summaryrefslogtreecommitdiff
path: root/ext/bg/js/backend.js
blob: 693a9ad65921976a67c23030b49f406ef90b4485 (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
/*
 * Copyright (C) 2016-2020  Yomichan Authors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

/* global
 * AnkiConnect
 * AnkiNoteBuilder
 * AudioSystem
 * AudioUriBuilder
 * BackendApiForwarder
 * ClipboardMonitor
 * Database
 * DictionaryImporter
 * JsonSchema
 * Mecab
 * Translator
 * conditionsTestValue
 * dictTermsSort
 * handlebarsRenderDynamic
 * jp
 * optionsLoad
 * optionsSave
 * profileConditionsDescriptor
 * requestJson
 * requestText
 * utilIsolate
 */

class Backend {
    constructor() {
        this.database = new Database();
        this.dictionaryImporter = new DictionaryImporter();
        this.translator = new Translator(this.database);
        this.anki = new AnkiConnect();
        this.mecab = new Mecab();
        this.clipboardMonitor = new ClipboardMonitor({getClipboard: this._onApiClipboardGet.bind(this)});
        this.options = null;
        this.optionsSchema = null;
        this.defaultAnkiFieldTemplates = null;
        this.audioUriBuilder = new AudioUriBuilder();
        this.audioSystem = new AudioSystem({
            audioUriBuilder: this.audioUriBuilder,
            useCache: false
        });
        this.ankiNoteBuilder = new AnkiNoteBuilder({
            anki: this.anki,
            audioSystem: this.audioSystem,
            renderTemplate: this._renderTemplate.bind(this)
        });

        this.optionsContext = {
            depth: 0,
            url: window.location.href
        };

        this.clipboardPasteTarget = document.querySelector('#clipboard-paste-target');

        this.popupWindow = null;

        this.apiForwarder = new BackendApiForwarder();

        this.messageToken = yomichan.generateId(16);

        this._defaultBrowserActionTitle = null;
        this._isPrepared = false;
        this._prepareError = false;
        this._badgePrepareDelayTimer = null;

        this._messageHandlers = new Map([
            ['yomichanCoreReady', {handler: this._onApiYomichanCoreReady.bind(this), async: false}],
            ['optionsSchemaGet', {handler: this._onApiOptionsSchemaGet.bind(this), async: false}],
            ['optionsGet', {handler: this._onApiOptionsGet.bind(this), async: false}],
            ['optionsGetFull', {handler: this._onApiOptionsGetFull.bind(this), async: false}],
            ['optionsSet', {handler: this._onApiOptionsSet.bind(this), async: true}],
            ['optionsSave', {handler: this._onApiOptionsSave.bind(this), async: true}],
            ['kanjiFind', {handler: this._onApiKanjiFind.bind(this), async: true}],
            ['termsFind', {handler: this._onApiTermsFind.bind(this), async: true}],
            ['textParse', {handler: this._onApiTextParse.bind(this), async: true}],
            ['definitionAdd', {handler: this._onApiDefinitionAdd.bind(this), async: true}],
            ['definitionsAddable', {handler: this._onApiDefinitionsAddable.bind(this), async: true}],
            ['noteView', {handler: this._onApiNoteView.bind(this), async: true}],
            ['templateRender', {handler: this._onApiTemplateRender.bind(this), async: true}],
            ['commandExec', {handler: this._onApiCommandExec.bind(this), async: false}],
            ['audioGetUri', {handler: this._onApiAudioGetUri.bind(this), async: true}],
            ['screenshotGet', {handler: this._onApiScreenshotGet.bind(this), async: true}],
            ['broadcastTab', {handler: this._onApiBroadcastTab.bind(this), async: false}],
            ['frameInformationGet', {handler: this._onApiFrameInformationGet.bind(this), async: true}],
            ['injectStylesheet', {handler: this._onApiInjectStylesheet.bind(this), async: true}],
            ['getEnvironmentInfo', {handler: this._onApiGetEnvironmentInfo.bind(this), async: true}],
            ['clipboardGet', {handler: this._onApiClipboardGet.bind(this), async: true}],
            ['getDisplayTemplatesHtml', {handler: this._onApiGetDisplayTemplatesHtml.bind(this), async: true}],
            ['getQueryParserTemplatesHtml', {handler: this._onApiGetQueryParserTemplatesHtml.bind(this), async: true}],
            ['getZoom', {handler: this._onApiGetZoom.bind(this), async: true}],
            ['getMessageToken', {handler: this._onApiGetMessageToken.bind(this), async: false}],
            ['getDefaultAnkiFieldTemplates', {handler: this._onApiGetDefaultAnkiFieldTemplates.bind(this), async: false}],
            ['getAnkiDeckNames', {handler: this._onApiGetAnkiDeckNames.bind(this), async: true}],
            ['getAnkiModelNames', {handler: this._onApiGetAnkiModelNames.bind(this), async: true}],
            ['getAnkiModelFieldNames', {handler: this._onApiGetAnkiModelFieldNames.bind(this), async: true}],
            ['getDictionaryInfo', {handler: this._onApiGetDictionaryInfo.bind(this), async: true}],
            ['getDictionaryCounts', {handler: this._onApiGetDictionaryCounts.bind(this), async: true}],
            ['purgeDatabase', {handler: this._onApiPurgeDatabase.bind(this), async: true}],
            ['getMedia', {handler: this._onApiGetMedia.bind(this), async: true}]
        ]);

