#include <dht.h>
#include <Wire.h>
#define DHT22_PIN 3
dht DHT;
#define photocellPin 0
#include <avr/sleep.h>
#include <avr/power.h>
#include <avr/wdt.h>
#define DHTPINVCC  2
#define PHOTOCELLVCC 9
#define disk1 0x50
unsigned int address = 0;

float temperature;
float humidity;


uint8_t counter=0;

//count number of entering into main loop
uint8_t loopCounter=150; //set to 1 for debug (short sleep) - 150 (20min)

//WATCHDOG
volatile int f_wdt=1;

ISR(WDT_vect) {
  if(f_wdt == 0) {
    f_wdt=1;
  } else {
    //nothing
  }
}

void enterSleep(void) {
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);   /* EDIT: could also use SLEEP_MODE_PWR_DOWN for lowest power consumption. */
  sleep_enable();

  /* Now enter sleep mode. */
  sleep_mode();

  /* The program will continue from here after the WDT timeout*/
  sleep_disable(); /* First thing to do is disable sleep. */

  /* Re-enable the peripherals. */
  power_all_enable();
}

void setup()
{
  //Serial.println("Initialising...");
  Serial.begin(9600);
  Wire.begin();
   //WATCHDOG
  /* Clear the reset flag. */
  MCUSR &= ~(1<<WDRF);
  /* In order to change WDE or the prescaler, we need to
   * set WDCE (This will allow updates for 4 clock cycles).
   */
  WDTCSR |= (1<<WDCE) | (1<<WDE);
  /* set new watchdog timeout prescaler value */
  WDTCSR = 1<<WDP0 | 1<<WDP3; /* 8.0 seconds */
  /* Enable the WD interrupt (note no reset). */
  WDTCSR |= _BV(WDIE);

  //CONFIGURE DHT11
  pinMode(DHTPINVCC, OUTPUT);
  pinMode(PHOTOCELLVCC, OUTPUT);
  //make it blink at startup
  digitalWrite(DHTPINVCC, HIGH);
  digitalWrite(PHOTOCELLVCC, HIGH);
  delay(500);
  digitalWrite(DHTPINVCC, LOW);
  digitalWrite(PHOTOCELLVCC, LOW);
  //Serial.println("alive");
  //Serial.println("\n");
  //Serial.println("dead");
  delay(1000);
  writeEEPROM(disk1, address, 123);
  Serial.print(readEEPROM(disk1, address), DEC);
}
void loop()
{
  if(f_wdt == 1) {
    loopCounter ++;
    if (loopCounter > 6) {
      // 110 *8 = 880s = 14.6min @ 16mhtz
      readSensor();
      loopCounter = 0;
    }
    f_wdt = 0;
    enterSleep();
  } else {
    //nothing
  }
}

void writeEEPROM(int deviceaddress, unsigned int eeaddress, byte data )
{
  Wire.beginTransmission(deviceaddress);
  Wire.write((int)(eeaddress >> 8));   // MSB
  Wire.write((int)(eeaddress & 0xFF)); // LSB
  Wire.write(data);
  Wire.endTransmission();

  delay(5);
}

byte readEEPROM(int deviceaddress, unsigned int eeaddress )
{
  byte rdata = 0xFF;

  Wire.beginTransmission(deviceaddress);
  Wire.write((int)(eeaddress >> 8));   // MSB
  Wire.write((int)(eeaddress & 0xFF)); // LSB
  Wire.endTransmission();

  Wire.requestFrom(deviceaddress,1);

  if (Wire.available()) rdata = Wire.read();

  return rdata;
}


void readSensor() {
  digitalWrite(DHTPINVCC, HIGH);
  delay(1500);
  digitalWrite(PHOTOCELLVCC, HIGH);
  delay(500);
  //Serial.println("\n");
  int photocellReading = analogRead(photocellPin);
  int chk = DHT.read22(DHT22_PIN);
  //Serial.print("Read sensor: ");
 switch (chk)
  {
    case DHTLIB_OK:
		Serial.print("OK,\t");
		break;
    case DHTLIB_ERROR_CHECKSUM:
		Serial.print("Checksum error,\t");
		break;
    case DHTLIB_ERROR_TIMEOUT:
		Serial.print("Time out error,\t");
		break;
    default:
		Serial.print("Unknown error,\t");
		break;
  }
  digitalWrite(DHTPINVCC, LOW);
  address ++;
  writeEEPROM(disk1, address, DHT.humidity);
  address ++;
  writeEEPROM(disk1, address, DHT.temperature);
  address ++;
  writeEEPROM(disk1, address, photocellReading);
  digitalWrite(PHOTOCELLVCC, LOW);
}