Tilo15
/
Statum


			
				
					
						
						
							12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394959697989910010110210310410510610710810911011111211311411511611711811912012112212312412512612712812913013113213313413513613713813914014114214314414514614714814915015115215315415515615715815916016116216316416516616716816917017117217317417517617717817918018118218318418518618718818919019119219319419519619719819920020120220320420520620720820921021121221321421521621721821922022122222322422522622722822923023123223323423523623723823924024124224324424524624724824925025125225325425525625725825926026126226326426526626726826927027127227327427527627727827928028128228328428528628728828929029129229329429529629729829930030130230330430530630730830931031131231331431531631731831932032132232332432532632732832933033133233333433533633733833934034134234334434534634734834935035135235335435535635735835936036136236336436536636736836937037137237337437537637737837938038138238338438538638738838939039139239339439539639739839940040140240340440540640740840941041141241341441541641741841942042142242342442542642742842943043143243343443543643743843944044144244344444544644744844945045145245345445545645745845946046146246346446546646746846947047147247347447547647747847948048148248348448548648748848949049149249349449549649749849950050150250350450550650750850951051151251351451551651751851952052152252352452552652752852953053153253353453553653753853954054154254354454554654754854955055155255355455555655755855956056156256356456556656756856957057157257357457557657757857958058158258358458558658758858959059159259359459559659759859960060160260360460560660760860961061161261361461561661761861962062162262362462562662762862963063163263363463563663763863964064164264364464564664764864965065165265365465565665765865966066166266366466566666766866967067167267367467567667767867968068168268368468568668768868969069169269369469569669769869970070170270370470570670770870971071171271371471571671771871972072172272372472572672772872973073173273373473573673773873974074174274374474574674774874975075175275375475575675775875976076176276376476576676776876977077177277377477577677777877978078178278378478578678778878979079179279379479579679779879980080180280380480580680780880981081181281381481581681781881982082182282382482582682782882983083183283383483583683783883984084184284384484584684784884985085185285385485585685785885986086186286386486586686786886987087187287387487587687787887988088188288388488588688788888989089189289389489589689789889990090190290390490590690790890991091191291391491591691791891992092192292392492592692792892993093193293393493593693793893994094194294394494594694794894995095195295395495595695795895996096196296396496596696796896997097197297397497597697797897998098198298398498598698798898999099199299399499599699799899910001001100210031004100510061007100810091010101110121013101410151016101710181019102010211022102310241025102610271028102910301031103210331034103510361037103810391040104110421043104410451046104710481049105010511052105310541055105610571058105910601061106210631064106510661067106810691070107110721073107410751076107710781079108010811082108310841085108610871088108910901091109210931094109510961097109810991100110111021103110411051106110711081109111011111112111311141115111611171118111911201121112211231124112511261127112811291130113111321133113411351136113711381139114011411142114311441145114611471148114911501151115211531154115511561157115811591160116111621163116411651166116711681169117011711172117311741175117611771178117911801181118211831184118511861187118811891190119111921193119411951196119711981199120012011202120312041205120612071208120912101211121212131214121512161217121812191220122112221223122412251226122712281229123012311232123312341235
							using Xml;
using Html;
using Astralis;
using Invercargill;
using Invercargill.DataStructures;
using Invercargill.Expressions;

namespace Statum.Tools {

    /**
     * `statum-mkpstm` — the build-time Statum pre-rendering pipeline.
     *
     * Turns an app HTML page (plus its templates/fragments) into a Vala
     * {@link Statum.StatumPage} subclass carrying precompressed variant byte
     * arrays and a compiled {@link Statum.StatumPage.select_variant} that
     * evaluates `pstm-guard`s and the `pstm-if` matrix against the request's held
     * slots using the Invercargill runtime expression evaluator.
     *
     * See `phase-1-plan.md` Subsystem B for the supported `pstm-*` directives.
     */
    public class Mkpstm : Object {

        private static string? output_file = null;
        private static string? namespace_name = null;
        private static string? class_name_override = null;
        private static string? route_override = null;
        private static List<string> template_dirs = new List<string>();

        private Dictionary<string, Xml.Doc*> templates_by_name = new Dictionary<string, Xml.Doc*>();
        private Dictionary<string, Xml.Doc*> fragments_by_name = new Dictionary<string, Xml.Doc*>();

        private const OptionEntry[] options = {
            { "output", 'o', 0, OptionArg.FILENAME, ref output_file, "Output Vala file name", "FILE" },
            { "ns", '\0', 0, OptionArg.STRING, ref namespace_name, "Namespace for the generated class", "NAMESPACE" },
            { "name", 'n', 0, OptionArg.STRING, ref class_name_override, "Generated class name (default: <InputName>Page)", "NAME" },
            { "route", 'r', 0, OptionArg.STRING, ref route_override, "Page route (default: from <pstm-uri>)", "ROUTE" },
            { "template-dir", 't', 0, OptionArg.FILENAME_ARRAY, ref template_dirs, "Directory to search for templates/fragments (repeatable)", "DIR" },
            { null }
        };

        public static int main(string[] args) {
            try {
                var opt = new OptionContext("PAGE_FILE - Generate a Statum StatumPage");
                opt.add_main_entries(options, null);
                opt.parse(ref args);
            } catch (OptionError e) {
                stderr.printf("Error: %s\n", e.message);
                return 1;
            }

            string? page_file = null;
            if (args.length > 1) {
                page_file = args[1];
            }
            if (page_file == null) {
                stderr.printf("Error: No page file specified.\n");
                return 1;
            }

            try {
                var tool = new Mkpstm();
                var generated = tool.run((!)page_file);
                var out_path = tool.output_file ?? (make_pascal_case((!)page_file) + "Page.vala");
                write_file(out_path, generated);
                stdout.printf("Generated: %s\n", out_path);
                return 0;
            } catch (GLib.Error e) {
                stderr.printf("Error: %s\n", e.message);
                return 1;
            }
        }

        public string run(string page_file) throws GLib.Error {
            if (template_dirs.length() == 0) {
                var parent = File.new_for_path(page_file).get_parent();
                template_dirs.append(parent != null ? ((!)parent).get_path() : ".");
            }

            load_templates_and_fragments(page_file);

