#!/usr/bin/perl -w

use strict;

my $arch;
my $old_split = $/;
my (@desktop_tasks, @user_tasks, @l10n_tasks, @server_tasks, @special_tasks);
my ($section, $taskname);

my $codename = $ENV{'CODENAME'};
if (! defined($codename)) {
    die "update_tasks: codename not specified\n";
}

my $mirror = $ENV{'MIRROR'};
if (! defined($mirror)) {
    die "update_tasks: mirror not specified\n";
}

my $bdir = $ENV{'BDIR'};
if (! defined($bdir)) {
    die "update_tasks: temp dir not specified\n";
}

my $basedir = $ENV{'BASEDIR'};
if (! defined($basedir)) {
    die "update_tasks: basedir not specified\n";
}

my $tdir = "$bdir/update_tasks";
system("mkdir -p $tdir");

# Default to using tasksel and tasks data from the same release we're
# using, but allow it to be overridden. For testing purposes - set up
# FORCE_SID_TASKSEL to force us to use sid's tasksel data even if
# we're using stable/testing.
my $tasks_codename = $codename;
if (defined($ENV{'FORCE_SID_TASKSEL'}) and $ENV{'FORCE_SID_TASKSEL'} eq '1') {
    print "update_tasks: forcing use of sid tasksel data\n";
    $tasks_codename = "sid";
}

# Look for the coreutils package (which should exist in all archs, and
# is a non -all package) to determine a valid arch for the rest of
# this script
my $coreutils_deb = `$basedir/tools/which_deb $mirror $codename coreutils binary`;
if ($coreutils_deb =~ m/_([[:alnum:]]+)\.deb/) {
    $arch = $1;
} else {
    die "update_tasks: Can't determine arch!\n";
}

# used in a few places to decide what happens when doing "generic"
# discs.
my $default_desktop; 

# Find the dependency information of the task-desktop deb to see what
# the default desktop should be
my $task_desktop_deb = `$basedir/tools/which_deb $mirror $tasks_codename task-desktop binary`;
open (TASKS, "dpkg --info $mirror/$task_desktop_deb |") or
    die "update_tasks: Can't run dpkg --info $mirror/$task_desktop_deb; $!\n";
while (<TASKS>) {
    chomp;
    /Recommends: task-(\S+)*-desktop/ and $default_desktop = $1;
}
print "update_tasks: Using \"$default_desktop\" as the default desktop, as specified by $task_desktop_deb\n";

# Extract the tasksel-data deb for our suite; we need to parse the
# data in it
my $tasksel_deb = `$basedir/tools/which_deb $mirror $tasks_codename tasksel-data binary`;
$tasksel_deb = "$mirror/$tasksel_deb";
chomp $tasksel_deb;

# Several types of task package we care about:
#
# task-$DESKTOP-desktop            - core package set for desktop $DESKTOP
# task-$LANGUAGE                   - core package set for language $LANGUAGE
# task-$LANGUAGE-desktop           - general desktop i18n packages for $LANGUAGE
# task-$LANGUAGE-$DESKTOP-desktop  - i18n packages for $DESKTOP, $LANGUAGE
# task-$FOO                        - package set for $FOO (mail-server, laptop, etc.)
#
# VERY much complicated by the freeform style of the names here:
# * languages can be 1, 2 or 3 words (eg. english, brazilian-portuguese, south-african-english)
# * non-desktop tasks can be 1 or 2 words (e.g. laptop, file-server)
#
# Need to parse debian-tasks.desc to work out what each type is

system("dpkg -x $tasksel_deb $tdir/tasksel");

my $descfile = "usr/share/tasksel/descs/debian-tasks.desc";

open (TASKS, "$tdir/tasksel/$descfile")
    or die "can't open $tdir/tasksel/$descfile: $!\n";

while (defined (my $task = <TASKS>)) {
    chomp $task;
    if ($task =~ m/^Task: (\S+)/) {
        $taskname = $1;
    }
    if ($task =~ m/^Section: (\S+)/) {
        $section = $1;
        if ($section eq "l10n") {
            push (@l10n_tasks, $taskname);
        } elsif ($section eq "server") {
            push (@server_tasks, $taskname);
        } elsif ($section eq "user") {
            if ($taskname =~ m/^[[:alnum:]]+-desktop/) {
                push (@desktop_tasks, $taskname);
            } else {
                push (@user_tasks, $taskname);
            }
        } elsif ($section eq "special") {
            push (@special_tasks, $taskname);
        } else {
            die "update_tasks: task $taskname has unknown section $section!\n";
        }

    }
}
close TASKS;

#print "l10n: @l10n_tasks\n";
#print "desktop: @desktop_tasks\n";
#print "user: @user_tasks\n";
#print "server: @server_tasks\n";
#print "special: @special_tasks\n";

# Reduce special-casing and duplicate code. Add "light-desktop",
# "generic-desktop" and "all-desktop" tasks that we can use here.
push (@desktop_tasks, "light-desktop");
push (@desktop_tasks, "generic-desktop");
push (@desktop_tasks, "all-desktop");

