#!/usr/bin/perl -w
use strict;
our $pgm = $0; $pgm =~ s#.*/##;
our $usage = <<'END';
usage:
 $pgm [<opts>] update <number>|<localpart>@[domain] [<reason>] [<comment>]
 $pgm [<opts>] assign <number>|<localpart>@[domain] <comment>
 $pgm [<opts>] show <count>              } will generate more aliases
 $pgm [<opts>] range [<from>-[<to>]]     }  if necessary
opts:
 -G<generator>           generator/lister program
 -N                      do not generate more aliases
 -l.., -d.., -F.., -m..  passed to generator
notes:
 Always use $pgm to edit the comment of a pregen alias;
  otherwise we may lose track of the next number alias to pregenerate
  and reuse numbers.
 <comment> must always start with #, and you will need to quote the
  whole comment to protect it from your shell
END

our $generator;
our @genopts;

sub fetch_list {
    open P, "-!", $generator, qw(list) or die $!;
    while (<P>) {
	my ($alias,$user);
	if (m/^\# user/) {
	    next;
	} elsif (m/^\# reject (\S+) (\#.*)$/) {
	    ($alias,$comment) = ($1,$2);
	} elsif (m/^\#/) {
	    next; # future extension
	} elsif (m/^([^#: ])\: [^#]* (\#.*)$/) {
	    ($alias,$comment) = ($1,$2);
	} else {
	    die "generator output $_ ?";
	}
	my $localpart = $alias;
	$localpart =~ s/\@.*//;
	my $row = { Alias => $alias, LocalPart => $localpart };
	if ($comment =~ m/^### PREGEN ([1-9]\d{0,8})$/) {
	    $row->{Number}= $1;
	}
	$by_localpart{$row->{LocalPart}} = $row;
	$by_number[$row->{Number}] = $row if defined $row->{Number};
    }
    $?=0; $!=0; close P or die "$generator $! $?";
    
}

sub parse_target {
    @ARGV or badusage "missing specification for alias to change";
    my $spec = shift @ARGV;
    my $target;
    if ($spec =~ m/^(\d{1,9})$/) {
	$target = $by_number[$spec];
	die "no alias number $target\n" unless $target;
    } elsif ($spec =~ m/^(.*)\@[^\@]*/) {
	$target = $by_localpart{$1};
	die "no alias with local part \`$1'\n" unless $target;
	die "incorrect or unchecked domain: \`$target->{Alias}' != \`$spec'\n"
	    unless $spec eq $target->{Alias} ||
	           $spec eq $target->{LocalPart}.'@';
    } else {
	badusage "bad specification for alias to change";
    }
}

sub action_update {
    my $target = parse_target;
    @ARGV or badusage "missing update info\n";
    if (defined $target->{Number} && $target->{Number} == $#by_number) {
	generate $target->{Number}+1;
    }
    exec $generator, qw(update), $target->{Alias}, @ARGV;
    die "$generator: $!";
}

sub action_assign {
    (@ARGV==2 &&
     $ARGV[1] =~ m/^#/) or
     badusage "invalid arguments to assign - forgot to quote it properly?";
    action_update;
}


    (@ARGV==1 && $ARGV[0] =~  or badusage "missing assignment info (new comment)";
    $ARGV[0]=~

for (;;) {
    last unless @ARGV;
    last unless $ARGV[0] =~ m/^-/;
    my $arg = shift @ARGV;
    last if $arg =~ m/^--?$/;
    if ($arg =~ m/^-[ldFm]/) {
	push @genopts, $arg;
    } elsif ($arg =~ m/^-G/) {
	$generator = $'; #';
    } else {
	badusage "unknown option \`$arg'";
    }
}

our $child = $pgm;
$child =~ s/-pregen/; fixme fixme this should be defaulting generator

@ARGV or badusage "missing action\n";
my $action = shift @ARGV;
$action =~ y/-/_/;
{ no strict qw(refs); &{"action_$action"}; }