        this._commandHandlers = new Map([
            ['search', this._onCommandSearch.bind(this)],
            ['help', this._onCommandHelp.bind(this)],
            ['options', this._onCommandOptions.bind(this)],
            ['toggle', this._onCommandToggle.bind(this)]
        ]);
    }

    async prepare() {
        try {
            this._defaultBrowserActionTitle = await this._getBrowserIconTitle();
            this._badgePrepareDelayTimer = setTimeout(() => {
                this._badgePrepareDelayTimer = null;
                this._updateBadge();
            }, 1000);
            this._updateBadge();

            await this.database.prepare();
            await this.translator.prepare();

            this.optionsSchema = await requestJson(chrome.runtime.getURL('/bg/data/options-schema.json'), 'GET');
            this.defaultAnkiFieldTemplates = await requestText(chrome.runtime.getURL('/bg/data/default-anki-field-templates.handlebars'), 'GET');
            this.options = await optionsLoad();
            this.options = JsonSchema.getValidValueOrDefault(this.optionsSchema, this.options);

            this.onOptionsUpdated('background');

            if (isObject(chrome.commands) && isObject(chrome.commands.onCommand)) {
                chrome.commands.onCommand.addListener(this._runCommand.bind(this));
            }
            if (isObject(chrome.tabs) && isObject(chrome.tabs.onZoomChange)) {
                chrome.tabs.onZoomChange.addListener(this._onZoomChange.bind(this));
            }
            chrome.runtime.onMessage.addListener(this.onMessage.bind(this));

            const options = this.getOptions(this.optionsContext);
            if (options.general.showGuide) {
                chrome.tabs.create({url: chrome.runtime.getURL('/bg/guide.html')});
            }

            this.clipboardMonitor.on('change', this._onClipboardText.bind(this));

            this._sendMessageAllTabs('backendPrepared');
            const callback = () => this.checkLastError(chrome.runtime.lastError);
            chrome.runtime.sendMessage({action: 'backendPrepared'}, callback);

            this._isPrepared = true;
        } catch (e) {
            this._prepareError = true;
            logError(e);
            throw e;
        } finally {
            if (this._badgePrepareDelayTimer !== null) {
                clearTimeout(this._badgePrepareDelayTimer);
                this._badgePrepareDelayTimer = null;
            }

            this._updateBadge();
        }
    }

    isPrepared() {
        return this._isPrepared;
    }

    _sendMessageAllTabs(action, params={}) {
        const callback = () => this.checkLastError(chrome.runtime.lastError);
        chrome.tabs.query({}, (tabs) => {
            for (const tab of tabs) {
                chrome.tabs.sendMessage(tab.id, {action, params}, callback);
            }
        });
    }

    onOptionsUpdated(source) {
        this.applyOptions();
        this._sendMessageAllTabs('optionsUpdated', {source});
    }

    onMessage({action, params}, sender, callback) {
        const messageHandler = this._messageHandlers.get(action);
        if (typeof messageHandler === 'undefined') { return false; }

        const {handler, async} = messageHandler;

        try {
            const promiseOrResult = handler(params, sender);
            if (async) {
                promiseOrResult.then(
                    (result) => callback({result}),
                    (error) => callback({error: errorToJson(error)})
                );
                return true;
            } else {
                callback({result: promiseOrResult});
                return false;
            }
        } catch (error) {
            callback({error: errorToJson(error)});
            return false;
        }
    }

