#!/usr/bin/perl 
use warnings;
use strict;
#Without using any built in date or time functions, write a 
#function or method that accepts two mandatory arguments. 
#The first argument is a string of the format "[H]H:MM {AM|PM}" 
#and the second argument is an integer. Assume the integer is 
#the number of minutes to add to the string. The return value of 
#the function should be a string of the same format as the first 
#argument. For example AddMinutes("9:13 AM", 10) would return 
#"9:23 AM". The exercise isn't meant to be too hard. We just 
#want to see how you code. Feel free to do it procedurally or 
#in an object oriented way, whichever you prefer. 
#Use any language you want. 
#
# Note, this is perl, one of my favorite languages
# along with php
#
#Subroutine/Function Section
sub Convert_to_min# 
# Input: A string of the form "9:23 AM" or "11:55 PM" for example
# denoting the time, note the space and colon positions.
#
# Returns a number between 0 and 
# 1500 minutes, note 720 is high noon and 1440 is midnight
# This is similar to military time, but just computed in minutes
# 9:30 AM is 570 minutes. Note anything over 1440 minutes is the next
# day. We have to flip the PM to AM then. This is taken care of in
# a later routine. see sub Convert_Military_time 

# 
  {
   my ($inline) = @_; 
   my $add_pm = 0;
   my $result = 0;
   my $hours = 0;
   my $minutes = 0;
   
   $result = index($inline, ":");
   if ($result  < 1  ) # i.e. False
     {  
     print "time must contain a colon \n";
     exit;
     }
   $hours = substr($inline,0, $result);
   $minutes = substr($inline, $result + 1 , 2);
   #Note, minutes will always be the next two digits after the colon
   $result =  index($inline, "PM");
   if ($result > 0 )
    {  $add_pm += 720; } # NOTE, assuming if not PM its AM
   # no need to add a value  for PM for minutes added.
   $minutes += $hours * 60 ;
   $minutes += $add_pm;
   return $minutes;
  }
#end sub Convert_to_min
sub Convert_Military_time 
# input is a number between 0 and 1500 denoting military minutes time
# output is normal time string, i.e. "12:05 PM"
{
my ($minutes_time) = @_;
my $hours = 0;
my $minutes = "00" ;
my $time_of_day = " AM";
my $normal_time = "0:00 AM";
my $position_decimal_pt = 0; # used later so I can do an integral divide
                             # that is throwing away the remainder if
                             # there is one.
# Watch out for next days entry right before midnight, ie.
   if ($minutes_time > 1440)  #example for entry of "11:55 PM , 10 "
                              # where we add 10 minutes to the initial 
                              # time yielding 1445 as military minutes 
                              # input for this function. 
      { $time_of_day = " AM"; 
        $minutes_time -= 1440;
      }
   else {if  ($minutes_time > 720)
      { $time_of_day = " PM"; }
   }
   $minutes = $minutes_time % 60 ;# % is mod operator
   if ($minutes < 10)
     {$minutes = "0" . $minutes ;} # so it looks pretty, ie. 05, not 5
     # for 12:05 PM 
   $hours = $minutes_time / 60 ; # note div for integral divide 
   # throwing away remainder by searching for stuff after decimal point
   # BUT if its a number with no remainder, there will be no decimal
   # point. 
   $position_decimal_pt = index($hours, "."); 
   if ($position_decimal_pt == -1) # means no decimal point in hours
      {
       $normal_time = $hours . ":" . $minutes . $time_of_day;
       return $normal_time;
      }
   else  # Got a decimal point
      { 
       $hours = substr($hours, 0 , $position_decimal_pt);
       $normal_time = $hours . ":" . $minutes . $time_of_day;
       return $normal_time; 
      }
   }
#end sub Convert_Military_time
# End Subroutine Section
# calculate desired element of standard Fibonacci sequence
# Main Section
#
#  usage    ./perltimeadd "9:23 AM" , 10
 my $inittimevalue = shift(@ARGV);
 unless($inittimevalue) {
 print " Sorry, you forgot to enter the time and minutes to add ";
 print " on.  \n i.e.  perltimeadd \"9:23 AM\" , 10 \n";
 exit;
 }
 my $comma = shift(@ARGV); # This should throw away the comma
 
 my $initminaddvalue = shift(@ARGV);
 unless($initminaddvalue) {
   print "Sorry, you forgot to enter the minutes to add  \n"; 
   print " or you negleacted to put in the comma buddy.\n";
   print " MAKE SURE their is a space before and after the comma too.\n";
   print " You know us computers are not too smart! \n";
   print " i.e.  perltimeadd \"9:23 AM\" , 10 \n";
   exit;
   }
 
my $minutes_time = Convert_to_min($inittimevalue);
my $normal_time = "0:00 AM";
print  "This is original input: $inittimevalue , $initminaddvalue \n";
print  "Mintes to add = $initminaddvalue \n";
        $minutes_time += $initminaddvalue;
print " Result in military minutes time = $minutes_time   \n";
print " Note 1440 minutes = midnight, 720 minutes = noon \n";
        $normal_time = Convert_Military_time($minutes_time);
print " Result in normal time = $normal_time \n";
exit;
# End Main Section