/*##############################################################################

    Copyright (C) <2010>  <LexisNexis Risk Data Management Inc.>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
############################################################################## */

export Date_i2_YYYYMM(unsigned2 i) := if(i=0,
                      '      ',
                      (string4)((i-1) div 12 + 1900)+intformat(((i-1) % 12)+1,2,1));

export Date_MMDDYY_I2(string6 s) := IF ( (unsigned8)s=0,
                      0,
                      (unsigned8)(IF(s[5..6]<'40','20','19')+s[5..6]+s[1..4]));

export date_overlap_first(unsigned8 lf, unsigned8 ll,
                          unsigned8 rf, unsigned8 rl) :=

  MAP ( lf > rl => 0,
        rf > ll => 0,
        lf > rf => lf,
        rf );

export date_overlap_last(unsigned8 lf, unsigned8 ll,
                         unsigned8 rf, unsigned8 rl) :=

  MAP ( lf > rl => 0,
        rf > ll => 0,
        ll > rl => rl,
        ll );

export date_overlap(unsigned8 lf, unsigned8 ll,
                    unsigned8 rf, unsigned8 rl) :=

  MAP( date_overlap_last(lf,ll,rf,rl)=0 => if (date_overlap_first(lf,ll,rf,rl)=0,0,1),
       date_overlap_first(lf,ll,rf,rl)=0 => 1,
       (date_overlap_last(lf,ll,rf,rl) div 100 - date_overlap_first(lf,ll,rf,rl) div 100) * 12 +
        date_overlap_last(lf,ll,rf,rl)%100-date_overlap_first(lf,ll,rf,rl) % 100);

export Date_YYYYMM_i2(string6 dte) := if(dte='',0,((integer)(dte[1..4])-1900)*12+(integer)(dte[5..6]));


export LeapYear(integer2 year) := year % 4 = 0 and ( year % 100 != 0 or year % 400 = 0);

INTEGER2 dayofyr(integer1 month,integer1 day) :=
        CHOOSE( month,0,31,59,90,120,151,181,212,243,273,304,334 ) + day;

export INTEGER2 DayOfYear(integer4 year,integer1 month,integer1 day) :=
        dayofyr(month,day) + IF( LeapYear(year) and month > 2, 1, 0);

export DaysSince1900(integer2 year, integer1 month, integer1 day) :=
  ((integer)year-1900)*365+(year-1901) div 4 + DayOfYear(year,month,day);

//this works only with dates in YYYYMMDD format
export integer8 DaysApart(string8 d1, string8 d2) :=
    abs(DaysSince1900((integer2)(d1[1..4]), (integer1)(d1[5..6]), (integer1)(d1[7..8])) -
    DaysSince1900((integer2)(d2[1..4]), (integer1)(d2[5..6]), (integer1)(d2[7..8])));

export EarliestDate(integer l, integer r) := if ( l=0 or (r<>0 and r<l),r,l);

export earliestdatestring(string20 l,string20 r) := if ( l='' or r<>'' and r<l,r,l);

export Format_Date(integer2 year, integer1 month, integer1 day) :=
          (string4)year+'/'+intformat(month,2,1)+'/'+intformat(day,2,1);

import lib_stringlib;

// WORKS FOR DATES IN FORMAT OF YYYYMMDD
today := lib_stringlib.StringLib.getdateYYYYMMDD();

thismonth := (integer2)(today[5..6]);
thisday := (integer2)(today[7..8]);
thisyear := (integer2)(today[1..4]);

export getage(string8 dob) := if(thismonth < (integer2)(dob[5..6]) or
          (thismonth = (integer2)(dob[5..6]) and thisday < (integer2)(dob[7..8])),
          thisyear - (integer2)(dob[1..4]) - 1,
          thisyear - (integer2)(dob[1..4]));

export LatestDate(integer l, integer r) := if ( r>l,r,l);