    _onClipboardText({text}) {
        this._onCommandSearch({mode: 'popup', query: text});
    }

    _onZoomChange({tabId, oldZoomFactor, newZoomFactor}) {
        const callback = () => this.checkLastError(chrome.runtime.lastError);
        chrome.tabs.sendMessage(tabId, {action: 'zoomChanged', params: {oldZoomFactor, newZoomFactor}}, callback);
    }

    applyOptions() {
        const options = this.getOptions(this.optionsContext);
        this._updateBadge();

        this.anki.setServer(options.anki.server);
        this.anki.setEnabled(options.anki.enable);

        if (options.parsing.enableMecabParser) {
            this.mecab.startListener();
        } else {
            this.mecab.stopListener();
        }

        if (options.general.enableClipboardPopups) {
            this.clipboardMonitor.start();
        } else {
            this.clipboardMonitor.stop();
        }
    }

    getOptionsSchema() {
        return this.optionsSchema;
    }

    getFullOptions() {
        return this.options;
    }

    setFullOptions(options) {
        try {
            this.options = JsonSchema.getValidValueOrDefault(this.optionsSchema, utilIsolate(options));
        } catch (e) {
            // This shouldn't happen, but catch errors just in case of bugs
            logError(e);
        }
    }

    getOptions(optionsContext) {
        return this.getProfile(optionsContext).options;
    }

    getProfile(optionsContext) {
        const profiles = this.options.profiles;
        if (typeof optionsContext.index === 'number') {
            return profiles[optionsContext.index];
        }
        const profile = this.getProfileFromContext(optionsContext);
        return profile !== null ? profile : this.options.profiles[this.options.profileCurrent];
    }

    getProfileFromContext(optionsContext) {
        for (const profile of this.options.profiles) {
            const conditionGroups = profile.conditionGroups;
            if (conditionGroups.length > 0 && Backend.testConditionGroups(conditionGroups, optionsContext)) {
                return profile;
            }
        }
        return null;
    }

    static testConditionGroups(conditionGroups, data) {
        if (conditionGroups.length === 0) { return false; }

        for (const conditionGroup of conditionGroups) {
            const conditions = conditionGroup.conditions;
            if (conditions.length > 0 && Backend.testConditions(conditions, data)) {
                return true;
            }
        }

        return false;
    }

    static testConditions(conditions, data) {
        for (const condition of conditions) {
            if (!conditionsTestValue(profileConditionsDescriptor, condition.type, condition.operator, condition.value, data)) {
                return false;
            }
        }
        return true;
    }

    checkLastError() {
        // NOP
    }

    _runCommand(command, params) {
        const handler = this._commandHandlers.get(command);
        if (typeof handler !== 'function') { return false; }

        handler(params);
        return true;
    }

    async importDictionary(archiveSource, onProgress, details) {
        return await this.dictionaryImporter.import(this.database, archiveSource, onProgress, details);
    }

    async _textParseScanning(text, options) {
        const results = [];
        while (text.length > 0) {
            const term = [];
            const [definitions, sourceLength] = await this.translator.findTerms(
                'simple',
                text.substring(0, options.scanning.length),
                {},
                options
            );
            if (definitions.length > 0 && sourceLength > 0) {
                dictTermsSort(definitions);
                const {expression, reading} = definitions[0];
                const source = text.substring(0, sourceLength);
                for (const {text: text2, furigana} of jp.distributeFuriganaInflected(expression, reading, source)) {
                    const reading2 = jp.convertReading(text2, furigana, options.parsing.readingMode);
                    term.push({text: text2, reading: reading2});
                }
                text = text.substring(source.length);
            } else {
                const reading = jp.convertReading(text[0], '', options.parsing.readingMode);
                term.push({text: text[0], reading});
                text = text.substring(1);
            }
            results.push(term);
        }
        return results;
    }

