/*
 * Very simple menu on an OLED display (with 8 lines of text).
 * Displays menu items from the array menu. Max. number of items is 7.
 * 
 * This sketch uses the library "U8g2", "Bounce2" and uses 3 buttons (up/down/select).
 * 
 */

#include <U8g2lib.h>
#include <Bounce2.h>

byte button_pins[] = {9, 5, 6}; // button pins, 4,5 = up/down, 6 = select
#define NUMBUTTONS sizeof(button_pins)
Bounce * buttons = new Bounce[NUMBUTTONS];

U8X8_SSD1306_128X64_NONAME_HW_I2C display(U8X8_PIN_NONE);

#define MENU_SIZE 3
char *menu[MENU_SIZE] = { "Polymer", "Temp", "RPM" };

#define POLY_MENU_SIZE 4
char *polyMenu[POLY_MENU_SIZE] = { "PET", "ABS", "PLA", "CUSTOM" };

int cursor=0;

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

  // Make input & enable pull-up resistors on switch pins
  for (int i=0; i<NUMBUTTONS; i++) {
    buttons[i].attach( button_pins[i], INPUT_PULLUP); // setup the bounce instance for the current button
    buttons[i].interval(25); // interval in ms
  }
  
  display.begin();
  display.setPowerSave(0);
  display.setFont(u8x8_font_pxplusibmcgathin_f);

  showMenu();
}

void loop() {
  // process button press:
  for (int i = 0; i<NUMBUTTONS; i++) {
    buttons[i].update(); // Update the Bounce instance
    if ( buttons[i].fell() ) { // If it fell
      if (i==2) { // select
         //display.clearLine(7);
         //display.setCursor(0,7);
         display.setCursor(0,cursor + 3);
         display.print(">>");
         //display.print(menu[cursor]);
         executeChoice(cursor);
      }
      else {
        // erase previous cursor:
        display.setCursor(0,cursor + 3);
        display.print("  ");
        if (i==0) { // up
          cursor++;
          if (cursor>(MENU_SIZE)) cursor=0;
        }
        else { // down
          cursor--;
          if (cursor<0) cursor=(MENU_SIZE);
        }
        // show cursor at new line:
        if (cursor != MENU_SIZE) { 
        display.setCursor(0,cursor + 3);
        display.print('>');
        }
      }
    } // end if button fell...
  } // end for-loop of button check
}

/**
 * Clear display and show the menu.
 */
void showMenu() {
  cursor=MENU_SIZE;
  display.clearDisplay();
  //display.print('POLYFORMER V0.0.1');
  display.drawString(0,0,"PolyFormer V0.01");
  // show menu items:
  for (int i = 0; i<MENU_SIZE; i++) {
    display.drawString(2,i + 3,menu[i]);
  }
  //display.setCursor(0,3);
  //display.print('>');
}

/**
 * Execute the task which matches the chosen menu item.
 */
void executeChoice(int choice) {
  switch(choice) {
      case 0 :
                Serial.print("Execute choice "); Serial.print(choice); Serial.print(" - "); Serial.println(menu[choice]);
                break;
      case 1 :
                Serial.print("Execute choice "); Serial.print(choice); Serial.print(" - "); Serial.println(menu[choice]);
                break;
      case 2 :
                Serial.print("Execute choice "); Serial.print(choice); Serial.print(" - "); Serial.println(menu[choice]);
                break;
      case 3 :
                Serial.print("Execute choice "); Serial.print(choice); Serial.print(" - "); Serial.println(menu[choice]);
                break;
      case 4 :
                Serial.print("Execute choice "); Serial.print(choice); Serial.print(" - "); Serial.println(menu[choice]);
                break;
      default :
                Serial.print("Execute choice "); Serial.print(choice); Serial.print(" - "); Serial.println(menu[choice]);
                break;
  }
  
}