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%# REST/1.0/dhandler
%#
<%ARGS>
@id => ()
$fields => undef
$format => undef
$content => undef
</%ARGS>
<%INIT>
use RT::Interface::REST;

my $output = "";
my $status = "200 Ok";
my $object = $m->dhandler_arg;

my $name   = qr{[\w.-]+};
my $list   = '(?:(?:\d+-)?\d+,)*(?:\d+-)?\d+';
my $label  = '[a-zA-Z0-9@_.+-]+';
my $field  = RT::Interface::REST->field_spec;
my $labels = "(?:$label,)*$label";

# We must handle requests such as the following:
#
# 1. http://.../REST/1.0/show (with a list of object specifications).
# 2. http://.../REST/1.0/edit (with a self-contained list of forms).
# 3. http://.../REST/1.0/ticket/show (implicit type specification).
#    http://.../REST/1.0/ticket/edit
# 4. http://.../REST/1.0/ticket/nn (all possibly with a single form).
#    http://.../REST/1.0/ticket/nn/history
#    http://.../REST/1.0/ticket/nn/comment
#    http://.../REST/1.0/ticket/nn/attachment/1
#
# Objects are specified by their type, and either a unique numeric ID,
# or a unique name (e.g. ticket/1, queue/foo). Multiple objects of the
# same type may be specified by a comma-separated list of identifiers
# (e.g., user/ams,rai or ticket/1-3,5-7).
#
# Ultimately, we want a list of object specifications to operate upon.
# The URLs in (4) provide enough information to identify an object. We
# will assemble submitted information into that format in other cases.
#
my (@objects, $forms);
my $utype;

if ($object eq 'show' ||                                # $REST/show
    (($utype) = ($object =~ m{^($name)/show$})))        # $REST/ticket/show
{
    # We'll convert type/range specifications ("ticket/1-3,7-9/history")
    # into a list of singular object specifications ("ticket/1/history").
    # If the URL specifies a type, we'll accept only that one.
    foreach my $id (@id) {
        $id =~ s|^(?:$utype/)?|$utype/| if $utype;
        if (my ($type, $oids, $extra) =
            ($id =~ m#^($name)/($list|$labels)(?:(/.*))?$#o))
        {
	    $extra ||= '';
	    my ($attr, $args) = $extra =~ m{^(?:/($name)(?:/(.*))?)?$}o;
	    my $tids;
	    if ($attr and $attr eq 'history' and $args) {
	       	($tids) = $args =~ m#id/(\d.*)#o;
	    }
	    # expand transaction and attachment range specifications
	    # (if applicable)
	    foreach my $oid (expand_list($oids)) {
		if ($tids) {
		    push(@objects, "$type/$oid/$attr/id/$_") for expand_list($tids);
		} else {
		    push(@objects, "$type/$oid$extra");
		}
	    }
	}
        else {
            $status = "400 Bad Request";
            $output = "Invalid object ID specified: '$id'";
            goto OUTPUT;
        }
    }
}
elsif ($object eq 'edit' ||                             # $REST/edit
    (($utype) = ($object =~ m{^($name)/edit$})))        # $REST/ticket/edit
{
    # We'll make sure each of the submitted forms is syntactically valid
    # and sufficiently identifies an object to operate upon, then add to
    # the object list as above.
    my @output;

    $forms = form_parse($content);
    foreach my $form (@$forms) {
        my ($c, $o, $k, $e) = @$form;

        if ($e) {
            push @output, [ "# Syntax error.", $o, $k, $e ];
        }
        else {
            my ($type, $id);

            # Look for matching types in the ID, form, and URL.
            $type = $utype || $k->{id};
            $type =~ s|^([^/]+)/\d+$|$1| if !$utype;
            $type =~ s|^(?:$utype)?|$utype/| if $utype;
            $type =~ s|/$|| if $type;

            if (exists $k->{id}) {
                $id = $k->{id};
                $id =~ s|^(?:$type/)?|$type/| if $type;

                if ($id =~ m#^$name/(?:$label|\d+)(?:/.*)?#o) {
                    push @objects, $id;
                }
                else {
                    push @output, [ "# Invalid object ID: '$id'", $o, $k, $e ];
                }
            }
            else {
                push @output, [ "# No object ID specified.", $o, $k, $e ];
            }
        }
    }
    # If we saw any errors at this stage, we won't process any part of
    # the submitted data.
    if (@output) {
        unshift @output, [ "# Please resubmit with errors corrected." ];
        $status = "409 Syntax Error";
        $output = form_compose(\@output);
        goto OUTPUT;
    }
}
else {
    # We'll assume that this is in the correct format already. Otherwise
    # it will be caught by the loop below.
    push @objects, $object;

    if ($content) {
        $forms = form_parse($content);

        if (@$forms > 1) {
            $status = "400 Bad Request";
            $output = "You may submit only one form to this object.";
            goto OUTPUT;
        }

        my ($c, $o, $k, $e) = @{ $forms->[0] };
        if ($e) {
            $status = "409 Syntax Error";
            $output = form_compose([ ["# Syntax error.", $o, $k, $e] ]);
            goto OUTPUT;
        }
    }
}

