#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>
#include <Wire.h>
//----------------------------------------------------------------------------------------------------------------------
//Screen Characteristics
const uint8_t SCREEN_WIDTH = 128;
const uint8_t SCREEN_HEIGHT = 64;
const uint8_t OLED_RESET = -1;

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
//----------------------------------------------------------------------------------------------------------------------
//button interrupts
#include "OneButton.h"
#define PIN_INPUT 3
OneButton button(PIN_INPUT, true);

// save the millis when a press has started.
unsigned long pressStartTime;
int presslength; //time that is button pressed

//----------------------------------------------------------------------------------------------------------------------
//options
String O1="Option 1:";
String O2="Option 2:";
String O3="Option 3:";
int highlightOption=2;
int changeOption=1;

//----------------------------------------------------------------------------------------------------------------------
//
void setup() {
  Serial.begin(115200);
  setup_Display();
  //setup_OLED();

  //button interrupts
  attachInterrupt(digitalPinToInterrupt(PIN_INPUT), checkTicks, CHANGE); //interrupt occurs when buttons are pressed
  button.attachClick(singleClick); //singleClick runs when button is clicked

  button.setPressTicks(800); // time waited until longpress
  button.attachLongPressStart(pressStart); //when button is first pressed
  button.attachLongPressStop(pressStop); //when button is released
}

void loop() {
  mainMenu();
}

//=============================================================================
//OLED Display setup
void setup_Display() {
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  
  //Setting display/message charateristics
  display.setTextColor(SSD1306_WHITE); // Draw white text
  display.setCursor(0, 0);     // Start at top-left corner
  display.cp437(true);         // Use full 256 char 'Code Page 437' font
  display.clearDisplay();
}
//===================================================================================================
//interrupts
void checkTicks() { //interrupt occurs when buttons are pressed                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
  button.tick();
}
void pressStart() {  //when button is first pressed
  pressStartTime = millis() - 800; // as set in setPressTicks()
}
// function called after long press
void pressStop() { //when button is released
  presslength = millis() - pressStartTime; //measures length of time button is pressed 
  Serial.print("Button Pressed for:"); Serial.println(presslength); //serial print is for testing 
}
void singleClick() {
  Serial.println("click");
  changeOption=1;
} // singleClick

//===================================================================================================
//menu display

void mainMenu(){
  if (changeOption==1){
    changeOption=0;
    highlightOption++;
    if (highlightOption>2) {highlightOption=0;}
    clearAndPrint_Display();
  }
}

void clearAndPrint_Display(){
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(0, 0); 
  display.print(" Main Menu");
  display.display();

  display.setTextSize(1);
  display.setCursor(10, 20); 
  display.println(O1);
  display.setCursor(10, 30); 
  display.println(O2);
  display.setCursor(10, 40); 
  display.println(O3);
  display.display();

  
  int arrowPos=20+highlightOption*10;
  display.setTextSize(1);
  display.setCursor(0, arrowPos); 
  display.write(16);
  display.display();
  
}