/* STANDARD DEFINES */
#define F_CPU 16000000UL
#define BAUD 9600

/* INCLUDED LIBRARIES */
#include <avr/io.h>
#include <util/delay.h>

#include <curl/curl.h>
#include <esp8266.h> /* https://github.com/camilstaps/ESP8266_PIC */

#define SSID "WiFi SSID"
#define PASSWORD "WiFi Password"

#define DHT11_PORT 6 /* PD6 */


/* HUMIDITY INFORMATION */
volatile uint8_t int_Hum; /* INTEGER */
volatile uint8_t dec_Hum; /* DECIMAL */
volatile uint8_t max_Hum; /* MAX VALUE */
volatile uint8_t min_Hum; /* MIN VALUE */

/* TEMPERATURE INFORMATION */
volatile uint8_t int_Temp; /* INTEGER */
volatile uint8_t dec_Temp; /* DECIMAL */
volatile uint8_t max_Temp; /* MAX VALUE */
volatile uint8_t min_Temp; /* MIN VALUE */

/* MISCELLANEOUS */
volatile uint8_t checkSum; /* CHECKSUM FOR DHT11 */
volatile uint8_t data = 0; /* TRANSMITTED DATA */
volatile uint8_t beenChecked = 0; /* BOOLEAN */


void usart_Init(void)
{
    UCSR0B |= (1<<TXEN)|(1<<RXEN); //  enable receive transmit of usart
    UCSR0C = (1<<UCSZ1)|(1<<UCSZ0);
    UBRR0L = 0x67; //  0x67=103 , baudrate = 9600 , Fosc=16MHz, set UBRR0L to 103
}
void usart_Transmit( unsigned char data) //TX
{
    UDR0 = data;
    while(!(UCSR0A & (1<<UDRE0)));              //Usart sending function
   
}
unsigned char usart_Receive(void)  //RX
{
    while (!(UCSR0A & (1<<RXC0)));             // usart receiving function
    return UDR0;
}
  
/* SEND INFORMATION TO THINGSPEAK */
void sendThingSpeak(){
  	char dot[] = "."; /* CREATE DOT */

    char int_Temp[64]; /* CREATE STRING FOR TEMPERATURE INTEGER */
    sprintf(int_Temp, "%d", int_Temp); /* PLACE CURRENT VALUE OF int_Temp INTO THE STRING */

    char dec_Temp[64]; /* CREATE STRING FOR TEMPERATURE DECIMAL */
    sprintf(dec_Temp, "%d", dec_Temp); /* PLACE CURRENT VALUE OF dec_Temp INTO THE STRING */

    char int_Hum[64]; /* CREATE STRING FOR HUMIDITY INTEGER */
    sprintf(int_Hum, "%d", int_Hum); /* PLACE CURRENT VALUE OF int_Hum INTO THE STRING */

    char dec_Hum[64]; /* CREATE STRING FOR HUMIDITY DECIMAL */
    sprintf(dec_Hum, "%d", dec_Hum); /* PLACE CURRENT VALUE OF dec_Hum INTO THE STRING */

    char field1[] = "https://api.thingspeak.com/update?api_key=AJT7CO2RH081W6JV&field1="; /* URL FOR UPDATING THINGSPEAK FIELD 1 */
    char field2[] = "&field2="; /* ADDITION TO UPDATE THINGSPEAK FIELD 2 */

    char URL[256]; /* CREATE STRING TO COMPILE ALL ABOVE */

    snprintf(URL, sizeof URL, "%s%s%s%s%s%s%s%s", field1, int_Temp, dot, dec_Temp, field2, int_Hum, dot, dec_Hum); /* ADD ALL STRING TO URL */
  
	if(curl) {
  	curl_easy_setopt(curl, CURLOPT_URL, URL);
  	curl_easy_perform(curl);
	}
}
                 
                 
/* SEND PULSE TO START SENSOR */                
void sensorRequest() {
  DDRD |= (1<<DHT11_PORT); /* SET DHT11 PIN TO OUTPUT */
	PORTD &= ~(1<<DHT11_PORT); /* SET PIN TO LOW */
  _delay_ms(18); /* WAIT FOR 18 MS ACCORDING TO DATA SHEET */
  PORTD |= (1<<DHT11_PORT); /* SET PIN TO HIGH */
}

/* RECEIVE RESPONSE FROM SENSOR */
void sensorResponse() {
  DDRD &= ~(1<<DHT11_PORT); /* SET DHT11 PIN TO INPUT */
  while(PIND & (1<<DHT11_PORT)); /* WAIT UNTIL DHT11 PIN IS LOW */
	while((PIND & (1<<DHT11_PORT)) == 0); /* WAIT UNTIL DHT11 PIN IS HIGH */
	while(PIND & (1<<DHT11_PORT)); /* WAIT UNTIL DHT11 PIN IS LOW */
}