# Make sure we have something to do.
unless (@objects) {
    $status = "400 Bad Request";
    $output = "No objects specified.";
    goto OUTPUT;
}

# Parse and validate any field specifications.
my (%fields, @fields);
if ($fields) {
    unless ($fields =~ /^(?:$field,)*$field$/) {
        $status = "400 Bad Request";
        $output = "Invalid field specification: $fields";
        goto OUTPUT;
    }
    @fields = map lc, split /\s*,\s*/, $fields;
    @fields{@fields} = ();
    unless (exists $fields{id}) {
        unshift @fields, "id";
        $fields{id} = ();
    }

    # canonicalize cf-foo to cf.{foo}
    for my $field (@fields) {
        if ($field =~ /^(c(?:ustom)?f(?:ield)?)-(.+)/) {
            $fields{"cf.{$2}"} = delete $fields{"$1-$2"};

            # overwrite the element in @fields
            $field = "cf.{$2}";
        }
    }
}

my (@comments, @output);

foreach $object (@objects) {
    my ($handler, $type, $id, $attr, $args);
    my ($c, $o, $k, $e) = ("", ["id"], {id => $object}, 0);

    my $i = 0;
    if ($object =~ m{^($name)/(\d+|$label)(?:/($name)(?:/(.*))?)?$}o ||
        $object =~ m{^($name)/(new)$}o)
    {
        ($type, $id, $attr, $args) = ($1, $2, ($3 || 'default'), $4);
        $handler = "Forms/$type/$attr";

        unless ($m->comp_exists($handler)) {
            $args = "$attr/$args";
            $handler = "Forms/$type/default";

            unless ($m->comp_exists($handler)) {
                $i = 2;
                $c = "# Unknown object type: $type";
            }
        }
        elsif ($id ne 'new' && $id !~ /^\d+$/) {
            my $ns = "Forms/$type/ns";

            # Can we resolve named objects?
            unless ($m->comp_exists($ns)) {
                $i = 3;
                $c = "# Objects of type $type must be specified by numeric id.";
            }
            else {
                my ($n, $s) = $m->comp("Forms/$type/ns", id => $id);
                if ($n <= 0) { $i = 4; $c = "# $s"; }
                else         { $i = 0; $id = $n;    }
            }
        }
        else {
            $i = 0;
        }
    }
    else {
        $i = 1;
        $c = "# Invalid object specification: '$object'";
    }

    if ($i != 0) {
        if ($content) {
            (undef, $o, $k, $e) = @{ shift @$forms };
        }
        push @output, [ $c, $o, $k ];
        next;
    }

    unless ($content) {
        my $d = $m->comp($handler, id => $id, args => $args, format => $format, fields => \%fields);
        my ($c, $o, $k, $e) = @$d;

        if (!$e && @$o && keys %fields) {
            my %lk = map { lc $_ => $_ } keys %$k;
            @$o = map { $lk{$_} } @fields;
            foreach my $key (keys %$k) {
                delete $k->{$key} unless exists $fields{lc $key};
            }
        }
        push(@output, [ $c, $o, $k ]) if ($c || @$o || keys %$k);
    }
    else {
        my ($c, $o, $k, $e) = @{ shift @$forms };
        my $d = $m->comp($handler, id => $id, args => $args, format => $format,
                         changes => $k);
        ($c, $o, $k, $e) = @$d;

        # We won't pass $e through to compose, trusting instead that the
        # handler added suitable comments for the user.
        if ($e) {
            if (@$o) {
                $status = "409 Syntax Error";
            } 
            else {
                $status = "400 Bad Request";
            }
            push @output, [ $c, $o, $k ];
        }
        else {
            push @comments, $c;
        }
    }
}

unshift(@output, [ join "\n", @comments ]) if @comments;
$output = form_compose(\@output);

OUTPUT:
$m->out("RT/".$RT::VERSION ." ".$status ."\n\n$output\n") if ($output || $status !~ /^200/);
return;
</%INIT>