    async _textParseMecab(text, options) {
        const results = [];
        const rawResults = await this.mecab.parseText(text);
        for (const [mecabName, parsedLines] of Object.entries(rawResults)) {
            const result = [];
            for (const parsedLine of parsedLines) {
                for (const {expression, reading, source} of parsedLine) {
                    const term = [];
                    for (const {text: text2, furigana} of jp.distributeFuriganaInflected(
                        expression.length > 0 ? expression : source,
                        jp.convertKatakanaToHiragana(reading),
                        source
                    )) {
                        const reading2 = jp.convertReading(text2, furigana, options.parsing.readingMode);
                        term.push({text: text2, reading: reading2});
                    }
                    result.push(term);
                }
                result.push([{text: '\n', reading: ''}]);
            }
            results.push([mecabName, result]);
        }
        return results;
    }

    // Message handlers

    _onApiYomichanCoreReady(_params, sender) {
        // tab ID isn't set in background (e.g. browser_action)
        const callback = () => this.checkLastError(chrome.runtime.lastError);
        const data = {action: 'backendPrepared'};
        if (typeof sender.tab === 'undefined') {
            chrome.runtime.sendMessage(data, callback);
            return false;
        } else {
            chrome.tabs.sendMessage(sender.tab.id, data, callback);
            return true;
        }
    }

    _onApiOptionsSchemaGet() {
        return this.getOptionsSchema();
    }

    _onApiOptionsGet({optionsContext}) {
        return this.getOptions(optionsContext);
    }

    _onApiOptionsGetFull() {
        return this.getFullOptions();
    }

    async _onApiOptionsSet({changedOptions, optionsContext, source}) {
        const options = this.getOptions(optionsContext);

        function getValuePaths(obj) {
            const valuePaths = [];
            const nodes = [{obj, path: []}];
            while (nodes.length > 0) {
                const node = nodes.pop();
                for (const key of Object.keys(node.obj)) {
                    const path = node.path.concat(key);
                    const obj2 = node.obj[key];
                    if (obj2 !== null && typeof obj2 === 'object') {
                        nodes.unshift({obj: obj2, path});
                    } else {
                        valuePaths.push([obj2, path]);
                    }
                }
            }
            return valuePaths;
        }

        function modifyOption(path, value) {
            let pivot = options;
            for (const key of path.slice(0, -1)) {
                if (!hasOwn(pivot, key)) {
                    return false;
                }
                pivot = pivot[key];
            }
            pivot[path[path.length - 1]] = value;
            return true;
        }

        for (const [value, path] of getValuePaths(changedOptions)) {
            modifyOption(path, value);
        }

        await this._onApiOptionsSave({source});
    }

    async _onApiOptionsSave({source}) {
        const options = this.getFullOptions();
        await optionsSave(options);
        this.onOptionsUpdated(source);
    }

    async _onApiKanjiFind({text, optionsContext}) {
        const options = this.getOptions(optionsContext);
        const definitions = await this.translator.findKanji(text, options);
        definitions.splice(options.general.maxResults);
        return definitions;
    }

    async _onApiTermsFind({text, details, optionsContext}) {
        const options = this.getOptions(optionsContext);
        const mode = options.general.resultOutputMode;
        const [definitions, length] = await this.translator.findTerms(mode, text, details, options);
        definitions.splice(options.general.maxResults);
        return {length, definitions};
    }

    async _onApiTextParse({text, optionsContext}) {
        const options = this.getOptions(optionsContext);
        const results = [];

        if (options.parsing.enableScanningParser) {
            results.push({
                source: 'scanning-parser',
                id: 'scan',
                content: await this._textParseScanning(text, options)
            });
        }

        if (options.parsing.enableMecabParser) {
            const mecabResults = await this._textParseMecab(text, options);
            for (const [mecabDictName, mecabDictResults] of mecabResults) {
                results.push({
                    source: 'mecab',
                    dictionary: mecabDictName,
                    id: `mecab-${mecabDictName}`,
                    content: mecabDictResults
                });
            }
        }

