#! /usr/bin/perl
###############################################################################
#
#  Update-MIME:  Install programs into "/etc/mailcap", resolve conflicts,
#                auto-uninstall, make dinner, and wash dishes.
#
#  Written by Brian White <bcwhite@pobox.com>.
#
#  This program has been placed in the public domain (the only true "free").
#  Do whatever you wish with it, though I'd appreciate it if my name stayed
#  on it as the original author.
#
###############################################################################

umask(022);

# These are pretty well always a Good Idea(tm)
use strict;
use warnings;


#
# Program Constants
# They can be overridden in $conffile, except of course $conffile itself
#
our $debug       = 0;
my  $conffile    = "/etc/update-mime.conf";
our $mailcap     = "/etc/mailcap";
our $mailcapdef  = "/usr/lib/mime/mailcap";
our $mimedir     = "/usr/lib/mime/packages";
our $appsdir     = "/usr/share/applications";
our $orderfile   = "/etc/mailcap.order";
our $defpriority = 5;
our $localgen    = 0;


# If the call comes from dpkg, only accept it if --triggered is passed
# This is so that we don't get useless calls from packages' postinsts
# that call update-mime due to dh_installmime adding that call for
# when there was no triggers support.
#
# When this 'hack' is removed, mime-support's postinst should be updated
# to not pass --triggered anymore in 'triggered'.
if (defined $ENV{"DPKG_RUNNING_VERSION"} && defined $ARGV[0] && $ARGV[0] ne "--triggered") {
    exit (0);
}


# Allow local run
if (defined $ARGV[0] && $ARGV[0] eq "--local") {
    $conffile	= "$ENV{HOME}/.update-mime.conf";
    $mailcap	= "$ENV{HOME}/.mailcap";
    $orderfile	= "$ENV{HOME}/.mailcap.order";
    $localgen	= 1;
}


#
# Allow local customizations
#
do $conffile if -f $conffile;


#
# Global Variables
#
my %entries;
my %packages;
my %priorities;
my @order;
my $counter=1;


sub ReadEntries
{
	my($pkg,$priority);

#	foreach my $file (glob "$mimedir/*") {
	foreach my $file (map { glob $_.'/*' } split ':',$mimedir) {
		next if ($file =~ m!(^|/)(\.|\#)|(\~)$!);
		($pkg) = ($file =~ m|/([^/]*)$|);
		print STDERR "$pkg:\n" if $debug;

		if (!defined $packages{$pkg}) {
			$packages{$pkg} = [];
		}

		if (open(FILE,"<$file")) {
			while (<FILE>) {
				chomp;
				next if m/^\s*$|^\s*\#/;
				if (! m(^[a-zA-Z0-9*][a-zA-Z0-9!#\$&^_.+-]*/[a-zA-Z0-9*][a-zA-Z0-9!#\$&^_.+-]*;) ) {
					print STDERR "Warning: mailcap line not starting with a media type in $pkg\n";
					print STDERR "Problematic line: $_\n";
				}
				if (m/priority\s*=\s*(\d+)\s*($|;)/i) {
					$priority=$1;
				} else {
					$priority=$defpriority;
				}
				if ($priority < 0 || $priority > 9) {
					print STDERR "Error: priority of $priority is out of range (0 <= pri <= 9)\n";
					print STDERR "       $_\n";
					$priority=$defpriority;
				}
				$entries{$counter} = $_;
				push @{$packages{$pkg}},$counter;
				push @{$priorities{$priority}},$counter;
				print STDERR "$counter: $_\n" if $debug;
				$counter++;
			}
			close(FILE);
		} else {
			print STDERR "Warning: could not open file '$file' -- $!\n";
		}
	}
}

sub RecurseIntoDirectories
{
	my @files;
	foreach my $dir (@_) {
		next if ($dir =~ m!(^|/)(\.|\#)|(\~)$!);
		my @entries = glob "$dir/*";
		push @files, RecurseIntoDirectories(grep { -d $_ } @entries);
		push @files, grep { -f $_ } @entries;
	}
	return @files;
}

sub ReadDesktopEntries
{
	my($pkg,$priority,%mime_priorities);

