« get me outta code hell

yaml.js « data « src - hsmusic-wiki - HSMusic - static wiki software cataloguing collaborative creation
about summary refs log tree commit diff
path: root/src/data/yaml.js
blob: 5026a97eb34e742c6771a059b4f44c77634993ea (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
// yaml.js - specification for HSMusic YAML data file format and utilities for
// loading, processing, and validating YAML files and documents

import {readFile, stat} from 'node:fs/promises';
import * as path from 'node:path';
import {inspect as nodeInspect} from 'node:util';

import yaml from 'js-yaml';

import {colors, ENABLE_COLOR, logInfo, logWarn} from '#cli';
import {sortByName} from '#sort';
import {atOffset, empty, filterProperties, typeAppearance, withEntries}
  from '#sugar';
import Thing from '#thing';
import thingConstructors from '#things';

import {
  filterReferenceErrors,
  reportContentTextErrors,
  reportDuplicateDirectories,
} from '#data-checks';

import {
  annotateErrorWithFile,
  decorateErrorWithIndex,
  decorateErrorWithAnnotation,
  openAggregate,
  showAggregate,
  withAggregate,
} from '#aggregate';

function inspect(value, opts = {}) {
  return nodeInspect(value, {colors: ENABLE_COLOR, ...opts});
}

// General function for inputting a single document (usually loaded from YAML)
// and outputting an instance of a provided Thing subclass.
//
// makeProcessDocument is a factory function: the returned function will take a
// document and apply the configuration passed to makeProcessDocument in order
// to construct a Thing subclass.
//
function makeProcessDocument(thingConstructor, {
  // The bulk of configuration happens here in the spec's `fields` property.
  // Each key is a field that's expected on the source document; fields that
  // don't match one of these keys will cause an error. Values are object
  // entries describing what to do with the field.
  //
  // A field entry's `property` tells what property the value for this field
  // will be put into, on the respective Thing (subclass) instance.
  //
  // A field entry's `transform` optionally allows converting the raw value in
  // YAML into some other format before providing setting it on the Thing
  // instance.
  //
  // If a field entry has `ignore: true`, it will be completely skipped by the
  // YAML parser - it won't be validated, read, or loaded into data objects.
  // This is mainly useful for fields that are purely annotational or are
  // currently placeholders.
  //
  fields: fieldSpecs = {},

  // List of fields which are invalid when coexisting in a document.
  // Data objects are generally allowing with regards to what properties go
  // together, allowing for properties to be set separately from each other
  // instead of complaining about invalid or unused-data cases. But it's
  // useful to see these kinds of errors when actually validating YAML files!
  //
  // Each item of this array should itself be an object with a descriptive
  // message and a list of fields. Of those fields, none should ever coexist
  // with any other. For example:
  //
  //   [
  //     {message: '...', fields: ['A', 'B', 'C']},
  //     {message: '...', fields: ['C', 'D']},
  //   ]
  //
  // ...means A can't coexist with B or C, B can't coexist with A or C, and
  // C can't coexist iwth A, B, or D - but it's okay for D to coexist with
  // A or B.
  //
  invalidFieldCombinations = [],
}) {
  if (!thingConstructor) {
    throw new Error(`Missing Thing class`);
  }

  if (!fieldSpecs) {
    throw new Error(`Expected fields to be provided`);
  }

  const knownFields = Object.keys(fieldSpecs);

  const ignoredFields =
    Object.entries(fieldSpecs)
      .filter(([, {ignore}]) => ignore)
      .map(([field]) => field);

  const propertyToField =
    withEntries(fieldSpecs, entries => entries
      .map(([field, {property}]) => [property, field]));

  // TODO: Is this function even necessary??
  // Aren't we doing basically the same work in the function it's decorating???
  const decorateErrorWithName = (fn) => {
    const nameField = propertyToField.name;
    if (!nameField) return fn;

    return (document) => {
      try {
        return fn(document);
      } catch (error) {
        const name = document[nameField];
        error.message = name
          ? `(name: ${inspect(name)}) ${error.message}`
          : `(${colors.dim(`no name found`)}) ${error.message}`;
        throw error;
      }
    };
  };

  return decorateErrorWithName((document) => {
    const nameField = propertyToField.name;
    const namePart =
      (nameField
        ? (document[nameField]
          ? ` named ${colors.green(`"${document[nameField]}"`)}`
          : ` (name field, "${nameField}", not specified)`)
        : ``);