            var doc = parse_html_file(page_file);
            // Capture the page's routes from the original document before
            // composition (structural <pstm-*> directives are dropped while
            // splicing templates, so they would no longer be present afterwards).
            var routes = read_routes(doc);
            var body = find_body(doc);
            if (body == null) {
                throw new IOError.FAILED("Page has no <body> element");
            }

            doc = compose_templates(doc, (!)body);
            inline_fragments(doc);
            rewrite_resources(doc);

            var collected = collect(doc);
            var class_name = class_name_override ?? (make_pascal_case(page_file) + "Page");
            var route = route_override ?? (routes.length > 0 ? routes[0] : "/");

            var variants = build_variants(doc, collected.groups);

            return emit(class_name, route, collected, variants);
        }

        // ------------------------------------------------------------------
        // Template/fragment loading
        // ------------------------------------------------------------------

        private void load_templates_and_fragments(string page_file) throws GLib.Error {
            foreach (var dir in template_dirs) {
                var dir_file = File.new_for_path(dir);
                if (!dir_file.query_exists()) {
                    continue;
                }
                var enumerator = dir_file.enumerate_children("standard::name", 0);
                FileInfo info;
                while ((info = enumerator.next_file()) != null) {
                    var name = info.get_name();
                    if (!name.has_suffix(".html") || name.has_prefix(".")) {
                        continue;
                    }
                    var path = Path.build_filename(dir, name);
                    if (path == page_file) {
                        continue;
                    }
                    var tdoc = parse_html_file(path);
                    var tname = read_pstm_name(tdoc);
                    if (tname == null) {
                        continue;
                    }
                    if (find_first_element(tdoc->get_root_element(), "pstm-content") != null) {
                        templates_by_name.set((!)tname, tdoc);
                    } else {
                        fragments_by_name.set((!)tname, tdoc);
                    }
                }
            }
        }

        // ------------------------------------------------------------------
        // Composition
        // ------------------------------------------------------------------

        private Xml.Doc* compose_templates(Xml.Doc* doc, Xml.Node* body) throws GLib.Error {
            Xml.Doc* current_doc = doc;
            Xml.Node* current_body = body;
            string merged_title = read_directive_in_doc(current_doc, "pstm-title") ?? "";

            // Guard against cyclic template chains (A templates B templates A).
            var visited = new HashSet<string>();

            while (true) {
                var parent_name = read_directive_in_doc(current_doc, "pstm-template");
                if (parent_name == null || parent_name.length == 0) {
                    break;
                }
                if (visited.contains((!)parent_name)) {
                    break;
                }
                visited.add((!)parent_name);

                Xml.Doc* parent_doc;
                if (!templates_by_name.try_get((!)parent_name, out parent_doc)) {
                    throw new IOError.FAILED(@"Unknown template \"$((!)parent_name)\"");
                }

                var parent_body = find_body(parent_doc);
                if (parent_body == null) {
                    throw new IOError.FAILED(@"Template \"$((!)parent_name)\" has no <body>");
                }

                // Splice this body's children into the parent's <pstm-content>
                // outlet, but drop structural <pstm-*> directives (pstm-template,
                // pstm-name, pstm-title, pstm-uri). These are page-level metadata
                // and must NOT be carried into the parent — otherwise the
                // spliced <pstm-template> would be re-discovered on the next pass
                // and recompose forever.
                var outlet = find_first_element(parent_body, "pstm-content");
                for (var child = current_body->children; child != null; child = child->next) {
                    if (is_structural_directive(child)) {
                        continue;
                    }
                    var copied = child->doc_copy(parent_doc, 1);
                    if (copied == null) {
                        continue;
                    }
                    if (outlet != null) {
                        outlet->add_prev_sibling(copied);
                    } else {
                        parent_body->add_child(copied);
                    }
                }
                if (outlet != null) {
                    outlet->unlink();
                }

                var parent_title = read_directive_in_doc(parent_doc, "pstm-title");
                if (parent_title != null && parent_title.length > 0) {
                    merged_title = merged_title + (!)parent_title;
                }

                current_doc = parent_doc;
                current_body = parent_body;
            }

            apply_title(current_doc, merged_title);
            return current_doc;
        }

        private static string? read_directive_in_doc(Xml.Doc* doc, string name) {
            var root = doc->get_root_element();
            if (root == null) {
                return null;
            }
            return read_directive_text(root, name);
        }

        private static bool is_structural_directive(Xml.Node* node) {
            if (!is_element(node)) {
                return false;
            }
            var name = (string) node->name;
            return name == "pstm-template" || name == "pstm-name" || name == "pstm-title" || name == "pstm-uri" || name == "pstm-content";
        }

        private void inline_fragments(Xml.Doc* doc) {
            bool changed = true;
            while (changed) {
                changed = false;
                var includes = find_all_elements(doc, "pstm-fragment");
                foreach (var include in includes) {
                    if (inline_one_fragment(doc, include)) {
                        changed = true;
                    }
                }
            }
        }

        private bool inline_one_fragment(Xml.Doc* doc, Xml.Node* include) {
            var name = include->get_prop("name");
            if (name == null) {
                return false;
            }
            Xml.Doc* fragment_doc;
            if (!fragments_by_name.try_get((!)name, out fragment_doc)) {
                return false;
            }

            var fragment_body = find_body(fragment_doc);
            if (fragment_body == null) {
                return false;
            }

            var inputs = collect_input_names(fragment_body);
            var materialise_as = include->get_prop("pstm-materialise-as");
            bool wrap = (materialise_as != null) || inputs.length > 0;
            string tag = materialise_as ?? "div";

            if (wrap) {
                var parent = include->parent;
                if (parent == null) {
                    return false;
                }
                var wrapper = parent->new_child(null, tag, null);
                wrapper->unlink();
                include->add_prev_sibling(wrapper);
                for (var child = fragment_body->children; child != null; child = child->next) {
                    var copied = child->doc_copy(doc, 1);
                    if (copied != null) {
                        wrapper->add_child(copied);
                    }
                }
                foreach (var input_name in inputs) {
                    var expr = include->get_prop(input_name);
                    if (expr != null) {
                        wrapper->set_prop(@"stm-def-$input_name-as", (!)expr);
                    }
                }
            } else {
                for (var child = fragment_body->children; child != null; child = child->next) {
                    var copied = child->doc_copy(doc, 1);
                    if (copied != null) {
                        include->add_prev_sibling(copied);
                    }
                }
            }