	# First, reach the mimeapps.list files, to inform priorities.
        # We don't implement any kind of relative priority between lists here;
        # we're just boosting the priority of anything that appears in any
        # list.
        my @mimeapps_lists = glob("/etc/xdg/*mimeapps.list");
        foreach my $dir (split ':',$appsdir) {
            push(@mimeapps_lists, glob("$dir/*mimeapps.list"));
        }
	foreach my $file (@mimeapps_lists) {
		next if ($file =~ m!(^|/)(\.|\#)|(\~)$!);
		next unless ($file =~ m|mimeapps\.list$|);
		unless (open(FILE,"<$file")) {
			print STDERR "Warning: could not open file '$file' -- $!\n";
			next;
		}
		# We don't handle "Added Associations"
		my $in_default_applications = 0;
		while (<FILE>) {
			chomp;
			next if (m/^\s*$|^\s*\#/);
			if (m/^\[Default Applications\]$/) {
				$in_default_applications = 1;
				next;
			}
			if (m/^\[.*\]$/) {
				$in_default_applications = 0;
				next;
			}
			next unless $in_default_applications;
			next unless m|^([^=]+)=(.*)$|;
			my $mime_type = $1;
			my $desktop_files = $2;
			foreach my $file (split(';', $desktop_files)) {
				unless ($file =~ m|^([^/]+)\.desktop$|) {
					print STDERR "Warning: '$mime_type' had non-desktop association '$file'\n";
					next;
				}
				$pkg = $1;
				if (!defined($mime_priorities{$mime_type})) {
					$mime_priorities{$mime_type} = {}
				}
				$mime_priorities{$mime_type}{$pkg} = $defpriority + 1;
			}
		}
		close(FILE);
	}

	foreach my $file (RecurseIntoDirectories(split ':',$appsdir)) {
		next if ($file =~ m!(^|/)(\.|\#)|(\~)$!);
		next unless ($file =~ m/\.desktop$/);
		($pkg) = ($file =~ m|/([^/]*)\.desktop$|);
		print STDERR "$pkg:\n" if $debug;

		next if (defined $packages{$pkg});
		$packages{$pkg} = [];

		if (open(FILE,"<$file")) {
			my($name, $icon, $exec, $terminal, $test, @types) = ($pkg);
			my $in_desktop_group = 0;
			while (<FILE>) {
				chomp;
				next if (m/^\s*$|^\s*\#/);
				if (m/^\[Desktop Entry\]$/) {
					$in_desktop_group = 1;
					next;
				}
				if (m/^\[.*\]$/) {
					$in_desktop_group = 0;
					next;
				}
				next unless $in_desktop_group;
				if (m/^Terminal=(\w+)/i) {
					$terminal = "needsterminal" if ($1 eq "true");
				}
				elsif (m/^Name=(.+)/i) {
					$name = $1;
				}
				elsif (m/^Icon=(.+)/i) {
					$icon = $1;
				}
				elsif (m/^Exec=(.*)$/i) {
					$exec = $1;
					$exec =~ s/((?:\\\\)*)\\?(;)/$1\\$2/g;
					$exec =~ s/%[fFuU]/%s/g;
					$exec .= " %s" if ($exec !~ m/%s/);
				}
				elsif (m/^TryExec=(.*)/i) {
					$test = "test=command -v $1 > /dev/null 2>&1";
				}
				elsif (m/MimeType=(.*)/i) {
					my $err = 0;
					push @types, grep { if (length>0) {1} else {++$err;0} }
						     split(/\s*;\s*/, $1);
					print STDERR "Warning: $file:$.: ignoring empty entries in MimeType\n" if $err;
				}
			}
			if (!defined($exec) || !scalar(@types)) {
				close(FILE);
				next;
			}
			if (!defined($terminal)) {
				if (defined($test)) {
					$terminal = "$test && test -n \"\$DISPLAY\"";
				} else {
					$terminal = "test=test -n \"\$DISPLAY\"";
				}
			} elsif (defined($test)) {
				$terminal .= "; $test";
			}
			$exec =~ s/%c/$name/g;
			$exec =~ s/%i/--icon $icon/g;
			foreach my $type (@types) {
				my $entry = "$type; $exec; $terminal";
				if (defined($mime_priorities{$type}) && defined($mime_priorities{$type}{$pkg})) {
					$priority = $mime_priorities{$type}{$pkg};
				} else {
					$priority = $defpriority;
				}
				$entries{$counter} = $entry;
				push @{$packages{$pkg}},$counter;
				push @{$priorities{$priority}},$counter;
				print STDERR "$counter: $entry\n" if $debug;
				$counter++;
			}
			close(FILE);
		} else {
			print STDERR "Warning: could not open file '$file' -- $!\n";
		}
	}
}


sub ReadOrder
{
	if (-e $orderfile) {
		if (open(FILE,"<$orderfile")) {
			while (<FILE>) {
				chomp;
				s/\s*\#.*$//;
				next if m/^\s*$/;
				push @order,$_;
				/(.*):/;
				my $pkg = $1;
				unless( grep {/^$pkg$/} keys(%packages)) {
					print STDERR "Warning: package $pkg listed in /etc/mailcap.order does not have mailcap entries.\n";
				}
			}
			close(FILE);
		} else {
			print STDERR "Warning: could not open file '$orderfile' -- $!\n";
		}
	}
}



sub OrderEntries
{
	my(@entrylist,@orderlist,@templist,$priority,$entrycode,$ordercode);

