#include <Arduino.h>

const int USER_STEPS = 2;
const int STAFF_STEPS = 16;

int maxVolume = 64;
int userVolume = 64;
int potPosition = 64;
int oldUserVolume = userVolume;

void volumeUp();
void volumeDown();

void setup()
{
  pinMode(11, OUTPUT);          // Green
  pinMode(12, OUTPUT);          // Red LED (D4)
  pinMode(LED_BUILTIN, OUTPUT); // Green LED

  pinMode(2, INPUT); // SW1
  pinMode(4, INPUT); // SW2

  // RF Receiver
  pinMode(A0, INPUT); // Remote Button D
  pinMode(A1, INPUT); // Remote Button C
  pinMode(A2, INPUT); // Remote Button B
  pinMode(A3, INPUT); // Remote Button A

  pinMode(10, OUTPUT); // D10 - CS
  pinMode(9, OUTPUT);  // D9 - U/D
  digitalWrite(10, HIGH);
  digitalWrite(9, LOW);

  for (int i = 0; i < 64; i++)
  {
    volumeUp();
  }
}

void loop()
{
  switch (maxVolume)
  {
  case 64:
    digitalWrite(11, HIGH);
    digitalWrite(12, LOW);
    digitalWrite(LED_BUILTIN, LOW);
    break;
  case 48:
    digitalWrite(11, LOW);
    digitalWrite(12, HIGH);
    digitalWrite(LED_BUILTIN, LOW);
    break;
  case 32:
    digitalWrite(11, LOW);
    digitalWrite(12, LOW);
    digitalWrite(LED_BUILTIN, HIGH);
    break;
  case 16:
    digitalWrite(11, HIGH);
    digitalWrite(12, HIGH);
    digitalWrite(LED_BUILTIN, HIGH);
    break;
  }

  // SW1 - Staff Volume Up
  if (!digitalRead(2))
  {
    if (maxVolume < 100)
    {
      maxVolume += STAFF_STEPS;
      delay(300);
    }
  }

  // SW2 - Staff Volume Down
  if (!digitalRead(4))
  {
    if (maxVolume > STAFF_STEPS)
    {
      maxVolume -= STAFF_STEPS;

      if (userVolume > maxVolume)
      {
        for (int i = 0; i < (userVolume - maxVolume); i++)
        {
          volumeDown();
          potPosition--;
        }

        userVolume = maxVolume;
        oldUserVolume = userVolume;
      }
      delay(300);
    }
  }

  // Remote D - Mute
  if (digitalRead(A0))
  {

    // Check if we are in a muted state
    if (oldUserVolume > userVolume)
    {
      if (oldUserVolume > maxVolume)
      {
        userVolume = maxVolume;
      }
      else
      {
        userVolume = oldUserVolume;
      }
    }
    else
    {
      oldUserVolume = userVolume;
      userVolume = 0;
    }

    delay(300);
  }

  // Remote A - Significantly Lower Volume
  if (digitalRead(A3))
  {
    if (oldUserVolume > userVolume)
    {
      if (oldUserVolume > maxVolume)
      {
        userVolume = maxVolume;
      }
      else
      {
        userVolume = oldUserVolume;
      }
    }
    else
    {
      oldUserVolume = userVolume;
      userVolume = 15;
    }

    delay(300);
  }

  // Remote B - Volume Up
  if (digitalRead(A2) && !(oldUserVolume > userVolume))
  {
    if ((userVolume + USER_STEPS) > maxVolume)
    {
      userVolume = maxVolume;
      oldUserVolume = userVolume;
    }
    else
    {
      userVolume += USER_STEPS;
      oldUserVolume = userVolume;
    }

    delay(300);
  }

  // Remote C - Volume Down
  if (digitalRead(A1) && !(oldUserVolume > userVolume))
  {
    if ((userVolume - USER_STEPS) < 0)
    {
      userVolume = 0;
      oldUserVolume = userVolume;
    }
    else
    {
      userVolume -= USER_STEPS;
      oldUserVolume = userVolume;
    }

    delay(300);
  }
}

void volumeUp()
{
  digitalWrite(9, HIGH);
  delay(1);
  digitalWrite(10, LOW);
  delay(1);
  digitalWrite(9, LOW);
  delay(1);
  digitalWrite(9, HIGH);
  delay(1);
  digitalWrite(10, HIGH);
  delay(1);
  digitalWrite(9, LOW);
  digitalWrite(10, HIGH);
}

void volumeDown()
{
  digitalWrite(9, LOW);
  delay(1);
  digitalWrite(10, LOW);
  delay(1);
  digitalWrite(9, HIGH);
  delay(1);
  digitalWrite(9, LOW);
  delay(1);
  digitalWrite(10, HIGH);
}