            include->unlink();
            return true;
        }

        private string[] collect_input_names(Xml.Node* fragment_body) {
            var names = new string[0];
            for (var n = fragment_body->children; n != null; n = n->next) {
                if (is_element(n) && (string) n->name == "pstm-input") {
                    var input_name = n->get_prop("name");
                    if (input_name != null) {
                        names += (!)input_name;
                    }
                }
            }
            return names;
        }

        private void rewrite_resources(Xml.Doc* doc) {
            var root = doc->get_root_element();
            if (root != null) {
                rewrite_resources_in(root);
            }
        }

        private void rewrite_resources_in(Xml.Node* node) {
            if (!is_element(node)) {
                return;
            }

            string[] to_add_attr = new string[0];
            string[] to_add_val = new string[0];
            string[] to_remove = new string[0];
            for (var attr = node->properties; attr != null; attr = attr->next) {
                var attr_name = (string) attr->name;
                if (attr_name.has_prefix("pstm-res-")) {
                    var target_attr = attr_name.substring("pstm-res-".length);
                    var value = node->get_prop(attr_name);
                    if (value != null) {
                        to_add_attr += target_attr;
                        to_add_val += @"/_statum/resource/$((!)value)";
                    }
                    to_remove += attr_name;
                }
            }
            for (int i = 0; i < to_add_attr.length; i++) {
                node->set_prop(to_add_attr[i], to_add_val[i]);
            }
            foreach (var attr_name in to_remove) {
                node->unset_prop(attr_name);
            }

            for (var child = node->children; child != null; child = child->next) {
                rewrite_resources_in(child);
            }
        }

        // ------------------------------------------------------------------
        // Group/guard collection
        // ------------------------------------------------------------------

        private Collected collect(Xml.Doc* doc) {
            var result = new Collected();
            var root = doc->get_root_element();
            if (root != null) {
                collect_guards(root, result);
                collect_groups_from(root, result);
            }
            return result;
        }

        private void collect_guards(Xml.Node* node, Collected result) {
            if (!is_element(node)) {
                return;
            }
            if (node->get_prop("pstm-guard") != null) {
                result.guards += new Guard() {
                    predicate = node->get_prop("predicate") ?? "",
                    require = node->get_prop("require"),
                    redirect = node->get_prop("redirect"),
                    status = node->get_prop("status")
                };
            }
            for (var child = node->children; child != null; child = child->next) {
                collect_guards(child, result);
            }
        }

        private void collect_groups_from(Xml.Node* node, Collected result) {
            var n = node->children;
            while (n != null) {
                if (!is_element(n)) {
                    n = n->next;
                    continue;
                }
                if (n->get_prop("pstm-if") != null) {
                    var chain = gather_chain(n);
                    result.groups += chain_to_group(chain);
                    foreach (var branch in chain) {
                        collect_groups_from(branch, result);
                    }
                    n = chain[chain.length - 1]->next;
                    continue;
                }
                collect_groups_from(n, result);
                n = n->next;
            }
        }

        private Xml.Node*[] gather_chain(Xml.Node* if_node) {
            Xml.Node*[] chain = new Xml.Node*[0];
            chain += if_node;
            var n = if_node->next;
            while (n != null) {
                if (!is_element(n)) {
                    n = n->next;
                    continue;
                }
                if (n->get_prop("pstm-else-if") != null || n->get_prop("pstm-else") != null) {
                    chain += n;
                    n = n->next;
                } else {
                    break;
                }
            }
            return chain;
        }

        private IfGroup chain_to_group(Xml.Node*[] chain) {
            var conditions = new string[0];
            bool has_else = false;
            foreach (var node in chain) {
                var else_if = node->get_prop("pstm-else-if");
                if (node->get_prop("pstm-if") != null) {
                    conditions += node->get_prop("pstm-if") ?? "";
                } else if (else_if != null) {
                    conditions += (!)else_if;
                } else if (node->get_prop("pstm-else") != null) {
                    has_else = true;
                }
            }
            return new IfGroup() { conditions = conditions, has_else = has_else };
        }

        // ------------------------------------------------------------------
        // Variant rendering
        // ------------------------------------------------------------------

        private VariantData[] build_variants(Xml.Doc* doc, IfGroup[] groups) throws GLib.Error {
            int total = 1;
            foreach (var group in groups) {
                total *= (group.conditions.length + 1);
            }
            if (total < 1) {
                total = 1;
            }

            VariantData[] variants = new VariantData[0];
            for (var index = 0; index < total; index++) {
                int[] choices = new int[groups.length];
                int stride = 1;
                for (int gi = 0; gi < groups.length; gi++) {
                    int outcomes = groups[gi].conditions.length + 1;
                    choices[gi] = (index / stride) % outcomes;
                    stride *= outcomes;
                }

                var copy = doc->copy(1);
                apply_choices(copy, choices);
                strip_pstm(copy);
                var html = serialize(copy);
                delete copy;

                variants += compress_variant(html);
            }
            return variants;
        }

        private VariantData compress_variant(string html) throws GLib.Error {
            var data = new VariantData();
            data.identity = html.data;
            var buffer = new ByteBuffer.from_byte_array(html.data);

            var gzip = new GzipCompressor(9).compress_buffer(buffer, null).to_array();
            var zstd = new ZstdCompressor(19).compress_buffer(buffer, null).to_array();
            var br = new BrotliCompressor(11).compress_buffer(buffer, null).to_array();

            data.has_gzip = gzip.length < html.length;
            data.has_zstd = zstd.length < html.length;
            data.has_br = br.length < html.length;
            data.gzip = data.has_gzip ? gzip : null;
            data.zstd = data.has_zstd ? zstd : null;
            data.br = data.has_br ? br : null;
            return data;
        }

        private void apply_choices(Xml.Doc* doc, int[] choices) {
            var root = doc->get_root_element();
            if (root == null) {
                return;
            }
            int gi = 0;
            apply_choices_from(root, choices, ref gi);
        }

        private void apply_choices_from(Xml.Node* node, int[] choices, ref int gi) {
            var n = node->children;
            while (n != null) {
                if (!is_element(n)) {
                    n = n->next;
                    continue;
                }
                if (n->get_prop("pstm-if") != null) {
                    var chain = gather_chain(n);
                    var after = chain[chain.length - 1]->next;

                    int conds = count_conditions(chain);
                    int choice = (gi < choices.length) ? choices[gi] : conds;
                    gi++;

