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

Adafruit_SSD1306 lcd(128, 64, &Wire, 4);

#define PIN_UP   digitalRead(6)
#define PIN_OK   digitalRead(3)
#define PIN_DOWN digitalRead(2)
#define PIN_BACK digitalRead(5)
#define PIN_MENU digitalRead(7)

float voltage, ampere;
uint32_t duration = 0, capacity = 0, energy = 0;
uint32_t lastmillis, nowmillis, interval, power, seconds;

int halaman  = 1;
int menuItem = 1;

#define TINGGI_LOGO   8
#define LEBAR_LOGO    16
static const unsigned char PROGMEM logo_bmp[] =
{ B11111111, B11111111,
  B11000000, B00000011,
  B11000000, B00000011,
  B11000000, B00000011,
  B11000000, B00000011,
  B11000000, B00000011,
  B11000000, B00000011,
  B11111111, B11111111
};

void setup() {
  Serial.begin(9600);
  lcd.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  lcd.clearDisplay();
  lcd.setTextColor(WHITE);
}

void loop() {
  callVoltage();
  callDisplay();
  callButton();
}

void callButton() {
  //  untuk button up
  if (!PIN_UP && halaman == 1) {
    menuItem --;
    if (menuItem < 1)menuItem = 4;
  }
  //untuk button down
  if (!PIN_DOWN && halaman == 1) {
    menuItem ++;
    if (menuItem > 4)menuItem = 1;
  }

  //  untuk button ok
  if (!PIN_OK) {
    if (halaman == 1 && menuItem == 1) {
      halaman = 2;
    } else if (halaman == 1 && menuItem == 2) {
      halaman = 3;
    } else if (halaman == 1 && menuItem == 3) {
      halaman = 4;
    } else if (halaman == 1 && menuItem == 4) {
      halaman = 5;
    }
  }

  //  untuk button back
  if (!PIN_BACK) {
    if (halaman == 2 || halaman == 3 || halaman == 4 || halaman == 5) {
      halaman = 1;
    }
  }
  //Serial.println(menuItem);
  //delay(100);
}

void callDisplay() {
  if (halaman == 1) {
    lcd.clearDisplay();
    lcd.setTextSize(1);

    if (menuItem == 1) {
      lcd.setCursor(5, 0);
      lcd.print("> menuItem 1");
    } else {
      lcd.setCursor(5, 0);
      lcd.print("  menuItem 1");
    }

    if (menuItem == 2) {
      lcd.setCursor(5, 8);
      lcd.print("> menuItem 2");
    } else {
      lcd.setCursor(5, 8);
      lcd.print("  menuItem 2");
    }

    if (menuItem == 3) {
      lcd.setCursor(5, 16);
      lcd.print("> menuItem 3");
    } else {
      lcd.setCursor(5, 16);
      lcd.print("  menuItem 3");
    }

    if (menuItem == 4) {
      lcd.setCursor(5, 24);
      lcd.print("> menuItem 4");
    } else {
      lcd.setCursor(5, 24);
      lcd.print("  menuItem 4");
    }

  } else if (halaman == 2) {
    lcd.clearDisplay();
    // lcd.setTextSize(2);
    // lcd.setCursor(5, 13);
    displayVolt();
  } else if (halaman == 3) {
    lcd.clearDisplay();
    lcd.setTextSize(2);
    lcd.setCursor(0, 0);
    //lcd.print("HALAMAN 2");
    testdrawbitmap();
  } else if (halaman == 4) {
    lcd.clearDisplay();
    displayVolt2();
  } else if (halaman == 5) {
    lcd.clearDisplay();
    lcd.setTextSize(2);
    lcd.setCursor(25, 25);
    lcd.print("HALAMAN 4");
  }

  lcd.display();
}

void callVoltage() {
  voltage = analogRead(A0) * (5.0 / 1023.0);
  ampere  = analogRead(A6) * (50.0 / 1023.0);

  // Calculate timings
  nowmillis   = millis();                   // read millis counter
  interval    = nowmillis - lastmillis;       // calculate recent time interval
  lastmillis  = nowmillis;                    // reset lastmillis
  duration   += interval;                     // calculate total duration in millis
  seconds     = duration / 1000;              // calculate total duration in seconds

  // Calculate power, capacity and energy
  power = (uint32_t)voltage * ampere;         // calculate power    in Watt
  capacity += interval * ampere / 3600;       // calculate capacity in uAh
  energy   += interval * power   / 3600;      // calculate energy   in uWh
}

void displayVolt() {
  lcd.setTextSize(1);
  lcd.setCursor(0, 0);
  lcd.print("V :" + String(voltage) + "V");
  lcd.setCursor(0, 8);
  lcd.print("A :" + String(ampere) + "A");
  lcd.setCursor(0, 16);
  lcd.print("P :" + String(power) + "W");
  lcd.setCursor(0, 24);
  lcd.print("E :" + String(energy) + "uWh");

}

void displayVolt2() {
  byte vol = voltage;
  lcd.setTextSize(2);
  lcd.setCursor(0, 0);
  if (vol < 10) {
  lcd.print("0" + String(voltage) + " V");
  }else{
  lcd.print(String(voltage) + " V");
  }
  lcd.setCursor(0, 16);
  lcd.print(String(voltage * 10) + " A");
  lcd.setTextSize(1);
  lcd.setCursor(85, 0);
  lcd.print(String(power) + "W");
  lcd.setCursor(85, 8);
  lcd.print(String(capacity) + "mAh");
  lcd.setCursor(85, 16);
  lcd.print(String(energy) + "uWh");
  lcd.setCursor(85, 24);
  lcd.print(String(seconds) + "S");
  Serial.println(vol);
}

void testdrawbitmap(void) {
  lcd.clearDisplay();

  lcd.drawBitmap(0, 0, logo_bmp, LEBAR_LOGO, TINGGI_LOGO, 1);
  lcd.display();
  delay(1000);
}