#! /usr/bin/env perl
# Description: Send mails due to 'birthday.json' file and a given
#              configuration file.
# Author: Farhad Fouladi (2012)

use Getopt::Std;
use JSON::PP;
use autodie;
use App::Birthday;

getopts('hxvi:c:', \ my %opt) or usage();
usage()   if $opt{h};
version() if $opt{v};
my $today = sprintf("%d.%d", sub {($_[3], $_[4]+1)}->(localtime));#5.2

$opt{i} = $opt{i} // 'birthday.json';
$opt{c} = $opt{c} // 'config.json';

# Read Input file
my $input = do {   # narrow scope
    local $/;      # Enter file slurp mode localized
    open my $in_fh, '<', $opt{i};
    <$in_fh>;      # slurp whole input file in a run
};

# Read Configuration file
my $conf = do {
    local $/;
    open my $conf_fh, '<', $opt{c};
    <$conf_fh>;
};

my $json     = JSON::PP->new->allow_nonref;
my $input_hr = $json->decode( $input );
my $conf_hr  = $json->decode( $conf );

for (keys %$input_hr) {
    if ($$input_hr{$_}{date} == $today or $opt{x}) {
        send_mails( $_, $input_hr, $conf_hr, $opt{i} );
    }
}

1;
__END__

=head1 NAME

B<birthday> 

=head1 SYNOPSIS

B<birthday> <option>

=head1 OPTION

   -h : help
   -i <file> : user defined input file, default "birthday.json"
   -c <file> : user defined configuration file, default "config.json"
   -x        : send to all users in "config.file", no date verification

=head1 DESCRIPTION

It sends birthday e-mails to your friends, on their anniversary date.

I have a bad habit that I almost always forget the birthdays of my
friends and colleagues. To solve this, I try to 'cheat' and write this
script and add it to my I<crontab>.

It sends an e-mail at his/hers anniversary date to a friend and a
reminder to me. (The other way, there was a risk that I forget again!)
Additionally all your common friends receive reminders that your friend
has his/hers birthday today.

The list of birthday children are saved in a JSON file, default is
F<birthday.json>, in the same directory as script. Any other file can be
selected using option I<-i>. See below for file format.

Additionally you need a configuration file for your e-mail system. This
file is also in JSON format and default is F<configuration.json>, in the
same directory as script. The file format is described below. Any other
file can be selected using option I<-c>.

=head2 Input Format

The format of input file can be best described by an example. Imagin Bob
has 3 friends: Carol, Ted, Alice. The following JSON structure can be
saved, e.g. in F<birthday.json>.

    {
        "carol" : {
            "date" : "16.9",
            "friends" : { 
                "names" : ["ted"],
                "subject" : "Carol has today birthday!"
            },
            "email" : "carol@somewhere.com",
            "subject" : "Happy Birthday Carol!",
            "text" : "Dear Carol, \nhappy birthday and all the best wishes \n\nYours,\nBob"
        },
        "ted" : {
            "date" : "25.11",
            "friends" : { 
                "names" : ["carol", "alice"],
                "subject" : "Ted has today birthday!"
            },
            "email" : "ted@another.com",
            "subject" : "*** Happy Birthday! ***",
            "text" : "Dear Ted, \n happy birthday \n\nRegards,\nBob"
        },
        "alice" : {
            "date" : "5.12",
            "friends" : { 
                "names" : ["other"],
                "subject" : "Alice has today birthday!"
            },
            "email" : "alice@somewhere.com",
            "subject" : "*** Happy Birthday! ***",
            "text" : "Dear Alice, \n happy birthday \n\nRegards,\nBob"
        }
    }

then at 16.9 (16th Sept.) following mails will be sent:

    bob -> carol    # congratulation mail
    bob -> ted      # reminder mail - carol has birthday
    bob -> bob      # copy of congratulation mail - bob email in F<configuration.json>

If word B<others> as his/her only friend is inserted, all
users minus birthday person in input file, will receive an reminder email. For
example in above file, following reminder e-mails will be sent at 5th of Dec.:

    bob -> ted
    bob -> carol

The option I<-x> will send to all your friends e-mails without
consideration to value of the "date" (their birthday). It can be for example
used for 'xmas' congratulations or an invitation.

=head2 Configuration Format

The format of configuration file can be best described by an example.

    {
        "from" : "bob@mycompany.com",
        "maintainer" : "bob@myhome.com",
        "transport" : {
            "host" : "mail.mycompany.net",
            "port" : "25"
        }
    }

Maintainer will receive an e-mail reminder, that he sent a
birthday e-mail. 

For example in above example Bob receive a copy of birthday e-mails at
his "bob@myhome.com".

=head2 Usage Examples

=over 4

=item * send at friend birthday a congratulations mail; use default
I<birthday.json> and I<configuration.json> configuration file

birthday

=item * send at friend birthday a congratulations mail; use
I<birthday_colleagues.json> and default configuration file

birthday -i somewhere/birthday_colleagues.json

=item * send immediately to all users Xmas congratulation, with default config file

birthday -x -i somewhere/xmas.json

=item * send immediately to all users Xmas congratulation, use not defalut config file

birthday -x -i xmas.json -c home_config.json

=back

=head1 AUTHOR

Farhad Fouladi

=cut