                    Xml.Node* keep = null;
                    int idx = 0;
                    foreach (var branch in chain) {
                        bool is_conditional = branch->get_prop("pstm-if") != null || branch->get_prop("pstm-else-if") != null;
                        if (is_conditional) {
                            if (idx == choice) {
                                keep = branch;
                            }
                            idx++;
                        } else if (branch->get_prop("pstm-else") != null) {
                            if (choice >= conds) {
                                keep = branch;
                            }
                        }
                    }

                    foreach (var branch in chain) {
                        if (branch == keep) {
                            continue;
                        }
                        branch->unlink();
                    }

                    if (keep != null) {
                        apply_choices_from(keep, choices, ref gi);
                    }

                    n = after;
                    continue;
                }
                apply_choices_from(n, choices, ref gi);
                n = n->next;
            }
        }

        private int count_conditions(Xml.Node*[] chain) {
            int count = 0;
            foreach (var node in chain) {
                if (node->get_prop("pstm-if") != null || node->get_prop("pstm-else-if") != null) {
                    count++;
                }
            }
            return count;
        }

        private void strip_pstm(Xml.Doc* doc) {
            var root = doc->get_root_element();
            if (root != null) {
                strip_pstm_from(root);
            }
        }

        private void strip_pstm_from(Xml.Node* node) {
            // pstm-guard's parameters (predicate/require/redirect/status) are not
            // pstm-prefixed, so remove them alongside the pstm-guard marker.
            bool is_guard = node->get_prop("pstm-guard") != null;
            string[] to_remove = new string[0];
            for (var attr = node->properties; attr != null; attr = attr->next) {
                var attr_name = (string) attr->name;
                if (attr_name.has_prefix("pstm-")) {
                    to_remove += attr_name;
                } else if (is_guard && (attr_name == "predicate" || attr_name == "require" || attr_name == "redirect" || attr_name == "status")) {
                    to_remove += attr_name;
                }
            }
            foreach (var attr_name in to_remove) {
                node->unset_prop(attr_name);
            }

            var child = node->children;
            while (child != null) {
                var next = child->next;
                if (is_element(child) && ((string) child->name).has_prefix("pstm-")) {
                    child->unlink();
                } else if (is_element(child)) {
                    strip_pstm_from(child);
                }
                child = next;
            }
        }

        // ------------------------------------------------------------------
        // Code generation
        // ------------------------------------------------------------------

        private string emit(string class_name, string route, Collected collected, VariantData[] variants) throws GLib.Error {
            var page_hash = compute_hash(variants.length > 0 ? variants[0].identity : new uint8[0]);

            var b = new StringBuilder();
            string i1 = namespace_name != null ? "    " : "";
            string i2 = namespace_name != null ? "        " : "    ";
            string i3 = namespace_name != null ? "            " : "        ";
            string i4 = namespace_name != null ? "                " : "            ";

            b.append("using Statum;\n");
            b.append("using Invercargill;\n");
            b.append("using Invercargill.DataStructures;\n");
            b.append("using Astralis;\n\n");

            if (namespace_name != null) {
                b.append_printf("namespace %s {\n\n", namespace_name);
            }

            b.append_printf("%s// Generated by statum-mkpstm\n", i1);
            b.append_printf("%spublic class %s : StatumPage {\n\n", i1, class_name);

            b.append_printf("%spublic const string ROUTE = \"%s\";\n", i2, escape(route));
            b.append_printf("%spublic override string content_type { get { return \"text/html; charset=utf-8\"; } }\n\n", i2);

            emit_select_variant(b, i2, i3, collected, variants.length);
            emit_encoding_methods(b, i2, i3, i4, variants, page_hash);
            emit_byte_arrays(b, i2, i3, variants);
            emit_helpers(b, i2, i3);

            b.append_printf("%s}\n", i1);
            if (namespace_name != null) {
                b.append("}\n");
            }

            return b.str;
        }

        private void emit_select_variant(StringBuilder b, string i2, string i3, Collected collected, int variant_count) {
            b.append_printf("%spublic override StatumVariantSelection select_variant(ReadOnlyAssociative<string, HeldSlot> held) throws GLib.Error {\n", i2);

            foreach (var guard in collected.guards) {
                string predicate_check;
                var compiled = @"el_truthy($(compile_predicate_string(guard.predicate)))";
                if (guard.require != null) {
                    predicate_check = @"held.has(\"$(escape((!)guard.require))\") && $(compiled)";
                } else {
                    predicate_check = compiled;
                }
                if (guard.redirect != null) {
                    b.append_printf("%sif (!(%s)) {\n", i3, predicate_check);
                    b.append_printf("%sreturn StatumVariantSelection.redirect_to(\"%s\");\n", i3, escape((!)guard.redirect));
                    b.append_printf("%s}\n", i3);
                } else {
                    var status = guard.status ?? "FORBIDDEN";
                    b.append_printf("%sif (!(%s)) {\n", i3, predicate_check);
                    b.append_printf("%sreturn StatumVariantSelection.failure(StatusCode.%s);\n", i3, status);
                    b.append_printf("%s}\n", i3);
                }
            }

            // Compute the variant index as a mixed-radix number of per-group choices.
            for (int gi = 0; gi < collected.groups.length; gi++) {
                var group = collected.groups[gi];
                b.append_printf("%sint g%d;\n", i3, gi);
                b.append_printf("%s{\n", i3);
                b.append_printf("%sint choice = %d;\n", i3, group.conditions.length);
                for (int ci = 0; ci < group.conditions.length; ci++) {
                    var compiled = @"el_truthy($(compile_predicate_string(group.conditions[ci])))";
                    if (ci == 0) {
                        b.append_printf("%sif (%s) { choice = 0; }\n", i3, compiled);
                    } else {
                        b.append_printf("%selse if (%s) { choice = %d; }\n", i3, compiled, ci);
                    }
                }
                b.append_printf("%sg%d = choice;\n", i3, gi);
                b.append_printf("%s}\n", i3);
            }

