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

#include "yaMBSiavr.h"

uint8_t font[] = {
    0xEE,
    0x82,
    0xDC,
    0xD6,
    0xB2,
    0x76,
    0x7E,
    0xC2,
    0xFE,
    0xF6,
};

uint16_t bcd;
uint8_t display[4];
volatile uint16_t holdingRegisters[4];
volatile uint8_t outstate = 0;
volatile uint8_t ejector_timer = 0;

void timer0_init()
{
    TCCR0 = (1<<WGM01); //TIMER0 SET-UP: CTC MODE
    TCCR0 = (1<<CS01)|(1<<CS00); // PS 1:64
    OCR0 = 249; // 1ms reach for clear (16mz:64=>250kHz:250-=>1kHz)
    TIMSK |= 1<<OCIE0;     //IRQ on TIMER0 output compareA
}

void timer1_init(void) {
	TCCR1B|= (1<<CS12) | (1<<WGM12); //prescaler 8
    OCR1A = 62500;
	TIMSK|=(1<<OCIE1A);
}

void timer2_init(void) {
	TCCR2|=(1<<CS21); //prescaler 8
	TIMSK|=(1<<TOIE2);
}

unsigned long bin2bcd (uint32_t n)     // convert 16 bit binary n to 5 digit BCD (packed)
{
    return n + 6 * (n/10 + 16*(n/100) + 256*(n/1000) + 4096*(n/10000));
}

void update_display(){
    uint8_t h = holdingRegisters[0] / 3600;
    uint8_t m = (holdingRegisters[0] / 60) % 60;
    uint8_t s = holdingRegisters[0] % 60;

    if(h)
        bcd = bin2bcd(m) | bin2bcd(h)<<8;
    else
        bcd = bin2bcd(s) | bin2bcd(m)<<8;

    display[0] = font[(bcd&0x000f)];
    display[1] = font[(bcd&0x00f0) >> 4];
    display[2] = font[(bcd&0x0f00) >> 8];
    display[3] = bcd&0xF000 ? font[(bcd&0xf000) >> 12] : 0;
}

void eject(){
    PORTA |= _BV(7);
    ejector_timer = 200;
    //outstate |= _BV(1);
}

void reset_timer(){
    outstate &= ~0x01;
    holdingRegisters[0] = 17*60;
    update_display();
}

void modbusGet(void) {
    if (modbusGetBusState() & (1<<ReceiveCompleted))
    {
        switch(rxbuffer[1]) {
            case fcReadHoldingRegisters:
                holdingRegisters[1] = PINA & 0x0F;
                holdingRegisters[2] = bcd;
                modbusExchangeRegisters(holdingRegisters,0,4);
                break;
            case fcPresetSingleRegister:
            case fcPresetMultipleRegisters:
                modbusExchangeRegisters(holdingRegisters,0,1);
                update_display();
                break;
            case fcReadCoilStatus:
                modbusExchangeBits(&outstate,0,8);
                if(modbusIsInRange(3))
                    outstate &= ~_BV(3);
                break;
            case fcForceMultipleCoils:
            case fcForceSingleCoil:
                ;
                uint8_t oldstates = outstate;
                modbusExchangeBits(&outstate,0,8);

                if(!(oldstates & _BV(0)) && outstate & _BV(0)){
                    //reset_timer();
                    update_display();
                    outstate |= _BV(0);
                }

                if(outstate & 0x02)
                    eject();

                break;
            default:
                modbusSendException(ecIllegalFunction);
                break;
        }
    }
}

int main(void){
    DDRB |= _BV(3) | _BV(2) | _BV(1) | _BV(0);  // led anodes
    DDRB |= _BV(4);                             // dots
    DDRD = 0xFC;                                // uln output 1
    DDRA |= _BV(5) | _BV(4);
    DDRC = 0xFE;                                // uln output 2
    DDRA |= _BV(7);                             // ejector out

    PORTA |= _BV(0) | _BV(1) | _BV(2);          // pullups on button inputs

	modbusSetAddress(24);
	modbusInit();

    timer0_init();
    timer1_init();
    timer2_init();

    outstate |= _BV(2);
    holdingRegisters[0] = 17*60;

    sei();

    uint8_t old_A = PINA;
    while(1){
        modbusGet();

        if(!(PINA & _BV(2))){
            holdingRegisters[0] += 5;
            update_display();
            _delay_ms(10);
        }
        if(!(PINA & _BV(1))){
            if(holdingRegisters[0]>5){
                holdingRegisters[0] -= 5;
                update_display();
                _delay_ms(10);
            }
        }
        if(!(PINA & _BV(0)) && (old_A & _BV(0))){
            if(!(outstate & 0x01)){
                reset_timer();
            }
            outstate ^= 0x01;
            _delay_ms(100);
        }
        old_A = PINA;
    }

}

ISR(TIMER0_COMP_vect) {
    if(outstate & 0x01){
        PORTB|=1<<4; // dots
        if(PORTB & 0x01){
            PORTB = (PORTB & 0xF0) | 1<<1 | 1<<3;
            PORTD = display[3] & 0xFC;
            PORTA = (PORTA & 0xCF) | (display[3] & 0x03) << 4;
            PORTC = display[1];
        }
        else{
            PORTB = (PORTB & 0xF0) | 1<<0 | 1<<2;
            PORTD = display[2] & 0xFC;
            PORTA = (PORTA & 0xCF) | (display[2] & 0x03) << 4;
            PORTC = display[0];
        }
    }
    else{
        PORTB&=~(1<<4); // dots
        PORTB &= ~0x0F;
    }

    if(ejector_timer > 0 && ejector_timer < 0xFF){
        ejector_timer--;
    }
    else if(ejector_timer == 0){
        PORTA &= ~_BV(7);
        outstate &= ~0x02;
        ejector_timer = 0xFF;
    }
}

ISR(TIMER1_COMPA_vect) {
    if(outstate & 0x01){
        holdingRegisters[0]--;
        update_display();
    }

    if(holdingRegisters[0] == 0){
        reset_timer();
        if(outstate & _BV(2)){
            eject();
            outstate |= _BV(3);
        }
    }
}

ISR(TIMER2_OVF_vect) { //this ISR is called 9765.625 times per second
	modbusTickTimer();
}