        return results;
    }

    async _onApiDefinitionAdd({definition, mode, context, details, optionsContext}) {
        const options = this.getOptions(optionsContext);
        const templates = this._getTemplates(options);

        if (mode !== 'kanji') {
            const {customSourceUrl} = options.audio;
            await this.ankiNoteBuilder.injectAudio(
                definition,
                options.anki.terms.fields,
                options.audio.sources,
                {textToSpeechVoice: null, customSourceUrl}
            );
        }

        if (details && details.screenshot) {
            await this.ankiNoteBuilder.injectScreenshot(
                definition,
                options.anki.terms.fields,
                details.screenshot
            );
        }

        const note = await this.ankiNoteBuilder.createNote(definition, mode, context, options, templates);
        return this.anki.addNote(note);
    }

    async _onApiDefinitionsAddable({definitions, modes, context, optionsContext}) {
        const options = this.getOptions(optionsContext);
        const templates = this._getTemplates(options);
        const states = [];

        try {
            const notes = [];
            for (const definition of definitions) {
                for (const mode of modes) {
                    const note = await this.ankiNoteBuilder.createNote(definition, mode, context, options, templates);
                    notes.push(note);
                }
            }

            const cannotAdd = [];
            const results = await this.anki.canAddNotes(notes);
            for (let resultBase = 0; resultBase < results.length; resultBase += modes.length) {
                const state = {};
                for (let modeOffset = 0; modeOffset < modes.length; ++modeOffset) {
                    const index = resultBase + modeOffset;
                    const result = results[index];
                    const info = {canAdd: result};
                    state[modes[modeOffset]] = info;
                    if (!result) {
                        cannotAdd.push([notes[index], info]);
                    }
                }

                states.push(state);
            }

            if (cannotAdd.length > 0) {
                const noteIdsArray = await this.anki.findNoteIds(cannotAdd.map((e) => e[0]));
                for (let i = 0, ii = Math.min(cannotAdd.length, noteIdsArray.length); i < ii; ++i) {
                    const noteIds = noteIdsArray[i];
                    if (noteIds.length > 0) {
                        cannotAdd[i][1].noteId = noteIds[0];
                    }
                }
            }
        } catch (e) {
            // NOP
        }

        return states;
    }

    async _onApiNoteView({noteId}) {
        return await this.anki.guiBrowse(`nid:${noteId}`);
    }

    async _onApiTemplateRender({template, data}) {
        return this._renderTemplate(template, data);
    }

    _onApiCommandExec({command, params}) {
        return this._runCommand(command, params);
    }

    async _onApiAudioGetUri({definition, source, details}) {
        return await this.audioUriBuilder.getUri(definition, source, details);
    }

    _onApiScreenshotGet({options}, sender) {
        if (!(sender && sender.tab)) {
            return Promise.resolve();
        }

        const windowId = sender.tab.windowId;
        return new Promise((resolve) => {
            chrome.tabs.captureVisibleTab(windowId, options, (dataUrl) => resolve(dataUrl));
        });
    }

    _onApiBroadcastTab({action, params}, sender) {
        if (!(sender && sender.tab)) {
            return false;
        }

        const tabId = sender.tab.id;
        const callback = () => this.checkLastError(chrome.runtime.lastError);
        chrome.tabs.sendMessage(tabId, {action, params}, callback);
        return true;
    }

    _onApiFrameInformationGet(params, sender) {
        const frameId = sender.frameId;
        return Promise.resolve({frameId});
    }

    _onApiInjectStylesheet({type, value}, sender) {
        if (!sender.tab) {
            return Promise.reject(new Error('Invalid tab'));
        }

        const tabId = sender.tab.id;
        const frameId = sender.frameId;
        const details = (
            type === 'file' ?
            {
                file: value,
                runAt: 'document_start',
                cssOrigin: 'author',
                allFrames: false,
                matchAboutBlank: true
            } :
            {
                code: value,
                runAt: 'document_start',
                cssOrigin: 'user',
                allFrames: false,
                matchAboutBlank: true
            }
        );
        if (typeof frameId === 'number') {
            details.frameId = frameId;
        }