    const constructorPart =
      (thingConstructor[Thing.friendlyName]
        ? thingConstructor[Thing.friendlyName]
     : thingConstructor.name
        ? thingConstructor.name
        : `document`);

    const aggregate = openAggregate({
      message: `Errors processing ${constructorPart}` + namePart,
    });

    const documentEntries = Object.entries(document)
      .filter(([field]) => !ignoredFields.includes(field));

    const skippedFields = new Set();

    const unknownFields = documentEntries
      .map(([field]) => field)
      .filter((field) => !knownFields.includes(field));

    if (!empty(unknownFields)) {
      aggregate.push(new UnknownFieldsError(unknownFields));

      for (const field of unknownFields) {
        skippedFields.add(field);
      }
    }

    const presentFields = Object.keys(document);

    const fieldCombinationErrors = [];

    for (const {message, fields} of invalidFieldCombinations) {
      const fieldsPresent =
        presentFields.filter(field => fields.includes(field));

      if (fieldsPresent.length >= 2) {
        const filteredDocument =
          filterProperties(
            document,
            fieldsPresent,
            {preserveOriginalOrder: true});

        fieldCombinationErrors.push(
          new FieldCombinationError(filteredDocument, message));

        for (const field of Object.keys(filteredDocument)) {
          skippedFields.add(field);
        }
      }
    }

    if (!empty(fieldCombinationErrors)) {
      aggregate.push(new FieldCombinationAggregateError(fieldCombinationErrors));
    }

    const fieldValues = {};

    for (const [field, documentValue] of documentEntries) {
      if (skippedFields.has(field)) continue;

      // This variable would like to certify itself as "not into capitalism".
      let propertyValue =
        (fieldSpecs[field].transform
          ? fieldSpecs[field].transform(documentValue)
          : documentValue);

      // Completely blank items in a YAML list are read as null.
      // They're handy to have around when filling out a document and shouldn't
      // be considered an error (or data at all).
      if (Array.isArray(propertyValue)) {
        const wasEmpty = empty(propertyValue);

        propertyValue =
          propertyValue.filter(item => item !== null);

        const isEmpty = empty(propertyValue);

        // Don't set arrays which are empty as a result of the above filter.
        // Arrays which were originally empty, i.e. `Field: []`, are still
        // valid data, but if it's just an array not containing any filled out
        // items, it should be treated as a placeholder and skipped over.
        if (isEmpty && !wasEmpty) {
          propertyValue = null;
        }
      }

      fieldValues[field] = propertyValue;
    }

    const thing = Reflect.construct(thingConstructor, []);

    const fieldValueErrors = [];

    for (const [field, value] of Object.entries(fieldValues)) {
      const {property} = fieldSpecs[field];

      try {
        thing[property] = value;
      } catch (caughtError) {
        skippedFields.add(field);
        fieldValueErrors.push(new FieldValueError(
          field, value, {cause: caughtError}));
      }
    }

    if (!empty(fieldValueErrors)) {
      aggregate.push(new FieldValueAggregateError(
        fieldValueErrors, thingConstructor));
    }

    if (skippedFields.size >= 1) {
      aggregate.push(
        new SkippedFieldsSummaryError(
          filterProperties(
            document,
            Array.from(skippedFields),
            {preserveOriginalOrder: true})));
    }

    return {thing, aggregate};
  });
}

export class UnknownFieldsError extends Error {
  constructor(fields) {
    super(`Unknown fields ignored: ${fields.map(field => colors.red(field)).join(', ')}`);
    this.fields = fields;
  }
}

export class FieldCombinationAggregateError extends AggregateError {
  constructor(errors) {
    super(errors, `Invalid field combinations - all involved fields ignored`);
  }
}

export class FieldCombinationError extends Error {
  constructor(fields, message) {
    const fieldNames = Object.keys(fields);

    const fieldNamesText =
      fieldNames
        .map(field => colors.red(field))
        .join(', ');

    const mainMessage = `Don't combine ${fieldNamesText}`;

    const causeMessage =
      (typeof message === 'function'
        ? message(fields)
     : typeof message === 'string'
        ? message
        : null);

    super(mainMessage, {
      cause:
        (causeMessage
          ? new Error(causeMessage)
          : null),
    });

