// simple project using Arduino UNO and 128x64 OLED Display to display a menu
// created by upir, 2022

#include "U8g2lib.h"

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0); // [full framebuffer, size = 1024 bytes]


// all the arrays below are generated from images using Image Magick
// scroll down to see the actual code

const unsigned char upir_logo [] PROGMEM = {  
  0xEA, 0x3A, 0xAA, 0x28, 0x6A, 0x1A, 0x26, 0x2A, };

// 'icon_battery', 16x16px
const unsigned char bitmap_icon_battery [] PROGMEM = {
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFC, 0x1F, 0x02, 0x20, 
  0xDA, 0x66, 0xDA, 0x66, 0xDA, 0x66, 0x02, 0x20, 0xFC, 0x1F, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, };

// 'icon_knob_over_oled', 16x16px
const unsigned char bitmap_icon_knob_over_oled [] PROGMEM = {
  0x00, 0x00, 0xF8, 0x0F, 0xC8, 0x0A, 0xD8, 0x0D, 0x88, 0x0A, 0xF8, 0x0F, 
  0xC0, 0x01, 0x80, 0x00, 0x00, 0x00, 0x90, 0x04, 0x92, 0x24, 0x04, 0x10, 
  0x00, 0x80, 0x01, 0x40, 0x00, 0x00, 0x00, 0x00, };

// Array of all bitmaps for convenience. (Total bytes used to store images in PROGMEM = 384)
const unsigned char* bitmap_icons[8] = {
  bitmap_icon_battery,
  bitmap_icon_knob_over_oled,
};

// 'scrollbar_background', 8x64px
const unsigned char bitmap_scrollbar_background [] PROGMEM = {
  0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 
  0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 
  0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 
  0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 
  0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 0x00, 0x40, 
  0x00, 0x40, 0x00, 0x00, };


// 'item_sel_outline', 128x21px
const unsigned char bitmap_item_sel_outline [] PROGMEM = {
  0xF8, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 
  0xFF, 0xFF, 0xFF, 0x03, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x02, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 
  0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 
  0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 
  0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 
  0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 
  0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 0x02, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C, 
  0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
  0x00, 0x00, 0x00, 0x0C, 0xFC, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 
  0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x07, 0xF8, 0xFF, 0xFF, 0xFF, 
  0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x03, 
  };





// ------------------ end generated bitmaps from image2cpp ---------------------------------



const int NUM_ITEMS = 2; // number of items in the list and also the number of screenshots and screenshots with QR codes (other screens)
const int MAX_ITEM_LENGTH = 20; // maximum characters for the item name

char menu_items [NUM_ITEMS] [MAX_ITEM_LENGTH] = {  // array with item names

  { "Battery" }, 
  { "Big Knob" },   
 };
// note - when changing the order of items above, make sure the other arrays referencing bitmaps
// also have the same order, for example array "bitmap_icons" for icons, and other arrays for screenshots and QR codes

#define BUTTON_UP_PIN 12 // pin for UP button 
#define BUTTON_SELECT_PIN 8 // pin for SELECT button
#define BUTTON_DOWN_PIN 4 // pin for DOWN button

int button_up_clicked = 0; // only perform action when button is clicked, and wait until another press
int button_select_clicked = 0; // same as above
int button_down_clicked = 0; // same as above

int item_selected = 0; // which item in the menu is selected

int item_sel_previous; // previous item - used in the menu screen to draw the item before the selected one
int item_sel_next; // next item - used in the menu screen to draw next item after the selected one

int current_screen = 0;   // 0 = menu, 1 = screenshot, 2 = qr

void setup() {
  u8g2.setColorIndex(1);  // set the color to white
  u8g2.begin();
  u8g2.setBitmapMode(1);

  // define pins for buttons
  // INPUT_PULLUP means the button is HIGH when not pressed, and LOW when pressed
  // since it´s connected between some pin and GND
  pinMode(BUTTON_UP_PIN, INPUT_PULLUP); // up button
  pinMode(BUTTON_SELECT_PIN, INPUT_PULLUP); // select button
  pinMode(BUTTON_DOWN_PIN, INPUT_PULLUP); // down button
 
