move dictionary files to dictionary folder (#429)

8 files changed, 2337 insertions, 0 deletions

diff --git a/ext/js/dictionary/dictionary-data-util.js b/ext/js/dictionary/dictionary-data-util.js
new file mode 100644
index 00000000..a54b043b
--- /dev/null
+++ b/ext/js/dictionary/dictionary-data-util.js
@@ -0,0 +1,391 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2020-2022  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/>.
+ */
+
+export class DictionaryDataUtil {
+    /**
+     * @param {import('dictionary').TermDictionaryEntry} dictionaryEntry
+     * @returns {import('dictionary-data-util').TagGroup[]}
+     */
+    static groupTermTags(dictionaryEntry) {
+        const {headwords} = dictionaryEntry;
+        const headwordCount = headwords.length;
+        const uniqueCheck = (headwordCount > 1);
+        const resultsIndexMap = new Map();
+        const results = [];
+        for (let i = 0; i < headwordCount; ++i) {
+            const {tags} = headwords[i];
+            for (const tag of tags) {
+                if (uniqueCheck) {
+                    const {name, category, content, dictionaries} = tag;
+                    const key = this._createMapKey([name, category, content, dictionaries]);
+                    const index = resultsIndexMap.get(key);
+                    if (typeof index !== 'undefined') {
+                        const existingItem = results[index];
+                        existingItem.headwordIndices.push(i);
+                        continue;
+                    }
+                    resultsIndexMap.set(key, results.length);
+                }
+
+                const item = {tag, headwordIndices: [i]};
+                results.push(item);
+            }
+        }
+        return results;
+    }
+
+    /**
+     * @param {import('dictionary').TermDictionaryEntry} dictionaryEntry
+     * @returns {import('dictionary-data-util').DictionaryFrequency<import('dictionary-data-util').TermFrequency>[]}
+     */
+    static groupTermFrequencies(dictionaryEntry) {
+        const {headwords, frequencies: sourceFrequencies} = dictionaryEntry;
+
+        /** @type {import('dictionary-data-util').TermFrequenciesMap1} */
+        const map1 = new Map();
+        for (const {headwordIndex, dictionary, hasReading, frequency, displayValue} of sourceFrequencies) {
+            const {term, reading} = headwords[headwordIndex];
+
+            let map2 = map1.get(dictionary);
+            if (typeof map2 === 'undefined') {
+                map2 = new Map();
+                map1.set(dictionary, map2);
+            }
+
+            const readingKey = hasReading ? reading : null;
+            const key = this._createMapKey([term, readingKey]);
+            let frequencyData = map2.get(key);
+            if (typeof frequencyData === 'undefined') {
+                frequencyData = {term, reading: readingKey, values: new Map()};
+                map2.set(key, frequencyData);
+            }
+
+            frequencyData.values.set(this._createMapKey([frequency, displayValue]), {frequency, displayValue});
+        }
+
+        const results = [];
+        for (const [dictionary, map2] of map1.entries()) {
+            const frequencies = [];
+            for (const {term, reading, values} of map2.values()) {
+                frequencies.push({
+                    term,
+                    reading,
+                    values: [...values.values()]
+                });
+            }
+            results.push({dictionary, frequencies});
+        }
+        return results;
+    }
+
+    /**
+     * @param {import('dictionary').KanjiFrequency[]} sourceFrequencies
+     * @returns {import('dictionary-data-util').DictionaryFrequency<import('dictionary-data-util').KanjiFrequency>[]}
+     */
+    static groupKanjiFrequencies(sourceFrequencies) {
+        /** @type {import('dictionary-data-util').KanjiFrequenciesMap1} */
+        const map1 = new Map();
+        for (const {dictionary, character, frequency, displayValue} of sourceFrequencies) {
+            let map2 = map1.get(dictionary);
+            if (typeof map2 === 'undefined') {
+                map2 = new Map();
+                map1.set(dictionary, map2);
+            }
+
+            let frequencyData = map2.get(character);
+            if (typeof frequencyData === 'undefined') {
+                frequencyData = {character, values: new Map()};
+                map2.set(character, frequencyData);
+            }
+
+            frequencyData.values.set(this._createMapKey([frequency, displayValue]), {frequency, displayValue});
+        }
+
+        const results = [];
+        for (const [dictionary, map2] of map1.entries()) {
+            const frequencies = [];
+            for (const {character, values} of map2.values()) {
+                frequencies.push({
+                    character,
+                    values: [...values.values()]
+                });
+            }
+            results.push({dictionary, frequencies});
+        }
+        return results;
+    }
+
+    /**
+     * @param {import('dictionary').TermDictionaryEntry} dictionaryEntry
+     * @returns {import('dictionary-data-util').DictionaryGroupedPronunciations[]}
+     */
+    static getGroupedPronunciations(dictionaryEntry) {
+        const {headwords, pronunciations} = dictionaryEntry;
+
+        const allTerms = new Set();
+        const allReadings = new Set();
+        for (const {term, reading} of headwords) {
+            allTerms.add(term);
+            allReadings.add(reading);
+        }
+
+        /** @type {Map<string, import('dictionary-data-util').GroupedPronunciationInternal[]>} */
+        const groupedPronunciationsMap = new Map();
+        for (const {headwordIndex, dictionary, pitches} of pronunciations) {
+            const {term, reading} = headwords[headwordIndex];
+            let dictionaryGroupedPronunciationList = groupedPronunciationsMap.get(dictionary);
+            if (typeof dictionaryGroupedPronunciationList === 'undefined') {
+                dictionaryGroupedPronunciationList = [];
+                groupedPronunciationsMap.set(dictionary, dictionaryGroupedPronunciationList);
+            }
+            for (const {position, nasalPositions, devoicePositions, tags} of pitches) {
+                let groupedPronunciation = this._findExistingGroupedPronunciation(reading, position, nasalPositions, devoicePositions, tags, dictionaryGroupedPronunciationList);
+                if (groupedPronunciation === null) {
+                    groupedPronunciation = {
+                        terms: new Set(),
+                        reading,
+                        position,
+                        nasalPositions,
+                        devoicePositions,
+                        tags
+                    };
+                    dictionaryGroupedPronunciationList.push(groupedPronunciation);
+                }
+                groupedPronunciation.terms.add(term);
+            }
+        }
+
+        /** @type {import('dictionary-data-util').DictionaryGroupedPronunciations[]} */
+        const results2 = [];
+        const multipleReadings = (allReadings.size > 1);
+        for (const [dictionary, dictionaryGroupedPronunciationList] of groupedPronunciationsMap.entries()) {
+            /** @type {import('dictionary-data-util').GroupedPronunciation[]} */
+            const pronunciations2 = [];
+            for (const groupedPronunciation of dictionaryGroupedPronunciationList) {
+                const {terms, reading, position, nasalPositions, devoicePositions, tags} = groupedPronunciation;
+                const exclusiveTerms = !this._areSetsEqual(terms, allTerms) ? this._getSetIntersection(terms, allTerms) : [];
+                const exclusiveReadings = [];
+                if (multipleReadings) {
+                    exclusiveReadings.push(reading);
+                }
+                pronunciations2.push({
+                    terms: [...terms],
+                    reading,
+                    position,
+                    nasalPositions,
+                    devoicePositions,
+                    tags,
+                    exclusiveTerms,
+                    exclusiveReadings
+                });
+            }
+            results2.push({dictionary, pronunciations: pronunciations2});
+        }
+        return results2;
+    }
+
+    /**
+     * @param {import('dictionary').Tag[]|import('anki-templates').Tag[]} termTags
+     * @returns {import('dictionary-data-util').TermFrequencyType}
+     */
+    static getTermFrequency(termTags) {
+        let totalScore = 0;
+        for (const {score} of termTags) {
+            totalScore += score;
+        }
+        if (totalScore > 0) {
+            return 'popular';
+        } else if (totalScore < 0) {
+            return 'rare';
+        } else {
+            return 'normal';
+        }
+    }
+
+    /**
+     * @param {import('dictionary').TermHeadword[]} headwords
+     * @param {number[]} headwordIndices
+     * @param {Set<string>} allTermsSet
+     * @param {Set<string>} allReadingsSet
+     * @returns {string[]}
+     */
+    static getDisambiguations(headwords, headwordIndices, allTermsSet, allReadingsSet) {
+        if (allTermsSet.size <= 1 && allReadingsSet.size <= 1) { return []; }
+
+        /** @type {Set<string>} */
+        const terms = new Set();
+        /** @type {Set<string>} */
+        const readings = new Set();
+        for (const headwordIndex of headwordIndices) {
+            const {term, reading} = headwords[headwordIndex];
+            terms.add(term);
+            readings.add(reading);
+        }
+
+        /** @type {string[]} */
+        const disambiguations = [];
+        const addTerms = !this._areSetsEqual(terms, allTermsSet);
+        const addReadings = !this._areSetsEqual(readings, allReadingsSet);
+        if (addTerms) {
+            disambiguations.push(...this._getSetIntersection(terms, allTermsSet));
+        }
+        if (addReadings) {
+            if (addTerms) {
+                for (const term of terms) {
+                    readings.delete(term);
+                }
+            }
+            disambiguations.push(...this._getSetIntersection(readings, allReadingsSet));
+        }
+        return disambiguations;
+    }
+
+    /**
+     * @param {string[]} wordClasses
+     * @returns {boolean}
+     */
+    static isNonNounVerbOrAdjective(wordClasses) {
+        let isVerbOrAdjective = false;
+        let isSuruVerb = false;
+        let isNoun = false;
+        for (const wordClass of wordClasses) {
+            switch (wordClass) {
+                case 'v1':
