#include <U8g2lib.h>
U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/U8X8_PIN_NONE);
//U8G2_SH1106_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

#include <Wire.h>  // must be included here so that Arduino library object file references work
#include <RtcDS1307.h>
RtcDS1307<TwoWire> Rtc(Wire);
RtcDateTime now;

volatile bool interrupt = false;
volatile unsigned long bounce = 0;
volatile unsigned long lpress = 0;

int page = 0;
bool displayOn = true;

// '012', 30x30px
const unsigned char term_012 [] PROGMEM = {
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xC0, 0x00, 0x00,
  0x00, 0x20, 0x01, 0x00, 0x00, 0x10, 0x02, 0x00, 0x00, 0x10, 0x1A, 0x00, 0x00, 0x10, 0x02, 0x00,
  0x00, 0x10, 0x02, 0x00, 0x00, 0x10, 0x1A, 0x00, 0x00, 0x10, 0x02, 0x00, 0x00, 0xD0, 0x02, 0x00,
  0x00, 0xD0, 0x1A, 0x00, 0x00, 0xD0, 0x02, 0x00, 0x00, 0xD0, 0x02, 0x00, 0x00, 0xD0, 0x02, 0x00,
  0x00, 0xD0, 0x02, 0x00, 0x00, 0xD0, 0x0A, 0x00, 0x00, 0xD0, 0x02, 0x00, 0x00, 0xD0, 0x02, 0x00,
  0x00, 0xD0, 0x02, 0x00, 0x00, 0xD0, 0x02, 0x00, 0x00, 0xE8, 0x05, 0x00, 0x00, 0xE8, 0x05, 0x00,
  0x00, 0xE8, 0x05, 0x00, 0x00, 0xD8, 0x06, 0x00, 0x00, 0x30, 0x03, 0x00, 0x00, 0xC0, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

// '013', 30x30px
const unsigned char term_013 [] PROGMEM = {
  0xFF, 0xFF, 0xFF, 0x3F, 0xFF, 0xBF, 0xFE, 0x3F, 0xFF, 0x03, 0xF8, 0x3F, 0xFF, 0xFC, 0xFF, 0x3F,
  0x3F, 0xFF, 0xFF, 0x3F, 0xBF, 0xFF, 0x7F, 0x3F, 0xDF, 0xFF, 0xFF, 0x3E, 0xDF, 0xFF, 0xFF, 0x3E,
  0xEF, 0xFF, 0x7F, 0x3C, 0xEF, 0xFF, 0x7F, 0x3C, 0x67, 0xE0, 0x03, 0x3C, 0x6F, 0xC3, 0x01, 0x3C,
  0x6F, 0xC0, 0x00, 0x3C, 0xFF, 0xFF, 0x0E, 0x3C, 0xFF, 0xFF, 0x7F, 0x3C, 0xFF, 0xFF, 0x7D, 0x3C,
  0xFF, 0x0B, 0x7C, 0x3E, 0xFF, 0xE1, 0x39, 0x3F, 0xFF, 0x03, 0x10, 0x3F, 0xFF, 0x7B, 0x18, 0x3F,
  0xFF, 0xFF, 0x98, 0x3F, 0xFF, 0x7F, 0x88, 0x3F, 0xFF, 0x1D, 0x80, 0x3F, 0xBF, 0x04, 0x40, 0x3F,
  0x9F, 0x00, 0x40, 0x3E, 0x87, 0x01, 0x40, 0x38, 0x81, 0x03, 0x60, 0x20, 0x80, 0x07, 0x70, 0x00,
  0x80, 0x1F, 0x7C, 0x00, 0x80, 0xFF, 0x7F, 0x00
};


void buttons_interrupt_handler() {

  interrupt = true;
  bounce = millis();
  lpress = millis();
}

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

  u8g2.begin();  // begin the u8g2 library
  u8g2.setContrast(255); // set display contrast/brightness

  Rtc.Begin();
  //  RtcDateTime compiled = RtcDateTime(__DATE__, __TIME__);
  // Rtc.SetDateTime(compiled + 1 * 8 * 60 * 60);
  //Rtc.SetDateTime(RtcDateTime(2018, 1, 17, 7, 53, 00));

  pinMode(2, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(2), buttons_interrupt_handler, FALLING);

  pinMode(8, OUTPUT);
}

void loop(void) {

  buttons();
  PowSave();
  display();