        return new Promise((resolve, reject) => {
            chrome.tabs.insertCSS(tabId, details, () => {
                const e = chrome.runtime.lastError;
                if (e) {
                    reject(new Error(e.message));
                } else {
                    resolve();
                }
            });
        });
    }

    async _onApiGetEnvironmentInfo() {
        const browser = await Backend._getBrowser();
        const platform = await new Promise((resolve) => chrome.runtime.getPlatformInfo(resolve));
        return {
            browser,
            platform: {
                os: platform.os
            }
        };
    }

    async _onApiClipboardGet() {
        /*
        Notes:
            document.execCommand('paste') doesn't work on Firefox.
            This may be a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1603985
            Therefore, navigator.clipboard.readText() is used on Firefox.

            navigator.clipboard.readText() can't be used in Chrome for two reasons:
            * Requires page to be focused, else it rejects with an exception.
            * When the page is focused, Chrome will request clipboard permission, despite already
              being an extension with clipboard permissions. It effectively asks for the
              non-extension permission for clipboard access.
        */
        const browser = await Backend._getBrowser();
        if (browser === 'firefox' || browser === 'firefox-mobile') {
            return await navigator.clipboard.readText();
        } else {
            const clipboardPasteTarget = this.clipboardPasteTarget;
            clipboardPasteTarget.value = '';
            clipboardPasteTarget.focus();
            document.execCommand('paste');
            const result = clipboardPasteTarget.value;
            clipboardPasteTarget.value = '';
            return result;
        }
    }

    async _onApiGetDisplayTemplatesHtml() {
        const url = chrome.runtime.getURL('/mixed/display-templates.html');
        return await requestText(url, 'GET');
    }

    async _onApiGetQueryParserTemplatesHtml() {
        const url = chrome.runtime.getURL('/bg/query-parser-templates.html');
        return await requestText(url, 'GET');
    }

    _onApiGetZoom(params, sender) {
        if (!sender || !sender.tab) {
            return Promise.reject(new Error('Invalid tab'));
        }

        return new Promise((resolve, reject) => {
            const tabId = sender.tab.id;
            if (!(
                chrome.tabs !== null &&
                typeof chrome.tabs === 'object' &&
                typeof chrome.tabs.getZoom === 'function'
            )) {
                // Not supported
                resolve({zoomFactor: 1.0});
                return;
            }
            chrome.tabs.getZoom(tabId, (zoomFactor) => {
                const e = chrome.runtime.lastError;
                if (e) {
                    reject(new Error(e.message));
                } else {
                    resolve({zoomFactor});
                }
            });
        });
    }

    _onApiGetMessageToken() {
        return this.messageToken;
    }

    _onApiGetDefaultAnkiFieldTemplates() {
        return this.defaultAnkiFieldTemplates;
    }

    async _onApiGetAnkiDeckNames(params, sender) {
        this._validatePrivilegedMessageSender(sender);
        return await this.anki.getDeckNames();
    }

    async _onApiGetAnkiModelNames(params, sender) {
        this._validatePrivilegedMessageSender(sender);
        return await this.anki.getModelNames();
    }

    async _onApiGetAnkiModelFieldNames({modelName}, sender) {
        this._validatePrivilegedMessageSender(sender);
        return await this.anki.getModelFieldNames(modelName);
    }

    async _onApiGetDictionaryInfo(params, sender) {
        this._validatePrivilegedMessageSender(sender);
        return await this.translator.database.getDictionaryInfo();
    }

    async _onApiGetDictionaryCounts({dictionaryNames, getTotal}, sender) {
        this._validatePrivilegedMessageSender(sender);
        return await this.translator.database.getDictionaryCounts(dictionaryNames, getTotal);
    }

    async _onApiPurgeDatabase(params, sender) {
        this._validatePrivilegedMessageSender(sender);
        return await this.translator.purgeDatabase();
    }

    async _onApiGetMedia({targets}) {
        return await this.database.getMedia(targets);
    }

