Lady’s Gitweb - GitWikiWeb/blob - build.js

   1 // 🐙🕸️ GitWikiWeb ∷ build.js
   2 // ====================================================================
   3 //
   4 // Copyright © 2023 Lady [@ Lady’s Computer].
   5 //
   6 // This Source Code Form is subject to the terms of the Mozilla Public
   7 // License, v. 2.0. If a copy of the MPL was not distributed with this
   8 // file, You can obtain one at <https://mozilla.org/MPL/2.0/>.
   9 //
  10 // --------------------------------------------------------------------
  11 //
  12 // A script for generating static wiki pages from a git repository.
  13 //
  14 // First, clone this repository to your machine in an accessible
  15 // location (for example, `/srv/git/GitWikiWeb`). A bare repository is
  16 // fine; customize the templates and stylesheets as you like. Then, use
  17 // this file as the post‐receive hook for your wiki as follows :—
  18 //
  19 //     #!/usr/bin/env -S sh
  20 //     export GITWIKIWEB=/srv/git/GitWikiWeb
  21 //     git archive --remote=$GITWIKIWEB HEAD build.js \
  22 //       | tar -xO \
  23 //       | deno run -A - ~/public/wiki $GITWIKIWEB current
  24 //
  25 // The directory `~/public/wiki` (or whatever you specify as the first
  26 // argument to `deno run -A -`) **will be deleted** and a new static
  27 // wiki will be generated in its place. This script is not very smart
  28 // (yet) and cannot selectively determine which pages will need
  29 // updating. It just wipes and regenerates the whole thing.
  30 //
  31 // This script will make a number of requests to `$GITWIKIWEB` to
  32 // download the latest templates, stylesheets, ⁊·c from this
  33 // repository. Consequently, it is best that you set it to a repository
  34 // you control and can ensure uptime for—ideally one local to the
  35 // computer hosting the wiki.
  36
  37 import {
  38   emptyDir,
  39   ensureDir,
  40 } from "https://deno.land/std@0.196.0/fs/mod.ts";
  41 import {
  42   JSON_SCHEMA,
  43   parse as parseYaml,
  44 } from "https://deno.land/std@0.196.0/yaml/mod.ts";
  45 import djot from "npm:@djot/djot@0.2.3";
  46 import { Parser } from "npm:htmlparser2@9.0.0";
  47 import { DomHandler, Element, Text } from "npm:domhandler@5.0.3";
  48 import * as domutils from "npm:domutils@3.1.0";
  49 import domSerializer from "npm:dom-serializer@2.0.0";
  50
  51 const DESTINATION = Deno.args[0] ?? "~/public/wiki";
  52 const REMOTE = Deno.args[1] ?? "/srv/git/GitWikiWeb";
  53 const REV = Deno.args[2] ?? "HEAD";
  54
  55 const READ_ONLY = {
  56   configurable: false,
  57   enumerable: true,
  58   writable: false,
  59 };
  60
  61 const NIL = Object.preventExtensions(Object.create(null));
  62
  63 const rawBlock = (strings, ...substitutions) => ({
  64   tag: "raw_block",
  65   format: "html",
  66   text: String.raw(strings, substitutions),
  67 });
  68 const rawInline = (strings, ...substitutions) => ({
  69   tag: "raw_inline",
  70   format: "html",
  71   text: String.raw(strings, substitutions),
  72 });
  73 const str = (strings, ...substitutions) => ({
  74   tag: "str",
  75   text: String.raw(strings, substitutions),
  76 });
  77
  78 const getDOM = (source) => {
  79   let result;
  80   const handler = new DomHandler((error, dom) => {
  81     if (error) {
  82       throw new Error("GitWikiWeb: Failed to process DOM.", {
  83         cause: error,
  84       });
  85     } else {
  86       result = dom;
  87     }
  88   });
  89   const parser = new Parser(handler);
  90   parser.write(source);
  91   parser.end();
  92   return result;
  93 };
  94
  95 const getRemoteContent = async (pathName) => {
  96   const getArchive = new Deno.Command("git", {
  97     args: ["archive", `--remote=${REMOTE}`, REV, pathName],
  98     stdout: "piped",
  99     stderr: "piped",
 100   }).spawn();
 101   const untar = new Deno.Command("tar", {
 102     args: ["-xO"],
 103     stdin: "piped",
 104     stdout: "piped",
 105     stderr: "piped",
 106   }).spawn();
 107   getArchive.stdout.pipeTo(untar.stdin);
 108   const [
 109     err1,
 110     getArchiveStatus,
 111     result,
 112     err2,
 113     untarStatus,
 114   ] = await Promise.allSettled([
 115     new Response(getArchive.stderr).text(),