# Write out all the groupings
foreach my $desktop (@desktop_tasks) {
    my $filename;
    my $desktop_name = $desktop;
    $desktop_name =~ s/-desktop//g;

    # Essential; $DESKTOP
    $filename = "task-essential-$desktop_name";    
    open (DESKOUT, "> $filename") or die "can't open file $filename for writing, $!\n";

    # in all-desktop, add all the desktop tasks
    if ($desktop_name eq "all") {
        foreach my $taskname (@desktop_tasks) {
            print DESKOUT "task-$taskname\n";
        }
    } elsif ($desktop_name eq "generic") {
        print DESKOUT "task-$default_desktop-desktop\n";
    } elsif ($desktop_name eq "light") {
        print DESKOUT "task-lxde-desktop\n";
        print DESKOUT "task-xfce-desktop\n";
    } else {
        print DESKOUT "task-$desktop\n";
    }

    # generic-desktop and all-desktop want all the server and user
    # tasks included too
    if ($desktop_name eq "all" or $desktop_name eq "generic") {
        foreach my $taskname (@user_tasks) {
            print DESKOUT "task-$taskname\n";
        }
        foreach my $taskname (@server_tasks) {
            print DESKOUT "task-$taskname\n";
        }
    }
    close DESKOUT;

    # Full; $DESKTOP
    $filename = "task-full-$desktop_name";    
    open (DESKOUT, "> $filename") or die "can't open file $filename for writing, $!\n";

    # in all-desktop, add all the desktop tasks now
    if ($desktop_name eq "all") {
        foreach my $taskname (@desktop_tasks) {
            print DESKOUT "task-$taskname\n";
        }
    } elsif ($desktop_name eq "generic") {
        print DESKOUT "task-$default_desktop-desktop\n";
    } elsif ($desktop_name eq "light") {
        print DESKOUT "task-lxde-desktop\n";
        print DESKOUT "task-xfce-desktop\n";
    } else {
        print DESKOUT "task-$desktop\n";
    }

    # generic-desktop and all-desktop want all the server and user
    # tasks included too
    if ($desktop_name eq "all" or $desktop_name eq "generic") {
        foreach my $taskname (@user_tasks) {
            print DESKOUT "task-$taskname\n";
        }
        foreach my $taskname (@server_tasks) {
            print DESKOUT "task-$taskname\n";
        }
    }

    # task-$LANGUAGE, same for all flavours
    foreach my $taskname (@l10n_tasks) {
        if ($taskname !~ m/desktop/) {
            print DESKOUT "task-$taskname\n";
        }
    }

    # task-$LANGUAGE-desktop, same for all flavours
    foreach my $taskname (@l10n_tasks) {
        if ($taskname =~ m/desktop/) {
            my $include = 1;
            foreach my $dsk (@desktop_tasks) {
                if ($taskname =~ m/$dsk/) {
                    $include = 0;
                    last;
                }
            }
            if ($include) {
                print DESKOUT "task-$taskname\n";
            }
        }
    }

    # in all-desktop, add all the desktop l10n tasks
    if ($desktop_name eq "all") {
        # task-$LANGUAGE-$DESKTOP-desktop
        foreach my $taskname (@l10n_tasks) {
            foreach my $dsk (@desktop_tasks) {
                if ($taskname =~ m/$dsk/) {
                    print DESKOUT "task-$taskname\n";
                }
            }
        }

    } elsif ($desktop_name eq "generic") {
        # in generic-desktop, add the desktop l10n tasks as though for
        # $default_desktop *first*. Others will come later

        # task-$LANGUAGE-$DESKTOP-desktop
        foreach my $taskname (@l10n_tasks) {
            if ($taskname =~ m/$default_desktop/) {
                print DESKOUT "task-$taskname\n";
            }
        }
        # task-!$default_desktop-desktop
        foreach my $taskname (@desktop_tasks) {
            if ($taskname !~ m/$default_desktop/) {
                print DESKOUT "task-$taskname\n";
            }
        }

        # task-$LANGUAGE-!$default_desktop-desktop
        foreach my $taskname (@l10n_tasks) {
            if ($taskname =~ m/desktop$/) {
                my $include = 0;
                foreach my $dsk (@desktop_tasks) {
                    if ($dsk !~ m/$default_desktop/ and $taskname =~ m/$dsk/) {
                        $include = 1;
                        last;
                    }
                }
                if ($include) {
                    print DESKOUT "task-$taskname\n";
                }
            }
        }
    } elsif ($desktop_name eq "light") {
        # task-$LANGUAGE-$DESKTOP-desktop
        foreach my $taskname (@l10n_tasks) {
            if ($taskname =~ m/lxde/ or $taskname =~ m/xfce/) {
                print DESKOUT "task-$taskname\n";
            }
        }        
    } else {
        # a specific desktop, just add the desktop l10n tasks for this
        # desktop

        # task-$LANGUAGE-$DESKTOP-desktop
        foreach my $taskname (@l10n_tasks) {
            if ($taskname =~ m/$desktop_name/) {
                print DESKOUT "task-$taskname\n";
            }
        }
    }
    close DESKOUT;
}