+                case 'v5':
+                case 'vk':
+                case 'vz':
+                case 'adj-i':
+                    isVerbOrAdjective = true;
+                    break;
+                case 'vs':
+                    isVerbOrAdjective = true;
+                    isSuruVerb = true;
+                    break;
+                case 'n':
+                    isNoun = true;
+                    break;
+            }
+        }
+        return isVerbOrAdjective && !(isSuruVerb && isNoun);
+    }
+
+    // Private
+
+    /**
+     * @param {string} reading
+     * @param {number} position
+     * @param {number[]} nasalPositions
+     * @param {number[]} devoicePositions
+     * @param {import('dictionary').Tag[]} tags
+     * @param {import('dictionary-data-util').GroupedPronunciationInternal[]} groupedPronunciationList
+     * @returns {?import('dictionary-data-util').GroupedPronunciationInternal}
+     */
+    static _findExistingGroupedPronunciation(reading, position, nasalPositions, devoicePositions, tags, groupedPronunciationList) {
+        for (const pitchInfo of groupedPronunciationList) {
+            if (
+                pitchInfo.reading === reading &&
+                pitchInfo.position === position &&
+                this._areArraysEqual(pitchInfo.nasalPositions, nasalPositions) &&
+                this._areArraysEqual(pitchInfo.devoicePositions, devoicePositions) &&
+                this._areTagListsEqual(pitchInfo.tags, tags)
+            ) {
+                return pitchInfo;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * @template [T=unknown]
+     * @param {T[]} array1
+     * @param {T[]} array2
+     * @returns {boolean}
+     */
+    static _areArraysEqual(array1, array2) {
+        const ii = array1.length;
+        if (ii !== array2.length) { return false; }
+        for (let i = 0; i < ii; ++i) {
+            if (array1[i] !== array2[i]) { return false; }
+        }
+        return true;
+    }
+
+    /**
+     * @param {import('dictionary').Tag[]} tagList1
+     * @param {import('dictionary').Tag[]} tagList2
+     * @returns {boolean}
+     */
+    static _areTagListsEqual(tagList1, tagList2) {
+        const ii = tagList1.length;
+        if (tagList2.length !== ii) { return false; }
+
+        for (let i = 0; i < ii; ++i) {
+            const tag1 = tagList1[i];
+            const tag2 = tagList2[i];
+            if (tag1.name !== tag2.name || !this._areArraysEqual(tag1.dictionaries, tag2.dictionaries)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * @template [T=unknown]
+     * @param {Set<T>} set1
+     * @param {Set<T>} set2
+     * @returns {boolean}
+     */
+    static _areSetsEqual(set1, set2) {
+        if (set1.size !== set2.size) {
+            return false;
+        }
+
+        for (const value of set1) {
+            if (!set2.has(value)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * @template [T=unknown]
+     * @param {Set<T>} set1
+     * @param {Set<T>} set2
+     * @returns {T[]}
+     */
+    static _getSetIntersection(set1, set2) {
+        const result = [];
+        for (const value of set1) {
+            if (set2.has(value)) {
+                result.push(value);
+            }
+        }
+        return result;
+    }
+
+    /**
+     * @param {unknown[]} array
+     * @returns {string}
+     */
+    static _createMapKey(array) {
+        return JSON.stringify(array);
+    }
+}
diff --git a/ext/js/dictionary/dictionary-database.js b/ext/js/dictionary/dictionary-database.js
new file mode 100644
index 00000000..45c5c6fd
--- /dev/null
+++ b/ext/js/dictionary/dictionary-database.js
@@ -0,0 +1,661 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2016-2022  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/>.
+ */
+
+import {log, stringReverse} from '../core.js';
+import {Database} from '../data/database.js';
+
+export class DictionaryDatabase {
+    constructor() {
+        /** @type {Database<import('dictionary-database').ObjectStoreName>} */
+        this._db = new Database();
+        /** @type {string} */
+        this._dbName = 'dict';
+        /** @type {import('dictionary-database').CreateQuery<string>} */
+        this._createOnlyQuery1 = (item) => IDBKeyRange.only(item);
+        /** @type {import('dictionary-database').CreateQuery<import('dictionary-database').DictionaryAndQueryRequest>} */
+        this._createOnlyQuery2 = (item) => IDBKeyRange.only(item.query);
+        /** @type {import('dictionary-database').CreateQuery<import('dictionary-database').TermExactRequest>} */
+        this._createOnlyQuery3 = (item) => IDBKeyRange.only(item.term);
+        /** @type {import('dictionary-database').CreateQuery<import('dictionary-database').MediaRequest>} */
+        this._createOnlyQuery4 = (item) => IDBKeyRange.only(item.path);
+        /** @type {import('dictionary-database').CreateQuery<string>} */
+        this._createBoundQuery1 = (item) => IDBKeyRange.bound(item, `${item}\uffff`, false, false);
+        /** @type {import('dictionary-database').CreateQuery<string>} */
+        this._createBoundQuery2 = (item) => { item = stringReverse(item); return IDBKeyRange.bound(item, `${item}\uffff`, false, false); };
+        /** @type {import('dictionary-database').CreateResult<import('dictionary-database').TermExactRequest, import('dictionary-database').DatabaseTermEntryWithId, import('dictionary-database').TermEntry>} */
+        this._createTermBind1 = this._createTermExact.bind(this);
+        /** @type {import('dictionary-database').CreateResult<import('dictionary-database').DictionaryAndQueryRequest, import('dictionary-database').DatabaseTermEntryWithId, import('dictionary-database').TermEntry>} */
+        this._createTermBind2 = this._createTermSequenceExact.bind(this);
+        /** @type {import('dictionary-database').CreateResult<string, import('dictionary-database').DatabaseTermMeta, import('dictionary-database').TermMeta>} */
+        this._createTermMetaBind = this._createTermMeta.bind(this);
+        /** @type {import('dictionary-database').CreateResult<string, import('dictionary-database').DatabaseKanjiEntry, import('dictionary-database').KanjiEntry>} */
+        this._createKanjiBind = this._createKanji.bind(this);
+        /** @type {import('dictionary-database').CreateResult<string, import('dictionary-database').DatabaseKanjiMeta, import('dictionary-database').KanjiMeta>} */
+        this._createKanjiMetaBind = this._createKanjiMeta.bind(this);
+        /** @type {import('dictionary-database').CreateResult<import('dictionary-database').MediaRequest, import('dictionary-database').MediaDataArrayBufferContent, import('dictionary-database').Media>} */
+        this._createMediaBind = this._createMedia.bind(this);
+    }
+
+    /** */
+    async prepare() {
+        await this._db.open(
+            this._dbName,
+            60,
+            /** @type {import('database').StructureDefinition<import('dictionary-database').ObjectStoreName>[]} */
+            ([
+                /** @type {import('database').StructureDefinition<import('dictionary-database').ObjectStoreName>} */
+                ({
+                    version: 20,
+                    stores: {
+                        terms: {
+                            primaryKey: {keyPath: 'id', autoIncrement: true},
+                            indices: ['dictionary', 'expression', 'reading']
+                        },
+                        kanji: {
+                            primaryKey: {autoIncrement: true},
+                            indices: ['dictionary', 'character']
+                        },
+                        tagMeta: {
+                            primaryKey: {autoIncrement: true},
+                            indices: ['dictionary']
+                        },
+                        dictionaries: {
+                            primaryKey: {autoIncrement: true},
+                            indices: ['title', 'version']
+                        }
+                    }
+                }),
+                {
+                    version: 30,
+                    stores: {
+                        termMeta: {
+                            primaryKey: {autoIncrement: true},
+                            indices: ['dictionary', 'expression']
+                        },
+                        kanjiMeta: {
+                            primaryKey: {autoIncrement: true},
+                            indices: ['dictionary', 'character']
+                        },
+                        tagMeta: {
+                            primaryKey: {autoIncrement: true},
+                            indices: ['dictionary', 'name']
+                        }
+                    }
+                },
+                {
+                    version: 40,
+                    stores: {
+                        terms: {
+                            primaryKey: {keyPath: 'id', autoIncrement: true},
+                            indices: ['dictionary', 'expression', 'reading', 'sequence']
+                        }
+                    }
+                },
+                {
+                    version: 50,
+                    stores: {
+                        terms: {
+                            primaryKey: {keyPath: 'id', autoIncrement: true},
+                            indices: ['dictionary', 'expression', 'reading', 'sequence', 'expressionReverse', 'readingReverse']
+                        }
+                    }
+                },
+                {
+                    version: 60,
+                    stores: {
+                        media: {
+                            primaryKey: {keyPath: 'id', autoIncrement: true},
+                            indices: ['dictionary', 'path']
+                        }
+                    }
+                }
+            ])
+        );
+    }
+
+    /** */
+    async close() {
+        this._db.close();
+    }
+
+    /**
+     * @returns {boolean}
+     */
+    isPrepared() {
+        return this._db.isOpen();
+    }
+
+    /**
+     * @returns {Promise<boolean>}
+     */
+    async purge() {
+        if (this._db.isOpening()) {
+            throw new Error('Cannot purge database while opening');
+        }
+        if (this._db.isOpen()) {
+            this._db.close();
+        }
+        let result = false;
+        try {
+            await Database.deleteDatabase(this._dbName);
+            result = true;
+        } catch (e) {
+            log.error(e);
+        }
+        await this.prepare();
+        return result;
+    }
+
+    /**
+     * @param {string} dictionaryName
+     * @param {number} progressRate
