#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <Servo.h>

#define IR_PIN_0 4 // S0 - uplne na pravo (pin D4)
#define IR_PIN_1 5 // S1 (pin D5)
#define IR_PIN_2 6 // S2 (pin D6)
#define IR_PIN_3 7 // S3 (pin D7)
#define IR_PIN_4 8 // S4 (pin D8)
#define IR_PIN_5 11 // S5 (pin D11)
#define IR_PIN_6 12 // S6 (pin D12)
#define IR_PIN_7 13 // S7 (pin D13)

Servo LeftServo;
#define SERVO_PIN_LEFT 9 // lave servo pripojene na pin D9

Servo RightServo;
#define SERVO_PIN_RIGHT 10 // prave servo pripojene na pin D10

#define TRIGGER_PIN 2 // (pin D2)
#define ECHO_PIN 3  // (pin D3)

#define FAST 110
#define SLOW 80

#define OBSTACLE_DISTANCE_THRESHOLD 3 // vzdialenost prekazky od robota pri ktorej sa jej zacne vyhybat

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

  LeftServo.attach(SERVO_PIN_LEFT);
  RightServo.attach(SERVO_PIN_RIGHT);

  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);

  pinMode(4, INPUT);
  pinMode(5, INPUT);
  pinMode(6, INPUT);
  pinMode(7, INPUT);
  pinMode(8, INPUT);
  pinMode(11, INPUT);
  pinMode(12, INPUT);
  pinMode(13, INPUT);
  
  // Povolenie prerusenia pre IR piny
  PCICR |= (1 << PCIE2) | (1 << PCIE0); // Povolenie PCIE2 pre piny od PCINT16 do PCINT23 a PCIE0 pre piny od PCINT0 do PCINT7
  PCMSK2 |= (1 << PCINT20) | (1 << PCINT21) | (1 << PCINT22) | (1 << PCINT23); // Povolenie preruseni pre PD4 az PD7
  PCMSK0 |= (1 << PCINT0) | (1 << PCINT3); // Povolenie preruseni pre PB0 a PB3
  sei();
}

void loop()
{
  Serial.print("S: ");
  Serial.print(digitalRead(IR_PIN_0));
  Serial.print(digitalRead(IR_PIN_1));
  Serial.print(digitalRead(IR_PIN_2));
  Serial.print(digitalRead(IR_PIN_3));
  Serial.print(digitalRead(IR_PIN_4));
  Serial.print(digitalRead(IR_PIN_5));
  Serial.print(digitalRead(IR_PIN_6));
  Serial.println(digitalRead(IR_PIN_7));
  delay(1);

  // pohyb
    if(digitalRead(IR_PIN_3) == 1 || digitalRead(IR_PIN_4) == 1) 
    { 
      // dopredu
      LeftServo.write(90-SLOW);
      RightServo.write(90+SLOW);
    }
    else if(digitalRead(IR_PIN_5) == 1 || digitalRead(IR_PIN_6) == 1)
    {
      // dolava
      LeftServo.write(90-SLOW);
      RightServo.write(90-SLOW);
    }
    else if(digitalRead(IR_PIN_1) == 1 || digitalRead(IR_PIN_2) == 1)
    {
      // do prava
      LeftServo.write(90+SLOW);
      RightServo.write(90+SLOW);
    }
    else if(digitalRead(IR_PIN_0) == 1)
    {
      // ostro do prava
      LeftServo.write(90+FAST);
      RightServo.write(90+FAST);
    }
    else if(digitalRead(IR_PIN_7) == 1)
    {
      // ostro dolava
      LeftServo.write(90-FAST);
      RightServo.write(90-FAST);
    }
    else
    {
      // stop
      LeftServo.write(90);
      RightServo.write(90);
    }
  
  delay(5);
  }
  
// Funkcia na kontrolu prekazok pomocou HC-SR04
bool check_obstacle() 
{
  // Generate trigger pulse for HC-SR04
  PORTD |= (1 << TRIGGER_PIN);
  _delay_us(5);
  PORTD &= ~(1 << TRIGGER_PIN);

  // Zmeranie sirky ozveny z echo pinu 
  uint32_t pulse_width = 0;
  while (!(PIND & (1 << ECHO_PIN))); // Cakanie na nabeznu hranu
  TCNT1 = 0; // Resetovanie casovaca
  while (PIND & (1 << ECHO_PIN)) 
  { // Cakanie na dobeznu hranu
    if (TCNT1 > 23200) // Maximalna povolena sirka impulzu (400cm)
      return false; // Ziadna prekazka nebola zaznamenana
  }
  pulse_width = TCNT1; // Ziskaj sirku impulzu

  // Premena sirky impulzu na vzdialenost v cm
  uint16_t distance = pulse_width / 58;

  // Kontrola ci prekazka je aspom 3cm od robota
  if (distance >= OBSTACLE_DISTANCE_THRESHOLD)
    return false; // V prahovej vzdialenosti nebola zistena ziadna prekazka

  return true; // Zistena prekazka
}