#include <avr/io.h>
#include <string.h>
#include <stdio.h>

void initialiseUART(void);
void initisliseIO(void);
void sendNumber(int number);
void sendString(char *stringToSend);
void transmitChar(unsigned char data);
int8_t readEncoder(void);
void delay(uint32_t ms);
void newLine(void);


int main(void)
{
    initialiseUART();
    initisliseIO();

    uint8_t number = 128;

    while (1)
    {
        int8_t direction = readEncoder();
        switch(direction)
        {
            case 1:
            if(number == 255)
            {
                ;
            }
            else
            {
                sendString("\x1B[2J");
                sendString("\x1B[H");
                sendNumber(++number);
                newLine();
            }
            break;
            case -1:
            if(number == 0)
            {
                ;
            }
            else
            {
                sendString("\x1B[2J"); //clear screan
                sendString("\x1B[H"); // cursor to home
                sendNumber(--number);
                newLine();
            }
            break;
            default:
            break;
        }
    }
}

void newLine(void)
{
    transmitChar(10);
    transmitChar(13);
}

void initialiseUART(void)
{
    uint16_t baud = 103;
    UBRR0H = (baud >> 8);
    UBRR0L = baud;

    UCSR0B |= (1<< TXEN0 | 1 << RXEN0);
}

void initisliseIO(void)
{
    DDRC &= ~(1 << DDC0 | 1 << DDC1);
}

void sendNumber(int number)
{
    char temp[10];

    sprintf(temp, "%d", number);
    sendString(temp);
}

void sendString(char *stringToSend)
{
    int lenght =strlen(stringToSend);
    for(int i = 0; i < lenght; i++)
    {
        transmitChar(stringToSend[i]);
    }
}

void transmitChar(unsigned char data)
{
    while( !(UCSR0A & (1 << UDRE0)) ); // or while( (UCSR0A & (1 << UDRE0)) ==0 );
    UDR0 = data;
}

int8_t readEncoder(void)
{
    int8_t states[] = {0, -1, 1, 0, 1, 0, 0, -1, -1, 0, 0, 1, 0, 1, -1, 0};
    static uint8_t state = 0;

    state <<=2;
    state |= (PINC & (1 << PINC0 | 1 << PINC1));

    //Make sure channel a is off
    if((PINC & (1 << PINC0)) !=0)
    {
        //make sure channel b is off
        if((PINC & (1 << PINC1)) !=0)
        {
            return states[(state & 0x0F)]; //mask the high nibble 0
        }
    }
    return 0;
}

void delay(uint32_t ms)
{
    uint32_t i = 471 * ms;
    while(--i > 0);
}