+     * @param {import('dictionary-database').DeleteDictionaryProgressCallback} onProgress
+     */
+    async deleteDictionary(dictionaryName, progressRate, onProgress) {
+        /** @type {[objectStoreName: import('dictionary-database').ObjectStoreName, key: string][][]} */
+        const targetGroups = [
+            [
+                ['kanji', 'dictionary'],
+                ['kanjiMeta', 'dictionary'],
+                ['terms', 'dictionary'],
+                ['termMeta', 'dictionary'],
+                ['tagMeta', 'dictionary'],
+                ['media', 'dictionary']
+            ],
+            [
+                ['dictionaries', 'title']
+            ]
+        ];
+
+        let storeCount = 0;
+        for (const targets of targetGroups) {
+            storeCount += targets.length;
+        }
+
+        /** @type {import('dictionary-database').DeleteDictionaryProgressData} */
+        const progressData = {
+            count: 0,
+            processed: 0,
+            storeCount,
+            storesProcesed: 0
+        };
+
+        /**
+         * @param {IDBValidKey[]} keys
+         * @returns {IDBValidKey[]}
+         */
+        const filterKeys = (keys) => {
+            ++progressData.storesProcesed;
+            progressData.count += keys.length;
+            onProgress(progressData);
+            return keys;
+        };
+        const onProgressWrapper = () => {
+            const processed = progressData.processed + 1;
+            progressData.processed = processed;
+            if ((processed % progressRate) === 0 || processed === progressData.count) {
+                onProgress(progressData);
+            }
+        };
+
+        for (const targets of targetGroups) {
+            const promises = [];
+            for (const [objectStoreName, indexName] of targets) {
+                const query = IDBKeyRange.only(dictionaryName);
+                const promise = this._db.bulkDelete(objectStoreName, indexName, query, filterKeys, onProgressWrapper);
+                promises.push(promise);
+            }
+            await Promise.all(promises);
+        }
+    }
+
+    /**
+     * @param {string[]} termList
+     * @param {import('dictionary-database').DictionarySet} dictionaries
+     * @param {import('dictionary-database').MatchType} matchType
+     * @returns {Promise<import('dictionary-database').TermEntry[]>}
+     */
+    findTermsBulk(termList, dictionaries, matchType) {
+        const visited = new Set();
+        /** @type {import('dictionary-database').FindPredicate<string, import('dictionary-database').DatabaseTermEntryWithId>} */
+        const predicate = (row) => {
+            if (!dictionaries.has(row.dictionary)) { return false; }
+            const {id} = row;
+            if (visited.has(id)) { return false; }
+            visited.add(id);
+            return true;
+        };
+
+        const indexNames = (matchType === 'suffix') ? ['expressionReverse', 'readingReverse'] : ['expression', 'reading'];
+
+        let createQuery = this._createOnlyQuery1;
+        switch (matchType) {
+            case 'prefix':
+                createQuery = this._createBoundQuery1;
+                break;
+            case 'suffix':
+                createQuery = this._createBoundQuery2;
+                break;
+        }
+
+        const createResult = this._createTermGeneric.bind(this, matchType);
+
+        return this._findMultiBulk('terms', indexNames, termList, createQuery, predicate, createResult);
+    }
+
+    /**
+     * @param {import('dictionary-database').TermExactRequest[]} termList
+     * @param {import('dictionary-database').DictionarySet} dictionaries
+     * @returns {Promise<import('dictionary-database').TermEntry[]>}
+     */
+    findTermsExactBulk(termList, dictionaries) {
+        /** @type {import('dictionary-database').FindPredicate<import('dictionary-database').TermExactRequest, import('dictionary-database').DatabaseTermEntry>} */
+        const predicate = (row, item) => (row.reading === item.reading && dictionaries.has(row.dictionary));
+        return this._findMultiBulk('terms', ['expression'], termList, this._createOnlyQuery3, predicate, this._createTermBind1);
+    }
+
+    /**
+     * @param {import('dictionary-database').DictionaryAndQueryRequest[]} items
+     * @returns {Promise<import('dictionary-database').TermEntry[]>}
+     */
+    findTermsBySequenceBulk(items) {
+        /** @type {import('dictionary-database').FindPredicate<import('dictionary-database').DictionaryAndQueryRequest, import('dictionary-database').DatabaseTermEntry>} */
+        const predicate = (row, item) => (row.dictionary === item.dictionary);
+        return this._findMultiBulk('terms', ['sequence'], items, this._createOnlyQuery2, predicate, this._createTermBind2);
+    }
+
+    /**
+     * @param {string[]} termList
+     * @param {import('dictionary-database').DictionarySet} dictionaries
+     * @returns {Promise<import('dictionary-database').TermMeta[]>}
+     */
+    findTermMetaBulk(termList, dictionaries) {
+        /** @type {import('dictionary-database').FindPredicate<string, import('dictionary-database').DatabaseTermMeta>} */
+        const predicate = (row) => dictionaries.has(row.dictionary);
+        return this._findMultiBulk('termMeta', ['expression'], termList, this._createOnlyQuery1, predicate, this._createTermMetaBind);
+    }
+
+    /**
+     * @param {string[]} kanjiList
+     * @param {import('dictionary-database').DictionarySet} dictionaries
+     * @returns {Promise<import('dictionary-database').KanjiEntry[]>}
+     */
+    findKanjiBulk(kanjiList, dictionaries) {
+        /** @type {import('dictionary-database').FindPredicate<string, import('dictionary-database').DatabaseKanjiEntry>} */
+        const predicate = (row) => dictionaries.has(row.dictionary);
+        return this._findMultiBulk('kanji', ['character'], kanjiList, this._createOnlyQuery1, predicate, this._createKanjiBind);
+    }
+
+    /**
+     * @param {string[]} kanjiList
+     * @param {import('dictionary-database').DictionarySet} dictionaries
+     * @returns {Promise<import('dictionary-database').KanjiMeta[]>}
+     */
+    findKanjiMetaBulk(kanjiList, dictionaries) {
+        /** @type {import('dictionary-database').FindPredicate<string, import('dictionary-database').DatabaseKanjiMeta>} */
+        const predicate = (row) => dictionaries.has(row.dictionary);
+        return this._findMultiBulk('kanjiMeta', ['character'], kanjiList, this._createOnlyQuery1, predicate, this._createKanjiMetaBind);
+    }
+
+    /**
+     * @param {import('dictionary-database').DictionaryAndQueryRequest[]} items
+     * @returns {Promise<(import('dictionary-database').Tag|undefined)[]>}
+     */
+    findTagMetaBulk(items) {
+        /** @type {import('dictionary-database').FindPredicate<import('dictionary-database').DictionaryAndQueryRequest, import('dictionary-database').Tag>} */
+        const predicate = (row, item) => (row.dictionary === item.dictionary);
+        return this._findFirstBulk('tagMeta', 'name', items, this._createOnlyQuery2, predicate);
+    }
+
+    /**
+     * @param {string} name
+     * @param {string} dictionary
+     * @returns {Promise<?import('dictionary-database').Tag>}
+     */
+    findTagForTitle(name, dictionary) {
+        const query = IDBKeyRange.only(name);
+        return this._db.find('tagMeta', 'name', query, (row) => (/** @type {import('dictionary-database').Tag} */ (row).dictionary === dictionary), null, null);
+    }
+
+    /**
+     * @param {import('dictionary-database').MediaRequest[]} items
+     * @returns {Promise<import('dictionary-database').Media[]>}
+     */
+    getMedia(items) {
+        /** @type {import('dictionary-database').FindPredicate<import('dictionary-database').MediaRequest, import('dictionary-database').MediaDataArrayBufferContent>} */
+        const predicate = (row, item) => (row.dictionary === item.dictionary);
+        return this._findMultiBulk('media', ['path'], items, this._createOnlyQuery4, predicate, this._createMediaBind);
+    }
+
+    /**
+     * @returns {Promise<import('dictionary-importer').Summary[]>}
+     */
+    getDictionaryInfo() {
+        return new Promise((resolve, reject) => {
+            const transaction = this._db.transaction(['dictionaries'], 'readonly');
+            const objectStore = transaction.objectStore('dictionaries');
+            this._db.getAll(objectStore, null, resolve, reject, null);
+        });
+    }
+
+    /**
+     * @param {string[]} dictionaryNames
+     * @param {boolean} getTotal
+     * @returns {Promise<import('dictionary-database').DictionaryCounts>}
+     */
+    getDictionaryCounts(dictionaryNames, getTotal) {
+        return new Promise((resolve, reject) => {
+            const targets = [
+                ['kanji', 'dictionary'],
+                ['kanjiMeta', 'dictionary'],
+                ['terms', 'dictionary'],
+                ['termMeta', 'dictionary'],
+                ['tagMeta', 'dictionary'],
+                ['media', 'dictionary']
+            ];
+            const objectStoreNames = targets.map(([objectStoreName]) => objectStoreName);
+            const transaction = this._db.transaction(objectStoreNames, 'readonly');
+            const databaseTargets = targets.map(([objectStoreName, indexName]) => {
+                const objectStore = transaction.objectStore(objectStoreName);
+                const index = objectStore.index(indexName);
+                return {objectStore, index};
+            });
+
+            /** @type {import('database').CountTarget[]} */
+            const countTargets = [];
+            if (getTotal) {
+                for (const {objectStore} of databaseTargets) {
+                    countTargets.push([objectStore, void 0]);
+                }
+            }
+            for (const dictionaryName of dictionaryNames) {
+                const query = IDBKeyRange.only(dictionaryName);
+                for (const {index} of databaseTargets) {
+                    countTargets.push([index, query]);
+                }
+            }
+
+            /**
+             * @param {number[]} results
+             */
+            const onCountComplete = (results) => {
+                const resultCount = results.length;
+                const targetCount = targets.length;
+                /** @type {import('dictionary-database').DictionaryCountGroup[]} */
+                const counts = [];
+                for (let i = 0; i < resultCount; i += targetCount) {
+                    /** @type {import('dictionary-database').DictionaryCountGroup} */
+                    const countGroup = {};
