//Clock source & fuse bits:
//Internal oscillator 8Mhz: CKSEL3..1=0010 SUT1..0=00
//External oscillator from board: CKSEL3..1=0000 SUT1..0=00
//Low Power Crystal Oscillator: CKSEL3..1=1111 SUT1..0=11
//LCD on port C
//Switches on port D
//LEDs on port B
//**********************************************************
//Game of Reflex
//**********************************************************
//Jacek Tadus
//Ehsan Ghasemi

#include<avr/io.h>
#include<avr/interrupt.h>
#include <avr/eeprom.h>
#include"lcd.h"
#include"stdlib.h"

//timeout values for each timer
#define t1 250
#define t2 1


//the three task subroutines
void task1(void); //blinks LED0 at 4 or 8 Hz
void task2(void); //turn off LEDs wait random time
void task3(void); //turn LEDs on

void initialize(void); //all the usual MCU stuff

volatile unsigned char time1, time2;        //timeout counters
volatile unsigned char led;                 //light states
volatile unsigned char state = 0;           //state
volatile unsigned int countDelay = 0;       //counter for delay
volatile short reactionTime;                //counter for reaction time
int flag = 0;                               //state flag
uint16_t MEM;                               //memory location in EEPROM value
int bestTime;                               //holder for best time read from EEPROM
volatile short tempTime;                    //temporary holder for best time
volatile unsigned char buttonDetect = 0;    //holder for switch value

char buffer2[7];                            //buffer size
char buffer3[17];                           //buffer size

//randomnumber generation
volatile double randomNumber;               //random number holder
volatile double low;                        //low random number
volatile double high;                       //high random number

uint16_t eeprom_read_word(const uint16_t *addr);
void eeprom_write_word(uint16_t *addr, uint16_t value);

//timer0 compare Interrupt Service Routine (ISR)
ISR(TIMER1_COMPA_vect) {
    //decrement the three times if they are not already zero
    if (time1 > 0)
        --time1;
    if (time2 > 0)
        --time2;
}
//external Interupt Service Routine (ISR) for port D
ISR(PCINT3_vect) {

    if (buttonDetect == 0b01111111) {
        state = 0;

    }
    else if (buttonDetect == 0b11111110){
        if (state == 0)
            state = 1;
        else if (state == 2)
            state = 3;
        else if (state > 3)
            state = 0;
    }
}

//entry point and task scheduler loop
int main(void) {
    initialize();

    //main task scheduler loop
    while (1) {

        switch (state) {

        //STATE ZERO
        //blining light at 1Hz
        case (0):
            if (time1 == 0)
                task1();
            buttonDetect = PIND;
            break;

        //STATE ONE
        //turn lights off
        //wait around two seconds
        //detect cheating if true go to state zero
        //move to state two
        case (1):
            task2();
            flag = 0;
            state = 2;
            if (PIND == 0b11111110) {
                lcd_clrscr();
                lcd_puts("Stop cheating \n");
                state = 4;
            }
            break;

        //STATE TWO
        //turn LEDs on
        //time reaction time
        //move to state three
        case (2):

            if (time2 == 0) {
                reactionTime++;
                task3();
            }
            break;

        //STATE THREE
        //display reaction time in ms
        //compare reaction time with reaction time stored in EEPROM if less write new calue to EEPROM
        //move to state zero after reset button pressed
        case (3):

            lcd_gotoxy(0,1);                                //set location on LCD
            itoa(reactionTime, buffer2, 10);                //convert integer to strin
            if (flag == 0) {
                lcd_clrscr();
                lcd_puts("Time (ms):");                     //score in ms
                lcd_puts(buffer2);
                tempTime = reactionTime;

                if (tempTime < eeprom_read_word(&MEM)) {
                      eeprom_write_word(&MEM, tempTime);
                    }

                bestTime = eeprom_read_word(&MEM);
                itoa(bestTime, buffer3, 10);
                lcd_puts("\nHigh (ms):");                   //score in ms
                lcd_puts(buffer3);
                flag = 1;
                reactionTime = 0;
            }

            buttonDetect = PIND;
            break;

        default:
            break;
        }

    }

}

//task 1
void task1(void) {
    time1 = t1;                 //reset the task timer
    led = led ^ 0xff;           //toggle the zero's to toggle the LEDs
    PORTB = led;
}

//task 2
void task2(void) {
    time1 = t1;                 //reset the task time
    countDelay = 0;             //reset the counter
    PORTB = 0xff;               //turn LEDs off

    while (countDelay <= 6)     //time delay
    {
        if (time1 == 0) {
            countDelay++;
            time1 = t1;
        }
    }

}
//task 3
void task3(void) {
    time2 = t2;                 //reset time
    PORTB &= 0x00;              //turn all LEDs on

}

//set it all up
void initialize(void) {

    //set up the ports
    DDRD = 0x00;        //PORTC is an input
    DDRB = 0xff;        //PORTB is an ouput

    //set timer0
    TCCR1A = 0b00000000; //CTC mode no PWM, the most significant 6 bits do not matter for this lab
    TCCR1B = 0b00001011; //prescaler 64
    TIMSK1 = 0b00000010; //enable Output Compare A Match interrupt
    OCR1A = 250;         //set the compare register to 250 clock ticks -> Output Compare A Match interrupt occurs with 1KHz frequency

    PCICR = 0b00001000;  //enable Pin Change Interrupt PCIE3
    PCMSK3 = 0b10000001; //enable I/O pin 0 this looks at switch 0.

    //initialize display, cursor off
    lcd_init(LCD_DISP_ON);

    //init the LED status (all off)
    led = 0xff;

    //init the task timers
    time1 = t1;
    time2 = t2;

    //initialize randomNumber
    randomNumber = 0;
    low = 8;
    high = 15;

    //clear display and home cursor
    lcd_clrscr();

    //crank up the ISRs
    sei();
}