            if (collected.groups.length == 0) {
                b.append_printf("%sreturn StatumVariantSelection.variant(0);\n", i3);
            } else {
                b.append_printf("%sint index = 0;\n", i3);
                int stride = 1;
                for (int gi = 0; gi < collected.groups.length; gi++) {
                    b.append_printf("%sindex += g%d * %d;\n", i3, gi, stride);
                    stride *= collected.groups[gi].conditions.length + 1;
                }
                b.append_printf("%sif (index < 0 || index >= %d) { index = 0; }\n", i3, variant_count);
                b.append_printf("%sreturn StatumVariantSelection.variant(index);\n", i3);
            }

            b.append_printf("%s}\n\n", i2);
        }

        private void emit_encoding_methods(StringBuilder b, string i2, string i3, string i4, VariantData[] variants, string page_hash) {
            // get_best_encoding: prefer the smallest supported, available encoding.
            b.append_printf("%spublic override string get_best_encoding(int variant, Set<string> supported) {\n", i2);
            b.append_printf("%sif (supported.has(\"br\") && has_encoding(variant, 3)) return \"br\";\n", i3);
            b.append_printf("%sif (supported.has(\"zstd\") && has_encoding(variant, 2)) return \"zstd\";\n", i3);
            b.append_printf("%sif (supported.has(\"gzip\") && has_encoding(variant, 1)) return \"gzip\";\n", i3);
            b.append_printf("%sreturn \"identity\";\n", i3);
            b.append_printf("%s}\n\n", i2);

            // get_encoding: nested switch over (variant, encoding).
            b.append_printf("%spublic override unowned uint8[] get_encoding(int variant, string encoding) {\n", i2);
            b.append_printf("%sswitch (variant) {\n", i3);
            for (int v = 0; v < variants.length; v++) {
                b.append_printf("%scase %d:\n", i4, v);
                b.append_printf("%sswitch (encoding) {\n", i4);
                b.append_printf("%scase \"identity\": return V_%d_IDENTITY;\n", i4, v);
                if (variants[v].has_gzip) {
                    b.append_printf("%scase \"gzip\": return V_%d_GZIP;\n", i4, v);
                }
                if (variants[v].has_zstd) {
                    b.append_printf("%scase \"zstd\": return V_%d_ZSTD;\n", i4, v);
                }
                if (variants[v].has_br) {
                    b.append_printf("%scase \"br\": return V_%d_BR;\n", i4, v);
                }
                b.append_printf("%sdefault: return V_%d_IDENTITY;\n", i4, v);
                b.append_printf("%s}\n", i4);
            }
            b.append_printf("%s}\n", i3);
            b.append_printf("%sreturn V_0_IDENTITY;\n", i3);
            b.append_printf("%s}\n\n", i2);

            // get_etag_for
            b.append_printf("%spublic override string get_etag_for(int variant, string encoding) {\n", i2);
            b.append_printf("%sreturn \"\\\"%s-%%s-%%d\\\"\".printf(encoding, variant);\n", i3, page_hash);
            b.append_printf("%s}\n\n", i2);

            // has_encoding
            b.append_printf("%sprivate static bool has_encoding(int variant, int encoding) {\n", i2);
            b.append_printf("%sswitch (variant) {\n", i3);
            for (int v = 0; v < variants.length; v++) {
                b.append_printf("%scase %d: return encoding == 0%s%s%s;\n", i4, v,
                    variants[v].has_gzip ? " || encoding == 1" : "",
                    variants[v].has_zstd ? " || encoding == 2" : "",
                    variants[v].has_br ? " || encoding == 3" : "");
            }
            b.append_printf("%s}\n", i3);
            b.append_printf("%sreturn false;\n", i3);
            b.append_printf("%s}\n\n", i2);
        }

        private void emit_byte_arrays(StringBuilder b, string i2, string i3, VariantData[] variants) {
            for (int v = 0; v < variants.length; v++) {
                emit_one_array(b, i2, i3, @"V_$(v)_IDENTITY", variants[v].identity);
                if (variants[v].has_gzip && variants[v].gzip != null) {
                    emit_one_array(b, i2, i3, @"V_$(v)_GZIP", (!)variants[v].gzip);
                }
                if (variants[v].has_zstd && variants[v].zstd != null) {
                    emit_one_array(b, i2, i3, @"V_$(v)_ZSTD", (!)variants[v].zstd);
                }
                if (variants[v].has_br && variants[v].br != null) {
                    emit_one_array(b, i2, i3, @"V_$(v)_BR", (!)variants[v].br);
                }
            }
        }

        private void emit_one_array(StringBuilder b, string i2, string i3, string name, uint8[] data) {
            b.append_printf("%sprivate const uint8[] %s = {\n", i2, name);
            for (int i = 0; i < data.length; i++) {
                if (i == 0) {
                    b.append(i3);
                } else if (i % 16 == 0) {
                    b.append(",\n").append(i3);
                } else {
                    b.append(", ");
                }
                b.append_printf("0x%02x", data[i]);
            }
            b.append_printf("\n%s};\n\n", i2);
        }