 116     getArchive.status,
 117     new Response(untar.stdout).text(),
 118     new Response(untar.stderr).text(),
 119     untar.status,
 120   ]).then(logErrorsAndCollectResults);
 121   if (err1 || err2) {
 122     console.error(err1 + err2);
 123   } else {
 124     /* do nothing */
 125   }
 126   if (!getArchiveStatus.success) {
 127     throw new Error(
 128       `GitWikiWeb: git archive returned nonzero exit code: ${getArchiveStatus.code}.`,
 129     );
 130   } else if (!untarStatus.success) {
 131     throw new Error(
 132       `GitWikiWeb: tar returned nonzero exit code: ${untarStatus.code}.`,
 133     );
 134   } else {
 135     return result || "";
 136   }
 137 };
 138
 139 const logErrorsAndCollectResults = (results) =>
 140   results.map(({ value, reason }) => {
 141     if (reason) {
 142       console.error(reason);
 143       return undefined;
 144     } else {
 145       return value;
 146     }
 147   });
 148
 149 const getReferenceFromPath = (path) =>
 150   /Sources\/([A-Z][0-9A-Za-z]*\/[A-Z][0-9A-Za-z]*)\.djot$/u.exec(path)
 151     ?.[1]?.replace?.("/", ":");
 152
 153 const listOfInternalLinks = (references, wrapper = ($) => $) => ({
 154   tag: "bullet_list",
 155   tight: true,
 156   style: "*",
 157   children: Array.from(
 158     references,
 159     (reference) => {
 160       const [namespace, pageName] = splitReference(reference);
 161       return {
 162         tag: "list_item",
 163         children: [{
 164           tag: "para",
 165           children: [wrapper({
 166             tag: "link",
 167             attributes: {
 168               "data-realm": "internal",
 169               "data-pagename": pageName,
 170               "data-namespace": namespace,
 171             },
 172             reference,
 173             children: [],
 174           })],
 175         }],
 176       };
 177     },
 178   ),
 179 });
 180
 181 const diffReferences = async (hash, againstHead = false) => {
 182   const diff = new Deno.Command("git", {
 183     args: [
 184       "diff-tree",
 185       "-r",
 186       "-z",
 187       "--name-only",
 188       "--no-renames",
 189       "--diff-filter=AM",
 190       ...(againstHead ? [hash, "HEAD"] : [hash]),
 191     ],
 192     stdout: "piped",
 193     stderr: "piped",
 194   }).spawn();
 195   const [diffNames] = await Promise.allSettled([
 196     new Response(diff.stdout).text(),
 197     new Response(diff.stderr).text(),
 198   ]).then(logErrorsAndCollectResults);
 199   return references(diffNames.split("\0")); // returns an iterable
 200 };
 201
 202 function* references(paths) {
 203   for (const path of paths) {
 204     const reference = getReferenceFromPath(path);
 205     if (reference) {
 206       yield reference;
 207     } else {
 208       /* do nothing */
 209     }
 210   }
 211 }
 212
 213 const splitReference = (reference) => {
 214   const colonIndex = reference.indexOf(":");
 215   return [
 216     reference.substring(0, colonIndex),
 217     reference.substring(colonIndex + 1),
 218   ];
 219 };
 220
 221 class GitWikiWebPage {
 222   #internalLinks = new Set();
 223   #externalLinks = new Map();
 224
 225   constructor(namespace, name, ast, source, config) {
 226     const internalLinks = this.#internalLinks;
 227     const externalLinks = this.#externalLinks;
 228     const sections = Object.create(null);
 229     djot.applyFilter(ast, () => {
 230       let titleSoFar = null; // used to collect strs from headings
 231       return {
 232         doc: {
 233           enter: (_) => {},
 234           exit: (e) => {
 235             const links_section = [];
 236             if (internalLinks.size || externalLinks.size) {
 237               links_section.push(
 238                 rawBlock`<nav id="links">`,
 239                 {
 240                   tag: "heading",
 241                   level: 2,
 242                   children: [str`this page contains links`],
 243                 },
 244               );
 245               if (internalLinks.size) {
 246                 links_section.push(
 247                   rawBlock`<details open="">`,
 248                   rawBlock`<summary>on this wiki</summary>`,
