#!/usr/bin/perl

# OddJob: a simple tool for tracking time
# Copyright (C) 2011  Ben Charlton <ben@spod.cx>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; see the file COPYING. If not, write to the Free 
# Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
# MA 02110-1301 USA, or see http://www.gnu.org

use strict;

my $command = shift;

my $data = $ENV{'HOME'} . "/.oddjob";
my $ymd = sub{sprintf '%04d-%02d-%02d', $_[5]+1900, $_[4]+1, $_[3]}->(localtime);
my $elapsed_regex = '^\d+[hmsd]$';
my %fields = ('date' => 0, 'time' => 1, 'cat' => 2, 'desc' => 3);

if ($command eq 'add') {
    my $elapsed = shift;
    my $category = shift;
    my $description = join(' ', @ARGV);

    if ($elapsed !~ /$elapsed_regex/) {
        &usage;
    }

    open F, ">>$data";
    print F "$ymd\t$elapsed\t$category\t$description\n";
    close F;
}

elsif ($command eq 'edit') {
    my $id = shift;
    my $args = join(' ', @ARGV);

    if ($id !~ /^\d+$/) {
        &usage;
    }

    open F, $data;
    my @lines = (<F>);
    close F;

    die ("Invalid ID\n") if ($id > $#lines);
  
    chomp($lines[$id]) ;
    my @edits = split(/\t+/, $lines[$id]); 
    
    my $f = join('|', keys %fields);
    if (my ($key, $value) = ($args =~ m/^($f)=(.*)/)) {

        if (($1 eq 'date') && ($2 !~ /^\d{4}-\d{2}-\d{2}$/)) {
            die "Invalid date format, must be YYYY-MM-DD\n";
        }
        if (($1 eq 'time') && ($2 !~ /$elapsed_regex/)) {
            die "Invalid time format, must match $elapsed_regex\n";
        }

        $edits[$fields{$key}] = $value;
        $lines[$id] = "" . join("\t", @edits) . "\n";
        open F, ">$data";
        print F join('', @lines);
        close F;
    } else { 
        &usage;
    }

    
}

elsif ($command eq 'list' or $command eq 'ls') {

    my $args = join (' ', @ARGV);

    open F, $data;
    my @lines = (<F>);
    close F;
    
    if ($args =~ m/\-(\d+)/) {
        # head
        my $from = $#lines - $1 +1;
        $from = 0 if ($from < 0);
        for (my $i = $from; $i <= $#lines; $i++) {
            print "$i\t" . $lines[$i];
        }
    } else {
        # grep
        for (my $i = 0; $i <= $#lines; $i++) {
            print "$i\t$lines[$i]" if ($lines[$i] =~ /$args/);
        }
    }
 

} else {
    &usage;
}

sub usage (){
    print "OddJob, a simple tool for tracking time.\n";
    print "Usage:\n";
    print "  oj add <time> <category> <description>\n";
    print "  oj list|ls [string]\n";
    print "  oj list|ls [-lines]\n";
    print "  oj edit <id> (date|time|cat|desc)=<new value>\n";
    exit;
}