#define F_CPU  1000000

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

#include "../helpers.h"
#include "../lcd.h"

static volatile uint8_t address = 0;
static volatile uint16_t cnt = 0;

static volatile uint8_t signal[60];        // signal that is recorded the first time

static uint8_t signals[] = {
	36, 0, 19, 24, 28, 32, 37, 46, 50, 54, 59, 67, 72, 81, 89, 94, 103, 111, 120, 124, 129, 137, 146, 155, 159, 168, 173, 181, 190, 194, 199, 203, 212, 216, 225, 164, 175,  // 0
	36, 0, 20, 24, 29, 33, 37, 46, 51, 55, 59, 68, 72, 81, 90, 94, 103, 112, 121, 125, 134, 142, 151, 160, 164, 169, 173, 182, 186, 191, 195, 200, 208, 217, 226, 165, 176,  // 1
	36, 0, 20, 24, 29, 33, 37, 46, 50, 55, 59, 68, 72, 81, 90, 94, 103, 112, 121, 125, 134, 143, 151, 160, 164, 173, 178, 186, 191, 195, 199, 204, 213, 217, 226, 165, 176,  // 2
	36, 0, 20, 24, 29, 33, 37, 46, 51, 55, 59, 68, 72, 81, 90, 94, 103, 112, 121, 125, 129, 134, 142, 151, 156, 165, 169, 177, 186, 195, 199, 204, 213, 217, 226, 165, 176,  // 3
};

// how many keys have you recorded
uint8_t numberKeys = 4;

void timer_init()
{
    // timer
	TCCR0 |= (1 << CS00); 
 	TIMSK |= (1 << OCIE0);

	// interrupt for changing port
	GICR |= (1 << INT1);
	MCUCR |= (1 << ISC10);
	MCUCR |= (1 << ISC11);
}

void var_init() {
	cnt = 0;      // timebase 
	address = 0;  // position in array
}

ISR(TIMER0_COMP_vect) {
	// count up a counter (timebase) 
	// but only if a signal has appeared on the port one time
	if (address > 0) { 
		cnt ++;
	}
}

ISR(INT1_vect) {
	// we got a signal change on the port, so save the timebase into array
	// and increase position in array
	signal[address] = cnt;
	address ++;
}

uint8_t matchSignal() {
	// check if signal equals one of the signals
	uint16_t signalSavedAddress = 0;
	uint16_t signalSavedLength = 0;
	uint8_t key = 0;
	
	// lopp all keys that are included in signals
	for (key = 0; key < numberKeys; key++) {
		// we have to increase the addresses by the number of bytes
		signalSavedAddress += signalSavedLength;
		signalSavedLength = signals[signalSavedAddress];
		signalSavedAddress ++;
		
		// save here if we have found something
		uint8_t matched = 1;

		for (uint8_t i = 0; i < signalSavedLength; i++) {
			// compare the two values
			uint8_t value1 = signal[i];
			uint8_t value2 = signals[signalSavedAddress + i];
			
			// ignore a difference of +-1
			if (value2 != value1 && (value2 + 1) != value1 && value2 != (value1 + 1)) {
				// did not match, so try the next one
				matched = 0;
				break;
			}		
		}	

		// we found a match, so return the index + 1 (because 0 is "no match found")
		if (matched == 1) {
			return key + 1;
		}
	}	
	
	return 0;
}

int main() {
	// deactivate all interrupts
	cli();

	// configure timer and interrupts
    timer_init();
	
	// configure variables
	var_init();

	// configure LCD
	lcd_init();

	// activate interrupts
	sei();

	while(1) {
		if (address > 0) {
			// if address is > 0 then we have received a signal
			_delay_ms(100);

			// block any other signals
			cli();
	
			// filter for valid signals
			if (address > 5) {
				uint8_t result = matchSignal();
				
				if (result > 0) {
					lcd_uint16(result);
				}
			} else {
				// no valid signal
				lcd_str("----");
			}

			var_init();
		
			// activate interrupts
			sei();
		}		
	}
}