}

void buttons() {

  bool impulse = false;
  static bool longpress = false;

  noInterrupts();

  if (digitalRead(2)) lpress = millis();
  else bounce = millis();

  if (interrupt) {
    if (millis() - bounce > 20) {
      interrupt = false;
      impulse = !longpress;
      longpress = false;
    }
  }

  if (impulse) {
    if (displayOn) {
      page++;
      if (page > 3) page = 0;
    } else displayOn = true;
  }

  if (!longpress) {
    if (millis() - lpress > 1000) {
      longpress = true;
      displayOn = false;
    }
  }

  if (displayOn) {
    if (millis() - bounce > 60000) {
      displayOn = false;
    }
  }

  interrupts();
}

void PowSave() {

  static bool laststate = !displayOn;

  if (laststate != displayOn) {
    laststate = displayOn;

    if (displayOn) {
      u8g2.setPowerSave(0);
      digitalWrite(8, HIGH);
    } else {
      u8g2.setPowerSave(1);
      digitalWrite(8, LOW);
    }
  }
}

void display() {

  if (!displayOn) return;

  static unsigned long elapse = millis();

  if (millis() - elapse > 100) {
    elapse = millis();

    switch (page) {
      case 0:
        page0();
        break;
      case 1:
        page1();
        break;
      case 2:
        page2();
        break;
      case 3:
        page3();
        break;
      default:
        page0();
        break;
    }
  }
}

void page0(void)
{
  static char date[11];
  static char time[ 9];

  now = Rtc.GetDateTime();
  bool err = !Rtc.IsDateTimeValid() | Rtc.LastError() != 0;

  snprintf(date, 11, "%02u-%02u-%04u", now.Month(), now.Day(), now.Year());
  snprintf(time,  9, "%02u:%02u:%02u", now.Hour(), now.Minute(), now.Second());

  u8g2.firstPage();
  do {
    u8g2.drawRFrame(0, 0, 128, 64, 10);
    u8g2.setFont(u8g2_font_t0_22b_mf);
    u8g2.drawStr( 8, 27, date);
    u8g2.drawStr(20, 53, time);
    if (err) {
      u8g2.setFont(u8g2_font_t0_12b_mf);
      u8g2.drawStr( 37, 37, "error rtc");
    }
  } while (u8g2.nextPage());
}


void page1(void)
{
  float t = random( 1000,  9999) / 100.0;
  float u = random( 5000, 16000) / 100.0;

  u8g2.firstPage();
  do {
    u8g2.drawFrame(0, 0, 128, 64);

    u8g2.setFont(u8g2_font_unifont_tr);

    u8g2.drawStr(20, 15, "Temperatura");
    u8g2.setCursor(40, 30);
    u8g2.print(t, 2);
    u8g2.drawStr(80, 30, " C");

    u8g2.drawStr(38, 45, "Umidita'");
    u8g2.setCursor(40, 60);
    u8g2.print(u, 2);
    u8g2.drawStr(80, 60, " %");

    u8g2.drawXBMP(1, 30, 30, 30, term_012);
  } while (u8g2.nextPage());
}

void page2(void)
{
  float t = random( 1000,  9999) / 100.0;
  float u = random( 5000, 16000) / 100.0;

  u8g2.firstPage();
  do {
    u8g2.drawFrame(0, 0, 128, 64);

    u8g2.setFont(u8g2_font_t0_22b_mf);

    u8g2.drawStr(5, 15, "Temp Page2");
    u8g2.setCursor(10, 30);
    u8g2.print(t, 2);
    u8g2.drawStr(80, 30, " C");

    u8g2.drawStr(38, 45, "UUUUUU'");
    u8g2.setCursor(35, 60);
    u8g2.print(u, 2);
    u8g2.drawStr(80, 60, " %");

    u8g2.drawXBMP(1, 30, 30, 30, term_013);
  } while (u8g2.nextPage());
}

void page3(void)
{
  float t = random( 1000,  9999) / 100.0;
  float u = random( 5000, 16000) / 100.0;

  u8g2.firstPage();
  do {
    u8g2.drawFrame(0, 0, 128, 64);

    //   u8g2.setFont(u8g_font_gdr12r);
    u8g2.setFont(u8g2_font_t0_12b_mf);

    u8g2.drawStr(5, 15, "Temp Page3");
    u8g2.setCursor(12, 30);
    u8g2.print(t, 2);
    u8g2.drawStr(80, 30, " C");

    u8g2.drawStr(38, 45, "UUUUUU'");
    u8g2.setCursor(40, 60);
    u8g2.print(u, 2);
    u8g2.drawStr(80, 60, " %");

    u8g2.drawXBMP(1, 30, 30, 30, term_012);
  } while (u8g2.nextPage());
}