 249                   listOfInternalLinks(internalLinks),
 250                   rawBlock`</details>`,
 251                 );
 252               } else {
 253                 /* do nothing */
 254               }
 255               if (externalLinks.size) {
 256                 links_section.push(
 257                   rawBlock`<details open="">`,
 258                   rawBlock`<summary>elsewhere on the Web</summary>`,
 259                   {
 260                     tag: "bullet_list",
 261                     tight: true,
 262                     style: "*",
 263                     children: Array.from(
 264                       externalLinks,
 265                       ([destination, text]) => ({
 266                         tag: "list_item",
 267                         children: [{
 268                           tag: "para",
 269                           children: [{
 270                             tag: "link",
 271                             attributes: { "data-realm": "external" },
 272                             destination,
 273                             children: text
 274                               ? [
 275                                 rawInline`<cite>`,
 276                                 str`${text}`,
 277                                 rawInline`</cite>`,
 278                               ]
 279                               : [
 280                                 rawInline`<code>`,
 281                                 str`${destination}`,
 282                                 rawInline`</code>`,
 283                               ],
 284                           }],
 285                         }],
 286                       }),
 287                     ),
 288                   },
 289                   rawBlock`</details>`,
 290                 );
 291               } else {
 292                 /* do nothing */
 293               }
 294               links_section.push(
 295                 rawBlock`</nav>`,
 296               );
 297             } else {
 298               /* do nothing */
 299             }
 300             e.children.push(
 301               rawBlock`<footer>`,
 302               rawBlock`${"\uFFFF"}`, // footnote placeholder
 303               ...links_section,
 304               rawBlock`</footer>`,
 305             );
 306           },
 307         },
 308         hard_break: {
 309           enter: (_) => {
 310             if (titleSoFar != null) {
 311               titleSoFar += " ";
 312             } else {
 313               /* do nothing */
 314             }
 315           },
 316           exit: (_) => {},
 317         },
 318         heading: {
 319           enter: (_) => {
 320             titleSoFar = "";
 321           },
 322           exit: (e) => {
 323             e.attributes ??= {};
 324             const { attributes } = e;
 325             attributes.title ??= titleSoFar;
 326             titleSoFar = null;
 327           },
 328         },
 329         link: {
 330           enter: (e) => {
 331             e.attributes ??= {};
 332             const { attributes, reference, destination } = e;
 333             if (
 334               /^(?:[A-Z][0-9A-Za-z]*|[@#])?:(?:[A-Z][0-9A-Za-z]*)?$/u
 335                 .test(reference ?? "")
 336             ) {
 337               const [namespacePrefix, pageName] = splitReference(
 338                 reference,
 339               );
 340               const expandedNamespace = {
 341                 "": "Page",
 342                 "@": "Editor",
 343                 "#": "Category",
 344               }[namespacePrefix] ?? namespacePrefix;
 345               const resolvedReference = pageName == ""
 346                 ? `Namespace:${expandedNamespace}`
 347                 : `${expandedNamespace}:${pageName}`;
 348               this.#internalLinks.add(resolvedReference);
 349               e.reference = resolvedReference;
 350               attributes["data-realm"] = "internal";
 351               attributes["data-pagename"] = pageName;
 352               attributes["data-namespace"] = expandedNamespace;
 353             } else {
 354               attributes["data-realm"] = "external";
 355               const remote = destination ??