+                    for (let j = 0; j < targetCount; ++j) {
+                        countGroup[targets[j][0]] = results[i + j];
+                    }
+                    counts.push(countGroup);
+                }
+                const total = getTotal ? /** @type {import('dictionary-database').DictionaryCountGroup} */ (counts.shift()) : null;
+                resolve({total, counts});
+            };
+
+            this._db.bulkCount(countTargets, onCountComplete, reject);
+        });
+    }
+
+    /**
+     * @param {string} title
+     * @returns {Promise<boolean>}
+     */
+    async dictionaryExists(title) {
+        const query = IDBKeyRange.only(title);
+        const result = await this._db.find('dictionaries', 'title', query, null, null, void 0);
+        return typeof result !== 'undefined';
+    }
+
+    /**
+     * @template {import('dictionary-database').ObjectStoreName} T
+     * @param {T} objectStoreName
+     * @param {import('dictionary-database').ObjectStoreData<T>[]} items
+     * @param {number} start
+     * @param {number} count
+     * @returns {Promise<void>}
+     */
+    bulkAdd(objectStoreName, items, start, count) {
+        return this._db.bulkAdd(objectStoreName, items, start, count);
+    }
+
+    // Private
+
+    /**
+     * @template [TRow=unknown]
+     * @template [TItem=unknown]
+     * @template [TResult=unknown]
+     * @param {import('dictionary-database').ObjectStoreName} objectStoreName
+     * @param {string[]} indexNames
+     * @param {TItem[]} items
+     * @param {import('dictionary-database').CreateQuery<TItem>} createQuery
+     * @param {import('dictionary-database').FindPredicate<TItem, TRow>} predicate
+     * @param {import('dictionary-database').CreateResult<TItem, TRow, TResult>} createResult
+     * @returns {Promise<TResult[]>}
+     */
+    _findMultiBulk(objectStoreName, indexNames, items, createQuery, predicate, createResult) {
+        return new Promise((resolve, reject) => {
+            const itemCount = items.length;
+            const indexCount = indexNames.length;
+            /** @type {TResult[]} */
+            const results = [];
+            if (itemCount === 0 || indexCount === 0) {
+                resolve(results);
+                return;
+            }
+
+            const transaction = this._db.transaction([objectStoreName], 'readonly');
+            const objectStore = transaction.objectStore(objectStoreName);
+            const indexList = [];
+            for (const indexName of indexNames) {
+                indexList.push(objectStore.index(indexName));
+            }
+            let completeCount = 0;
+            const requiredCompleteCount = itemCount * indexCount;
+            /**
+             * @param {TRow[]} rows
+             * @param {import('dictionary-database').FindMultiBulkData<TItem>} data
+             */
+            const onGetAll = (rows, data) => {
+                for (const row of rows) {
+                    if (predicate(row, data.item)) {
+                        results.push(createResult(row, data));
+                    }
+                }
+                if (++completeCount >= requiredCompleteCount) {
+                    resolve(results);
+                }
+            };
+            for (let i = 0; i < itemCount; ++i) {
+                const item = items[i];
+                const query = createQuery(item);
+                for (let j = 0; j < indexCount; ++j) {
+                    /** @type {import('dictionary-database').FindMultiBulkData<TItem>} */
+                    const data = {item, itemIndex: i, indexIndex: j};
+                    this._db.getAll(indexList[j], query, onGetAll, reject, data);
+                }
+            }
+        });
+    }
+
+    /**
+     * @template [TRow=unknown]
+     * @template [TItem=unknown]
+     * @param {import('dictionary-database').ObjectStoreName} objectStoreName
+     * @param {string} indexName
+     * @param {TItem[]} items
+     * @param {import('dictionary-database').CreateQuery<TItem>} createQuery
+     * @param {import('dictionary-database').FindPredicate<TItem, TRow>} predicate
+     * @returns {Promise<(TRow|undefined)[]>}
+     */
+    _findFirstBulk(objectStoreName, indexName, items, createQuery, predicate) {
+        return new Promise((resolve, reject) => {
+            const itemCount = items.length;
+            /** @type {(TRow|undefined)[]} */
+            const results = new Array(itemCount);
+            if (itemCount === 0) {
+                resolve(results);
+                return;
+            }
+
+            const transaction = this._db.transaction([objectStoreName], 'readonly');
+            const objectStore = transaction.objectStore(objectStoreName);
+            const index = objectStore.index(indexName);
+            let completeCount = 0;
+            /**
+             * @param {TRow|undefined} row
+             * @param {number} itemIndex
+             */
+            const onFind = (row, itemIndex) => {
+                results[itemIndex] = row;
+                if (++completeCount >= itemCount) {
+                    resolve(results);
+                }
+            };
+            for (let i = 0; i < itemCount; ++i) {
+                const item = items[i];
+                const query = createQuery(item);
+                this._db.findFirst(index, query, onFind, reject, i, predicate, item, void 0);
+            }
+        });
+    }
+
+    /**
+     * @param {import('dictionary-database').MatchType} matchType
+     * @param {import('dictionary-database').DatabaseTermEntryWithId} row
+     * @param {import('dictionary-database').FindMultiBulkData<string>} data
+     * @returns {import('dictionary-database').TermEntry}
+     */
+    _createTermGeneric(matchType, row, data) {
+        const matchSourceIsTerm = (data.indexIndex === 0);
+        const matchSource = (matchSourceIsTerm ? 'term' : 'reading');
+        if ((matchSourceIsTerm ? row.expression : row.reading) === data.item) {
+            matchType = 'exact';
+        }
+        return this._createTerm(matchSource, matchType, row, data.itemIndex);
+    }
+
+    /**
+     * @param {import('dictionary-database').DatabaseTermEntryWithId} row
+     * @param {import('dictionary-database').FindMultiBulkData<import('dictionary-database').TermExactRequest>} data
+     * @returns {import('dictionary-database').TermEntry}
+     */
+    _createTermExact(row, data) {
+        return this._createTerm('term', 'exact', row, data.itemIndex);
+    }
+
+    /**
+     * @param {import('dictionary-database').DatabaseTermEntryWithId} row
+     * @param {import('dictionary-database').FindMultiBulkData<import('dictionary-database').DictionaryAndQueryRequest>} data
+     * @returns {import('dictionary-database').TermEntry}
+     */
+    _createTermSequenceExact(row, data) {
+        return this._createTerm('sequence', 'exact', row, data.itemIndex);
+    }
+
+    /**
+     * @param {import('dictionary-database').MatchSource} matchSource
+     * @param {import('dictionary-database').MatchType} matchType
+     * @param {import('dictionary-database').DatabaseTermEntryWithId} row
+     * @param {number} index
+     * @returns {import('dictionary-database').TermEntry}
+     */
+    _createTerm(matchSource, matchType, row, index) {
+        const {sequence} = row;
+        return {
+            index,
+            matchType,
+            matchSource,
+            term: row.expression,
+            reading: row.reading,
+            definitionTags: this._splitField(row.definitionTags || row.tags),
+            termTags: this._splitField(row.termTags),
+            rules: this._splitField(row.rules),
+            definitions: row.glossary,
+            score: row.score,
+            dictionary: row.dictionary,
+            id: row.id,
+            sequence: typeof sequence === 'number' ? sequence : -1
+        };
+    }
+
+    /**
+     * @param {import('dictionary-database').DatabaseKanjiEntry} row
+     * @param {import('dictionary-database').FindMultiBulkData<string>} data
+     * @returns {import('dictionary-database').KanjiEntry}
+     */
+    _createKanji(row, {itemIndex: index}) {
+        const {stats} = row;
+        return {
+            index,
+            character: row.character,
+            onyomi: this._splitField(row.onyomi),
+            kunyomi: this._splitField(row.kunyomi),
+            tags: this._splitField(row.tags),
+            definitions: row.meanings,
+            stats: typeof stats === 'object' && stats !== null ? stats : {},
+            dictionary: row.dictionary
+        };
+    }
+
+    /**
+     * @param {import('dictionary-database').DatabaseTermMeta} row
+     * @param {import('dictionary-database').FindMultiBulkData<string>} data
+     * @returns {import('dictionary-database').TermMeta}
+     * @throws {Error}
+     */
+    _createTermMeta({expression: term, mode, data, dictionary}, {itemIndex: index}) {
+        switch (mode) {
+            case 'freq':
+                return {index, term, mode, data, dictionary};
+            case 'pitch':
+                return {index, term, mode, data, dictionary};
+            default:
+                throw new Error(`Unknown mode: ${mode}`);
+        }
+    }
+
+    /**
+     * @param {import('dictionary-database').DatabaseKanjiMeta} row
+     * @param {import('dictionary-database').FindMultiBulkData<string>} data
+     * @returns {import('dictionary-database').KanjiMeta}
+     */
+    _createKanjiMeta({character, mode, data, dictionary}, {itemIndex: index}) {
+        return {index, character, mode, data, dictionary};
+    }
+
+    /**
+     * @param {import('dictionary-database').MediaDataArrayBufferContent} row
+     * @param {import('dictionary-database').FindMultiBulkData<import('dictionary-database').MediaRequest>} data
+     * @returns {import('dictionary-database').Media}
+     */
+    _createMedia(row, {itemIndex: index}) {
+        const {dictionary, path, mediaType, width, height, content} = row;
+        return {index, dictionary, path, mediaType, width, height, content};
+    }
+
+    /**
+     * @param {unknown} field
+     * @returns {string[]}
+     */
+    _splitField(field) {
+        return typeof field === 'string' && field.length > 0 ? field.split(' ') : [];
+    }
+}
diff --git a/ext/js/dictionary/dictionary-importer-media-loader.js b/ext/js/dictionary/dictionary-importer-media-loader.js
new file mode 100644
index 00000000..a5857dce
--- /dev/null
+++ b/ext/js/dictionary/dictionary-importer-media-loader.js
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2021-2022  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/>.