    this.fields = fields;
  }
}

export class FieldValueAggregateError extends AggregateError {
  [Symbol.for('hsmusic.aggregate.translucent')] = true;

  constructor(errors, thingConstructor) {
    const constructorText =
      colors.green(thingConstructor.name);

    super(
      errors,
      `Errors processing field values for ${constructorText}`);
  }
}

export class FieldValueError extends Error {
  constructor(field, value, options) {
    const fieldText =
      colors.green(`"${field}"`);

    const valueText =
      inspect(value, {maxStringLength: 40});

    super(
      `Failed to set ${fieldText} field to ${valueText}`,
      options);
  }
}

export class SkippedFieldsSummaryError extends Error {
  constructor(filteredDocument) {
    const entries = Object.entries(filteredDocument);

    const lines =
      entries.map(([field, value]) =>
        ` - ${field}: ` +
        inspect(value, {maxStringLength: 70})
          .split('\n')
          .map((line, index) => index === 0 ? line : `   ${line}`)
          .join('\n'));

    const numFieldsText =
      (entries.length === 1
        ? `1 field`
        : `${entries.length} fields`);

    super(
      colors.bright(colors.yellow(`Altogether, skipped ${numFieldsText}:\n`)) +
      lines.join('\n') + '\n' +
      colors.bright(colors.yellow(`See above errors for details.`)));
  }
}

export function parseDate(date) {
  return new Date(date);
}

export function parseDuration(string) {
  if (typeof string !== 'string') {
    return string;
  }

  const parts = string.split(':').map((n) => parseInt(n));
  if (parts.length === 3) {
    return parts[0] * 3600 + parts[1] * 60 + parts[2];
  } else if (parts.length === 2) {
    return parts[0] * 60 + parts[1];
  } else {
    return 0;
  }
}

export function parseAdditionalFiles(array) {
  if (!Array.isArray(array)) {
    // Error will be caught when validating against whatever this value is
    return array;
  }

  return array.map((item) => ({
    title: item['Title'],
    description: item['Description'] ?? null,
    files: item['Files'],
  }));
}

export const extractAccentRegex =
  /^(?<main>.*?)(?: \((?<accent>.*)\))?$/;

export const extractPrefixAccentRegex =
  /^(?:\((?<accent>.*)\) )?(?<main>.*?)$/;

export function parseContributors(contributionStrings) {
  // If this isn't something we can parse, just return it as-is.
  // The Thing object's validators will handle the data error better
  // than we're able to here.
  if (!Array.isArray(contributionStrings)) {
    return contributionStrings;
  }

  return contributionStrings.map(item => {
    if (typeof item === 'object' && item['Who'])
      return {
        artist: item['Who'],
        annotation: item['What'] ?? null,
      };

    if (typeof item === 'object' && item['Artist'])
      return {
        artist: item['Artist'],
        annotation: item['Annotation'] ?? null,
      };

    if (typeof item !== 'string') return item;

    const match = item.match(extractAccentRegex);
    if (!match) return item;

    return {
      artist: match.groups.main,
      annotation: match.groups.accent ?? null,
    };
  });
}

export function parseAdditionalNames(additionalNameStrings) {
  if (!Array.isArray(additionalNameStrings)) {
    return additionalNameStrings;
  }

  return additionalNameStrings.map(item => {
    if (typeof item === 'object' && item['Name'])
      return {name: item['Name'], annotation: item['Annotation'] ?? null};

    if (typeof item !== 'string') return item;

    const match = item.match(extractAccentRegex);
    if (!match) return item;

    return {
      name: match.groups.main,
      annotation: match.groups.accent ?? null,
    };
  });
}

export function parseDimensions(string) {
  // It's technically possible to pass an array like [30, 40] through here.
  // That's not really an issue because if it isn't of the appropriate shape,
  // the Thing object's validators will handle the error.
  if (typeof string !== 'string') {
    return string;
  }

  const parts = string.split(/[x,* ]+/g);

  if (parts.length !== 2) {
    throw new Error(`Invalid dimensions: ${string} (expected "width & height")`);
  }

  const nums = parts.map((part) => Number(part.trim()));

  if (nums.includes(NaN)) {
    throw new Error(`Invalid dimensions: ${string} (couldn't parse as numbers)`);
  }

  return nums;
}

// documentModes: Symbols indicating sets of behavior for loading and processing
// data files.
export const documentModes = {
  // onePerFile: One document per file. Expects files array (or function) and
  // processDocument function. Obviously, each specified data file should only
  // contain one YAML document (an error will be thrown otherwise). Calls save
  // with an array of processed documents (wiki objects).
  onePerFile: Symbol('Document mode: onePerFile'),

