#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 uint32_t eepromaddress = 0;

static volatile uint8_t signal[60];        // signal that is recorded the first time
static volatile uint8_t firstsignal[60];   // all following signals that is compared with the first signal
static volatile uint8_t firstsignallength; // length of the first signal

// how many keys do you want to record
uint8_t numberKeys = 20;

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

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

void eeprom_init() {
	// position in eeprom
	eepromaddress = 0;
}

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 ++;
}

void recordSignal() {
	firstsignallength = address;
	
	// save the signal to the array "firstsignal"
	for (uint8_t i = 0; i < address; i++) {
		firstsignal[i] = signal[i];
	}	
}

uint8_t matchSignal() {
	// check if firstsignal equals signal
	// ignore a difference of +-1
	for (uint8_t i = 0; i < firstsignallength; i++) {
		if (firstsignal[i] != signal[i] && 
			(firstsignal[i] + 1) != signal[i] &&
			firstsignal[i] != (signal[i] + 1)) {
			return 0;
		}			
	}	
	
	return 1;
}

void finishSignal() {
	// write length of signal
	eeprom_write_byte(eepromaddress, firstsignallength);
	eepromaddress ++;

	// write all parts of the signal
	for (uint8_t i = 0; i < firstsignallength; i++) {
		eeprom_write_byte(eepromaddress, firstsignal[i]);
		eepromaddress ++;
	}
}

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

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

	// configure eeprom
	eeprom_init();

	// configure LCD
	lcd_init();

	// loop all keys, that you want to record
	for (uint8_t key = 0; key < numberKeys; key++) {
		for (int16_t loop = 0; loop < 3; loop++) {
			// show the user the number what key on the remote control is expected
			lcd_uint16(key);
			// reset all variables
			var_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) {
						if (loop == 0) {	
							// the first signal should be recorded as it is
							recordSignal();
						} else {
							// all following signals should match the first one
							if (matchSignal() == 0) {
								// if not, start again including recording the first signal
								loop = -1;
							}
						}	
						//#####################################
					} else {
						// no valid signal
						lcd_str("----");
						// reset variables but do not leave the loop
						var_init();
						
						// activate interrupts
						sei();
						continue;
					}
			
					// leave loop to get the next signal					
					break;
				}		
			}
		}
	
		// write signal to eeprom	
		finishSignal();
	}
}