#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

const unsigned char epd_bitmap__icon_AND [] PROGMEM = {
	0x00, 0x00, 0x07, 0xc0, 0x18, 0x30, 0x20, 0x08, 0x40, 0x04, 0x41, 0x04, 0x82, 0x82, 0x84, 0x42, 
	0x88, 0x22, 0x8f, 0xe2, 0x88, 0x22, 0x48, 0x24, 0x40, 0x04, 0x20, 0x08, 0x18, 0x30, 0x07, 0xc0
};

const unsigned char epd_bitmap__icon_addition [] PROGMEM = {
	0x07, 0xe0, 0x18, 0x18, 0x20, 0x04, 0x50, 0x02, 0x41, 0x82, 0x81, 0x81, 0x81, 0x81, 0x8f, 0xf1, 
	0x8f, 0xf1, 0x81, 0x81, 0x81, 0x81, 0x41, 0x82, 0x40, 0x02, 0x20, 0x04, 0x18, 0x18, 0x07, 0xe0
};

const unsigned char epd_bitmap__item_sel_outline [] PROGMEM = {
  0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0, 
	0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 
	0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 
	0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe0, 
	0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0
};

const unsigned char epd_bitmap__icon_subtraction [] PROGMEM = {
0x0f, 0xe0, 0x30, 0x18, 0x40, 0x04, 0x40, 0x06, 0x80, 0x02, 0x80, 0x02, 0x9f, 0xfa, 0x9f, 0xfa, 
	0x9f, 0xfa, 0x80, 0x02, 0x80, 0x02, 0x40, 0x04, 0x40, 0x04, 0x30, 0x18, 0x0f, 0xe0
};

const unsigned char epd_bitmap__scrollbar_background [] PROGMEM = {
	0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 
	0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 
	0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 
	0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x02, 0x00, 0x00
};

const unsigned char epd_bitmap_icon_a_invert_ [] PROGMEM = {
	0x00, 0x00, 0x00, 0x00, 0x03, 0xc0, 0x0c, 0x30, 0x10, 0x08, 0x17, 0xe8, 0x20, 0x04, 0x21, 0x04, 
	0x22, 0x84, 0x24, 0x44, 0x17, 0xc8, 0x14, 0x48, 0x0c, 0x30, 0x03, 0xc0, 0x00, 0x00, 0x00, 0x00
};

const unsigned char epd_bitmap_icon_a_inc [] PROGMEM = {
	0x00, 0x00, 0x00, 0x00, 0x03, 0xc0, 0x0c, 0x30, 0x10, 0x48, 0x10, 0xe8, 0x20, 0x44, 0x21, 0x04, 
	0x22, 0x84, 0x24, 0x44, 0x17, 0xc8, 0x14, 0x48, 0x0c, 0x30, 0x03, 0xc0, 0x00, 0x00, 0x00, 0x00
};

const unsigned char epd_bitmap_icon_a_dec [] PROGMEM = {
	0x00, 0x00, 0x00, 0x00, 0x03, 0xc0, 0x0c, 0x30, 0x10, 0x08, 0x10, 0xe8, 0x20, 0x04, 0x21, 0x04, 
	0x22, 0x84, 0x24, 0x44, 0x17, 0xc8, 0x14, 0x48, 0x0c, 0x30, 0x03, 0xc0, 0x00, 0x00, 0x00, 0x00
};

const unsigned char epd_bitmap_icon_or [] PROGMEM = {
	0x00, 0x00, 0x00, 0x00, 0x03, 0xc0, 0x0c, 0x30, 0x10, 0x08, 0x13, 0x88, 0x24, 0x44, 0x24, 0x44, 
	0x24, 0x44, 0x24, 0x44, 0x13, 0x88, 0x10, 0x08, 0x0c, 0x30, 0x03, 0xc0, 0x00, 0x00, 0x00, 0x00
};

const unsigned char epd_bitmap_icon_xor [] PROGMEM = {
	0x00, 0x00, 0x00, 0x00, 0x03, 0xc0, 0x0c, 0x30, 0x10, 0x08, 0x14, 0x28, 0x22, 0x44, 0x21, 0x84, 
	0x21, 0x84, 0x22, 0x44, 0x14, 0x28, 0x10, 0x08, 0x0c, 0x30, 0x03, 0xc0, 0x00, 0x00, 0x00, 0x00
};