  // headerAndEntries: One or more documents per file; the first document is
  // treated as a "header" and represents data which pertains to all following
  // "entry" documents. Expects files array (or function) and
  // processHeaderDocument and processEntryDocument functions. Calls save with
  // an array of {header, entries} objects.
  //
  // Please note that the final results loaded from each file may be "missing"
  // data objects corresponding to entry documents if the processEntryDocument
  // function throws on any entries, resulting in partial data provided to
  // save() - errors will be caught and thrown in the final buildSteps
  // aggregate. However, if the processHeaderDocument function fails, all
  // following documents in the same file will be ignored as well (i.e. an
  // entire file will be excempt from the save() function's input).
  headerAndEntries: Symbol('Document mode: headerAndEntries'),

  // allInOne: One or more documents, all contained in one file. Expects file
  // string (or function) and processDocument function. Calls save with an
  // array of processed documents (wiki objects).
  allInOne: Symbol('Document mode: allInOne'),

  // oneDocumentTotal: Just a single document, represented in one file.
  // Expects file string (or function) and processDocument function. Calls
  // save with the single processed wiki document (data object).
  //
  // Please note that if the single document fails to process, the save()
  // function won't be called at all, generally resulting in an altogether
  // missing property from the global wikiData object. This should be caught
  // and handled externally.
  oneDocumentTotal: Symbol('Document mode: oneDocumentTotal'),
};

// dataSteps: Top-level array of "steps" for loading YAML document files.
//
// title:
//   Name of the step (displayed in build output)
//
// documentMode:
//   Symbol which indicates by which "mode" documents from data files are
//   loaded and processed. See documentModes export.
//
// file, files:
//   String or array of strings which are paths to YAML data files, or a
//   function which returns the above (may be async). All paths are appended to
//   the global dataPath provided externally (e.g. HSMUSIC_DATA env variable).
//   Which to provide (file or files) depends on documentMode. If this is a
//   function, it will be provided with dataPath (e.g. so that a sub-path may be
//   readdir'd), but don't path.join(dataPath) the returned value(s) yourself -
//   this will be done automatically.
//
// processDocument, processHeaderDocument, processEntryDocument:
//   Functions which take a YAML document and return an actual wiki data object;
//   all actual conversion between YAML and wiki data happens here. Which to
//   provide (one or a combination) depend on documentMode.
//
// save:
//   Function which takes all documents processed (now as wiki data objects) and
//   actually applies them to a global wiki data object, for use in page
//   generation and other behavior. Returns an object to be assigned over the
//   global wiki data object (so specify any new properties here). This is also
//   the place to perform any final post-processing on data objects (linking
//   them to each other, setting additional properties, etc). Input argument
//   format depends on documentMode.
//
export const getDataSteps = () => {
  const steps = [];

  for (const thingConstructor of Object.values(thingConstructors)) {
    const getSpecFn = thingConstructor[Thing.getYamlLoadingSpec];
    if (!getSpecFn) continue;

    steps.push(getSpecFn({
      documentModes,
      thingConstructors,
    }));
  }

  sortByName(steps, {getName: step => step.title});

  return steps;
};

export async function loadAndProcessDataDocuments({dataPath}) {
  const processDataAggregate = openAggregate({
    message: `Errors processing data files`,
  });
  const wikiDataResult = {};

  function decorateErrorWithFile(fn) {
    return decorateErrorWithAnnotation(fn,
      (caughtError, firstArg) =>
        annotateErrorWithFile(
          caughtError,
          path.relative(
            dataPath,
            (typeof firstArg === 'object'
              ? firstArg.file
              : firstArg))));
  }

  function asyncDecorateErrorWithFile(fn) {
    return decorateErrorWithFile(fn).async;
  }

  for (const dataStep of getDataSteps()) {
    await processDataAggregate.nestAsync(
      {
        message: `Errors during data step: ${colors.bright(dataStep.title)}`,
        translucent: true,
      },
      async ({call, callAsync, map, mapAsync, push}) => {
        const {documentMode} = dataStep;

        if (!Object.values(documentModes).includes(documentMode)) {
          throw new Error(`Invalid documentMode: ${documentMode.toString()}`);
        }

