#include <avr/pgmspace.h>
#include "TimeStuff.h"

/*******************/
/** Aus der RTClib entlehnt, aber ohne den Wire.h-Kram **/

#define SECONDS_FROM_1970_TO_2000 946684800

#if (ARDUINO >= 100)
 #include <Arduino.h> // capital A so it is error prone on case-sensitive filesystems
#else
 #include <WProgram.h>
#endif

int i = 0; //The new wire library needs to take an int when you are sending for the zero register
////////////////////////////////////////////////////////////////////////////////
// utility code, some of this could be exposed in the DateTime API if needed

const uint8_t daysInMonth [] PROGMEM = { 31,28,31,30,31,30,31,31,30,31,30,31 }; //has to be const or compiler complaints

// number of days since 2000/01/01, valid for 2001..2099
static uint16_t date2days(uint16_t y, uint8_t m, uint8_t d) {
    if (y >= 2000)
        y -= 2000;
    uint16_t days = d;
    for (uint8_t i = 1; i < m; ++i)
        days += pgm_read_byte(daysInMonth + i - 1);
    if (m > 2 && y % 4 == 0)
        ++days;
    return days + 365 * y + (y + 3) / 4 - 1;
}

static long time2long(uint16_t days, uint8_t h, uint8_t m, uint8_t s) {
    return ((days * 24L + h) * 60 + m) * 60 + s;
}

////////////////////////////////////////////////////////////////////////////////
// DateTime implementation - ignores time zones and DST changes
// NOTE: also ignores leap seconds, see http://en.wikipedia.org/wiki/Leap_second

DateTime::DateTime (uint32_t t) {
  t -= SECONDS_FROM_1970_TO_2000; // bring to 2000 timestamp from 1970

    ss = t % 60;
    t /= 60;
    mm = t % 60;
    t /= 60;
    hh = t % 24;
    uint16_t days = t / 24;
    uint8_t leap;
    for (yOff = 0; ; ++yOff) {
        leap = yOff % 4 == 0;
        if (days < 365 + leap)
            break;
        days -= 365 + leap;
    }
    for (m = 1; ; ++m) {
        uint8_t daysPerMonth = pgm_read_byte(daysInMonth + m - 1);
        if (leap && m == 2)
            ++daysPerMonth;
        if (days < daysPerMonth)
            break;
        days -= daysPerMonth;
    }
    d = days + 1;
}

DateTime::DateTime (uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t min, uint8_t sec) {
    if (year >= 2000)
        year -= 2000;
    yOff = year;
    m = month;
    d = day;
    hh = hour;
    mm = min;
    ss = sec;
}

static uint8_t conv2d(const char* p) {
    uint8_t v = 0;
    if ('0' <= *p && *p <= '9')
        v = *p - '0';
    return 10 * v + *++p - '0';
}

// A convenient constructor for using "the compiler's time":
// DateTime now (__DATE__, __TIME__);
// NOTE: using PSTR would further reduce the RAM footprint
DateTime::DateTime (const char* date, const char* time) {
    // sample input: date = "Dec 26 2009", time = "12:34:56"
    yOff = conv2d(date + 9);
    // Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
    switch (date[0]) {
        case 'J': m = date[1] == 'a' ? 1 : m = date[2] == 'n' ? 6 : 7; break;
        case 'F': m = 2; break;
        case 'A': m = date[2] == 'r' ? 4 : 8; break;
        case 'M': m = date[2] == 'r' ? 3 : 5; break;
        case 'S': m = 9; break;
        case 'O': m = 10; break;
        case 'N': m = 11; break;
        case 'D': m = 12; break;
    }
    d = conv2d(date + 4);
    hh = conv2d(time);
    mm = conv2d(time + 3);
    ss = conv2d(time + 6);
}

uint8_t DateTime::dayOfWeek() const {
    uint16_t day = date2days(yOff, m, d);
    return (day + 6) % 7; // Jan 1, 2000 is a Saturday, i.e. returns 6
}

uint32_t DateTime::unixtime(void) const {
  uint32_t t;
  uint16_t days = date2days(yOff, m, d);
  t = time2long(days, hh, mm, ss);
  t += SECONDS_FROM_1970_TO_2000; // seconds from 1970 to 2000

  return t;
}

/**************/

void SerialTime(DateTime& t) {
  Serial.print(t.day(), DEC);
  Serial.print('.');
  Serial.print(t.month(), DEC);
  Serial.print('.');
  Serial.print(t.year(), DEC);
  Serial.print(' ');
  Serial.print(t.hour(), DEC);
  Serial.print(':');
  Serial.print(t.minute(), DEC);
  Serial.print(':');
  Serial.print(t.second(), DEC);
  Serial.println();
}

void summertime(DateTime& globalDateTime)
{
  // http://www.mikrocontroller.net/topic/25069#186265
  // by Peter Dannegger
  // modified to work with Arduino
  uint8_t hour, day, dayOfWeek, month; // locals for faster access

  hour = globalDateTime.hour();
  day = globalDateTime.day();
  dayOfWeek = globalDateTime.dayOfWeek();
  month = globalDateTime.month();

  if( month < 3 || month > 10 )			
    return;					

  if( day - dayOfWeek >= 25 && (dayOfWeek || hour >= 2) ){ // after last Sunday 2:00
    if( month == 10 )				// October -> Winter
      return;
  }else{					// before last Sunday 2:00
    if( month == 3 )				// March -> Winter
      return;
  }
  
  // Add one hour, the rest is handled by DateTime
  globalDateTime = DateTime (globalDateTime.unixtime() + 3600);
}