#include <SPI.h>
#include <Wire.h>
#include <RTClib.h>
#include <U8g2lib.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);
//U8G2            -> what library is being used
//SSD1306         -> which OLED is being used
//128X64          -> the resolution size of the OLED
//NONAME          -> suggests that it's a generic or unspecified variant OLED (just a normal OLED really)
//F_HW_I2C        -> indicates that it uses hardware I2C communication.

// U8G2_R0        -> this parameter specifies the rotation of the display. U8G2_R0 means no rotation. You can change this parameter based on how your display is physically oriented.
// U8X8_PIN_NONE  -> this part is specifying that the reset pin is set to U8X8_PIN_NONE, meaning that no reset pin is used. If your display has a reset pin and you want to use it, you can replace U8X8_PIN_NONE with the appropriate pin number.

RTC_DS1307 rtc; // the real time clock component variable name (rtc)

const int selectButtonPin = 8;
int lastSelectButtonPinState = LOW; // Variable to store the last state of the button
int currentSelectButtonPinState; // Variable to store the current state of the button

const int buttonPin = 7; // Define the pin for the button
int lastButtonPinState = HIGH; // Variable to store the last state of the button
int currentButtonPinState; // Variable to store the current state of the button

const int leftButtonPin = 6;
int lastLeftButtonPinState = LOW; // Variable to store the last state of the button
int currentLeftButtonPinState; // Variable to store the current state of the button

const int rightButtonPin = 5; 
int lastRightButtonPinState = LOW; // Variable to store the last state of the button
int currentRightButtonPinState; // Variable to store the current state of the button