 356                 ast.references[reference]?.destination;
 357               if (remote) {
 358                 externalLinks.set(remote, attributes?.title);
 359               } else {
 360                 /* do nothing */
 361               }
 362             }
 363           },
 364         },
 365         non_breaking_space: {
 366           enter: (_) => {
 367             if (titleSoFar != null) {
 368               titleSoFar += "\xA0";
 369             } else {
 370               /* do nothing */
 371             }
 372           },
 373           exit: (_) => {},
 374         },
 375         section: {
 376           enter: (_) => {},
 377           exit: (e) => {
 378             e.attributes ??= {};
 379             const { attributes, children } = e;
 380             const heading = children.find(({ tag }) =>
 381               tag == "heading"
 382             );
 383             const title = (() => {
 384               if (heading?.attributes?.title) {
 385                 const result = heading.attributes.title;
 386                 delete heading.attributes.title;
 387                 return result;
 388               } else {
 389                 return heading.level == 1
 390                   ? `${namespace}:${name}`
 391                   : "untitled section";
 392               }
 393             })();
 394             const variantTitles = Object.create(null);
 395             for (const attr in attributes) {
 396               if (attr.startsWith("v-")) {
 397                 Object.defineProperty(
 398                   variantTitles,
 399                   attr.substring(2),
 400                   { ...READ_ONLY, value: attributes[attr] },
 401                 );
 402                 delete attributes[attr];
 403               } else {
 404                 continue;
 405               }
 406             }
 407             const definition = Object.create(null, {
 408               title: { ...READ_ONLY, value: title },
 409               variantTitles: {
 410                 ...READ_ONLY,
 411                 value: Object.preventExtensions(variantTitles),
 412               },
 413             });
 414             if (heading.level == 1 && !("main" in sections)) {
 415               attributes.id = "main";
 416               heading.attributes ??= {};
 417               heading.attributes.class = "main";
 418             } else {
 419               /* do nothing */
 420             }
 421             try {
 422               Object.defineProperty(
 423                 sections,
 424                 attributes.id,
 425                 {
 426                   ...READ_ONLY,
 427                   writable: true,
 428                   value: Object.preventExtensions(definition),
 429                 },
 430               );
 431             } catch (cause) {
 432               throw new Error(
 433                 `GitWikiWeb: A section with the provided @id already exists: ${attributes.id}`,
 434                 { cause },
 435               );
 436             }
 437           },
 438         },
 439         soft_break: {
 440           enter: (_) => {
 441             if (titleSoFar != null) {
 442               titleSoFar += " ";
 443             } else {
 444               /* do nothing */
 445             }
 446           },
 447           exit: (_) => {},
 448         },
 449         str: {
 450           enter: ({ text }) => {
 451             if (titleSoFar != null) {
 452               titleSoFar += text;
 453             } else {
 454               /* do nothing */
 455             }
 456           },
 457           exit: (_) => {},
 458         },
 459         symb: {
 460           enter: (e) => {
 461             const { alias } = e;
 462             const codepoint = /^U\+([0-9A-Fa-f]+)$/u.exec(alias)?.[1];
 463             if (codepoint) {
 464               return str`${
 465                 String.fromCodePoint(parseInt(codepoint, 16))
 466               }`;
 467             } else {
 468               const resolved = config.symbols?.[alias];
 469               return resolved != null ? str`${resolved}` : e;
 470             }
 471           },
 472         },
 473       };
 474     });
 475     Object.defineProperties(this, {
 476       ast: { ...READ_ONLY, value: ast },
 477       namespace: { ...READ_ONLY, value: namespace },
 478       name: { ...READ_ONLY, value: name },
 479       sections: {
 480         ...READ_ONLY,
 481         value: Object.preventExtensions(sections),
 482       },
 483       source: { ...READ_ONLY, value: source },
 484     });
 485   }
 486
 487   *externalLinks() {
 488     yield* this.#externalLinks;
 489   }
 490
 491   *internalLinks() {
 492     yield* this.#internalLinks;
 493   }
 494 }
 495
 496 {
 497   // Patches for Djot HTML renderer.
