 
    case 1:
      RTC();
      break;
 
    case 2:
      IRReceiver();
      break;
 
    case 3:
      DistanceSensor();
      break;
 
    case 4:
      mode = -1;
      printLCD("Frequency:", String(encoderPosCount) + " MHz");
      break;
 
    default:
      break;
  }
 
  // Reset the buttonPressed flag after handling the press
  buttonPressed = false;
}
 
 
void handleRotaryRotate() {
  int aVal = digitalRead(pinA);
  if (aVal != pinALast) {
    if (digitalRead(pinB) != aVal) {
      encoderPosCount += 0.1;
      if (encoderPosCount > 108.0) {
        encoderPosCount = 76.0;
      }
    } else {
      encoderPosCount -= 0.1;
      if (encoderPosCount < 76.0) {
        encoderPosCount = 108.0;
      }
    }
 
    pinALast = aVal;
 
    // Update LCD and Serial output with the new frequency
    printLCD("Frequency:", String(encoderPosCount) + " MHz");
    printSerial("Frequency:", String(encoderPosCount) + " MHz");
    FMModule(encoderPosCount);
 
    mode = -1;
  }
}