+ */
+
+import {EventListenerCollection} from '../core.js';
+
+/**
+ * Class used for loading and validating media during the dictionary import process.
+ */
+export class DictionaryImporterMediaLoader {
+    /** @type {import('dictionary-importer-media-loader').GetImageDetailsFunction} */
+    getImageDetails(content, mediaType, transfer) {
+        return new Promise((resolve, reject) => {
+            const image = new Image();
+            const eventListeners = new EventListenerCollection();
+            const cleanup = () => {
+                image.removeAttribute('src');
+                URL.revokeObjectURL(url);
+                eventListeners.removeAllEventListeners();
+            };
+            eventListeners.addEventListener(image, 'load', () => {
+                const {naturalWidth: width, naturalHeight: height} = image;
+                if (Array.isArray(transfer)) { transfer.push(content); }
+                cleanup();
+                resolve({content, width, height});
+            }, false);
+            eventListeners.addEventListener(image, 'error', () => {
+                cleanup();
+                reject(new Error('Image failed to load'));
+            }, false);
+            const blob = new Blob([content], {type: mediaType});
+            const url = URL.createObjectURL(blob);
+            image.src = url;
+        });
+    }
+}
diff --git a/ext/js/dictionary/dictionary-importer.js b/ext/js/dictionary/dictionary-importer.js
new file mode 100644
index 00000000..2c0c7e9c
--- /dev/null
+++ b/ext/js/dictionary/dictionary-importer.js
@@ -0,0 +1,796 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2020-2022  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/>.
+ */
+
+import * as ajvSchemas0 from '../../lib/validate-schemas.js';
+import {
+    BlobWriter as BlobWriter0,
+    TextWriter as TextWriter0,
+    Uint8ArrayReader as Uint8ArrayReader0,
+    ZipReader as ZipReader0,
+    configure
+} from '../../lib/zip.js';
+import {stringReverse} from '../core.js';
+import {ExtensionError} from '../core/extension-error.js';
+import {parseJson} from '../core/json.js';
+import {MediaUtil} from '../media/media-util.js';
+
+const ajvSchemas = /** @type {import('dictionary-importer').CompiledSchemaValidators} */ (/** @type {unknown} */ (ajvSchemas0));
+const BlobWriter = /** @type {typeof import('@zip.js/zip.js').BlobWriter} */ (/** @type {unknown} */ (BlobWriter0));
+const TextWriter = /** @type {typeof import('@zip.js/zip.js').TextWriter} */ (/** @type {unknown} */ (TextWriter0));
+const Uint8ArrayReader = /** @type {typeof import('@zip.js/zip.js').Uint8ArrayReader} */ (/** @type {unknown} */ (Uint8ArrayReader0));
+const ZipReader = /** @type {typeof import('@zip.js/zip.js').ZipReader} */ (/** @type {unknown} */ (ZipReader0));
+
+export class DictionaryImporter {
+    /**
+     * @param {import('dictionary-importer-media-loader').GenericMediaLoader} mediaLoader
+     * @param {import('dictionary-importer').OnProgressCallback} [onProgress]
+     */
+    constructor(mediaLoader, onProgress) {
+        /** @type {import('dictionary-importer-media-loader').GenericMediaLoader} */
+        this._mediaLoader = mediaLoader;
+        /** @type {import('dictionary-importer').OnProgressCallback} */
+        this._onProgress = typeof onProgress === 'function' ? onProgress : () => {};
+        /** @type {import('dictionary-importer').ProgressData} */
+        this._progressData = this._createProgressData();
+    }
+
+    /**
+     * @param {import('./dictionary-database.js').DictionaryDatabase} dictionaryDatabase
+     * @param {ArrayBuffer} archiveContent
+     * @param {import('dictionary-importer').ImportDetails} details
+     * @returns {Promise<import('dictionary-importer').ImportResult>}
+     */
+    async importDictionary(dictionaryDatabase, archiveContent, details) {
+        if (!dictionaryDatabase) {
+            throw new Error('Invalid database');
+        }
+        if (!dictionaryDatabase.isPrepared()) {
+            throw new Error('Database is not ready');
+        }
+
+        this._progressReset();
+
+        configure({
+            workerScripts: {
+                deflate: ['../../lib/z-worker.js'],
+                inflate: ['../../lib/z-worker.js']
+            }
+        });
+
+        // Read archive
+        const zipFileReader = new Uint8ArrayReader(new Uint8Array(archiveContent));
+        const zipReader = new ZipReader(zipFileReader);
+        const zipEntries = await zipReader.getEntries();
+        /** @type {import('dictionary-importer').ArchiveFileMap} */
+        const fileMap = new Map();
+        for (const entry of zipEntries) {
+            fileMap.set(entry.filename, entry);
+        }
+        // Read and validate index
+        const indexFileName = 'index.json';
+        const indexFile = fileMap.get(indexFileName);
+        if (typeof indexFile === 'undefined') {
+            throw new Error('No dictionary index found in archive');
+        }
+        const indexFile2 = /** @type {import('@zip.js/zip.js').Entry} */ (indexFile);
+
+        const indexContent = await this._getData(indexFile2, new TextWriter());
+        const index = /** @type {import('dictionary-data').Index} */ (parseJson(indexContent));
+
+        if (!ajvSchemas.dictionaryIndex(index)) {
+            throw this._formatAjvSchemaError(ajvSchemas.dictionaryIndex, indexFileName);
+        }
+
+        const dictionaryTitle = index.title;
+        const version = typeof index.format === 'number' ? index.format : index.version;
+
+        if (typeof version !== 'number' || !dictionaryTitle || !index.revision) {
+            throw new Error('Unrecognized dictionary format');
+        }
+
+        // Verify database is not already imported
+        if (await dictionaryDatabase.dictionaryExists(dictionaryTitle)) {
+            throw new Error('Dictionary is already imported');
+        }
+
+        // Load schemas
+        this._progressNextStep(0);
+        const dataBankSchemas = this._getDataBankSchemas(version);
+
+        // Files
+        /** @type {import('dictionary-importer').QueryDetails} */
+        const queryDetails = new Map([
+            ['termFiles', /^term_bank_(\d+)\.json$/],
+            ['termMetaFiles', /^term_meta_bank_(\d+)\.json$/],
+            ['kanjiFiles', /^kanji_bank_(\d+)\.json$/],
+            ['kanjiMetaFiles', /^kanji_meta_bank_(\d+)\.json$/],
+            ['tagFiles', /^tag_bank_(\d+)\.json$/]
+        ]);
+        const {termFiles, termMetaFiles, kanjiFiles, kanjiMetaFiles, tagFiles} = Object.fromEntries(this._getArchiveFiles(fileMap, queryDetails));
+
+        // Load data
+        this._progressNextStep(termFiles.length + termMetaFiles.length + kanjiFiles.length + kanjiMetaFiles.length + tagFiles.length);
+        const termList = await (
+            version === 1 ?
+            this._readFileSequence(termFiles, this._convertTermBankEntryV1.bind(this), dataBankSchemas[0], dictionaryTitle) :
+            this._readFileSequence(termFiles, this._convertTermBankEntryV3.bind(this), dataBankSchemas[0], dictionaryTitle)
+        );
+        const termMetaList = await this._readFileSequence(termMetaFiles, this._convertTermMetaBankEntry.bind(this), dataBankSchemas[1], dictionaryTitle);
+        const kanjiList = await (
+            version === 1 ?