    // Command handlers

    async _onCommandSearch(params) {
        const {mode='existingOrNewTab', query} = params || {};

        const options = this.getOptions(this.optionsContext);
        const {popupWidth, popupHeight} = options.general;

        const baseUrl = chrome.runtime.getURL('/bg/search.html');
        const queryParams = {mode};
        if (query && query.length > 0) { queryParams.query = query; }
        const queryString = new URLSearchParams(queryParams).toString();
        const url = `${baseUrl}?${queryString}`;

        const isTabMatch = (url2) => {
            if (url2 === null || !url2.startsWith(baseUrl)) { return false; }
            const {baseUrl: baseUrl2, queryParams: queryParams2} = parseUrl(url2);
            return baseUrl2 === baseUrl && (queryParams2.mode === mode || (!queryParams2.mode && mode === 'existingOrNewTab'));
        };

        const openInTab = async () => {
            const tab = await Backend._findTab(1000, isTabMatch);
            if (tab !== null) {
                await Backend._focusTab(tab);
                if (queryParams.query) {
                    await new Promise((resolve) => chrome.tabs.sendMessage(
                        tab.id, {action: 'searchQueryUpdate', params: {text: queryParams.query}}, resolve
                    ));
                }
                return true;
            }
        };

        switch (mode) {
            case 'existingOrNewTab':
                try {
                    if (await openInTab()) { return; }
                } catch (e) {
                    // NOP
                }
                chrome.tabs.create({url});
                return;
            case 'newTab':
                chrome.tabs.create({url});
                return;
            case 'popup':
                try {
                    // chrome.windows not supported (e.g. on Firefox mobile)
                    if (!isObject(chrome.windows)) { return; }
                    if (await openInTab()) { return; }
                    // if the previous popup is open in an invalid state, close it
                    if (this.popupWindow !== null) {
                        const callback = () => this.checkLastError(chrome.runtime.lastError);
                        chrome.windows.remove(this.popupWindow.id, callback);
                    }
                    // open new popup
                    this.popupWindow = await new Promise((resolve) => chrome.windows.create(
                        {url, width: popupWidth, height: popupHeight, type: 'popup'},
                        resolve
                    ));
                } catch (e) {
                    // NOP
                }
                return;
        }
    }

    _onCommandHelp() {
        chrome.tabs.create({url: 'https://foosoft.net/projects/yomichan/'});
    }

    _onCommandOptions(params) {
        const {mode='existingOrNewTab'} = params || {};
        if (mode === 'existingOrNewTab') {
            chrome.runtime.openOptionsPage();
        } else if (mode === 'newTab') {
            const manifest = chrome.runtime.getManifest();
            const url = chrome.runtime.getURL(manifest.options_ui.page);
            chrome.tabs.create({url});
        }
    }

    async _onCommandToggle() {
        const optionsContext = {
            depth: 0,
            url: window.location.href
        };
        const source = 'popup';

        const options = this.getOptions(optionsContext);
        options.general.enable = !options.general.enable;
        await this._onApiOptionsSave({source});
    }

    // Utilities

    _validatePrivilegedMessageSender(sender) {
        const url = sender.url;
        if (!(typeof url === 'string' && yomichan.isExtensionUrl(url))) {
            throw new Error('Invalid message sender');
        }
    }

    _getBrowserIconTitle() {
        return (
            isObject(chrome.browserAction) &&
            typeof chrome.browserAction.getTitle === 'function' ?
                new Promise((resolve) => chrome.browserAction.getTitle({}, resolve)) :
                Promise.resolve('')
        );
    }

    _updateBadge() {
        let title = this._defaultBrowserActionTitle;
        if (title === null || !isObject(chrome.browserAction)) {
            // Not ready or invalid
            return;
        }

        let text = '';
        let color = null;
        let status = null;

        if (!this._isPrepared) {
            if (this._prepareError) {
                text = '!!';
                color = '#f04e4e';
                status = 'Error';
            } else if (this._badgePrepareDelayTimer === null) {
                text = '...';
                color = '#f0ad4e';
                status = 'Loading';
            }
        } else if (!this._anyOptionsMatches((options) => options.general.enable)) {
            text = 'off';
            color = '#555555';
            status = 'Disabled';
        } else if (!this._anyOptionsMatches((options) => this._isAnyDictionaryEnabled(options))) {
            text = '!';
            color = '#f0ad4e';
            status = 'No dictionaries installed';
        }

        if (color !== null && typeof chrome.browserAction.setBadgeBackgroundColor === 'function') {
            chrome.browserAction.setBadgeBackgroundColor({color});
        }
        if (text !== null && typeof chrome.browserAction.setBadgeText === 'function') {
            chrome.browserAction.setBadgeText({text});
        }
        if (typeof chrome.browserAction.setTitle === 'function') {
            if (status !== null) {
                title = `${title} - ${status}`;
            }
            chrome.browserAction.setTitle({title});
        }
    }

