#!/usr/bin/perl -wT
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
#
# This Source Code Form is "Incompatible With Secondary Licenses", as
# defined by the Mozilla Public License, v. 2.0.

use strict;

use lib qw(. lib);

use Bugzilla;
use Bugzilla::Error;
use Bugzilla::Bug;

use List::Util qw(max);

my $user = Bugzilla->login();

my $cgi = Bugzilla->cgi;
my $template = Bugzilla->template;
my $vars = {};
# Connect to the shadow database if this installation is using one to improve
# performance.
my $dbh = Bugzilla->switch_to_shadow_db();

################################################################################
# Data/Security Validation                                                     #
################################################################################

# Make sure the bug ID is a positive integer representing an existing
# bug that the user is authorized to access.
my $bug = Bugzilla::Bug->check(scalar $cgi->param('id'));
my $id = $bug->id;

local our $hide_resolved = $cgi->param('hide_resolved') ? 1 : 0;

local our $maxdepth = $cgi->param('maxdepth') || 0;
if ($maxdepth !~ /^\d+$/) { $maxdepth = 0 };

################################################################################
# Main Section                                                                 #
################################################################################

# Stores the greatest depth to which either tree goes.
local our $realdepth = 0;

# Generate the tree of bugs that this bug depends on and a list of IDs
# appearing in the tree.
my $dependson_tree = { $id => $bug };
my $dependson_ids = {};
GenerateTree($id, "dependson", 1, $dependson_tree, $dependson_ids);
$vars->{'dependson_tree'} = $dependson_tree;
$vars->{'dependson_ids'} = [keys(%$dependson_ids)];

# Generate the tree of bugs that this bug blocks and a list of IDs
# appearing in the tree.
my $blocked_tree = { $id => $bug };
my $blocked_ids = {};
GenerateTree($id, "blocked", 1, $blocked_tree, $blocked_ids);
$vars->{'blocked_tree'} = $blocked_tree;
$vars->{'blocked_ids'} = [keys(%$blocked_ids)];

$vars->{'realdepth'}      = $realdepth;

$vars->{'bugid'}          = $id;
$vars->{'maxdepth'}       = $maxdepth;
$vars->{'hide_resolved'}  = $hide_resolved;

print $cgi->header();
$template->process("bug/dependency-tree.html.tmpl", $vars)
  || ThrowTemplateError($template->error());

################################################################################
# Recursive Tree Generation Function                                           #
################################################################################

sub GenerateTree {
    # Generates a dependency tree for a given bug.  Calls itself recursively
    # to generate sub-trees for the bug's dependencies.
    my ($bug_id, $relationship, $depth, $bugs, $ids) = @_;

    my @dependencies;
    if ($relationship eq 'dependson') {
        @dependencies = @{$bugs->{$bug_id}->dependson};
    }
    else {
        @dependencies = @{$bugs->{$bug_id}->blocked};
    }

    # Don't do anything if this bug doesn't have any dependencies.
    return unless scalar(@dependencies);

    # Record this depth in the global $realdepth variable if it's farther 
    # than we've gone before.
    $realdepth = max($realdepth, $depth);
    Bugzilla->user->visible_bugs(\@dependencies); 
    foreach my $dep_id (@dependencies) {
        # Get this dependency's record from the database and generate
        # its sub-tree if we haven't already done so (which happens
        # when bugs appear in dependency trees multiple times).
        if (!$bugs->{$dep_id}) {
            $bugs->{$dep_id} = new Bugzilla::Bug($dep_id);
            GenerateTree($dep_id, $relationship, $depth+1, $bugs, $ids);
        }

        # Add this dependency to the list of this bug's dependencies 
        # if it exists, if we haven't exceeded the maximum depth the user 
        # wants the tree to go, and if the dependency isn't resolved 
        # (if we're ignoring resolved dependencies).
        if (!$bugs->{$dep_id}->{'error'}
            && Bugzilla->user->can_see_bug($dep_id)
            && (!$maxdepth || $depth <= $maxdepth) 
            && ($bugs->{$dep_id}->isopened || !$hide_resolved))
        {
            # Due to AUTOLOAD in Bug.pm, we cannot add 'dependencies'
            # as a bug object attribute from here.
            push(@{$bugs->{'dependencies'}->{$bug_id}}, $dep_id);
            $ids->{$dep_id} = 1;
        }
    }
}