        private void emit_helpers(StringBuilder b, string i2, string i3) {
            // Static helpers used by the compiled predicates in select_variant.
            // Each predicate AST node is translated at build time into calls to
            // these, so no expression is parsed/evaluated at request time.
            b.append_printf("%sprivate static Element? held_pub(ReadOnlyAssociative<string, HeldSlot> held, string type_name) {\n", i2);
            b.append_printf("%sHeldSlot slot;\n", i3);
            b.append_printf("%sif (held.try_get(type_name, out slot)) { return new NativeElement<Properties>(slot.@public); }\n", i3);
            b.append_printf("%sreturn null;\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static Element? held_priv(ReadOnlyAssociative<string, HeldSlot> held, string type_name) {\n", i2);
            b.append_printf("%sHeldSlot slot;\n", i3);
            b.append_printf("%sif (held.try_get(type_name, out slot)) { return new NativeElement<Properties>(slot.@private); }\n", i3);
            b.append_printf("%sreturn null;\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static Element? el_get(Element? target, string name) {\n", i2);
            b.append_printf("%sif (target == null) { return null; }\n", i3);
            b.append_printf("%sProperties props;\n", i3);
            b.append_printf("%sif (!((!)target).try_get_as<Properties>(out props)) { return null; }\n", i3);
            b.append_printf("%sElement value;\n", i3);
            b.append_printf("%sif (!props.try_get(name, out value)) { return null; }\n", i3);
            b.append_printf("%sreturn value;\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static bool el_is_null(Element? e) {\n", i2);
            b.append_printf("%sreturn e == null || ((!)e) is NullElement || ((!)e).is_null();\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static bool el_truthy(Element? e) {\n", i2);
            b.append_printf("%sif (el_is_null(e)) { return false; }\n", i3);
            b.append_printf("%sbool? b = ((!)e).as_bool_or_null();\n", i3);
            b.append_printf("%sreturn b != null ? (!)b : true;\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static double? el_num_of(Element e) {\n", i2);
            b.append_printf("%sint? i = e.as_int_or_null(); if (i != null) { return (double)(!)i; }\n", i3);
            b.append_printf("%sint64? i64 = e.as_int64_or_null(); if (i64 != null) { return (double)(!)i64; }\n", i3);
            b.append_printf("%sdouble? d = e.as_double_or_null(); if (d != null) { return d; }\n", i3);
            b.append_printf("%sfloat? f = e.as_float_or_null(); if (f != null) { return (double)(!)f; }\n", i3);
            b.append_printf("%slong? l = e.as_long_or_null(); if (l != null) { return (double)(!)l; }\n", i3);
            b.append_printf("%sreturn null;\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static double? el_num_of_opt(Element? e) {\n", i2);
            b.append_printf("%sif (el_is_null(e)) { return null; }\n", i3);
            b.append_printf("%sreturn el_num_of((!)e);\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static int? el_cmp_values(Element a, Element b) {\n", i2);
            b.append_printf("%sdouble? na = el_num_of(a), nb = el_num_of(b);\n", i3);
            b.append_printf("%sif (na != null && nb != null) { return na < nb ? -1 : (na > nb ? 1 : 0); }\n", i3);
            b.append_printf("%sstring? sa = a.as_string_or_null(), sb = b.as_string_or_null();\n", i3);
            b.append_printf("%sif (sa != null && sb != null) { int c = strcmp((!)sa, (!)sb); return c < 0 ? -1 : (c > 0 ? 1 : 0); }\n", i3);
            b.append_printf("%sreturn null;\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static bool el_values_equal(Element a, Element b) {\n", i2);
            b.append_printf("%sint? c = el_cmp_values(a, b);\n", i3);
            b.append_printf("%sif (c != null) { return (!)c == 0; }\n", i3);
            b.append_printf("%sbool? ba = a.as_bool_or_null(), bb = b.as_bool_or_null();\n", i3);
            b.append_printf("%sif (ba != null && bb != null) { return ba == bb; }\n", i3);
            b.append_printf("%sreturn false;\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static Element? el_str(string s) { return new NativeElement<string>(s); }\n", i2);
            b.append_printf("%sprivate static Element? el_num(double d) { return new NativeElement<double?>(d); }\n", i2);
            b.append_printf("%sprivate static Element? el_bool(bool b) { return new NativeElement<bool>(b); }\n", i2);
            b.append_printf("%sprivate static Element? el_null() { return new NullElement(); }\n", i2);

            b.append_printf("%sprivate static Element? el_eq(Element? a, Element? b) {\n", i2);
            b.append_printf("%sbool an = el_is_null(a), bn = el_is_null(b);\n", i3);
            b.append_printf("%sif (an || bn) { return el_bool(an == bn); }\n", i3);
            b.append_printf("%sreturn el_bool(el_values_equal((!)a, (!)b));\n", i3);
            b.append_printf("%s}\n", i2);

            b.append_printf("%sprivate static Element? el_neq(Element? a, Element? b) { return el_bool(!el_truthy(el_eq(a, b))); }\n", i2);

            b.append_printf("%sprivate static Element? el_gt(Element? a, Element? b) {\n", i2);
            b.append_printf("%sif (el_is_null(a) || el_is_null(b)) { return el_bool(false); }\n", i3);
            b.append_printf("%sint? c = el_cmp_values((!)a, (!)b);\n", i3);
            b.append_printf("%sreturn el_bool(c != null && (!)c > 0);\n", i3);
            b.append_printf("%s}\n", i2);
            b.append_printf("%sprivate static Element? el_ge(Element? a, Element? b) {\n", i2);
            b.append_printf("%sif (el_is_null(a) || el_is_null(b)) { return el_bool(false); }\n", i3);
            b.append_printf("%sint? c = el_cmp_values((!)a, (!)b);\n", i3);
            b.append_printf("%sreturn el_bool(c != null && (!)c >= 0);\n", i3);
            b.append_printf("%s}\n", i2);
            b.append_printf("%sprivate static Element? el_lt(Element? a, Element? b) {\n", i2);
            b.append_printf("%sif (el_is_null(a) || el_is_null(b)) { return el_bool(false); }\n", i3);
            b.append_printf("%sint? c = el_cmp_values((!)a, (!)b);\n", i3);
            b.append_printf("%sreturn el_bool(c != null && (!)c < 0);\n", i3);
            b.append_printf("%s}\n", i2);
            b.append_printf("%sprivate static Element? el_le(Element? a, Element? b) {\n", i2);
            b.append_printf("%sif (el_is_null(a) || el_is_null(b)) { return el_bool(false); }\n", i3);
            b.append_printf("%sint? c = el_cmp_values((!)a, (!)b);\n", i3);
            b.append_printf("%sreturn el_bool(c != null && (!)c <= 0);\n", i3);
            b.append_printf("%s}\n", i2);
            b.append_printf("%sprivate static Element? el_and(Element? a, Element? b) { return el_bool(el_truthy(a) && el_truthy(b)); }\n", i2);
            b.append_printf("%sprivate static Element? el_or(Element? a, Element? b) { return el_bool(el_truthy(a) || el_truthy(b)); }\n", i2);
            b.append_printf("%sprivate static Element? el_not(Element? a) { return el_bool(!el_truthy(a)); }\n", i2);