 498   const { HTMLRenderer: { prototype: htmlRendererPrototype } } = djot;
 499   const { inTags: upstreamInTags } = htmlRendererPrototype;
 500   htmlRendererPrototype.inTags = function (
 501     tag,
 502     node,
 503     newlines,
 504     extraAttrs = undefined,
 505   ) {
 506     const attributes = node.attributes ?? NIL;
 507     if ("as" in attributes) {
 508       const newTag = attributes.as;
 509       delete attributes.as;
 510       return upstreamInTags.call(
 511         this,
 512         newTag,
 513         node,
 514         newlines,
 515         extraAttrs,
 516       );
 517     } else {
 518       return upstreamInTags.call(
 519         this,
 520         tag,
 521         node,
 522         newlines,
 523         extraAttrs,
 524       );
 525     }
 526   };
 527 }
 528 {
 529   const config = await getRemoteContent("config.yaml").then((yaml) =>
 530     parseYaml(yaml, { schema: JSON_SCHEMA })
 531   );
 532   const ls = new Deno.Command("git", {
 533     args: ["ls-tree", "-rz", "HEAD"],
 534     stdout: "piped",
 535     stderr: "piped",
 536   }).spawn();
 537   const [
 538     objects,
 539     lserr,
 540     lsstatus,
 541   ] = await Promise.allSettled([
 542     new Response(ls.stdout).text().then((lsout) =>
 543       lsout
 544         .split("\0")
 545         .slice(0, -1) // drop the last entry; it is empty
 546         .map(($) => $.split(/\s+/g))
 547     ),
 548     new Response(ls.stderr).text(),
 549     ls.status,
 550   ]).then(logErrorsAndCollectResults);
 551   if (lserr) {
 552     console.error(lserr);
 553   } else {
 554     /* do nothing */
 555   }
 556   if (!lsstatus.success) {
 557     throw new Error(
 558       `GitWikiWeb: git ls-tree returned nonzero exit code: ${lsstatus.code}.`,
 559     );
 560   } else {
 561     const requiredButMissingPages = new Map([
 562       ["Special:FrontPage", "front page"],
 563       ["Special:NotFound", "not found"],
 564       ["Special:RecentlyChanged", "recently changed"],
 565     ]);
 566     const pages = new Map();
 567     const promises = [emptyDir(DESTINATION)];
 568     for (const object of objects) {
 569       const hash = object[2];
 570       const path = object[3];
 571       const reference = getReferenceFromPath(path);
 572       if (reference == null) {
 573         continue;
 574       } else {
 575         const [namespace, pageName] = splitReference(reference);
 576         const cat = new Deno.Command("git", {
 577           args: ["cat-file", "blob", hash],
 578           stdout: "piped",
 579           stderr: "piped",
 580         }).spawn();
 581         const promise = Promise.allSettled([
 582           new Response(cat.stdout).text(),
 583           new Response(cat.stderr).text(),
 584           cat.status,
 585         ]).then(logErrorsAndCollectResults).then(
 586           ([source, caterr, catstatus]) => {
 587             if (caterr) {
 588               console.error(caterr);
 589             } else {
 590               /* do nothing */
 591             }
 592             if (!catstatus.success) {
 593               throw new Error(
 594                 `GitWikiWeb: git cat-file returned nonzero exit code: ${catstatus.code}.`,
 595               );
 596             } else {
 597               const page = new GitWikiWebPage(
 598                 namespace,
 599                 pageName,
 600                 djot.parse(source, {
 601                   warn: ($) =>
 602                     console.warn(`Djot(${reference}): ${$.render()}`),
 603                 }),
 604                 source,
 605                 config,
 606               );
 607               const reference = `${namespace}:${pageName}`;
 608               pages.set(reference, page);
 609               requiredButMissingPages.delete(reference);
 610             }
 611           },
 612         );
 613         promises.push(promise);
 614       }
 615     }
 616     for (const [reference, defaultTitle] of requiredButMissingPages) {
 617       const [namespace, pageName] = splitReference(reference);
 618       const source = `# ${defaultTitle}\n`;
 619       const page = new GitWikiWebPage(
 620         namespace,
 621         pageName,
 622         djot.parse(source, {
 623           warn: ($) =>
 624             console.warn(`Djot(${reference}): ${$.render()}`),
 625         }),
 626         source,
 627         config,
 628       );
 629       pages.set(reference, page);
 630     }
 631     await Promise.allSettled(promises).then(
 632       logErrorsAndCollectResults,
 633     );
 634     const [template, recentlyChanged] = await Promise.allSettled([
 635       getRemoteContent("template.html"),
 636       (async () => {
 637         const dateParse = new Deno.Command("git", {
 638           args: ["rev-parse", "--after=1 week ago"],
 639           stdout: "piped",
 640           stderr: "piped",