/* RECEIVE DATA FROM SENSOR */
uint8_t receiveData() {
	for(int i=0; i<8; i++) { /* READING 8 BITS AT THE TIME */
    while((PIND & (1<<DHT11_PORT)) == 0); /* WAIT UNTIL DHT11 PIN IS HIGH */
    _delay_us(29); /* DELAY PER DATASHEET */
    
    if(PIND & (1<<DHT11_PORT)) { /* IF HIGH PULSE IS GREATER THAN 29 MICROSECONDS MEANS BIT IS "1" */
      data = (data<<1)|(0x01); /* SET DATA TO HIGH */
    } else { /* ELSE IF HIGH PULSE IS LESS THAN 29 MICROSECONDS MEANS BIT IS "0" */
      data = (data<<1); /* SET DATA TO LOW */
    }
    
    while(PIND & (1<<DHT11_PORT))); /* WAIT UNTIL DHT11 PIN IS LOW FOR NEW BIT */
  }
  return data;
}

/* CACULATE EXTREME VALUES FROM SENSOR */
void calcExtremeValues(uint8_t hum, uint8_t temp) {
	if(beenChecked == 0) { /* IF FUNCTION IS RAN FOR FIRST TIME, CURRENT VALUES ARE SET TO MAX/MIN */
    max_Hum = hum; /* MAX HUMIDITY IS SET TO CURRENT HUMIDITY */
    min_Hum = hum; /* MIN HUMIDITY IS SET TO CURRENT HUMIDITY */
    max_Temp = temp; /* MAX TEMP IS SET TO CURRENT TEMPERATURE */
    min_Temp = temp; /* MIN TEMP IS SET TO CURRENT TEMEPRATURE */
    
    beenChecked = 1; /* SET BOOL beenChecked TO 1 IN ORDER TO KNOW THAT THE FUNCTION HAS RAN ATLEAST ONCE */
  }
  
  if(hum > maxHum) { /* IF CURRENT HUMIDITY IS GREATER THAN MAX HUMIDITY */
    maxHum = hum; /* SET MAX HUMIDITY TO CURRENT HUMIDITY */
  }
  
  if(hum < minHum) { /* IF CURRENT HUMIDITY IS LESS THAN MIN HUMIDITY */
    minHum = hum; /* SET MIN HUMIDITY TO CURRENT HUMIDITY */
  }
  
  if(temp > maxTemp) { /* IF MAX TEMPERATURE IS GREATER THAN MAX TEMPERATURE */
    maxTemp = temp; /* SET MAX TEMPERATURE TO CURRENT TEMPERATURE */
  }
  
  if(hum < minHum) { /* IF MIN TEMPERATURE IS LESS THAN MIN TEMPERATURE */
    minTemp = temp; /* SET MIN TEMPERATURE TO CURRENT TEMPERATUR */
  }
}
    
void pinConfig() [
	DDRD |= (1<<6)|(1<<5)|(1<<1);
}

int main(void) {
  usart_Init;
  uint8_t usartData = usart_Receive();
  
  esp8266_connect(SSID, PASSWORD); /* CONNECT TO WIFI */
  
  CURL *curl;
  CURLcode res;
  CURL *curl = curl_easy_init(); /*Initiserar CURL */
  
  while(1) {
    pinConfig(); /* CONFIGURE PINS */
    
    sensorRequest(); /* SEND PULSE TO START SENSOR */
    sensorResponse(); /* RECEIVE RESPONSE FROM SENSOR */
    
    int_Hum = receiveData(); /* READ INTEGER PART OF HUMIDITY */
    dec_Hum = receiveData(); /* READ DECIMAL PART OF HUMIDITY */
    int_Temp = receiveData(); /* READ INTEGER PART OF TEMPERATURE */
    dec_Temp = receiveData(); /* READ DECIMAL PART OF TEMPERATURE */
    checkSum = receiveData(); /* READ CHECKSUM */
    
    if ((int_Hum + dec_Hum + int_Temp + dec_Temp) != checkSum) { /* IF CHECKSUM IS NOT EQUAL TO VALUES ADDED TOGETHER */
      /* TRANSMITTION ERROR, DISCARD THE CURRENT VALUES */
    } else { /* IF CHECKSUM IS CORRECT */
    	calcExtemeValues(int_Hum, int_Temp); /* CALCULATE EXTREME VALUES */
      sendThingSpeak(); /* SEND VALUES TO THINGSPEAK */
    }
  }
}