+            this._readFileSequence(kanjiFiles, this._convertKanjiBankEntryV1.bind(this), dataBankSchemas[2], dictionaryTitle) :
+            this._readFileSequence(kanjiFiles, this._convertKanjiBankEntryV3.bind(this), dataBankSchemas[2], dictionaryTitle)
+        );
+        const kanjiMetaList = await this._readFileSequence(kanjiMetaFiles, this._convertKanjiMetaBankEntry.bind(this), dataBankSchemas[3], dictionaryTitle);
+        const tagList = await this._readFileSequence(tagFiles, this._convertTagBankEntry.bind(this), dataBankSchemas[4], dictionaryTitle);
+        this._addOldIndexTags(index, tagList, dictionaryTitle);
+
+        // Prefix wildcard support
+        const prefixWildcardsSupported = !!details.prefixWildcardsSupported;
+        if (prefixWildcardsSupported) {
+            for (const entry of termList) {
+                entry.expressionReverse = stringReverse(entry.expression);
+                entry.readingReverse = stringReverse(entry.reading);
+            }
+        }
+
+        // Extended data support
+        this._progressNextStep(termList.length);
+        const formatProgressInterval = 1000;
+        /** @type {import('dictionary-importer').ImportRequirement[]} */
+        const requirements = [];
+        for (let i = 0, ii = termList.length; i < ii; ++i) {
+            const entry = termList[i];
+            const glossaryList = entry.glossary;
+            for (let j = 0, jj = glossaryList.length; j < jj; ++j) {
+                const glossary = glossaryList[j];
+                if (typeof glossary !== 'object' || glossary === null) { continue; }
+                glossaryList[j] = this._formatDictionaryTermGlossaryObject(glossary, entry, requirements);
+            }
+            if ((i % formatProgressInterval) === 0) {
+                this._progressData.index = i;
+                this._progress();
+            }
+        }
+        this._progress();
+
+        // Async requirements
+        this._progressNextStep(requirements.length);
+        const {media} = await this._resolveAsyncRequirements(requirements, fileMap);
+
+        // Add dictionary descriptor
+        this._progressNextStep(termList.length + termMetaList.length + kanjiList.length + kanjiMetaList.length + tagList.length + media.length);
+
+        /** @type {import('dictionary-importer').SummaryCounts} */
+        const counts = {
+            terms: {total: termList.length},
+            termMeta: this._getMetaCounts(termMetaList),
+            kanji: {total: kanjiList.length},
+            kanjiMeta: this._getMetaCounts(kanjiMetaList),
+            tagMeta: {total: tagList.length},
+            media: {total: media.length}
+        };
+        const summary = this._createSummary(dictionaryTitle, version, index, {prefixWildcardsSupported, counts});
+        dictionaryDatabase.bulkAdd('dictionaries', [summary], 0, 1);
+
+        // Add data
+        /** @type {Error[]} */
+        const errors = [];
+        const maxTransactionLength = 1000;
+
+        /**
+         * @template {import('dictionary-database').ObjectStoreName} T
+         * @param {T} objectStoreName
+         * @param {import('dictionary-database').ObjectStoreData<T>[]} entries
+         */
+        const bulkAdd = async (objectStoreName, entries) => {
+            const ii = entries.length;
+            for (let i = 0; i < ii; i += maxTransactionLength) {
+                const count = Math.min(maxTransactionLength, ii - i);
+
+                try {
+                    await dictionaryDatabase.bulkAdd(objectStoreName, entries, i, count);
+                } catch (e) {
+                    errors.push(e instanceof Error ? e : new Error(`${e}`));
+                }
+
+                this._progressData.index += count;
+                this._progress();
+            }
+        };
+
+        await bulkAdd('terms', termList);
+        await bulkAdd('termMeta', termMetaList);
+        await bulkAdd('kanji', kanjiList);
+        await bulkAdd('kanjiMeta', kanjiMetaList);
+        await bulkAdd('tagMeta', tagList);
+        await bulkAdd('media', media);
+
+        this._progress();
+
+        return {result: summary, errors};
+    }
+
+    /**
+     * @returns {import('dictionary-importer').ProgressData}
+     */
+    _createProgressData() {
+        return {
+            stepIndex: 0,
+            stepCount: 6,
+            index: 0,
+            count: 0
+        };
+    }
+
+    /** */
+    _progressReset() {
+        this._progressData = this._createProgressData();
+        this._progress();
+    }
+
+    /**
+     * @param {number} count
+     */
+    _progressNextStep(count) {
+        ++this._progressData.stepIndex;
+        this._progressData.index = 0;
+        this._progressData.count = count;
+        this._progress();
+    }
+
+    /** */
+    _progress() {
+        this._onProgress(this._progressData);
+    }
+
+    /**
+     * @param {string} dictionaryTitle
+     * @param {number} version
+     * @param {import('dictionary-data').Index} index
+     * @param {{prefixWildcardsSupported: boolean, counts: import('dictionary-importer').SummaryCounts}} details
+     * @returns {import('dictionary-importer').Summary}
+     */
+    _createSummary(dictionaryTitle, version, index, details) {
+        const indexSequenced = index.sequenced;
+        const {prefixWildcardsSupported, counts} = details;
+
+        /** @type {import('dictionary-importer').Summary} */
+        const summary = {
+            title: dictionaryTitle,
+            revision: index.revision,
+            sequenced: typeof indexSequenced === 'boolean' && indexSequenced,
+            version,
+            importDate: Date.now(),
+            prefixWildcardsSupported,
+            counts
+        };
+
+        const {author, url, description, attribution, frequencyMode} = index;
+        if (typeof author === 'string') { summary.author = author; }
+        if (typeof url === 'string') { summary.url = url; }
+        if (typeof description === 'string') { summary.description = description; }
+        if (typeof attribution === 'string') { summary.attribution = attribution; }
+        if (typeof frequencyMode === 'string') { summary.frequencyMode = frequencyMode; }
+
+        return summary;
+    }
+
+    /**
+     * @param {import('ajv').ValidateFunction} schema
+     * @param {string} fileName
+     * @returns {ExtensionError}
+     */
+    _formatAjvSchemaError(schema, fileName) {
+        const e2 = new ExtensionError(`Dictionary has invalid data in '${fileName}'`);
+        e2.data = schema.errors;
+
+        return e2;
+    }
+
+    /**
+     * @param {number} version
+     * @returns {import('dictionary-importer').CompiledSchemaNameArray}
+     */
+    _getDataBankSchemas(version) {
+        const termBank = (
+            version === 1 ?
+            'dictionaryTermBankV1' :
+            'dictionaryTermBankV3'
+        );
+        const termMetaBank = 'dictionaryTermMetaBankV3';
+        const kanjiBank = (
+            version === 1 ?
+            'dictionaryKanjiBankV1' :
+            'dictionaryKanjiBankV3'
+        );
+        const kanjiMetaBank = 'dictionaryKanjiMetaBankV3';
+        const tagBank = 'dictionaryTagBankV3';
+
+        return [termBank, termMetaBank, kanjiBank, kanjiMetaBank, tagBank];
+    }
+
+    /**
+     * @param {import('dictionary-data').TermGlossaryText|import('dictionary-data').TermGlossaryImage|import('dictionary-data').TermGlossaryStructuredContent} data
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     * @param {import('dictionary-importer').ImportRequirement[]} requirements
+     * @returns {import('dictionary-data').TermGlossary}
+     * @throws {Error}
+     */
+    _formatDictionaryTermGlossaryObject(data, entry, requirements) {
+        switch (data.type) {
+            case 'text':
+                return data.text;
+            case 'image':
+                return this._formatDictionaryTermGlossaryImage(data, entry, requirements);
+            case 'structured-content':
+                return this._formatStructuredContent(data, entry, requirements);
+            default:
+                throw new Error(`Unhandled data type: ${/** @type {import('core').SerializableObject} */ (data).type}`);
+        }
+    }
+
+    /**
+     * @param {import('dictionary-data').TermGlossaryImage} data
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     * @param {import('dictionary-importer').ImportRequirement[]} requirements
+     * @returns {import('dictionary-data').TermGlossaryImage}
+     */
+    _formatDictionaryTermGlossaryImage(data, entry, requirements) {
+        /** @type {import('dictionary-data').TermGlossaryImage} */
+        const target = {
+            type: 'image',
+            path: '' // Will be populated during requirement resolution
+        };
+        requirements.push({type: 'image', target, source: data, entry});
+        return target;
+    }
+
+    /**
+     * @param {import('dictionary-data').TermGlossaryStructuredContent} data
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     * @param {import('dictionary-importer').ImportRequirement[]} requirements
+     * @returns {import('dictionary-data').TermGlossaryStructuredContent}
+     */
+    _formatStructuredContent(data, entry, requirements) {
+        const content = this._prepareStructuredContent(data.content, entry, requirements);
+        return {
+            type: 'structured-content',
+            content
+        };
+    }
+
+    /**
+     * @param {import('structured-content').Content} content
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     * @param {import('dictionary-importer').ImportRequirement[]} requirements
+     * @returns {import('structured-content').Content}
+     */
+    _prepareStructuredContent(content, entry, requirements) {
+        if (typeof content === 'string' || !(typeof content === 'object' && content !== null)) {
+            return content;
+        }
+        if (Array.isArray(content)) {
+            for (let i = 0, ii = content.length; i < ii; ++i) {
+                content[i] = this._prepareStructuredContent(content[i], entry, requirements);
+            }
+            return content;
+        }
+        const {tag} = content;
+        switch (tag) {
+            case 'img':
+                return this._prepareStructuredContentImage(content, entry, requirements);
+        }
+        const childContent = content.content;
+        if (typeof childContent !== 'undefined') {
