#include <kernel/cmos.h>

int _check_update_in_progress(void) {
  unsigned char ret_val = 0;
  __asm__ volatile("mov $0x0A, %%al\n\t" "outb %%al, $0x70\n\t" "inb $0x71, %%al\n\t" "mov %%al, %0":"=b" (ret_val)::"%al");
  return ret_val;
}

unsigned char _get_rtc_reg(unsigned char reg) {
  unsigned char ret_val = 0;
  __asm__ volatile("mov %1, %%al\n\t" "outb %%al, $0x70\n\t" "inb $0x71, %%al\n\t" "mov %%al, %0":"=b" (ret_val):"c" (reg):"%al");
  return ret_val;
}

unsigned long int read_rtc() {
  unsigned char regb;
  unsigned long int ret_val;

  /* I might need to add this check back in, but it's fine for now. */
  /* while(_check_update_in_progress()); */

  cur_time.second = _get_rtc_reg(0x00);
  cur_time.minute = _get_rtc_reg(0x02);
  cur_time.hour = _get_rtc_reg(0x04);
  cur_time.day = _get_rtc_reg(0x07);
  cur_time.month = _get_rtc_reg(0x08);
  cur_time.year = _get_rtc_reg(0x09);

  regb = _get_rtc_reg(0x0B);

  /* Convert bcd to binary if needed */
  if(!(regb & 0x04)) {
    cur_time.second = (cur_time.second & 0x0F) + ((cur_time.second / 16) * 10);
    cur_time.minute = (cur_time.minute & 0x0F) + ((cur_time.minute / 16) * 10);
    cur_time.hour = ((cur_time.hour & 0x0F) + (((cur_time.hour & 0x70) / 16) * 10)) | (cur_time.hour & 0x80);
    cur_time.day = (cur_time.day & 0x0F) + ((cur_time.day / 16) * 10);
    cur_time.month = (cur_time.month & 0x0F) + ((cur_time.month / 16) * 10);
    cur_time.year = (cur_time.year & 0x0F) + ((cur_time.year / 16) * 10);
  }

  /* Convert to 24H time if needed */
  if(!(regb & 0x02) && (cur_time.hour & 0x80)) {
    cur_time.hour = ((cur_time.hour & 0x7F) + 12) % 24;
  }

  /* Get year. TODO: Use century register for this. */
  cur_time.year += (RELEASE_YEAR / 100) * 100; /* Add century of release year */
  if(cur_time.year < RELEASE_YEAR) cur_time.year += 100;

  ret_val = cur_time.second;
  ret_val += cur_time.minute * 60;
  ret_val += cur_time.hour * 3600;
  unsigned int tot_days = cur_time.day;
  unsigned char month_days[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  for(unsigned int i = 1970; i < cur_time.year; i++) {
    if(i % 400 == 0 || (i % 100 != 0 && i % 4 == 0)) {
      tot_days += 366;
    }
    else {
      tot_days += 365;
    }
  }
  for(int i = 0; i < (cur_time.month - 1); i++) {
    tot_days += month_days[i];
  }
  ret_val += tot_days * 86400;
  return ret_val;
}