static const unsigned char image_CoolHi_25x27_bits[] U8X8_PROGMEM = {0xf8,0xff,0x3f,0x00,0x04,0x00,0x40,0x00,0x02,0x00,0x80,0x00,0x01,0x10,0x00,0x01,0x01,0x92,0x00,0x01,0x81,0x54,0x02,0x01,0x81,0x38,0x02,0x01,0xe1,0x10,0x0e,0x01,0x01,0x11,0x01,0x01,0x11,0x92,0x10,0x01,0x21,0x54,0x08,0x01,0x41,0x38,0x04,0x01,0xf9,0xff,0x3f,0x01,0x41,0x38,0x04,0x01,0x21,0x54,0x08,0x01,0x11,0x92,0x10,0x01,0x01,0x11,0x01,0x01,0xe1,0x10,0x0e,0x01,0x81,0x38,0x02,0x01,0x81,0x54,0x02,0x01,0x01,0x92,0x00,0x01,0x01,0x10,0x00,0x01,0x01,0x00,0x00,0x01,0x03,0x00,0x80,0x01,0x06,0x00,0xc0,0x00,0xfc,0xff,0x7f,0x00,0xf8,0xff,0x3f,0x00};
static const unsigned char image_Dehumidify_25x27_bits[] U8X8_PROGMEM = {0xf8,0xff,0x3f,0x00,0x04,0x00,0x40,0x00,0x02,0x00,0x80,0x00,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x10,0x00,0x01,0x01,0x10,0x00,0x01,0x01,0x18,0x00,0x01,0x01,0x38,0x00,0x01,0x01,0x3c,0x00,0x01,0x01,0x7c,0x00,0x01,0x01,0xfe,0x00,0x01,0x01,0xfe,0x00,0x01,0x01,0xbf,0x01,0x01,0x01,0x7f,0x01,0x01,0x81,0x7f,0x03,0x01,0x81,0xff,0x03,0x01,0x01,0xff,0x01,0x01,0x01,0xff,0x01,0x01,0x01,0xfe,0x00,0x01,0x01,0x78,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x03,0x00,0x80,0x01,0x06,0x00,0xc0,0x00,0xfc,0xff,0x7f,0x00,0xf8,0xff,0x3f,0x00};
static const unsigned char image_HeatHi_25x27_bits[] U8X8_PROGMEM = {0xf8,0xff,0x3f,0x00,0x04,0x00,0x40,0x00,0x02,0x00,0x80,0x00,0x01,0x10,0x00,0x01,0x11,0x10,0x10,0x01,0x21,0x10,0x08,0x01,0x41,0x10,0x04,0x01,0x81,0x00,0x02,0x01,0x01,0x7c,0x00,0x01,0x01,0x82,0x00,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x79,0x01,0x3d,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x82,0x00,0x01,0x01,0x7c,0x00,0x01,0x81,0x00,0x02,0x01,0x41,0x10,0x04,0x01,0x21,0x10,0x08,0x01,0x11,0x10,0x10,0x01,0x01,0x10,0x00,0x01,0x01,0x00,0x00,0x01,0x03,0x00,0x80,0x01,0x06,0x00,0xc0,0x00,0xfc,0xff,0x7f,0x00,0xf8,0xff,0x3f,0x00};
static const unsigned char image_Mute_25x27_bits[] U8X8_PROGMEM = {0xf8,0xff,0x3f,0x00,0x04,0x00,0x40,0x00,0x02,0x00,0x80,0x00,0x01,0x00,0x00,0x01,0x01,0x00,0x03,0x01,0x21,0x80,0x14,0x01,0x41,0x40,0x0c,0x01,0x81,0x20,0x04,0x01,0x01,0x1f,0x06,0x01,0x81,0x02,0x05,0x01,0x81,0x84,0x04,0x01,0x81,0x48,0x04,0x01,0x81,0x30,0x04,0x01,0x81,0x30,0x04,0x01,0x81,0x48,0x04,0x01,0x81,0x84,0x04,0x01,0x81,0x02,0x05,0x01,0x01,0x1f,0x06,0x01,0x81,0x20,0x04,0x01,0x41,0x40,0x0c,0x01,0x21,0x80,0x14,0x01,0x01,0x00,0x03,0x01,0x01,0x00,0x00,0x01,0x03,0x00,0x80,0x01,0x06,0x00,0xc0,0x00,0xfc,0xff,0x7f,0x00,0xf8,0xff,0x3f,0x00};
static const unsigned char image_Power_25x27_bits[] U8X8_PROGMEM = {0xf8,0xff,0x3f,0x00,0x04,0x00,0x40,0x00,0x02,0x00,0x80,0x00,0x01,0x00,0x00,0x01,0x01,0x10,0x00,0x01,0x01,0x38,0x00,0x01,0x01,0x38,0x00,0x01,0x81,0x39,0x03,0x01,0xc1,0x39,0x07,0x01,0xe1,0x38,0x0e,0x01,0x61,0x38,0x0c,0x01,0x61,0x38,0x0c,0x01,0x61,0x10,0x0c,0x01,0x61,0x00,0x0c,0x01,0x61,0x00,0x0c,0x01,0x61,0x00,0x0c,0x01,0xe1,0x00,0x0e,0x01,0xc1,0x01,0x07,0x01,0x81,0x83,0x03,0x01,0x01,0xff,0x01,0x01,0x01,0x7c,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x03,0x00,0x80,0x01,0x06,0x00,0xc0,0x00,0xfc,0xff,0x7f,0x00,0xf8,0xff,0x3f,0x00};
static const unsigned char image_Off_25x27_bits[] U8X8_PROGMEM = {0xf8,0xff,0x3f,0x00,0x04,0x00,0x40,0x00,0x02,0x00,0x80,0x00,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0xe1,0xf8,0x3e,0x01,0xb1,0x19,0x06,0x01,0x19,0x1b,0x06,0x01,0x19,0x7b,0x1e,0x01,0x19,0x1b,0x06,0x01,0x19,0x1b,0x06,0x01,0xb1,0x19,0x06,0x01,0xe1,0x18,0x06,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x01,0x00,0x00,0x01,0x03,0x00,0x80,0x01,0x06,0x00,0xc0,0x00,0xfc,0xff,0x7f,0x00,0xf8,0xff,0x3f,0x00};
// drawing frames, shapes and those that aren't images/bitmaps are different as whatever dimension is defined in the parameters are where the pixels will be drawn