 641         }).spawn();
 642         const [maxAge] = await Promise.allSettled([
 643           new Response(dateParse.stdout).text(),
 644           new Response(dateParse.stderr).text(),
 645         ]).then(logErrorsAndCollectResults);
 646         let commit;
 647         if (!maxAge) {
 648           /* do nothing */
 649         } else {
 650           const revList = new Deno.Command("git", {
 651             args: ["rev-list", maxAge, "--reverse", "HEAD"],
 652             stdout: "piped",
 653             stderr: "piped",
 654           }).spawn();
 655           [commit] = await Promise.allSettled([
 656             new Response(revList.stdout).text().then((list) =>
 657               list.split("\n")[0]
 658             ),
 659             new Response(revList.stderr).text(),
 660           ]).then(logErrorsAndCollectResults);
 661         }
 662         if (!commit) {
 663           const revList2 = new Deno.Command("git", {
 664             args: ["rev-list", "--max-count=1", "HEAD^"],
 665             stdout: "piped",
 666             stderr: "piped",
 667           }).spawn();
 668           [commit] = await Promise.allSettled([
 669             new Response(revList2.stdout).text().then((list) =>
 670               list.trim()
 671             ),
 672             new Response(revList2.stderr).text(),
 673           ]).then(logErrorsAndCollectResults);
 674         } else {
 675           /* do nothing */
 676         }
 677         const results = new Array(6);
 678         const seen = new Set();
 679         const maxRecency = Math.max(config.max_recency | 0, 0);
 680         let recency = maxRecency;
 681         let current;
 682         do {
 683           const show = new Deno.Command("git", {
 684             args: [
 685               "show",
 686               "-s",
 687               "--format=%H%x00%cI%x00%cD",
 688               recency ? `HEAD~${maxRecency - recency}` : commit,
 689             ],
 690             stdout: "piped",
 691             stderr: "piped",
 692           }).spawn();
 693           const [
 694             [hash, dateTime, humanReadable],
 695           ] = await Promise.allSettled([
 696             new Response(show.stdout).text().then((rev) =>
 697               rev.trim().split("\0")
 698             ),
 699             new Response(show.stderr).text(),
 700           ]).then(logErrorsAndCollectResults);
 701           const refs = [];
 702           current = hash;
 703           for (
 704             const ref of (await diffReferences(current, !recency))
 705           ) {
 706             if (seen.has(ref)) {
 707               /* do nothing */
 708             } else {
 709               refs.push(ref);
 710               seen.add(ref);
 711             }
 712           }
 713           results[recency] = { dateTime, hash, humanReadable, refs };
 714         } while (recency-- > 0 && current && current != commit);
 715         return results;
 716       })(),
 717       ...Array.from(
 718         pages.keys(),
 719         (name) => ensureDir(`${DESTINATION}/${name}`),
 720       ),
 721       ["style.css"].map((dependency) =>
 722         getRemoteContent(dependency).then((source) =>
 723           Deno.writeTextFile(
 724             `${DESTINATION}/${dependency}`,
 725             source,
 726             { createNew: true },
 727           )
 728         )
 729       ),
 730     ]).then(logErrorsAndCollectResults);
 731     promises.length = 0;
 732     const redLinks = (() => {
 733       const result = new Set();
 734       for (const page of pages.values()) {
 735         for (const link of page.internalLinks()) {
 736           if (pages.has(link)) {
 737             continue;
 738           } else {
 739             result.add(link);
 740           }
 741         }
 742       }
 743       return result;
 744     })();
 745     for (
 746       const [pageRef, { ast, namespace, sections, source }] of pages
 747     ) {
 748       const title = sections.main?.title ?? pageRef;
 749       djot.applyFilter(ast, () => {
 750         let isNavigationPage = true;
 751         return {
 752           doc: {
 753             enter: (e) => {
 754               const { content, navigation } = (() => {
 755                 const navigation = [];
 756                 if (pageRef == "Special:RecentlyChanged") {
 757                   navigation.push({
 758                     tag: "bullet_list",
 759                     attributes: { class: "recent-changes" },
 760                     tight: true,
 761                     style: "*",
 762                     children: Array.from(function* () {
 763                       for (
 764                         const [index, result] of recentlyChanged
 765                           .entries()
 766                       ) {
 767                         if (result != null) {
 768                           const {