        // Hear me out, it's been like 1200 years since I wrote the rest of
        // this beautifully error-containing code and I don't know how to
        // integrate this nicely. So I'm just returning the result and the
        // error that should be thrown. Yes, we're back in callback hell,
        // just without the callbacks. Thank you.
        const filterBlankDocuments = documents => {
          const aggregate = openAggregate({
            message: `Found blank documents - check for extra '${colors.cyan(`---`)}'`,
          });

          const filteredDocuments =
            documents
              .filter(doc => doc !== null);

          if (filteredDocuments.length !== documents.length) {
            const blankIndexRangeInfo =
              documents
                .map((doc, index) => [doc, index])
                .filter(([doc]) => doc === null)
                .map(([doc, index]) => index)
                .reduce((accumulator, index) => {
                  if (accumulator.length === 0) {
                    return [[index, index]];
                  }
                  const current = accumulator.at(-1);
                  const rest = accumulator.slice(0, -1);
                  if (current[1] === index - 1) {
                    return rest.concat([[current[0], index]]);
                  } else {
                    return accumulator.concat([[index, index]]);
                  }
                }, [])
                .map(([start, end]) => ({
                  start,
                  end,
                  count: end - start + 1,
                  previous: atOffset(documents, start, -1),
                  next: atOffset(documents, end, +1),
                }));

            for (const {start, end, count, previous, next} of blankIndexRangeInfo) {
              const parts = [];

              if (count === 1) {
                const range = `#${start + 1}`;
                parts.push(`${count} document (${colors.yellow(range)}), `);
              } else {
                const range = `#${start + 1}-${end + 1}`;
                parts.push(`${count} documents (${colors.yellow(range)}), `);
              }

              if (previous === null) {
                parts.push(`at start of file`);
              } else if (next === null) {
                parts.push(`at end of file`);
              } else {
                const previousDescription = Object.entries(previous).at(0).join(': ');
                const nextDescription = Object.entries(next).at(0).join(': ');
                parts.push(`between "${colors.cyan(previousDescription)}" and "${colors.cyan(nextDescription)}"`);
              }

              aggregate.push(new Error(parts.join('')));
            }
          }

          return {documents: filteredDocuments, aggregate};
        };

        const processDocument = (document, thingClassOrFn) => {
          const thingClass =
            (thingClassOrFn.prototype instanceof Thing
              ? thingClassOrFn
              : thingClassOrFn(document));

          if (typeof thingClass !== 'function') {
            throw new Error(`Expected a thing class, got ${typeAppearance(thingClass)}`);
          }

          if (!(thingClass.prototype instanceof Thing)) {
            throw new Error(`Expected a thing class, got ${thingClass.name}`);
          }

          const spec = thingClass[Thing.yamlDocumentSpec];

          if (!spec) {
            throw new Error(`Class "${thingClass.name}" doesn't specify Thing.yamlDocumentSpec`);
          }

          // TODO: Making a function to only call it just like that is
          // obviously pretty jank! It should be created once per data step.
          const fn = makeProcessDocument(thingClass, spec);
          return fn(document);
        };

        if (
          documentMode === documentModes.allInOne ||
          documentMode === documentModes.oneDocumentTotal
        ) {
          if (!dataStep.file) {
            throw new Error(`Expected 'file' property for ${documentMode.toString()}`);
          }

          const file = path.join(
            dataPath,
            typeof dataStep.file === 'function'
              ? await callAsync(dataStep.file, dataPath)
              : dataStep.file);

          const statResult = await callAsync(() =>
            stat(file).then(
              () => true,
              error => {
                if (error.code === 'ENOENT') {
                  return false;
                } else {
                  throw error;
                }
              }));

          if (statResult === false) {
            const saveResult = call(dataStep.save, {
              [documentModes.allInOne]: [],
              [documentModes.oneDocumentTotal]: {},
            }[documentMode]);

            if (!saveResult) return;

