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

Adafruit_SSD1306 display = Adafruit_SSD1306(128, 32, &Wire);

// OLED FeatherWing buttons map to different pins depending on board:
#if defined(ESP8266)
  #define BUTTON_A  0
  #define BUTTON_B 16
  #define BUTTON_C  2
#elif defined(ESP32)
  #define BUTTON_A 15
  #define BUTTON_B 32
  #define BUTTON_C 14
#elif defined(ARDUINO_STM32_FEATHER)
  #define BUTTON_A PA15
  #define BUTTON_B PC7
  #define BUTTON_C PC5
#elif defined(TEENSYDUINO)
  #define BUTTON_A  4
  #define BUTTON_B  3
  #define BUTTON_C  8
#elif defined(ARDUINO_FEATHER52832)
  #define BUTTON_A 31
  #define BUTTON_B 30
  #define BUTTON_C 27
#else // 32u4, M0, M4, nrf52840 and 328p
  #define BUTTON_A  9
  #define BUTTON_B  6
  #define BUTTON_C  5
#endif

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

  Serial.println("OLED FeatherWing test");
  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C); // Address 0x3C for 128x32

  Serial.println("OLED begun");

  // Show image buffer on the display hardware.
  // Since the buffer is intialized with an Adafruit splashscreen
  // internally, this will display the splashscreen.
  display.display();
  delay(1000);

  // Clear the buffer.
  display.clearDisplay();
  display.display();

  Serial.println("IO test");

  pinMode(BUTTON_A, INPUT_PULLUP);
  pinMode(BUTTON_B, INPUT_PULLUP);
  pinMode(BUTTON_C, INPUT_PULLUP);

  // text display tests
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.print("Connecting to SSID\n'adafruit':");
  display.print("connected!");
  display.println("IP: 10.0.1.23");
  display.println("Sending val #0");
  display.setCursor(0,0);
  display.display(); // actually display all of the above
}

void loop() {
  if(!digitalRead(BUTTON_A)) display.print("A");
  if(!digitalRead(BUTTON_B)) display.print("B");
  if(!digitalRead(BUTTON_C)) display.print("C");
  delay(10);
  yield();
  display.display();
}