+            content.content = this._prepareStructuredContent(childContent, entry, requirements);
+        }
+        return content;
+    }
+
+    /**
+     * @param {import('structured-content').ImageElement} content
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     * @param {import('dictionary-importer').ImportRequirement[]} requirements
+     * @returns {import('structured-content').ImageElement}
+     */
+    _prepareStructuredContentImage(content, entry, requirements) {
+        /** @type {import('structured-content').ImageElement} */
+        const target = {
+            tag: 'img',
+            path: '' // Will be populated during requirement resolution
+        };
+        requirements.push({type: 'structured-content-image', target, source: content, entry});
+        return target;
+    }
+
+    /**
+     * @param {import('dictionary-importer').ImportRequirement[]} requirements
+     * @param {import('dictionary-importer').ArchiveFileMap} fileMap
+     * @returns {Promise<{media: import('dictionary-database').MediaDataArrayBufferContent[]}>}
+     */
+    async _resolveAsyncRequirements(requirements, fileMap) {
+        /** @type {Map<string, import('dictionary-database').MediaDataArrayBufferContent>} */
+        const media = new Map();
+        /** @type {import('dictionary-importer').ImportRequirementContext} */
+        const context = {fileMap, media};
+
+        for (const requirement of requirements) {
+            await this._resolveAsyncRequirement(context, requirement);
+        }
+
+        return {
+            media: [...media.values()]
+        };
+    }
+
+    /**
+     * @param {import('dictionary-importer').ImportRequirementContext} context
+     * @param {import('dictionary-importer').ImportRequirement} requirement
+     */
+    async _resolveAsyncRequirement(context, requirement) {
+        switch (requirement.type) {
+            case 'image':
+                await this._resolveDictionaryTermGlossaryImage(
+                    context,
+                    requirement.target,
+                    requirement.source,
+                    requirement.entry
+                );
+                break;
+            case 'structured-content-image':
+                await this._resolveStructuredContentImage(
+                    context,
+                    requirement.target,
+                    requirement.source,
+                    requirement.entry
+                );
+                break;
+            default:
+                return;
+        }
+        ++this._progressData.index;
+        this._progress();
+    }
+
+    /**
+     * @param {import('dictionary-importer').ImportRequirementContext} context
+     * @param {import('dictionary-data').TermGlossaryImage} target
+     * @param {import('dictionary-data').TermGlossaryImage} source
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     */
+    async _resolveDictionaryTermGlossaryImage(context, target, source, entry) {
+        await this._createImageData(context, target, source, entry);
+    }
+
+    /**
+     * @param {import('dictionary-importer').ImportRequirementContext} context
+     * @param {import('structured-content').ImageElement} target
+     * @param {import('structured-content').ImageElement} source
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     */
+    async _resolveStructuredContentImage(context, target, source, entry) {
+        const {verticalAlign, sizeUnits} = source;
+        await this._createImageData(context, target, source, entry);
+        if (typeof verticalAlign === 'string') { target.verticalAlign = verticalAlign; }
+        if (typeof sizeUnits === 'string') { target.sizeUnits = sizeUnits; }
+    }
+
+    /**
+     * @param {import('dictionary-importer').ImportRequirementContext} context
+     * @param {import('structured-content').ImageElementBase} target
+     * @param {import('structured-content').ImageElementBase} source
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     */
+    async _createImageData(context, target, source, entry) {
+        const {
+            path,
+            width: preferredWidth,
+            height: preferredHeight,
+            title,
+            alt,
+            description,
+            pixelated,
+            imageRendering,
+            appearance,
+            background,
+            collapsed,
+            collapsible
+        } = source;
+        const {width, height} = await this._getImageMedia(context, path, entry);
+        target.path = path;
+        target.width = width;
+        target.height = height;
+        if (typeof preferredWidth === 'number') { target.preferredWidth = preferredWidth; }
+        if (typeof preferredHeight === 'number') { target.preferredHeight = preferredHeight; }
+        if (typeof title === 'string') { target.title = title; }
+        if (typeof alt === 'string') { target.alt = alt; }
+        if (typeof description === 'string') { target.description = description; }
+        if (typeof pixelated === 'boolean') { target.pixelated = pixelated; }
+        if (typeof imageRendering === 'string') { target.imageRendering = imageRendering; }
+        if (typeof appearance === 'string') { target.appearance = appearance; }
+        if (typeof background === 'boolean') { target.background = background; }
+        if (typeof collapsed === 'boolean') { target.collapsed = collapsed; }
+        if (typeof collapsible === 'boolean') { target.collapsible = collapsible; }
+    }
+
+    /**
+     * @param {import('dictionary-importer').ImportRequirementContext} context
+     * @param {string} path
+     * @param {import('dictionary-database').DatabaseTermEntry} entry
+     * @returns {Promise<import('dictionary-database').MediaDataArrayBufferContent>}
+     */
+    async _getImageMedia(context, path, entry) {
+        const {media} = context;
+        const {dictionary} = entry;
+
+        /**
+         * @param {string} message
+         * @returns {Error}
+         */
+        const createError = (message) => {
+            const {expression, reading} = entry;
+            const readingSource = reading.length > 0 ? ` (${reading})` : '';
+            return new Error(`${message} at path ${JSON.stringify(path)} for ${expression}${readingSource} in ${dictionary}`);
+        };
+
+        // Check if already added
+        let mediaData = media.get(path);
+        if (typeof mediaData !== 'undefined') {
+            if (MediaUtil.getFileExtensionFromImageMediaType(mediaData.mediaType) === null) {
+                throw createError('Media file is not a valid image');
+            }
+            return mediaData;
+        }
+
+        // Find file in archive
+        const file = context.fileMap.get(path);
+        if (typeof file === 'undefined') {
+            throw createError('Could not find image');
+        }
+
+        // Load file content
+        let content = await (await this._getData(file, new BlobWriter())).arrayBuffer();
+
+        const mediaType = MediaUtil.getImageMediaTypeFromFileName(path);
+        if (mediaType === null) {
+            throw createError('Could not determine media type for image');
+        }
+
+        // Load image data
+        let width;
+        let height;
+        try {
+            ({content, width, height} = await this._mediaLoader.getImageDetails(content, mediaType));
+        } catch (e) {
+            throw createError('Could not load image');
+        }
+
+        // Create image data
+        mediaData = {
+            dictionary,
+            path,
+            mediaType,
+            width,
+            height,
+            content
+        };
+        media.set(path, mediaData);
+
+        return mediaData;
+    }
+
+    /**
+     * @param {import('dictionary-data').TermV1} entry
+     * @param {string} dictionary
+     * @returns {import('dictionary-database').DatabaseTermEntry}
+     */
+    _convertTermBankEntryV1(entry, dictionary) {
+        let [expression, reading, definitionTags, rules, score, ...glossary] = entry;
+        expression = this._normalizeTermOrReading(expression);
+        reading = this._normalizeTermOrReading(reading.length > 0 ? reading : expression);
+        return {expression, reading, definitionTags, rules, score, glossary, dictionary};
+    }
+
+    /**
+     * @param {import('dictionary-data').TermV3} entry
+     * @param {string} dictionary
+     * @returns {import('dictionary-database').DatabaseTermEntry}
+     */
+    _convertTermBankEntryV3(entry, dictionary) {
+        let [expression, reading, definitionTags, rules, score, glossary, sequence, termTags] = entry;
+        expression = this._normalizeTermOrReading(expression);
+        reading = this._normalizeTermOrReading(reading.length > 0 ? reading : expression);
+        return {expression, reading, definitionTags, rules, score, glossary, sequence, termTags, dictionary};
+    }
+
+    /**
+     * @param {import('dictionary-data').TermMeta} entry
+     * @param {string} dictionary
+     * @returns {import('dictionary-database').DatabaseTermMeta}
+     */
+    _convertTermMetaBankEntry(entry, dictionary) {
+        const [expression, mode, data] = entry;
+        return /** @type {import('dictionary-database').DatabaseTermMeta} */ ({expression, mode, data, dictionary});
+    }
+
+    /**
+     * @param {import('dictionary-data').KanjiV1} entry
+     * @param {string} dictionary
+     * @returns {import('dictionary-database').DatabaseKanjiEntry}
+     */
+    _convertKanjiBankEntryV1(entry, dictionary) {
+        const [character, onyomi, kunyomi, tags, ...meanings] = entry;
+        return {character, onyomi, kunyomi, tags, meanings, dictionary};
+    }
+
+    /**
+     * @param {import('dictionary-data').KanjiV3} entry
+     * @param {string} dictionary
+     * @returns {import('dictionary-database').DatabaseKanjiEntry}
+     */
+    _convertKanjiBankEntryV3(entry, dictionary) {
+        const [character, onyomi, kunyomi, tags, meanings, stats] = entry;
+        return {character, onyomi, kunyomi, tags, meanings, stats, dictionary};
+    }
+
+    /**
+     * @param {import('dictionary-data').KanjiMeta} entry
+     * @param {string} dictionary
+     * @returns {import('dictionary-database').DatabaseKanjiMeta}
+     */
+    _convertKanjiMetaBankEntry(entry, dictionary) {
+        const [character, mode, data] = entry;
+        return {character, mode, data, dictionary};
+    }
+
+    /**
+     * @param {import('dictionary-data').Tag} entry
+     * @param {string} dictionary
