#include  "U8glib.h"
#include "Adafruit_BME280.h"

U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_DEV_0 | U8G_I2C_OPT_NO_ACK | U8G_I2C_OPT_FAST);
Adafruit_BME280 bme;

#define DOWN_BUTTON 3
#define UP_BUTTON 2
#define SELECT_BUTTON 4
#define SEALEVELPRESSURE_HPA (1013.25)
#define echoPin 6 //connect echo pin of ultrasonic sensor
#define trigPin 7 //connect trigger pin of ultrasonic sensor

// next item - used in the menu screen to draw next item after the selected one
int p;
int m;
int current_screen =0;
long duration;
int distance;

float temperature = 21.0;
float humidity = 28.0;
float pressure = 0;

void pageEnvironmentalData();     // Page-1
void pageTemperature(); // Page-2
void pageHumidity();    // Page-3
void pagePressure();

void Main1();
void Main2();
void Main3();
void Main4();
void (*pages[])() = { pageEnvironmentalData, pageTemperature, pageHumidity, pagePressure};
//void (*pages[])() = { pageEnvironmentalData, pageTemperature, pageHumidity, pagePressure } ;

static bool down_state = false;
static bool up_state = false;
static bool select_state = false;
static bool selected = false;

void setup() {
  bme.begin(0x76);
  u8g.setFont(u8g_font_profont12);
  u8g.setColorIndex(1);  // set the color to white
  pinMode(DOWN_BUTTON, INPUT_PULLUP);
  pinMode(UP_BUTTON, INPUT_PULLUP);
  pinMode(SELECT_BUTTON, INPUT_PULLUP);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, OUTPUT);
  p = 0;
  m = 0;
}


void loop() 
 {
   digitalWrite(trigPin, LOW);
   delayMicroseconds(2);
   digitalWrite(trigPin, HIGH);
   delayMicroseconds(10);
   digitalWrite(trigPin, LOW);
   duration = pulseIn(echoPin, HIGH);
   distance = duration * 0.034 / 2;

   up_state = digitalRead(UP_BUTTON);
   down_state = digitalRead(DOWN_BUTTON);
   select_state = digitalRead(SELECT_BUTTON);
  
    u8g.firstPage();
     do 
     {
       (*pages[m])();
     }  while (u8g.nextPage());

    /*if ( up_state == LOW )
    {
      p = p - 1;
      if ( p == -1)
      {
        p = 3;
      }
    }
    else if  (down_state == LOW)    
    {
      p = p + 1;
      if (p == 4)
      {
        p = 0;
      }
    }*/
    if ( up_state == LOW )
    {
      m = m - 1;
      if ( m == -1)
      {
        m = 3;
      }
    }
    else if  (down_state == LOW)    
    {
      m = m + 1;
      if (m == 4)
      {
        m = 0;
      }
    }
    else if (select_state == LOW)
    {
      selected = true;
    }

  /*if (m == 0 && select_state == LOW)
  {
    if (select_state == LOW)
    {
      selected = false;
    }
  }*/
}

void Main1()
{
  u8g.drawStr( 12, 12, "Environmental Data");
  u8g.drawCircle( 5, 8, 2);
  u8g.drawStr( 12, 24, "Battery Stats");
  u8g.drawStr( 12, 36, "Scanning");
  u8g.setPrintPos( 12, 46);
  u8g.print(m);
  u8g.setPrintPos( 12, 56);
  u8g.print(select_state);
}

void Main2()
{
  u8g.drawStr( 12, 12, "Environmental Data");
  u8g.drawCircle( 5, 20, 2);
  u8g.drawStr( 12, 24, "Battery Stats");
  u8g.drawStr( 12, 36, "Scanning");
  u8g.setPrintPos( 12, 46);
  u8g.print(m);
}

void Main3()
{
  u8g.drawStr( 12, 12, "Environmental Data");
  u8g.drawCircle( 5, 32, 2);
  u8g.drawStr( 12, 24, "Battery Stats");
  u8g.drawStr( 12, 36, "Scanning");
  u8g.setPrintPos( 12, 46);
  u8g.print(m);
}


void pageEnvironmentalData() {
  temperature = bme.readTemperature();
  u8g.drawStr( 0, 12, "Temperat:");
  u8g.setPrintPos( 60, 12);
  u8g.print(temperature);
  humidity = bme.readHumidity();
  u8g.drawStr( 0, 24, "Humidity:"); 
  u8g.setPrintPos( 60, 24);
  u8g.print(humidity);
  pressure = bme.readPressure();
  u8g.drawStr( 0, 36, "Pressure:");
  u8g.setPrintPos( 60, 36);
  u8g.print(pressure);
  u8g.setPrintPos( 12, 46);
  u8g.print(distance);
}
void pageTemperature(){
  temperature = bme.readTemperature();
  u8g.drawStr( 0, 15, "Temperature:");
  u8g.setPrintPos( 0, 31);
  u8g.print(distance); 
  return 0;
}
void pageHumidity() {
  humidity = bme.readHumidity();
  u8g.drawStr( 0, 15, "Humidity:"); 
  u8g.setPrintPos( 0, 31);
  u8g.print(distance);
  return 0;
}
void pagePressure(){
  pressure = bme.readPressure();
  u8g.drawStr( 0, 15, "Pressure:");
  u8g.setPrintPos( 0, 31);
  u8g.print(distance); 
  return 0;
}