const int epd_bitmap_allArray_LEN = 8;
const unsigned char* epd_bitmap_allArray[8] = {
	epd_bitmap__icon_AND,
	epd_bitmap__icon_addition,
	epd_bitmap__icon_subtraction,
  epd_bitmap_icon_a_invert_,
	epd_bitmap_icon_a_inc,
	epd_bitmap_icon_a_dec,
	epd_bitmap_icon_or,
	epd_bitmap_icon_xor
};

const int NUM_ITEMS = 8;

char menu_items[NUM_ITEMS] [20] = {
  {"AND"},
	{"Addition"},
	{"Subtraction"},
  {"Invert A"},
  {"Increment A"},
  {"Decrement A"},
  {"OR"},
  {"XOR"}
};


const unsigned int control_signals[NUM_ITEMS] = {
  7,
  0,
  3,
  31,
  2,
  3,
  12,
  23
};

#define outputA 15
#define outputB 2
#define select_sw 4

#define clk 16
#define dt 17
#define sw 5

int item_selected = 0;
int item_sel_previous;
int item_sel_next;

int current_screen = 0;
int button_select_clicked = 0;
int value_select_clicked = 0;

volatile int lastEncoded = 0;
volatile long encoderValue = 0;
volatile long data_a = 0,data_b = 0;
const int debounceDelay = 10;

#define DATA_PIN  25 
#define LATCH_PIN 26  
#define CLOCK_PIN 27 
#define DATAB_PIN 13

#define CD_PIN 12
#define CLATCH_PIN 14
#define CCLOCK_PIN 0

void setup() {
  Serial.begin(115200);
  pinMode(outputA, INPUT_PULLUP);
  pinMode(outputB, INPUT_PULLUP);
  pinMode(select_sw, INPUT_PULLUP);
  pinMode(DATA_PIN, OUTPUT);
  pinMode(CLOCK_PIN, OUTPUT);
  pinMode(LATCH_PIN, OUTPUT);
  pinMode(clk, INPUT_PULLUP);
  pinMode(dt, INPUT_PULLUP);
  pinMode(sw, INPUT_PULLUP);
  pinMode(CD_PIN, OUTPUT);
  pinMode(CLATCH_PIN, OUTPUT);
  pinMode(CCLOCK_PIN, OUTPUT);
  pinMode(DATAB_PIN, OUTPUT);

  attachInterrupt(digitalPinToInterrupt(outputA), updateEncoder, CHANGE);
  attachInterrupt(digitalPinToInterrupt(outputB), updateEncoder, CHANGE);
  attachInterrupt(digitalPinToInterrupt(select_sw), select_ISR, CHANGE);
  attachInterrupt(digitalPinToInterrupt(clk), encoder_ISR, CHANGE);
  attachInterrupt(digitalPinToInterrupt(dt), encoder_ISR, CHANGE);
  attachInterrupt(digitalPinToInterrupt(sw), value_select_ISR, CHANGE);
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    for(;;);
  }
  delay(1000);
  display.clearDisplay();
  display.setCursor(45,30);
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.print("WELCOME");
  display.display();
  delay(500);
  display.clearDisplay();
  }
 
void loop() {
item_sel_previous = item_selected - 1;
if (item_sel_previous < 0) {item_sel_previous = NUM_ITEMS - 1;} // previous item would be below first = make it the last
item_sel_next = item_selected + 1;  
if (item_sel_next >= NUM_ITEMS) {item_sel_next = 0;}
if(current_screen == 0){
display.setTextSize(1);
display.setTextColor(WHITE);

display.setCursor(25,50);
display.print(menu_items[item_sel_previous]);
display.drawBitmap(4,46,epd_bitmap_allArray[item_sel_previous],16,16,1);

display.setCursor(25,10);
display.print(menu_items[item_selected]);   
display.drawBitmap(4,06,epd_bitmap_allArray[item_selected],16,16,1);

display.setCursor(25,30);
display.print(menu_items[item_sel_next]);
display.drawBitmap(4,26,epd_bitmap_allArray[item_sel_next],15,15,1);