	foreach $priority (sort {$b <=> $a} keys %priorities) {
		print STDERR " - Priority $priority:" if $debug;
		@templist = @{$priorities{$priority}};
		@templist = sort {
			my $ae  = $entries{$a};
			my $ac  = 0;
			$ac += 1 if $ae =~ m!^\S+/\*!;
			$ac += 2 if $ae =~ m!^\*/!;
			my $be  = $entries{$b};
			my $bc  = 0;
			$bc += 1 if $be =~ m!^\S+/\*!;
			$bc += 2 if $be =~ m!^\*/!;
			$ac <=> $bc;
		} @templist;
		foreach my $entry (@templist) {
			print STDERR " $entry" if $debug;
			push @entrylist,$entry;
		}
		print STDERR "\n" if $debug;
	}

	print STDERR "entrylist: @entrylist\n" if $debug;
	foreach $ordercode (@order) {
		my($pkg,$typ);
		if ($ordercode =~ m/:/) {
			($pkg,$typ) = ($ordercode =~ m/^(.*):(\S*)/);
		} else {
			$pkg = $ordercode;
			$typ = "*/*";
		}
		$typ = "*/*" unless $typ;
		print STDERR " - Ordering '$ordercode'...  (package=$pkg, type=$typ, orderlist=@orderlist)\n" if $debug;
		$typ =~ s/\*/\.\*/g;
		foreach $entrycode (@entrylist) {
			next if grep(/^\Q$entrycode\E$/,@orderlist);
			print STDERR "    - Checking entrycode '$entrycode' against (@{$packages{$pkg}})...\n" if $debug;
			if (grep(/^\Q$entrycode\E$/,@{$packages{$pkg}})) {
				my $entry = $entries{$entrycode};
				my($etype) = ($entry =~ m/^(.*?)(;|\s)/);
				print STDERR "       - entry found, type=$etype, checking against '$typ'\n" if $debug;
				if ($etype =~ m!^$typ$!) {
#					print STDERR "       - matched!\n" if $debug;
#					my($oaction) = ($ordercode =~ m/action=([^\s;]*)/i);
#					my($eaction) = ($entry     =~ m/action=([^\s;]*)/i);
#					$eaction="view" unless $eaction;
#					print STDERR "       - checking entry action '$eaction' against '$oaction'\n" if $debug;
#					if (!$oaction || $eaction =~ m/^($oaction)$/) {
						push @orderlist,$entrycode;
						print STDERR "       - matched!  (orderlist=@orderlist)\n" if $debug;
#					}
				}
			}
		}
	}

	foreach $entrycode (@entrylist) {
		next if grep(/^\Q$entrycode\E$/,@orderlist);
		push @orderlist,$entrycode;
	}

	print STDERR "orderlist: @orderlist\n" if $debug;
	return @orderlist;
}



#
# Generate new mailcap file
#
sub UpdateMailcap
{
	my(@entrylist) = @_;
	my(@above,@user,@below,$state,$entrycode);
	$state = 0;
	if (!open(PATH,"<$mailcap")) {
		if (!open(PATH,"<$mailcapdef")) {
#			print STDERR "Warning: could not read '$mailcap' (update stopped) -- $!\n";
#			print STDERR "         restore from backup or delete and re-install mime-support package";
			return;
		}
	}

	while (<PATH>) {
		s/install-mime/update-mime/g;
		if ($state == 0) {
			push @above,$_;
		}
		$state=2 if ($state == 1 && /^\# ----- .* Ends /);
		if ($state == 1) {
			push @user,$_;
		}
		$state=1 if ($state == 0 && /^\# ----- .* Begins /);
		if ($state == 2) {
			push @below,$_;
		}
		$state=3 if ($state == 2);
	}

	close PATH;

	if ($state == 3) {
		my $newfile = join('',@above,@user,@below);
		$newfile .= "\n###############################################################################\n\n";
		foreach $entrycode (@entrylist) {
			my $entry = $entries{$entrycode};
			$entry =~ s/\s*priority\s*=\s*\d+\s*($|;)//;
			$entry =~ s/\s*;\s*$//;
			$newfile .= $entry."\n";
		}

		if (!open(PATH,">$mailcap.new")) {
			print STDERR "Error: could not write '$mailcap.new' -- $!\n";
			exit(1) unless ($debug);
			open(PATH,">-");
		}
		print PATH $newfile;
		close PATH;
		if (!open(PATH,"<$mailcap.new")) {
			die "Error: could not read generated '$mailcap.new' -- $!\n";
		}
		my $savfile = "";
		$savfile .= $_ while (<PATH>);
		if ($savfile ne $newfile) {
			die "Error: contents of '$mailcap.new' do not match what was written -- abort\n";
		}
		rename "$mailcap.new","$mailcap";
	} else {
		print STDERR "Error: '$mailcap' is not in required format -- not updated\n";
		print STDERR "       Restore from backup or delete and re-install mime-support package";
	}
}



ReadEntries();
ReadDesktopEntries();
ReadOrder();
my @list = OrderEntries();
UpdateMailcap(@list);