#!/usr/bin/env perl

use strict;

my $operation = shift @ARGV;

if ($operation !~ m/^(install|uninstall)$/) {
    print STDERR "$0: unknown operation $operation\n";
    exit(1);
}

my %options = ();

for my $arg (@ARGV) {
    if ($arg =~ m/([^=]*)=(.*)/) {
        $options{$1} = $2;
    }
    else {
        print STDERR "$0: can't parse option [$arg]\n";
        exit(1);
    }
}

for my $option (qw(command directory extension file)) {
    unless (defined($options{$option})) {
        print STDERR "$0: required variable $option not provided\n";
        exit(1);
    }
}

my $fh;
unless (open $fh, '<', $options{file}) {
    print STDERR "$0: can't open links file '$options{file}': $!";
    exit(1);
}

my @cmd = split /\s+/, $options{command};

while (my $line = <$fh>) {
    chomp $line;
    my @args = split /\s+/, $line;

    process(@args);
}

sub process {
    my ($source, @destinations) = @_;

    my @args = (@cmd);

    if ($operation eq 'install') {
        push @args, "$options{directory}/$source.$options{extension}";
    }

    for my $destination (@destinations) {
        push @args, "$options{directory}/$destination.$options{extension}";
        run_command(@args);
        pop @args;
    }
}

sub run_command {
    print (join ' ', @_);
    print "\n";

    my $ret = system(@_);

    if ($ret != 0) {
        print STDERR "$0: command failed: $?\n";
        exit(1);
    }

    return 1;
}