#include "serial.h"

char rxBuffer[BUFFER_SIZE];
volatile uint16_t interruptIndex = 0;

ISR (USART_RX_vect) //I have seen worse interrupt sintax
{
	rxBuffer[interruptIndex % BUFFER_SIZE] = UDR0;
	interruptIndex++;
}

Serial::Serial()
{
    UBRR0H = UBRRH_VALUE;
    UBRR0L = UBRRL_VALUE;
    UCSR0C = _BV(UCSZ01) | _BV(UCSZ00); 
    UCSR0B = _BV(RXEN0) | _BV(TXEN0);   //Enable RX and TX
    UCSR0B |= (1 << RXCIE0); //Enable Rx interuppt
}

void Serial::putChar(const char c)
{
    loop_until_bit_is_set(UCSR0A, UDRE0);
    UDR0 = c;
}

void Serial::putString(const char* in, const unsigned int length)
{
    for(unsigned int i = 0; i < length && in[i] != '\0'; i++)
    {
        putChar(in[i]);
    }
}

void Serial::putString(const char in[])
{
    for(unsigned int i = 0; i < strlen(in); i++)
    {
        putChar(in[i]);
    }
}

bool Serial::dataIsWaiting()
{
    return (interruptIndex > _rxIndex);
}

char Serial::getChar()
{
    if( _rxIndex >= (32768) - 2*BUFFER_SIZE ) flush(); //may explode only occasionaly
    if(dataIsWaiting())
    {
        _rxIndex++;
        return rxBuffer[(_rxIndex -1) % BUFFER_SIZE];
    }
    else return '\0';
}

unsigned int Serial::getString(char* buffer, const int bufferLength)
{
    int i = 0;
    for(; i <= (interruptIndex-_rxIndex) && i <= BUFFER_SIZE && rxBuffer[(_rxIndex+i) % BUFFER_SIZE] != _terminator; i++);
    
    if( i < (interruptIndex-_rxIndex) && i > 0)
    {
       int j = 0;
       for(; j < i &&  j < bufferLength-1 ; j++)
       {
           buffer[j] = getChar();
       }
       buffer[j+1]='\0';
       _rxIndex++;
    }
    else
    {
         i = 0;
         if( _rxIndex >= (32768) - 2*BUFFER_SIZE ) flush();
    }

    if (rxBuffer[(_rxIndex+i) % BUFFER_SIZE] == _terminator) _rxIndex++;
    
    return i;
}

void Serial::flush()
{
    _rxIndex = 0;
    interruptIndex = 0;
    for(int i = 0; i < BUFFER_SIZE; i++) rxBuffer[i] = ' ';
}

void Serial::setTerminator(char terminator){_terminator = terminator;}