    _isAnyDictionaryEnabled(options) {
        for (const {enabled} of Object.values(options.dictionaries)) {
            if (enabled) {
                return true;
            }
        }
        return false;
    }

    _anyOptionsMatches(predicate) {
        for (const {options} of this.options.profiles) {
            const value = predicate(options);
            if (value) { return value; }
        }
        return false;
    }

    async _renderTemplate(template, data) {
        return handlebarsRenderDynamic(template, data);
    }

    _getTemplates(options) {
        const templates = options.anki.fieldTemplates;
        return typeof templates === 'string' ? templates : this.defaultAnkiFieldTemplates;
    }

    static _getTabUrl(tab) {
        return new Promise((resolve) => {
            chrome.tabs.sendMessage(tab.id, {action: 'getUrl'}, {frameId: 0}, (response) => {
                let url = null;
                if (!chrome.runtime.lastError) {
                    url = (response !== null && typeof response === 'object' && !Array.isArray(response) ? response.url : null);
                    if (url !== null && typeof url !== 'string') {
                        url = null;
                    }
                }
                resolve({tab, url});
            });
        });
    }

    static async _findTab(timeout, checkUrl) {
        // This function works around the need to have the "tabs" permission to access tab.url.
        const tabs = await new Promise((resolve) => chrome.tabs.query({}, resolve));
        let matchPromiseResolve = null;
        const matchPromise = new Promise((resolve) => { matchPromiseResolve = resolve; });

        const checkTabUrl = ({tab, url}) => {
            if (checkUrl(url, tab)) {
                matchPromiseResolve(tab);
            }
        };

        const promises = [];
        for (const tab of tabs) {
            const promise = Backend._getTabUrl(tab);
            promise.then(checkTabUrl);
            promises.push(promise);
        }

        const racePromises = [
            matchPromise,
            Promise.all(promises).then(() => null)
        ];
        if (typeof timeout === 'number') {
            racePromises.push(new Promise((resolve) => setTimeout(() => resolve(null), timeout)));
        }

        return await Promise.race(racePromises);
    }

    static async _focusTab(tab) {
        await new Promise((resolve, reject) => {
            chrome.tabs.update(tab.id, {active: true}, () => {
                const e = chrome.runtime.lastError;
                if (e) {
                    reject(new Error(e.message));
                } else {
                    resolve();
                }
            });
        });

        if (!(typeof chrome.windows === 'object' && chrome.windows !== null)) {
            // Windows not supported (e.g. on Firefox mobile)
            return;
        }

        try {
            const tabWindow = await new Promise((resolve, reject) => {
                chrome.windows.get(tab.windowId, {}, (value) => {
                    const e = chrome.runtime.lastError;
                    if (e) {
                        reject(new Error(e.message));
                    } else {
                        resolve(value);
                    }
                });
            });
            if (!tabWindow.focused) {
                await new Promise((resolve, reject) => {
                    chrome.windows.update(tab.windowId, {focused: true}, () => {
                        const e = chrome.runtime.lastError;
                        if (e) {
                            reject(new Error(e.message));
                        } else {
                            resolve();
                        }
                    });
                });
            }
        } catch (e) {
            // Edge throws exception for no reason here.
        }
    }

    static async _getBrowser() {
        if (EXTENSION_IS_BROWSER_EDGE) {
            return 'edge';
        }
        if (typeof browser !== 'undefined') {
            try {
                const info = await browser.runtime.getBrowserInfo();
                if (info.name === 'Fennec') {
                    return 'firefox-mobile';
                }
            } catch (e) {
                // NOP
            }
            return 'firefox';
        } else {
            return 'chrome';
        }
    }
}