#include <main.h>
#include <console.h>

#define MINUTE 60
#define HOUR (60*MINUTE)
#define DAY (24*HOUR)
#define YEAR (365*DAY)

int tage_pro_monat[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

int CMOS_READ(int address)
{
	if(address < 10)
    {
        outb(0x70, 0xa);
        while((inb(0x71) & (1 << 7)) != 0)
        {
            asm volatile("nop");
        }
    }

    outb(0x70, address);
    return inb(0x71);
}

int bcd_to_bin(int val)
{
	//Ueberpruefen, ob BCD verwendet wird
    if((val & (1 << 2)) == 0)
    {
        return (val & 0xf) + ((val >> 4) & 0xf) * 10;
    }
    else
    {
        return val;
    }
}

time_t system_time;

void init_time()
{
	do {
		system_time.tm_sec = bcd_to_bin(CMOS_READ(0));
		system_time.tm_min = bcd_to_bin(CMOS_READ(2));
		system_time.tm_hour = bcd_to_bin(CMOS_READ(4));
		system_time.tm_mday = bcd_to_bin(CMOS_READ(7));
		system_time.tm_mon = bcd_to_bin(CMOS_READ(8));
		system_time.tm_year = bcd_to_bin(CMOS_READ(9)) + 2000;
	} while (system_time.tm_sec != bcd_to_bin(CMOS_READ(0)));
	system_time.tm_timestamp = time_t_to_unix(system_time);
}

long time_t_to_unix(time_t tm)
{
	int jahr, stunde, minute, sekunde, monat, tag;
	
	jahr = tm.tm_year;
	stunde = tm.tm_hour;
	minute = tm.tm_min;
	sekunde = tm.tm_sec;
	monat = tm.tm_mon;
	tag = tm.tm_mday;
	
	const short tage_bis_monatsanfang[12] = /* ohne Schalttag */
				{0,31,59,90,120,151,181,212,243,273,304,334};
				
	long unix_zeit;
	long long jahre=jahr-1970;
	int schaltjahre=((jahr-1)-1968)/4 - ((jahr-1)-1900)/100 + ((jahr-1)-1600)/400;
	
	unix_zeit=sekunde + 60*minute + 60*60*stunde +
				(tage_bis_monatsanfang[monat-1]+tag-1)*60*60*24 +
				(jahre*365+schaltjahre)*60*60*24;

	if ( (monat>2) && (jahr%4==0 && (jahr%100!=0 || jahr%400==0)) )
		unix_zeit+=60*60*24; /* +Schalttag wenn jahr Schaltjahr ist */
	return unix_zeit;
}