            Object.assign(wikiDataResult, saveResult);

            return;
          }

          const readResult = await callAsync(readFile, file, 'utf-8');

          if (!readResult) {
            return;
          }

          let processResults;

          switch (documentMode) {
            case documentModes.oneDocumentTotal: {
              const yamlResult = call(yaml.load, readResult);

              if (!yamlResult) {
                processResults = null;
                break;
              }

              const {thing, aggregate} =
                processDocument(yamlResult, dataStep.documentThing);

              processResults = thing;

              call(() => aggregate.close());

              break;
            }

            case documentModes.allInOne: {
              const yamlResults = call(yaml.loadAll, readResult);

              if (!yamlResults) {
                processResults = [];
                return;
              }

              const {documents, aggregate: filterAggregate} =
                filterBlankDocuments(yamlResults);

              call(filterAggregate.close);

              processResults = [];

              map(documents, decorateErrorWithIndex(document => {
                const {thing, aggregate} =
                  processDocument(document, dataStep.documentThing);

                processResults.push(thing);
                aggregate.close();
              }), {message: `Errors processing documents`});

              break;
            }
          }

          if (!processResults) return;

          const saveResult = call(dataStep.save, processResults);

          if (!saveResult) return;

          Object.assign(wikiDataResult, saveResult);

          return;
        }

        if (!dataStep.files) {
          throw new Error(`Expected 'files' property for ${documentMode.toString()}`);
        }

        const filesFromDataStep =
          (typeof dataStep.files === 'function'
            ? await callAsync(() =>
                dataStep.files(dataPath).then(
                  files => files,
                  error => {
                    if (error.code === 'ENOENT') {
                      return [];
                    } else {
                      throw error;
                    }
                  }))
            : dataStep.files);

        const filesUnderDataPath =
          filesFromDataStep
            .map(file => path.join(dataPath, file));

        const yamlResults = [];

        await mapAsync(filesUnderDataPath, {message: `Errors loading data files`},
          asyncDecorateErrorWithFile(async file => {
            let contents;
            try {
              contents = await readFile(file, 'utf-8');
            } catch (caughtError) {
              throw new Error(`Failed to read data file`, {cause: caughtError});
            }

            let documents;
            try {
              documents = yaml.loadAll(contents);
            } catch (caughtError) {
              throw new Error(`Failed to parse valid YAML`, {cause: caughtError});
            }

            const {documents: filteredDocuments, aggregate: filterAggregate} =
              filterBlankDocuments(documents);

            try {
              filterAggregate.close();
            } catch (caughtError) {
              // Blank documents aren't a critical error, they're just something
              // that should be noted - the (filtered) documents still get pushed.
              const pathToFile = path.relative(dataPath, file);
              annotateErrorWithFile(caughtError, pathToFile);
              push(caughtError);
            }

            yamlResults.push({file, documents: filteredDocuments});
          }));

        const processResults = [];

        switch (documentMode) {
          case documentModes.headerAndEntries:
            map(yamlResults, {message: `Errors processing documents in data files`, translucent: true},
              decorateErrorWithFile(({documents}) => {
                const headerDocument = documents[0];
                const entryDocuments = documents.slice(1).filter(Boolean);

                if (!headerDocument)
                  throw new Error(`Missing header document (empty file or erroneously starting with "---"?)`);

                withAggregate({message: `Errors processing documents`}, ({push}) => {
                  const {thing: headerObject, aggregate: headerAggregate} =
                    processDocument(headerDocument, dataStep.headerDocumentThing);

                  try {
                    headerAggregate.close();
                  } catch (caughtError) {
                    caughtError.message = `(${colors.yellow(`header`)}) ${caughtError.message}`;
                    push(caughtError);
                  }

                  const entryObjects = [];

                  for (let index = 0; index < entryDocuments.length; index++) {
                    const entryDocument = entryDocuments[index];

                    const {thing: entryObject, aggregate: entryAggregate} =
                      processDocument(entryDocument, dataStep.entryDocumentThing);

                    entryObjects.push(entryObject);

                    try {
                      entryAggregate.close();
                    } catch (caughtError) {
                      caughtError.message = `(${colors.yellow(`entry #${index + 1}`)}) ${caughtError.message}`;
                      push(caughtError);
                    }
                  }

                  processResults.push({
                    header: headerObject,
                    entries: entryObjects,
                  });
                });
              }));
            break;

          case documentModes.onePerFile:
            map(yamlResults, {message: `Errors processing data files as valid documents`},
              decorateErrorWithFile(({documents}) => {
                if (documents.length > 1)
                  throw new Error(`Only expected one document to be present per file, got ${documents.length} here`);

                if (empty(documents) || !documents[0])
                  throw new Error(`Expected a document, this file is empty`);

                const {thing, aggregate} =
                  processDocument(documents[0], dataStep.documentThing);

                processResults.push(thing);
                aggregate.close();
              }));
            break;
        }

        const saveResult = call(dataStep.save, processResults);

        if (!saveResult) return;