// Create an array of pointers to these constant arrays
const unsigned char* iconArray[] = {
  image_CoolHi_25x27_bits,
  image_Dehumidify_25x27_bits,
  image_HeatHi_25x27_bits,
  image_Mute_25x27_bits,
  image_Power_25x27_bits,
  image_Off_25x27_bits
};

int iconArrayLength = (sizeof(iconArray) / sizeof(iconArray[0])) - 1; 
// to get total length of icon array (0-indexed based)
// so right now, *iconArrayLength* = 5 (because 6 - 1 = 5)

bool isDisplayOn = true; // Flag to track the OLED display state

int index = 0; // an index to keep track of what icon we're up to

int pageNumber = 0;
// clock page = 0
// menu page = 1
// icon 1 page = 2


void setup() {
  Serial.begin(115200);

  if (!rtc.begin()) {
    Serial.println("Couldn't find RTC");
    while (1);
  }

  if (!rtc.isrunning()) {
    Serial.println("RTC is not running, let's set the time!");
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  }

  u8g2.begin();

  pinMode(selectButtonPin, INPUT);
  pinMode(buttonPin, INPUT);
  pinMode(leftButtonPin, INPUT);
  pinMode(rightButtonPin, INPUT);

  u8g2.clearBuffer(); // display.clearDisplay();
}


void loop() {
  u8g2.setBitmapMode(1);

  displayState(); // ON/OFF CODE

  if (pageNumber == 0) {
    displayTime();
  } 
  else if (pageNumber == 1) {
    displayMenu();
  } 
  else if (pageNumber == 2) {
    icon1Page();
  }

  rightButtonPressed(); // right button is pressed
  
  selectButtonPressed(); // select button is pressed
  
  leftButtonPressed(); // left button is pressed

  u8g2.sendBuffer(); // display.display();
}


void rightButtonPressed() {
  if (digitalRead(rightButtonPin) != lastRightButtonPinState) {
    delay(50);
    currentRightButtonPinState = digitalRead(rightButtonPin);

    if (currentRightButtonPinState == LOW && lastRightButtonPinState == HIGH) {
      if (pageNumber == 1) {
        index += 1;
      }
    }
    lastRightButtonPinState = currentRightButtonPinState;
  }
}


void leftButtonPressed() {
  if (digitalRead(leftButtonPin) != lastLeftButtonPinState) {
    delay(50);
    currentLeftButtonPinState = digitalRead(leftButtonPin);

      if (currentLeftButtonPinState == LOW && lastLeftButtonPinState == HIGH) {
        if (pageNumber == 1) {
          index -= 1;
        }

        if (pageNumber == 2) {
          pageNumber = 1;
          index = 0;
        }
      }
    lastLeftButtonPinState = currentLeftButtonPinState;
  }
}


void selectButtonPressed() {
  if (digitalRead(selectButtonPin) != lastSelectButtonPinState) {
    delay(50);
    currentSelectButtonPinState = digitalRead(selectButtonPin);

    if (currentSelectButtonPinState == LOW && lastSelectButtonPinState == HIGH) {
      if (pageNumber == 0) {
        pageNumber = 1;
      } 
      else if (pageNumber == 1 && index == 0) { // I have this as an *else if* rather than a separate *if* because if I enter press *selectButton* when in *timeDisplay*, then the Arduino will make my next page display as icon1 rather than the menu display because they are two different if statements
        pageNumber = 2;
      }
    }
  lastSelectButtonPinState = currentSelectButtonPinState;
  }
}


