#include <avr/io.h>
#include <avr/interrupt.h>
#include <math.h>
#include <TimeLib.h>


//TODO: set up seven segment decoder pins as outputs
//and bit combinations for them, and since no register is enought to host
//all of them u need to use 2 registers' pins 
const int ledPin=5;
const int debounceTime=20;
unsigned long int currentTime0=0;
unsigned long int currentTime1=0;
volatile unsigned long int triggerTime0=0;
volatile unsigned long int triggerTime1=0;
volatile int luminosity=0;

void setup(){
 //TODO: setting up an analog pin for the PWM for the LED
 DDRB|=(1<<PB5|1<<PB4|1<<PB3|1<<PB2|1<<PB1|1<<PB0);//outputs for segments A B C D E F
 DDRD|=(1<<PD7|1<<PD5);//output for G segment and PWM output on pin5 for LED
 DDRD&=~(1<<PD2|1<<PD3);//configuring pin 2 and 3 as inputs
 PORTB=(1<<PB5|1<<PB4|1<<PB3|1<<PB2|1<<PB1|1<<PB0);//7 segment default will be 0
 PORTD&=~(1<<PD7|1<<PD5);//setting G segment and LED to 0   
 PORTD|=(1<<PD2|1<<PD3);//pullup resistor for both pins
 EIMSK|=0b00000011;//configuring both INT0 and INT1 interrupts
 EICRA|=0b00000000;//interrupt if low level is detected
 Serial.begin(9600);
 sei();
}

ISR(INT0_vect){
//debouncing on low level but since it steps in every time it sees a low
//level on the pin the millis() function cant progress beyond a few (2-3)
// iterations so the current time wont be able to change until we release
//the button, cuz it steps in the interrupt so fast the other proccesses cant 
//progress
 currentTime0=millis();
 if(currentTime0-triggerTime0>debounceTime){
  if(luminosity>0)luminosity--;
  triggerTime0=millis();
 }


}

ISR(INT1_vect){

currentTime1=millis();

if(currentTime1-triggerTime1>debounceTime){
  if(luminosity<9)luminosity++;
  triggerTime1=millis();
  }
  //for some reason it doesnt step into this part ever even if i hold the button
  //i suspect its cuz once low level was detected and it triggerd an interrupt
  //it wont trigger one again until it goes back to high and than again low
  

  //on the other hand it does step into the ISR constantly, but since
  //the interrupt is immediately triggered after it steps out the millis() 
  //doesn't go forward so it will never reach the 
  //currentTime-triggerTime>debounceTime condition
  //and if we remove the condition it will quickly count up since there are 
  //no blocking conditions
  /*
  if(currentTime1-triggerTime1>=debounceTime-10&&!(PIND&1<<PD3)){
    Serial.print("curr time- trig time1: ");
    Serial.println(currentTime1-triggerTime1);    
    Serial.print("curr time1- 10: ");
    Serial.println(currentTime1-10);
  triggerTime1=millis();
 }*/
}

void updateLuminosity();

int main(){
  init();
  setup();
  while(true){
    updateLuminosity();
  }
}

void updateLuminosity(){
 switch (luminosity){
      case 0:
       PORTB=1<<PB5|1<<PB4|1<<PB3|1<<PB2|1<<PB1|1<<PB0;
       PORTD&=~(1<<PD7);
       break;
      case 1: 
       PORTB=1<<PB4|1<<PB3;
       PORTD&=~(1<<PD7);
       break;
      case 2: 
       PORTB=1<<PB5|1<<PB4|1<<PB2|1<<PB1;
       PORTD|=1<<PD7;
       break;
      case 3: 
       PORTB=1<<PB5|1<<PB4|1<<PB3|1<<PB2;
       PORTD|=1<<PD7;
       break;
      case 4: 
       PORTB=1<<PB4|1<<PB3|1<<PB0;
       PORTD|=1<<PD7;
       break;
      case 5: 
       PORTB=1<<PB5|1<<PB3|1<<PB2|1<<PB0;
       PORTD|=1<<PD7;
       break;
      case 6: 
       PORTB=1<<PB5|1<<PB3|1<<PB2|1<<PB1|1<<PB0;
       PORTD|=1<<PD7;
       break;
      case 7: 
       PORTB=1<<PB5|1<<PB4|1<<PB3;
       PORTD&=~(1<<PD7);
       break;
      case 8: 
       PORTB=1<<PB5|1<<PB4|1<<PB3|1<<PB2|1<<PB1|1<<PB0;
       PORTD|=1<<PD7;
       break;
      case 9: 
       PORTB=1<<PB5|1<<PB4|1<<PB3|1<<PB2|1<<PB0;
       PORTD|=1<<PD7;
       break;
    }
    analogWrite(ledPin,pow(1.851,luminosity)-0.5);//the task was to do 9 steps of 28 but this way brightness increases somewhat linearly
}