 769                             dateTime,
 770                             humanReadable,
 771                             refs,
 772                           } = result;
 773                           yield* listOfInternalLinks(refs, (link) => ({
 774                             tag: index == 0 ? "span" : "strong",
 775                             attributes: { "data-recency": `${index}` },
 776                             children: [
 777                               link,
 778                               ...(index == 0 ? [] : [
 779                                 str` `,
 780                                 rawInline`<small>(<time dateTime="${dateTime}">`,
 781                                 str`${humanReadable}`,
 782                                 rawInline`</time>)</small>`,
 783                               ]),
 784                             ],
 785                           })).children;
 786                         } else {
 787                           /* do nothing */
 788                         }
 789                       }
 790                     }()).reverse(),
 791                   });
 792                 } else {
 793                   isNavigationPage = false;
 794                   return { content: e.children, navigation };
 795                 }
 796                 return {
 797                   content: [
 798                     {
 799                       tag: "heading",
 800                       attributes: {
 801                         class: "main",
 802                         generated: "", // will be removed later
 803                       },
 804                       level: 1,
 805                       children: [str`${title}`],
 806                     },
 807                     rawBlock`<details id="navigation-about" open="">`,
 808                     rawBlock`<summary>about this listing</summary>`,
 809                     rawBlock`<article>`,
 810                     ...e.children,
 811                     rawBlock`</article>`,
 812                     rawBlock`</details>`,
 813                   ],
 814                   navigation: [
 815                     rawBlock`<nav id="navigation">`,
 816                     ...navigation,
 817                     rawBlock`</nav>`,
 818                   ],
 819                 };
 820               })();
 821               e.children = [
 822                 rawBlock`<article>`,
 823                 ...content,
 824                 ...navigation,
 825                 rawBlock`</article>`,
 826               ];
 827             },
 828             exit: (_) => {},
 829           },
 830           heading: {
 831             enter: (e) => {
 832               const attributes = e.attributes ?? NIL;
 833               if (
 834                 isNavigationPage && e.level == 1 &&
 835                 attributes?.class == "main"
 836               ) {
 837                 if ("generated" in attributes) {
 838                   delete attributes.generated;
 839                 } else {
 840                   return { stop: [] };
 841                 }
 842               } else {
 843                 /* do nothing */
 844               }
 845             },
 846             exit: (e) => {
 847               if (e.level == 1 && e.attributes?.class == "main") {
 848                 return [
 849                   rawBlock`<header class="main">`,
 850                   e,
 851                   { tag: "verbatim", text: pageRef },
 852                   rawBlock`</header>`,
 853                 ];
 854               } else {
 855                 /* do nothing */
 856               }
 857             },
 858           },
 859           link: {
 860             enter: (_) => {},
 861             exit: (e) => {
 862               e.attributes ??= {};
 863               const { attributes, children, reference } = e;
 864               if (attributes["data-realm"] == "internal") {
 865                 delete e.reference;
 866                 if (redLinks.has(reference)) {
 867                   e.destination =
 868                     `/Special:NotFound?path=/${reference}`;
 869                   attributes["data-notfound"] = "";
 870                 } else {
 871                   e.destination = `/${reference}`;
 872                 }
 873                 if (children.length == 0) {
 874                   const section =
 875                     pages.get(reference)?.sections?.main ?? NIL;
 876                   const { v } = attributes;
 877                   if (v == null) {
 878                     children.push(
 879                       str`${section.title ?? reference}`,
 880                     );
 881                   } else {
 882                     delete attributes.v;
 883                     children.push(
 884                       str`${
 885                         section.variantTitles?.[v] ?? section.title ??
