// Uses Monocrome OLEDs based on SSD1306 driver
// Uses Adafruit GX Grafics library
// Uses Adaruit SSD1306 library

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

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
// The pins for I2C are defined by the Wire-library. 
// On an arduino Nano:       A4(SDA), A5(SCL)
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x32, 0x3C for 128x64

#define MEM_DEVICE_ADDRESS 0x50 //If Adress pinnns tied to Vdd, 0x54 if tied to Vss.
// https://www.arduino.cc/reference/en/libraries/i2c_eeprom/


// declare an SSD1306 display object connected to I2C
Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

  int upButton = 10;
  int downButton = 11;
  int selectButton = 12;
  int menu = 1;

void setup() {
  Serial.begin(9600);

  // initialize OLED display with address 0x3C for 128x64
  if (!oled.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    while (true);
  }


  pinMode(upButton, INPUT_PULLUP);
  pinMode(downButton, INPUT_PULLUP);
  pinMode(selectButton, INPUT_PULLUP);

  updateMenu();

  delay(2000);         // wait for initializing

  oled.clearDisplay(); // clear display
  oled.setTextSize(2);          // text size
  oled.setTextColor(WHITE);     // text color
  oled.setCursor(0, 0);
  oled.println(">Read Mem");
  oled.setCursor(0, 16);
  oled.println(" Write Mem");
  oled.display();               // show on OLED
}

void loop() {
  if (!digitalRead(downButton)){
    menu++;
    updateMenu();
    delay(100);
    while (!digitalRead(downButton));
  }
  if (!digitalRead(upButton)){
    menu--;
    updateMenu();
    delay(100);
    while(!digitalRead(upButton));
  }
  if (!digitalRead(selectButton)){
    executeAction();
    updateMenu();
    delay(100);
    while (!digitalRead(selectButton));
  }
}

void eeprom_i2c_write(byte address, byte from_addr, byte data) {
  Wire.beginTransmission(address);
  Wire.send(from_addr);
  Wire.send(data);
  Wire.endTransmission();
}

byte eeprom_i2c_read(int MEM_DEVICE_ADDRESS, int from_addr) {
  Wire.beginTransmission(address);
  Wire.send(from_addr);
  Wire.endTransmission();

  Wire.requestFrom(address, 1);
  if(Wire.available())
    return Wire.receive();
  else
    return 0xFF;
}


void updateMenu() {
  switch (menu) {
    case 0:
      menu = 1;
      break;
    case 1:
      oled.clearDisplay();
      oled.setCursor(0, 0);
      oled.println(">Read Mem");
      oled.setCursor(0, 16);
      oled.println(" Write Mem");
      oled.display();               // show on OLED
      break;
    case 2:
      oled.clearDisplay();
      oled.setCursor(0, 0);
      oled.println(" Read Mem");
      oled.setCursor(0, 16);
      oled.println(">Write Mem");
      oled.display();               // show on OLED
      break;
    case 3:
      oled.clearDisplay();
      oled.setCursor(0, 0);
      oled.println(">MenuItem3");
      oled.setCursor(0, 16);
      oled.println(" MenuItem4");
      oled.display();               // show on OLED
      break;
    case 4:
      oled.clearDisplay();
      oled.setCursor(0, 0);
      oled.println(" MenuItem3");
      oled.setCursor(0, 16);
      oled.println(">MenuItem4");
      oled.display();               // show on OLED
      break;
    case 5:
      menu = 4;
      break;
  }
}

void executeAction() {
  switch (menu) {
    case 1:
      action1();
      break;
    case 2:
      action2();
      break;
    case 3:
      action3();
      break;
    case 4:
      action4();
      break;
  }
}

void action1() {
  int data = 0;
  data = eeprom_i2c_read(int address, int from_addr);
  oled.clearDisplay();
  oled.println(">Executing #1");
  oled.display();               // show on OLED
  delay(1500);
}
void action2() {
  oled.clearDisplay();
  oled.println(">Executing #2");
  oled.display();               // show on OLED
  delay(1500);
}
void action3() {
  oled.clearDisplay();
  oled.println(">Executing #3");
  oled.display();               // show on OLED
  delay(1500);
}
void action4() {
  oled.clearDisplay();
  oled.println(">Executing #4");
  oled.display();               // show on OLED
  delay(1500);
}