        Object.assign(wikiDataResult, saveResult);
      }
    );
  }

  return {
    aggregate: processDataAggregate,
    result: wikiDataResult,
  };
}

// Data linking! Basically, provide (portions of) wikiData to the Things which
// require it - they'll expose dynamically computed properties as a result (many
// of which are required for page HTML generation and other expected behavior).
export function linkWikiDataArrays(wikiData) {
  const linkWikiDataSpec = new Map([
    [wikiData.albumData, [
      'artTagData',
      'artistData',
      'groupData',
    ]],

    [wikiData.artTagData, [
      'albumData',
      'trackData',
    ]],

    [wikiData.artistData, [
      'albumData',
      'artistData',
      'flashData',
      'trackData',
    ]],

    [wikiData.flashData, [
      'artistData',
      'flashActData',
      'trackData',
    ]],

    [wikiData.flashActData, [
      'flashData',
      'flashSideData',
    ]],

    [wikiData.flashSideData, [
      'flashActData',
    ]],

    [wikiData.groupData, [
      'albumData',
      'groupCategoryData',
    ]],

    [wikiData.groupCategoryData, [
      'groupData',
    ]],

    [wikiData.homepageLayout?.rows, [
      'albumData',
      'groupData',
    ]],

    [wikiData.trackData, [
      'albumData',
      'artTagData',
      'artistData',
      'flashData',
      'trackData',
    ]],

    [[wikiData.wikiInfo], [
      'groupData',
    ]],
  ]);

  for (const [things, keys] of linkWikiDataSpec.entries()) {
    if (things === undefined) continue;
    for (const thing of things) {
      if (thing === undefined) continue;
      for (const key of keys) {
        if (!(key in wikiData)) continue;
        thing[key] = wikiData[key];
      }
    }
  }
}

export function sortWikiDataArrays(wikiData) {
  for (const [key, value] of Object.entries(wikiData)) {
    if (!Array.isArray(value)) continue;
    wikiData[key] = value.slice();
  }

  const steps = getDataSteps();

  for (const step of steps) {
    if (!step.sort) continue;
    step.sort(wikiData);
  }

  // Re-link data arrays, so that every object has the new, sorted versions.
  // Note that the sorting step deliberately creates new arrays (mutating
  // slices instead of the original arrays) - this is so that the object
  // caching system understands that it's working with a new ordering.
  // We still need to actually provide those updated arrays over again!
  linkWikiDataArrays(wikiData);
}

// Utility function for loading all wiki data from the provided YAML data
// directory (e.g. the root of the hsmusic-data repository). This doesn't
// provide much in the way of customization; it's meant to be used more as
// a boilerplate for more specialized output, or as a quick start in utilities
// where reporting info about data loading isn't as relevant as during the
// main wiki build process.
export async function quickLoadAllFromYAML(dataPath, {
  bindFind,
  getAllFindSpecs,

  showAggregate: customShowAggregate = showAggregate,
}) {
  const showAggregate = customShowAggregate;

  let wikiData;

  {
    const {aggregate, result} = await loadAndProcessDataDocuments({dataPath});

    wikiData = result;

    try {
      aggregate.close();
      logInfo`Loaded data without errors. (complete data)`;
    } catch (error) {
      showAggregate(error);
      logWarn`Loaded data with errors. (partial data)`;
    }
  }

  linkWikiDataArrays(wikiData);

  try {
    reportDuplicateDirectories(wikiData, {getAllFindSpecs});
    logInfo`No duplicate directories found. (complete data)`;
  } catch (error) {
    showAggregate(error);
    logWarn`Duplicate directories found. (partial data)`;
  }

  try {
    filterReferenceErrors(wikiData, {bindFind}).close();
    logInfo`No reference errors found. (complete data)`;
  } catch (error) {
    showAggregate(error);
    logWarn`Reference errors found. (partial data)`;
  }

  try {
    reportContentTextErrors(wikiData, {bindFind});
    logInfo`No content text errors found.`;
  } catch (error) {
    showAggregate(error);
    logWarn`Content text errors found.`;
  }

  sortWikiDataArrays(wikiData);

  return wikiData;
}