 886                           reference
 887                       }`,
 888                     );
 889                   }
 890                 }
 891               } else {
 892                 if (children.length == 0 && "title" in attributes) {
 893                   children.push(
 894                     rawInline`<cite>`,
 895                     str`${attributes.title}`,
 896                     rawInline`</cite>`,
 897                   );
 898                 }
 899               }
 900               if (
 901                 (attributes.class ?? "").split(/\s/gu).includes("sig")
 902               ) {
 903                 return {
 904                   tag: "span",
 905                   attributes: { class: "sig" },
 906                   children: [str`—${"\xA0"}`, e],
 907                 };
 908               } else {
 909                 /* do nothing */
 910               }
 911             },
 912           },
 913           section: {
 914             enter: (_) => {},
 915             exit: (e) => {
 916               if (e.children.length < 1) {
 917                 // The heading for this section was removed and it had
 918                 // no other children.
 919                 return [];
 920               } else {
 921                 /* do nothing */
 922               }
 923             },
 924           },
 925         };
 926       });
 927       const renderedAST = djot.renderAST(ast);
 928       const doc = getDOM(template);
 929       const result = getDOM(djot.renderHTML(ast, {
 930         overrides: {
 931           raw_block: (node, context) => {
 932             if (node.format == "html" && node.text == "\uFFFF") {
 933               if (context.nextFootnoteIndex > 1) {
 934                 const result = context.renderNotes(ast.footnotes);
 935                 context.nextFootnoteIndex = 1;
 936                 return result;
 937               } else {
 938                 return "";
 939               }
 940             } else {
 941               return context.renderAstNodeDefault(node);
 942             }
 943           },
 944         },
 945       }));
 946       const headElement = domutils.findOne(
 947         (node) => node.name == "head",
 948         doc,
 949       );
 950       const titleElement = domutils.findOne(
 951         (node) => node.name == "title",
 952         headElement,
 953       );
 954       const contentElement = domutils.findOne(
 955         (node) => node.name == "gitwikiweb-content",
 956         doc,
 957       );
 958       if (headElement == null) {
 959         throw new Error(
 960           "GitWikiWeb: Template must explicitly include a <head> element.",
 961         );
 962       } else {
 963         domutils.appendChild(
 964           headElement,
 965           new Element("link", {
 966             rel: "source",
 967             type: "text/x.djot",
 968             href: `/${pageRef}/source.djot`,
 969           }),
 970         );
 971         if (titleElement == null) {
 972           domutils.prependChild(
 973             headElement,
 974             new Element("title", {}, [new Text(title)]),
 975           );
 976         } else {
 977           domutils.prependChild(titleElement, new Text(`${title} | `));
 978         }
 979       }
 980       if (contentElement == null) {
 981         throw new Error(
 982           "GitWikiWeb: Template did not include a <gitwikiweb-content> element.",
 983         );
 984       } else {
 985         for (const node of [...result]) {
 986           domutils.prepend(contentElement, node);
 987         }
 988         domutils.removeElement(contentElement);
 989       }
 990       promises.push(
 991         Deno.writeTextFile(
 992           `${DESTINATION}/${pageRef}/index.html`,
 993           domSerializer(doc, {
 994             emptyAttrs: true,
 995             encodeEntities: "utf8",
 996             selfClosingTags: true,
 997             xmlMode: false,
 998           }),
 999           { createNew: true },
1000         ),
1001       );
1002       promises.push(
1003         Deno.writeTextFile(
1004           `${DESTINATION}/${pageRef}/index.ast`,
1005           renderedAST,
1006           { createNew: true },
1007         ),
1008       );
1009       promises.push(
1010         Deno.writeTextFile(
1011           `${DESTINATION}/${pageRef}/source.djot`,
1012           source,
1013           { createNew: true },
1014         ),
1015       );
1016     }
1017     await Promise.allSettled(promises).then(
1018       logErrorsAndCollectResults,
1019     );
1020     console.log(`GitWikiWeb: Wrote ${pages.size} page(s).`);
1021   }
1022 }