#include <Arduino.h>
#include <U8g2lib.h>

//U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); 
U8G2_SH1106_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

const int CLK = 2;
const int SW = 3;
const int DT = 4;

const int minus_0p5dB = 5;
const int minus_1dB = 6;
const int minus_2dB = 7;
const int minus_4dB = 8;
const int minus_8dB = 9;
const int minus_16dB = 10;
const int minus_32dB = 11;
const int enable_output = 12;


float dB_number = 63.50;

byte volume_switched = 0;
volatile byte volume = 0;
volatile byte volume_saved = 0;
volatile byte muted = 1;

void setup()
{
  pinMode(SW, INPUT_PULLUP);
  pinMode(CLK, INPUT);
  pinMode(DT, INPUT);
  pinMode(minus_32dB, OUTPUT);
  digitalWrite(minus_32dB, HIGH);
  pinMode(minus_16dB, OUTPUT);
  digitalWrite(minus_16dB, HIGH);
  pinMode(minus_8dB, OUTPUT);
  digitalWrite(minus_8dB, HIGH);
  pinMode(minus_4dB, OUTPUT);
  digitalWrite(minus_4dB, HIGH);
  pinMode(minus_2dB, OUTPUT);
  digitalWrite(minus_2dB, HIGH);
  pinMode(minus_1dB, OUTPUT);
  digitalWrite(minus_1dB, HIGH);
  pinMode(minus_0p5dB, OUTPUT);
  digitalWrite(minus_0p5dB, HIGH);
  pinMode(enable_output, OUTPUT);
  delay(5000);
  digitalWrite(enable_output, LOW);
  attachInterrupt(digitalPinToInterrupt(SW), Mute, FALLING);
  attachInterrupt(digitalPinToInterrupt(CLK), Encoder, RISING);
  Serial.begin(9600);
  u8g2.begin();
  u8g2.setFont(u8g2_font_lubB18_tf); //設定字型
}

void loop()
{  
  dB_number = 63.50 - 0.5 * volume;

  if (muted == 1) {
    u8g2.firstPage();
      do {
        u8g2.drawStr(24, 42, "MUTE");
      } while ( u8g2.nextPage() );
      delay(500);
  }
  else{
    u8g2.firstPage();
      do {
        u8g2.drawStr(0, 42, "-");
        if (volume >= 108) {
          u8g2.setCursor(31, 40);
        }
        else{
          u8g2.setCursor(15, 40);
        }
        u8g2.print(dB_number);
        u8g2.drawStr(94, 40, "dB");
      } while ( u8g2.nextPage() );
      delay(500);
  }
 
  if (volume != volume_switched && muted == 0) RelaySwitching(volume);
  else if (muted == 0) digitalWrite(enable_output, HIGH);
  else digitalWrite(enable_output, LOW);

  Serial.println(volume);
  delay(500);
}

void Mute() 
{
  if (muted == 0) {
    muted = 1;
  }
  else {
    muted = 0;
  }
}

void Encoder() 
{
  if (muted == 1) {
    muted = 0;
  }
  if (volume == 127) {
    volume += (digitalRead(CLK) != digitalRead(DT) ? 0 : -1);
  }
  else if (volume == 0) {
    volume += (digitalRead(CLK) != digitalRead(DT) ? 1 : 0);
  }
  else {
    volume += (digitalRead(CLK) != digitalRead(DT) ? 1 : -1);
  }
}

void RelaySwitching(byte remainder) {
  digitalWrite(enable_output, LOW);
  delay(200);

  volume_switched = remainder;
  byte remainder_tmp = remainder;

  remainder = remainder % 64;
  if (remainder != remainder_tmp) {
    digitalWrite(minus_32dB, LOW);
    remainder_tmp = remainder;
  }
  else {
    digitalWrite(minus_32dB, HIGH);
  }
  remainder = remainder % 32;
  if (remainder != remainder_tmp) {
    digitalWrite(minus_16dB, LOW);
    remainder_tmp = remainder;
  }
  else {
    digitalWrite(minus_16dB, HIGH);
  }
remainder = remainder % 16;
  if (remainder != remainder_tmp) {
    digitalWrite(minus_8dB, LOW);
    remainder_tmp = remainder;
  }
  else {
    digitalWrite(minus_8dB, HIGH);
  }
  remainder = remainder % 8;
  if (remainder != remainder_tmp) {
    digitalWrite(minus_4dB, LOW);
    remainder_tmp = remainder;
  }
  else {
    digitalWrite(minus_4dB, HIGH);
  }
  remainder = remainder % 4;
  if (remainder != remainder_tmp) {
    digitalWrite(minus_2dB, LOW);
    remainder_tmp = remainder;
  }
  else {
    digitalWrite(minus_2dB, HIGH);
  }
  remainder = remainder % 2;
  if (remainder != remainder_tmp) {
    digitalWrite(minus_1dB, LOW);
    remainder_tmp = remainder;
  }
  else {
    digitalWrite(minus_1dB, HIGH);
  }
  
  if (remainder != 0) {
    digitalWrite(minus_0p5dB, LOW);
    remainder_tmp = remainder;
  }
  else {
    digitalWrite(minus_0p5dB, HIGH);
  }

  delay(200);
  if (volume != 0) digitalWrite(enable_output, HIGH);
}