#!/usr/bin/env perl
#
# vim: set ts=4:noet
#
# sboremove
# script to remove an installed SlackBuild
#
# author: Luke Williams <xocel@iquidus.org>
# license: WTFPL <http://sam.zoy.org/wtfpl/COPYING>

use 5.16.0;
use strict;
use warnings FATAL => 'all';
use SBO::Lib;
use Getopt::Long qw(:config bundling);
use File::Basename;

my $self = basename ($0);

sub show_usage () {
	print <<EOF
Usage: $self [options] sbo

Options (defaults shown first where applicable):
  -h|--help:
    this screen.
  -v|--version:
    version information.
  -R|--norequirements:
    do not parse requirements.
  -a|--alwaysask:
    always ask to remove, even if required by other packages on system.

Note: optional dependencies need to be removed separately. 

EOF
}

my ($help, $vers, $non_int, $no_reqs, $alwaysask, @excluded);

GetOptions (
	'help|h'			=> \$help,
	'version|v'			=> \$vers,
	'norequirements|R'	=> \$no_reqs, 
	'nointeractive'		=> \$non_int,
	'alwaysask|a'		=> \$alwaysask,
);

show_usage and exit 0 if $help;
show_version and exit 0 if $vers;
show_usage and exit 0 unless exists $ARGV[0];

my $inst_names = get_inst_names (get_installed_sbos);

my @remove;
for my $sbo (@ARGV) {
	if (get_sbo_location ($sbo)) {
		if ($sbo ~~ @$inst_names) {
			push @remove, $sbo; 
		} else {
			say "$sbo is not installed";
		} 
	} else {
		say "Unable to locate $sbo in the SlackBuilds.org tree."
	}
}

my ($remove_queue, %required_by, %warnings, @confirmed);

sub get_requires ($) {
	my $location = get_sbo_location (shift);
	my $requires = get_from_info (LOCATION => $location, GET => 'REQUIRES')
		if $location;
	return $requires;
}

# Determine required by for all installed sbo's
sub get_reverse_reqs () {
	FIRST: for my $inst (@$inst_names) {
		my $requires = get_requires $inst;
		next FIRST unless $$requires[0];
		for my $req (@$requires) {
			unless ( $req eq "%README%" ) {
				push @{$required_by{$req}}, $inst if $req ~~ $inst_names;
			}		
		}	
	}
}

sub get_required_by ($) {
	my $sbo = shift;
	my @dep_of;
	get_reverse_reqs unless keys %required_by > 0;
	if ( $required_by{$sbo} ) {
		for my $req_by (@{$required_by{$sbo}}) {
			unless ($req_by ~~ @confirmed) {
				push @dep_of, $req_by;
			}
		}
	}
	return \@dep_of;
}

sub confirm_remove ($) {
	my $sbo = shift;
	unless ($sbo ~~ @confirmed) {
		push @confirmed, $sbo;
	}
}

# Determine dependencies & warnings
if ($no_reqs) {
	$remove_queue = \@remove;
} else {
	$remove_queue = get_build_queue(\@remove, \%warnings);
	@$remove_queue = reverse(@$remove_queue);
}

# Check if packages in queue are actually installed on system 
my @temp;
if ($inst_names) {
	for my $sbo (@$remove_queue) {
		if ($sbo ~~ $inst_names) {
			push @temp, $sbo;
		}
	}
	$remove_queue = \@temp;
}

# Gather instructions from user
unless ($non_int) {
	my ($req_by, $req_count, $cnf_count);
	for my $pkg (@$remove_queue) {
		$req_by = get_required_by $pkg;
		$cnf_count = 0;
		for my $val (@$req_by) {
			if ( $val ~~ @confirmed ) { $cnf_count++; }  
		}
		my $rootpkg = ($pkg ~~ @remove);
		if ($cnf_count == @$req_by or $rootpkg or $alwaysask) {  
			say $pkg;
			if ( @$req_by ) {
				say "Required by: " . join(' ', @$req_by);
			} else {
				unless ($rootpkg) {
					#Skip this prompt if the pkg in question was passed by user.
					say "It appears $pkg will no longer be required on your system";
				}
			}
			if ( exists $warnings{$pkg} ) {
				say "$pkg suggests you view its README before proceeding,";
				print "view now? [y] : ";
				chomp(my $viewrm = <STDIN>);
				if ($viewrm =~ /^[Yy]/) {
					print "\n";
					my $locrm = get_sbo_location ($pkg);
					$locrm .= '/README';
					open(README, '<', $locrm) or die "could not open $locrm";
					for my $line (<README>) {
						print $line;
					}
				}
			}
			print "Remove $pkg? [n] : ";
			chomp(my $userin = <STDIN>);
			if ($userin =~ /^[Yy]/) {
				confirm_remove $pkg;
				say "* added $pkg to remove queue\n";
			} else {
				say "* ignoring $pkg\n"
			}
		}
	}
} else {
	for my $sbo (@$remove_queue) {
		confirm_remove $sbo;
	}
}

# Show remove queue
my $remove_count = @confirmed;
if ($remove_count) {
	say "Removing $remove_count package(s)";
	for my $pkg (@confirmed) {
		print "$pkg ";
	}
	say "\n";	
} else {
	say 'Nothing to remove.';
	exit 0;
}

unless ($non_int) {
	print 'Are you sure you want to continue? [n] : ';
	unless (<STDIN> =~ /^[Yy]/) {
		say 'Exiting.';
		exit 0;
	}
}

system ("/sbin/removepkg $_") for @confirmed;

say "All operations have completed successfully.";

exit 0;