#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include "EEPROM.h"
// Size Address
#define EEPROM_SIZE 4096
 
// Display Resolution
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define SCREEN_ADDRESS 0x3c
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire);
 
// Define Switch
#define SW 5
 
// Define GPIO of POT and LED
#define potPin 34
#define LED 25
 
// Initial Value
int potValue = 0;
int lastTime1000ms = 0;
int Value_0x000, Value_0x3CA;
int Now_ADDR = 0;
 
void setup() {
  // Begin
  Serial.begin(115200);
  Wire.begin();
 
  // Set PIN MODE
  pinMode(LED, OUTPUT);
  pinMode(SW, INPUT_PULLUP);
 
  // Setup EEPROM
  if (!EEPROM.begin(EEPROM_SIZE)) {
    Serial.println("Failed init EEPROM");
    delay(1000);
    ESP.restart();
  }
  Serial.println("Success init EEPROM");
 
  // Setup Initial Value of ADDR: 0x000, 0x3CA
  EEPROM.writeUChar(0x000, 0);
  EEPROM.commit();
  EEPROM.writeUChar(0x3CA, potValue);
  EEPROM.commit();
 
  // Read Value From EEPROM
  Value_0x000 = EEPROM.readUChar(0x000);
  Value_0x3CA = EEPROM.readUChar(0x3CA);
  potValue = analogRead(potPin);
 
  // Setup Display
  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
  }
  display.display();
  display.clearDisplay();
  // Test Draw Char
  display.setTextSize(1.5);
  display.setTextColor(WHITE);
  display.setCursor(0, 0);
  display.printf("EEPROM    ADC : %d", potValue*255/4095);
  display.setCursor(0, 30);
  display.printf("Address : 0000(0x000)");
  display.setCursor(0, 45);
  display.printf("Data : %d", Value_0x000);
  display.display();
 
  // setup LED
  analogWrite(LED, Value_0x000);
 
}
void loop() {
  // Reading Value
  potValue = analogRead(potPin);
  Value_0x000 = EEPROM.readUChar(0x000);
  Value_0x3CA = EEPROM.readUChar(0x3CA);
 
  // Show Value every 1 sec
  if(millis() - lastTime1000ms >= 1000) {
    lastTime1000ms = millis();
    Serial.printf("POT : %d  CONV : %d \n", potValue, potValue*255/4095);
  }
 
  // Switch Display from SW Mode
  if(Now_ADDR == 0) {
    display.clearDisplay();
    // Test Draw Char
    display.setTextSize(1.5);
    display.setTextColor(WHITE);
    display.setCursor(0, 0);
    display.printf("EEPROM    ADC : %d", potValue*255/4095);
    display.setCursor(0, 30);
    display.printf("Address : 0000(0x000)");
    display.setCursor(0, 45);
    display.printf("Data : %d", Value_0x000);
    display.display();
  } else {
    display.clearDisplay();
    // Test Draw Char
    display.setTextSize(1.5);
    display.setTextColor(WHITE);
    display.setCursor(0, 0);
    display.printf("EEPROM    ADC : %d", potValue*255/4095);
    display.setCursor(0, 30);
    display.printf("Address : 0970(0x3CA)");
    display.setCursor(0, 45);
    display.printf("Data : %d", Value_0x3CA);
    display.display();
  }
 
  // Check SW State
  if (digitalRead(SW1) == LOW) {
    Serial.println("SW1 : DOWN");
    analogWrite(LED, Value_0x000);
    Now_ADDR = 0;
  } else if (digitalRead(SW2) == LOW) {
    Serial.println("SW2 : DOWN");
    analogWrite(LED, Value_0x3CA);
    Now_ADDR = 1;
  } else if (digitalRead(SW3) == LOW) {
    Serial.println("SW3 : DOWN");
    if(Now_ADDR == 0) {
      EEPROM.writeUChar(0x000, potValue*255/4095);
      EEPROM.commit();
      analogWrite(LED, potValue*255/4095);
    } else {
      EEPROM.writeUChar(0x3CA, potValue*255/4095);
      EEPROM.commit();
      analogWrite(LED, potValue*255/4095);
    }
  }