}


void loop() {

  if (current_screen == 0) { // MENU SCREEN

      // up and down buttons only work for the menu screen
      if ((digitalRead(BUTTON_UP_PIN) == LOW) && (button_up_clicked == 0)) { // up button clicked - jump to previous menu item
        item_selected = item_selected - 1; // select previous item
        button_up_clicked = 1; // set button to clicked to only perform the action once
        if (item_selected < 0) { // if first item was selected, jump to last item
          item_selected = NUM_ITEMS-1;
        }
      }
      else if ((digitalRead(BUTTON_DOWN_PIN) == LOW) && (button_down_clicked == 0)) { // down button clicked - jump to next menu item
        item_selected = item_selected + 1; // select next item
        button_down_clicked = 1; // set button to clicked to only perform the action once
        if (item_selected >= NUM_ITEMS) { // last item was selected, jump to first menu item
          item_selected = 0;
          }
      } 

      if ((digitalRead(BUTTON_UP_PIN) == HIGH) && (button_up_clicked == 1)) { // unclick 
        button_up_clicked = 0;
      }
      if ((digitalRead(BUTTON_DOWN_PIN) == HIGH) && (button_down_clicked == 1)) { // unclick
        button_down_clicked = 0;
      }

  }


  if ((digitalRead(BUTTON_SELECT_PIN) == LOW) && (button_select_clicked == 0)) { // select button clicked, jump between screens
     button_select_clicked = 1; // set button to clicked to only perform the action once
     if (current_screen == 0) {current_screen = 1;} // menu items screen --> screenshots screen
     else if (current_screen == 1) {current_screen = 2;} // screenshots screen --> qr codes screen
     else {current_screen = 0;} // qr codes screen --> menu items screen
  }
  if ((digitalRead(BUTTON_SELECT_PIN) == HIGH) && (button_select_clicked == 1)) { // unclick 
    button_select_clicked = 0;
  }

  // set correct values for the previous and next items
  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;} // next item would be after last = make it the first



  u8g2.clearBuffer();  // clear buffer for storing display content in RAM

    if (current_screen == 0) { // MENU SCREEN

      // selected item background
      u8g2.drawXBMP(0, 22, 128, 21, bitmap_item_sel_outline);

      // draw previous item as icon + label
      u8g2.setFont(u8g_font_7x14);
      u8g2.drawStr(25, 15, menu_items[item_sel_previous]); 
      u8g2.drawXBMP( 4, 2, 16, 16, bitmap_icons[item_sel_previous]);          

      // draw selected item as icon + label in bold font
      u8g2.setFont(u8g_font_7x14B);    
      u8g2.drawStr(25, 15+20+2, menu_items[item_selected]);   
      u8g2.drawXBMP( 4, 24, 16, 16, bitmap_icons[item_selected]);     

      // draw next item as icon + label
      u8g2.setFont(u8g_font_7x14);     
      u8g2.drawStr(25, 15+20+20+2+2, menu_items[item_sel_next]);   
      u8g2.drawXBMP( 4, 46, 16, 16, bitmap_icons[item_sel_next]);  

      // draw scrollbar background
      u8g2.drawXBMP(128-8, 0, 8, 64, bitmap_scrollbar_background);

      // draw scrollbar handle
      u8g2.drawBox(125, 64/NUM_ITEMS * item_selected, 3, 64/NUM_ITEMS); 

      // draw upir logo
      u8g2.drawXBMP(128-16-4, 64-4, 16, 4, upir_logo);               

    } 
    else if (current_screen == 1) { // SCREENSHOTS SCREEN
        //u8g2.drawXBMP( 0, 0, 128, 64, bitmap_screenshots[item_selected]); // draw screenshot
    }

  u8g2.sendBuffer(); // send buffer from RAM to display controller


}