            b.append_printf("%sprivate static Element? el_arith(Element? a, Element? b, string op) {\n", i2);
            b.append_printf("%sdouble? x = el_num_of_opt(a), y = el_num_of_opt(b);\n", i3);
            b.append_printf("%sif (x == null || y == null) { return null; }\n", i3);
            b.append_printf("%sdouble xv = (!)x, yv = (!)y;\n", i3);
            b.append_printf("%sif (op == \"+\") { return el_num(xv + yv); }\n", i3);
            b.append_printf("%sif (op == \"-\") { return el_num(xv - yv); }\n", i3);
            b.append_printf("%sif (op == \"*\") { return el_num(xv * yv); }\n", i3);
            b.append_printf("%sif (op == \"/\") { return yv == 0 ? null : el_num(xv / yv); }\n", i3);
            b.append_printf("%sif (op == \"%%\") { return yv == 0 ? null : el_num((double)((int64)xv %% (int64)yv)); }\n", i3);
            b.append_printf("%sreturn null;\n", i3);
            b.append_printf("%s}\n", i2);
            b.append_printf("%sprivate static Element? el_add(Element? a, Element? b) { return el_arith(a, b, \"+\"); }\n", i2);
            b.append_printf("%sprivate static Element? el_sub(Element? a, Element? b) { return el_arith(a, b, \"-\"); }\n", i2);
            b.append_printf("%sprivate static Element? el_mul(Element? a, Element? b) { return el_arith(a, b, \"*\"); }\n", i2);
            b.append_printf("%sprivate static Element? el_div(Element? a, Element? b) { return el_arith(a, b, \"/\"); }\n", i2);
            b.append_printf("%sprivate static Element? el_mod(Element? a, Element? b) { return el_arith(a, b, \"%%\"); }\n", i2);
            b.append_printf("%sprivate static Element? el_neg(Element? a) { double? x = el_num_of_opt(a); return x == null ? null : el_num(-(!)x); }\n", i2);
            b.append_printf("%sprivate static Element? el_ternary(Element? c, Element? a, Element? b) { return el_truthy(c) ? a : b; }\n", i2);

            b.append("\n");
        }

        // ------------------------------------------------------------------
        // Predicate compilation (build-time AST → Vala)
        // ------------------------------------------------------------------

        private string compile_predicate_string(string predicate) {
            try {
                return compile_predicate(ExpressionParser.parse(predicate));
            } catch (ExpressionError e) {
                // Unparseable predicate → always false.
                return "el_bool(false)";
            }
        }

        private string compile_predicate(Expression expr) {
            if (expr is VariableExpression) {
                var v = (VariableExpression) expr;
                return @"held_pub(held, \"$(escape(v.variable_name))\")";
            }
            if (expr is PropertyExpression) {
                var p = (PropertyExpression) expr;
                if (p.property_name == "private" && p.target is VariableExpression) {
                    var root = (VariableExpression) p.target;
                    return @"held_priv(held, \"$(escape(root.variable_name))\")";
                }
                return @"el_get($(compile_predicate(p.target)), \"$(escape(p.property_name))\")";
            }
            if (expr is LiteralExpression) {
                return compile_literal((LiteralExpression) expr);
            }
            if (expr is UnaryExpression) {
                var u = (UnaryExpression) expr;
                var operand = compile_predicate(u.operand);
                if (u.operator == UnaryOperator.NOT) {
                    return @"el_not($(operand))";
                }
                if (u.operator == UnaryOperator.NEGATE) {
                    return @"el_neg($(operand))";
                }
                return "el_null()";
            }
            if (expr is BinaryExpression) {
                return compile_binary((BinaryExpression) expr);
            }
            if (expr is BracketedExpression) {
                return compile_predicate(((BracketedExpression) expr).inner);
            }
            if (expr is TernaryExpression) {
                var t = (TernaryExpression) expr;
                return @"el_ternary($(compile_predicate(t.condition)), $(compile_predicate(t.true_expression)), $(compile_predicate(t.false_expression)))";
            }
            // Unsupported node (function call, lambda, lot literal, parameter).
            return "el_null()";
        }

        private string compile_binary(BinaryExpression b) {
            var l = compile_predicate(b.left);
            var r = compile_predicate(b.right);
            switch (b.op) {
                case BinaryOperator.EQUAL: return @"el_eq($(l), $(r))";
                case BinaryOperator.NOT_EQUAL: return @"el_neq($(l), $(r))";
                case BinaryOperator.GREATER_THAN: return @"el_gt($(l), $(r))";
                case BinaryOperator.LESS_THAN: return @"el_lt($(l), $(r))";
                case BinaryOperator.GREATER_EQUAL: return @"el_ge($(l), $(r))";
                case BinaryOperator.LESS_EQUAL: return @"el_le($(l), $(r))";
                case BinaryOperator.AND: return @"el_and($(l), $(r))";
                case BinaryOperator.OR: return @"el_or($(l), $(r))";
                case BinaryOperator.ADD: return @"el_add($(l), $(r))";
                case BinaryOperator.SUBTRACT: return @"el_sub($(l), $(r))";
                case BinaryOperator.MULTIPLY: return @"el_mul($(l), $(r))";
                case BinaryOperator.DIVIDE: return @"el_div($(l), $(r))";
                case BinaryOperator.MODULO: return @"el_mod($(l), $(r))";
                default: return "el_null()";
            }
        }

        private string compile_literal(LiteralExpression lit) {
            var v = lit.value;
            if (v == null || v is NullElement) {
                return "el_null()";
            }
            string? s;
            if (v.try_get_as<string>(out s)) {
                return @"el_str(\"$(escape_vala_string((!)s))\")";
            }
            bool? bv;
            if (v.try_get_as<bool>(out bv)) {
                return (!)bv ? "el_bool(true)" : "el_bool(false)";
            }
            var d = numeric_value_of(v);
            if (d != null) {
                return @"el_num($((!)d))";
            }
            return "el_null()";
        }

        private static double? numeric_value_of(Invercargill.Element v) {
            int64? i64;
            if (v.try_get_as<int64?>(out i64)) {
                return (double)(!)i64;
            }
            int? i;
            if (v.try_get_as<int?>(out i)) {
                return (double)(!)i;
            }
            double? d;
            if (v.try_get_as<double?>(out d)) {
                return d;
            }
            float? f;
            if (v.try_get_as<float?>(out f)) {
                return (double)(!)f;
            }
            long? l;
            if (v.try_get_as<long?>(out l)) {
                return (double)(!)l;
            }
            return null;
        }

        private static string escape_vala_string(string s) {
            return s.replace("\\", "\\\\")
                .replace("\"", "\\\"")
                .replace("\n", "\\n")
                .replace("\r", "\\r")
                .replace("\t", "\\t");
        }