display.drawBitmap(0,22,epd_bitmap__item_sel_outline,128,21,1);
display.drawBitmap(120,0,epd_bitmap__scrollbar_background,8,64,1);
display.display();
display.clearDisplay();
}
else if(current_screen == 1)
{
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.drawBitmap(100,8,epd_bitmap_allArray[item_selected+1],16,16,1);
  display.setCursor(30,20);
  display.print("Select A");
  display.setCursor(30,40);
  display.print(encoderValue);
  display.display();
}
else if(current_screen == 2){
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.drawBitmap(100,8,epd_bitmap_allArray[item_selected+1],16,16,1);
  display.setCursor(30,20);
  display.print("Select B");
  display.setCursor(30,40);
  display.print(encoderValue);
  display.display();
 }

else if(current_screen == 3){
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.drawBitmap(100,8,epd_bitmap_allArray[item_selected+1],16,16,1);
  display.setCursor(30,30);
  display.print("Result");
  display.display();
}
}

void updateEncoder()
{
  static unsigned long lastDebounceTime = 0;
  static int lastEncodedA = 0;
  static int lastEncodedB = 0;
  int MSB = digitalRead(outputA);
  int LSB = digitalRead(outputB);
  int encoded = (MSB << 1) | LSB;
   int sum = (lastEncodedA << 3) | (lastEncodedB << 2) | (encoded << 1) | (encoded);
    if((sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011) && current_screen == 0)
    {
      item_selected = item_selected-1;
      if(item_selected < 0){
      item_selected = NUM_ITEMS - 1;
    }
     }
    else if ((sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) && current_screen == 0) {
      item_selected = item_selected + 1;
      if(item_selected >= NUM_ITEMS){
        item_selected = 0;
      }
    }
     if (millis() - lastDebounceTime > debounceDelay) {
    lastDebounceTime = millis();
  }

  lastEncodedA = MSB;
  lastEncodedB = LSB;
  }


void select_ISR()
{
   if((digitalRead(select_sw)  == LOW) && (button_select_clicked == 0)){
      button_select_clicked = 1;
      if(current_screen == 0){current_screen = 1; writeControlSignal(control_signals[item_selected+1]);}
      else if(current_screen == 1){current_screen = 0;}
      else{current_screen = 0;}
    }
    if(digitalRead(select_sw) == HIGH && (button_select_clicked == 1)){
      button_select_clicked = 0;
    }
}

void encoder_ISR(){
  static unsigned long lastDebounceTime = 0;
  static int lastEncodedA = 0;
  static int lastEncodedB = 0;
  int MSB = digitalRead(clk);
  int LSB = digitalRead(dt);
  int encoded = (MSB << 1) | LSB;
   int sum = (lastEncodedA << 3) | (lastEncodedB << 2) | (encoded << 1) | (encoded);
    if(sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011)
    {
      encoderValue++;
     }
    else if (sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) {
      encoderValue--;
    }
     if (millis() - lastDebounceTime > debounceDelay) {
    lastDebounceTime = millis();
  }

  lastEncodedA = MSB;
  lastEncodedB = LSB;
  encoderValue = constrain(encoderValue, 0, 65535);
}

void value_select_ISR(){
  if((digitalRead(sw)  == LOW) && (value_select_clicked == 0)){
      value_select_clicked = 1;
      if(current_screen == 1){current_screen = 2; data_a = encoderValue; encoderValue = 0;}
      else if(current_screen == 2){current_screen = 3; data_b = encoderValue; writeRegisters(data_a,data_b);}
      else{current_screen = 0; encoderValue = 0;}
    }
    if(digitalRead(sw) == HIGH && (value_select_clicked == 1)){
      value_select_clicked = 0;
    }
}

void writeRegisters(int DATA_A,int DATA_B)
{
  digitalWrite(LATCH_PIN,LOW);
  shiftOut(DATA_PIN,CLOCK_PIN,MSBFIRST,DATA_A);
  digitalWrite(LATCH_PIN, HIGH);
  digitalWrite(LATCH_PIN, LOW);
}

void writeControlSignal(int data)
{
  digitalWrite(CLATCH_PIN,LOW);
  shiftOut(CD_PIN,CCLOCK_PIN,MSBFIRST,data);
  digitalWrite(CLATCH_PIN, HIGH);
  digitalWrite(CLATCH_PIN, LOW);
}