void drawIcons() {
  u8g2.drawXBMP( 5, 3, 25, 27, image_CoolHi_25x27_bits); // the first four parameters (x1, y2, width, height) define the dimension for the image to be drawn in (which is the fifth parameter)
  u8g2.drawXBMP( 52, 3, 25, 27, image_Dehumidify_25x27_bits);
  u8g2.drawXBMP( 98, 3, 25, 27, image_HeatHi_25x27_bits);
  u8g2.drawXBMP( 5, 34, 25, 27, image_Mute_25x27_bits);
  u8g2.drawXBMP( 52, 34, 25, 27, image_Power_25x27_bits);
  u8g2.drawXBMP( 98, 34, 25, 27, image_Off_25x27_bits);
}


void displayTime() {
  DateTime now = rtc.now();

  u8g2.firstPage();
    do {
      u8g2.setFont(u8g2_font_ncenB08_tr);
      u8g2.setCursor(35, 24);
      u8g2.print(now.day(), DEC);
      u8g2.print('/');
      u8g2.print(now.month(), DEC);
      u8g2.print('/');
      u8g2.print(now.year(), DEC);

      u8g2.setCursor(44,44);
      u8g2.print(now.hour(), DEC);
      u8g2.print(':');
      u8g2.print(now.minute(), DEC);
      u8g2.print(':');
      u8g2.print(now.second(), DEC);
    } while (u8g2.nextPage());

  delay(50);
}


void displayMenu() {
  if (index == 0) {
    u8g2.clearBuffer(); 
    drawIcons();
    u8g2.drawFrame(2, 0, 31, 33); // x1 = 2 for first icon
  }
  else if (index == 1) {
    u8g2.clearBuffer(); 
    drawIcons();
    u8g2.drawFrame(49, 0, 31, 33); // x1 = 49 for second icon
  }
  else if (index == 2) {
    u8g2.clearBuffer(); 
    drawIcons();
    u8g2.drawFrame(95, 0, 31, 33); // x1 = 95 for third icon
  }
  else if (index == 3) {
    u8g2.clearBuffer(); 
    drawIcons();
    u8g2.drawFrame(2, 31, 31, 33); // x1 = 95 for fourth icon
  }
  else if (index == 4) {
    u8g2.clearBuffer(); 
    drawIcons();
    u8g2.drawFrame(49, 31, 31, 33); // x1 = 95 for fifth icon
  }
  else if (index == 5) {
    u8g2.clearBuffer(); 
    drawIcons();
    u8g2.drawFrame(95, 31, 31, 33); // x1 = 95 for sixth icon
  }

  if (index < 0) {
    index = iconArrayLength;
  } else if (index > iconArrayLength) {
    index = 0;
  }
}


void icon1Page() {
  u8g2.clearBuffer();

  u8g2.firstPage(); // with ug82 library, you have to declare the first page and next page to put text on the OLED. the *nextPage()* will only be called for the pages that are required to have pixels displayed, so this function won't call all pages if it doesn't need to.
    do { // Rendering code for the current page
      u8g2.setFont(u8g2_font_ncenB10_tr);
      u8g2.drawStr(0, 20, "Hello, World!"); // x, y, string
    } while (u8g2.nextPage());
}


void displayState() {
  if (digitalRead(buttonPin) != lastButtonPinState) {
    delay(50); // Delay for debounce
    currentButtonPinState = digitalRead(buttonPin);

    if (currentButtonPinState == LOW && lastButtonPinState == HIGH) { // when sketch is run for the first time, this if-code block actually runs as *lastButtonState* is set to HIGH initially which then changes when I press the button 
      // Button is pressed for the first time
      isDisplayOn = !isDisplayOn; // Toggle the display state

      if (isDisplayOn) { // turn on
        pageNumber = 0;
        u8g2.setPowerSave(0); // Wake up the display (display.ssd1306_command(SSD1306_DISPLAYON);)
      } else { // turn off
        index = 0; // reset back to 0
        pageNumber = 0;
        u8g2.clearBuffer();
        u8g2.setPowerSave(1); // Put the display to sleep (display.ssd1306_command(SSD1306_DISPLAYOFF);)
      }
   }
  lastButtonPinState = currentButtonPinState;
  }
}