        // ------------------------------------------------------------------
        // DOM helpers
        // ------------------------------------------------------------------

        private Xml.Doc* parse_html_file(string path) throws GLib.Error {
            var file = File.new_for_path(path);
            if (!file.query_exists()) {
                throw new IOError.NOT_FOUND(@"Page file '$path' does not exist");
            }

            uint8[] contents;
            string etag_out;
            file.load_contents(null, out contents, out etag_out);

            // Parse with libxml2's HTML parser (mirrors Astralis' MarkupDocument)
            // so the tree has HTML semantics and serializes as HTML, not XML.
            int opts = (int)(Html.ParserOption.RECOVER |
                Html.ParserOption.NOERROR |
                Html.ParserOption.NOWARNING |
                Html.ParserOption.NOBLANKS |
                Html.ParserOption.NONET);
            char[] buffer = ((string) contents).to_utf8();
            var doc = Html.Doc.read_memory(buffer, buffer.length, path, "utf-8", opts);
            if (doc == null) {
                throw new IOError.FAILED(@"Failed to parse HTML file '$path'");
            }
            return doc;
        }

        private static Xml.Node* find_body(Xml.Doc* doc) {
            var root = doc->get_root_element();
            if (root == null) {
                return null;
            }
            return find_first_element(root, "body");
        }

        private static Xml.Node* find_first_element(Xml.Node* root, string name) {
            if (!is_element(root)) {
                return null;
            }
            if (((string) root->name).down() == name.down()) {
                return root;
            }
            for (var child = root->children; child != null; child = child->next) {
                var found = find_first_element(child, name);
                if (found != null) {
                    return found;
                }
            }
            return null;
        }

        private static Xml.Node*[] find_all_elements(Xml.Doc* doc, string name) {
            var collected = new Series<Xml.Node*>();
            var root = doc->get_root_element();
            if (root != null) {
                find_all_from(root, name, collected);
            }
            return collected.to_array();
        }

        private static void find_all_from(Xml.Node* node, string name, Series<Xml.Node*> result) {
            if (is_element(node) && ((string) node->name).down() == name.down()) {
                result.add(node);
            }
            if (is_element(node)) {
                for (var child = node->children; child != null; child = child->next) {
                    find_all_from(child, name, result);
                }
            }
        }

        private static string? read_directive_text(Xml.Node* body, string directive) {
            var node = find_first_element(body, directive);
            if (node == null) {
                return null;
            }
            var text = element_text(node);
            return text.strip().length > 0 ? text.strip() : null;
        }

        private static string? read_pstm_name(Xml.Doc* doc) {
            var node = find_first_element(doc->get_root_element(), "pstm-name");
            if (node == null) {
                return null;
            }
            return element_text(node).strip();
        }

        private static string[] read_routes(Xml.Doc* doc) {
            string[] routes = new string[0];
            var nodes = find_all_elements(doc, "pstm-uri");
            foreach (var node in nodes) {
                var text = element_text(node).strip();
                if (text.length > 0) {
                    routes += text;
                }
            }
            return routes;
        }

        private static string element_text(Xml.Node* node) {
            var b = new StringBuilder();
            for (var child = node->children; child != null; child = child->next) {
                if (child->type == ElementType.TEXT_NODE && child->content != null) {
                    b.append((string) child->content);
                } else if (is_element(child)) {
                    b.append(element_text(child));
                }
            }
            return b.str;
        }

        private static void apply_title(Xml.Doc* doc, string? title) {
            if (title == null || title.length == 0) {
                return;
            }
            var head = find_first_element(doc->get_root_element(), "head");
            if (head == null) {
                return;
            }
            var title_node = find_first_element(head, "title");
            if (title_node == null) {
                title_node = head->new_child(null, "title", null);
            }
            for (var child = title_node->children; child != null; child = child->next) {
                child->unlink();
            }
            title_node->add_content(title);
        }

        private static string serialize(Xml.Doc* doc) {
            // Serialize with libxml2's HTML serializer (htmlDocDumpMemory) so the
            // output is valid HTML: no <?xml?> prolog, no self-closing
            // `<script/>`, and correct void/non-void element handling. The doc was
            // produced by the HTML parser, so it carries HTML structure.
            string mem;
            int len;
            ((Html.Doc*) doc)->dump_memory(out mem, out len);
            return len > 0 ? mem.substring(0, len) : mem;
        }

        private static bool is_element(Xml.Node* node) {
            return node != null && node->type == ElementType.ELEMENT_NODE;
        }

        private static string compute_hash(uint8[] data) {
            var checksum = new Checksum(ChecksumType.SHA512);
            checksum.update(data, data.length);
            return checksum.get_string();
        }

        private static string escape(string s) {
            return s.replace("\\", "\\\\").replace("\"", "\\\"");
        }

        private static void write_file(string path, string contents) throws GLib.Error {
            var file = File.new_for_path(path);
            var stream = new DataOutputStream(file.replace(null, false, FileCreateFlags.NONE));
            stream.put_string(contents);
            stream.close();
        }

        private static string make_pascal_case(string input) {
            var basename = Path.get_basename(input);
            var dot = basename.last_index_of(".");
            if (dot > 0) {
                basename = basename.substring(0, dot);
            }
            var result = new StringBuilder();
            var capitalize_next = true;
            foreach (var c in basename.data) {
                if (c == '-' || c == '_' || c == ' ' || c == '.') {
                    capitalize_next = true;
                } else {
                    if (capitalize_next) {
                        result.append_printf("%c", c >= 'a' && c <= 'z' ? c - 32 : c);
                        capitalize_next = false;
                    } else {
                        result.append_printf("%c", c);
                    }
                }
            }
            return result.str;
        }

        // ------------------------------------------------------------------
        // Model
        // ------------------------------------------------------------------

        private class Guard : Object {
            public string predicate;
            public string? require;
            public string? redirect;
            public string? status;
        }

        private class IfGroup : Object {
            public string[] conditions = new string[0];
            public bool has_else;
        }

        private class Collected : Object {
            public Guard[] guards = new Guard[0];
            public IfGroup[] groups = new IfGroup[0];
        }

        private class VariantData : Object {
            public uint8[] identity;
            public uint8[]? gzip;
            public uint8[]? zstd;
            public uint8[]? br;
            public bool has_gzip;
            public bool has_zstd;
            public bool has_br;
        }
    }
}