#include <xc.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#define _XTAL_FREQ 4000000

// CONFIG
#pragma config FOSC = INTRCIO   // Oscillator Selection bits (INTOSC oscillator: I/O function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN)
#pragma config WDTE = OFF       // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = ON       // Power-up Timer Enable bit (PWRT enabled)
#pragma config MCLRE = OFF      // RA3/MCLR pin function select (RA3/MCLR pin function is digital I/O, MCLR internally tied to VDD)
#pragma config BOREN = ON       // Brown-out Detect Enable bit (BOD enabled)
#pragma config CP = OFF         // Code Protection bit (Program Memory code protection is disabled)
#pragma config CPD = OFF        // Data Code Protection bit (Data memory code protection is disabled)

#define BUTTON_ACTIVE   (PORTAbits.RA0 == 0)
#define	VF_LOW          PORTAbits.RA1 = 0
#define	VF_HIGH         PORTAbits.RA1 = 1

#define	RST		RA2
#define RST_T	TRISA2

// common cathode LED
#define LED_MASK_OFF    0b00000000;
#define LED_MASK_RED    0b00100000;
#define LED_MASK_GREEN  0b00010000;
#define LED_MASK_YELLOW 0b00110000;

// common anode LED
//#define LED_MASK_OFF    0b00110000;
//#define LED_MASK_RED    0b00010000;
//#define LED_MASK_GREEN  0b00100000;
//#define LED_MASK_YELLOW 0b00000000;

enum eMode
{
    m50Hz,
    m60Hz
};

enum eMode CurrentMode;
enum eMode NewMode;

enum eFunction
{
    fIdle,
    fReset,
    fSelecting
};

enum eFunction Function;

uint8_t press_time;
bit old_button_state;

void load_from_ee(void);
void save_to_ee(void);
void reset_pulse(void);
void update_mode_pin(enum eMode M);
void update_mode_led(enum eMode M);
void init(void);

void main()
{
    init();
	load_from_ee();
    update_mode_pin(CurrentMode);
    update_mode_led(CurrentMode);
    Function = fIdle;
	while(1)
    {
        if(BUTTON_ACTIVE) // button pressed
        {
            __delay_ms(100);
            switch(Function)
            {
                case fIdle:
                    Function = fReset; // idle -> reset
                    PORTC = (PORTC & 0b00000111) | LED_MASK_OFF;
                    break;
                case fReset:
                    press_time++;
                    if(press_time == 10)
                    {
                        press_time = 0;
                        Function = fSelecting; // reset -> selecting
                        if(CurrentMode == m50Hz)
                            NewMode = m60Hz;
                        else
                            NewMode = m50Hz;
                        update_mode_led(NewMode);
                    }
                    break;
                case fSelecting:
                    press_time++;
                    if(press_time == 10)
                    {
                        press_time = 0;
                        if(NewMode == m50Hz)
                            NewMode = m60Hz;
                        else
                            NewMode = m50Hz;
                        update_mode_led(NewMode);
                    }
                    break;
            }
        }
        else // button not pressed
        {
            switch(Function)
            {
                case fIdle: // still idle
                    break;
                case fReset: // released after short press
                    reset_pulse();
                    Function = fIdle;
                    press_time = 0;
                    break;
                case fSelecting: // released after long press
                    if(NewMode != CurrentMode)
                    {
                        CurrentMode = NewMode;
                        update_mode_pin(CurrentMode);
                    }
                    Function = fIdle;
                    press_time = 0;
                    break;
            }
        }
	}
}

void load_from_ee(void)
{
    CurrentMode = eeprom_read(0x00);
    if(CurrentMode > m60Hz)
    {
        CurrentMode = m50Hz;
        save_to_ee();
    }
}

void save_to_ee(void)
{
    eeprom_write(0x00, CurrentMode);
}

void reset_pulse()
{
	RST = 0;
	RST_T = 0;
	__delay_ms(200);
	RST_T = 1;
	RST = 1;
}

void update_mode_pin(enum eMode M)
{
    switch(M)
    {
        case m50Hz:
            VF_LOW;
            break;
        case m60Hz:
            VF_HIGH;
            break;
    }
}

void update_mode_led(enum eMode M)
{
    switch(M)
    {
        case m50Hz:
            PORTC = (PORTC & 0b00000111) | LED_MASK_RED;
            break;
        case m60Hz:
            PORTC = (PORTC & 0b00000111) | LED_MASK_GREEN;
            break;
    }
}

void init(void)
{
	CMCON = 0x07;       // disable comparator

	PORTA = 0b00000000;
	TRISA = 0b00001101;

	WPUA = 0b00000001;  // weak pull-up on input from reset switch
	OPTION_REGbits.nRAPU = 0;

	PORTC = 0b00000000;
	TRISC = 0b00001000;
}