+     * @returns {import('dictionary-database').Tag}
+     */
+    _convertTagBankEntry(entry, dictionary) {
+        const [name, category, order, notes, score] = entry;
+        return {name, category, order, notes, score, dictionary};
+    }
+
+    /**
+     * @param {import('dictionary-data').Index} index
+     * @param {import('dictionary-database').Tag[]} results
+     * @param {string} dictionary
+     */
+    _addOldIndexTags(index, results, dictionary) {
+        const {tagMeta} = index;
+        if (typeof tagMeta !== 'object' || tagMeta === null) { return; }
+        for (const [name, value] of Object.entries(tagMeta)) {
+            const {category, order, notes, score} = value;
+            results.push({name, category, order, notes, score, dictionary});
+        }
+    }
+
+    /**
+     * @param {import('dictionary-importer').ArchiveFileMap} fileMap
+     * @param {import('dictionary-importer').QueryDetails} queryDetails
+     * @returns {import('dictionary-importer').QueryResult}
+     */
+    _getArchiveFiles(fileMap, queryDetails) {
+        /** @type {import('dictionary-importer').QueryResult} */
+        const results = new Map();
+        for (const [name, value] of fileMap.entries()) {
+            for (const [fileType, fileNameFormat] of queryDetails.entries()) {
+                let entries = results.get(fileType);
+                if (typeof entries === 'undefined') {
+                    entries = [];
+                    results.set(fileType, entries);
+                }
+
+                if (fileNameFormat.test(name)) {
+                    entries.push(value);
+                    break;
+                }
+            }
+        }
+        return results;
+    }
+
+    /**
+     * @template [TEntry=unknown]
+     * @template [TResult=unknown]
+     * @param {import('@zip.js/zip.js').Entry[]} files
+     * @param {(entry: TEntry, dictionaryTitle: string) => TResult} convertEntry
+     * @param {import('dictionary-importer').CompiledSchemaName} schemaName
+     * @param {string} dictionaryTitle
+     * @returns {Promise<TResult[]>}
+     */
+    async _readFileSequence(files, convertEntry, schemaName, dictionaryTitle) {
+        const progressData = this._progressData;
+        let startIndex = 0;
+
+        const results = [];
+        for (const file of files) {
+            const content = await this._getData(file, new TextWriter());
+            const entries = /** @type {unknown} */ (parseJson(content));
+
+            startIndex = progressData.index;
+            this._progress();
+
+            const schema = ajvSchemas[schemaName];
+            if (!schema(entries)) {
+                throw this._formatAjvSchemaError(schema, file.filename);
+            }
+
+            progressData.index = startIndex + 1;
+            this._progress();
+
+            if (Array.isArray(entries)) {
+                for (const entry of entries) {
+                    results.push(convertEntry(/** @type {TEntry} */ (entry), dictionaryTitle));
+                }
+            }
+        }
+        return results;
+    }
+
+    /**
+     * @param {import('dictionary-database').DatabaseTermMeta[]|import('dictionary-database').DatabaseKanjiMeta[]} metaList
+     * @returns {import('dictionary-importer').SummaryMetaCount}
+     */
+    _getMetaCounts(metaList) {
+        /** @type {Map<string, number>} */
+        const countsMap = new Map();
+        for (const {mode} of metaList) {
+            let count = countsMap.get(mode);
+            count = typeof count !== 'undefined' ? count + 1 : 1;
+            countsMap.set(mode, count);
+        }
+        /** @type {import('dictionary-importer').SummaryMetaCount} */
+        const counts = {total: metaList.length};
+        for (const [key, value] of countsMap.entries()) {
+            if (Object.prototype.hasOwnProperty.call(counts, key)) { continue; }
+            counts[key] = value;
+        }
+        return counts;
+    }
+
+    /**
+     * @param {string} text
+     * @returns {string}
+     */
+    _normalizeTermOrReading(text) {
+        // Note: this function should not perform String.normalize on the text,
+        // as it will normalize characters in an undesirable way.
+        // Thus, this function is currently a no-op.
+        // Example:
+        // - '\u9038'.normalize('NFC') => '\u9038' (逸)
+        // - '\ufa67'.normalize('NFC') => '\u9038' (逸 => 逸)
+        return text;
+    }
+
+    /**
+     * @template [T=unknown]
+     * @param {import('@zip.js/zip.js').Entry} entry
+     * @param {import('@zip.js/zip.js').Writer<T>|import('@zip.js/zip.js').WritableWriter} writer
+     * @returns {Promise<T>}
+     */
+    async _getData(entry, writer) {
+        if (typeof entry.getData === 'undefined') {
+            throw new Error(`Cannot read ${entry.filename}`);
+        }
+        return await entry.getData(writer);
+    }
+}
diff --git a/ext/js/dictionary/dictionary-worker-handler.js b/ext/js/dictionary/dictionary-worker-handler.js
new file mode 100644
index 00000000..9a724386
--- /dev/null
+++ b/ext/js/dictionary/dictionary-worker-handler.js
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2021-2022  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/>.
+ */
+
+import {ExtensionError} from '../core/extension-error.js';
+import {DictionaryDatabase} from './dictionary-database.js';
+import {DictionaryImporter} from './dictionary-importer.js';
+import {DictionaryWorkerMediaLoader} from './dictionary-worker-media-loader.js';
+
+export class DictionaryWorkerHandler {
+    constructor() {
+        /** @type {DictionaryWorkerMediaLoader} */
+        this._mediaLoader = new DictionaryWorkerMediaLoader();
+    }
+
+    /** */
+    prepare() {
+        self.addEventListener('message', this._onMessage.bind(this), false);
+    }
+
+    // Private
+
+    /**
+     * @param {MessageEvent<import('dictionary-worker-handler').Message>} event
+     */
+    _onMessage(event) {
+        const {action, params} = event.data;
+        switch (action) {
+            case 'importDictionary':
+                this._onMessageWithProgress(params, this._importDictionary.bind(this));
+                break;
+            case 'deleteDictionary':
+                this._onMessageWithProgress(params, this._deleteDictionary.bind(this));
+                break;
+            case 'getDictionaryCounts':
+                this._onMessageWithProgress(params, this._getDictionaryCounts.bind(this));
+                break;
+            case 'getImageDetails.response':
+                this._mediaLoader.handleMessage(params);
+                break;
+        }
+    }
+
+    /**
+     * @template [T=unknown]
+     * @param {T} params
+     * @param {(details: T, onProgress: import('dictionary-worker-handler').OnProgressCallback) => Promise<unknown>} handler
+     */
+    async _onMessageWithProgress(params, handler) {
+        /**
+         * @param {...unknown} args
+         */
+        const onProgress = (...args) => {
+            self.postMessage({
+                action: 'progress',
+                params: {args}
+            });
+        };
+        let response;
+        try {
+            const result = await handler(params, onProgress);
+            response = {result};
+        } catch (e) {
+            response = {error: ExtensionError.serialize(e)};
+        }
+        self.postMessage({action: 'complete', params: response});
+    }
+
+    /**
+     * @param {import('dictionary-worker-handler').ImportDictionaryMessageParams} details
+     * @param {import('dictionary-worker-handler').OnProgressCallback} onProgress
+     * @returns {Promise<import('dictionary-worker').MessageCompleteResultSerialized>}
+     */
+    async _importDictionary({details, archiveContent}, onProgress) {
+        const dictionaryDatabase = await this._getPreparedDictionaryDatabase();
+        try {
+            const dictionaryImporter = new DictionaryImporter(this._mediaLoader, onProgress);
+            const {result, errors} = await dictionaryImporter.importDictionary(dictionaryDatabase, archiveContent, details);
+            return {
+                result,
+                errors: errors.map((error) => ExtensionError.serialize(error))
+            };
+        } finally {
+            dictionaryDatabase.close();
+        }
+    }
+
+    /**
+     * @param {import('dictionary-worker-handler').DeleteDictionaryMessageParams} details
+     * @param {import('dictionary-database').DeleteDictionaryProgressCallback} onProgress
+     * @returns {Promise<void>}
+     */
+    async _deleteDictionary({dictionaryTitle}, onProgress) {
+        const dictionaryDatabase = await this._getPreparedDictionaryDatabase();
+        try {
+            return await dictionaryDatabase.deleteDictionary(dictionaryTitle, 1000, onProgress);
+        } finally {
+            dictionaryDatabase.close();
+        }
+    }
+
+    /**
+     * @param {import('dictionary-worker-handler').GetDictionaryCountsMessageParams} details
+     * @returns {Promise<import('dictionary-database').DictionaryCounts>}
+     */
+    async _getDictionaryCounts({dictionaryNames, getTotal}) {
+        const dictionaryDatabase = await this._getPreparedDictionaryDatabase();
+        try {
+            return await dictionaryDatabase.getDictionaryCounts(dictionaryNames, getTotal);
+        } finally {
+            dictionaryDatabase.close();
+        }
+    }
+
+    /**
+     * @returns {Promise<DictionaryDatabase>}
+     */
+    async _getPreparedDictionaryDatabase() {
+        const dictionaryDatabase = new DictionaryDatabase();
+        await dictionaryDatabase.prepare();
+        return dictionaryDatabase;
+    }
+}
diff --git a/ext/js/dictionary/dictionary-worker-main.js b/ext/js/dictionary/dictionary-worker-main.js
new file mode 100644
index 00000000..8ae283b8
--- /dev/null
+++ b/ext/js/dictionary/dictionary-worker-main.js
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2021-2022  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/>.
+ */
+
+import {log} from '../core.js';
+import {DictionaryWorkerHandler} from './dictionary-worker-handler.js';
+
+/** Entry point. */
+function main() {
+    try {
+        const dictionaryWorkerHandler = new DictionaryWorkerHandler();
+        dictionaryWorkerHandler.prepare();
+    } catch (e) {
+        log.error(e);
+    }
+}
+
+main();
diff --git a/ext/js/dictionary/dictionary-worker-media-loader.js b/ext/js/dictionary/dictionary-worker-media-loader.js
new file mode 100644
index 00000000..e19a13d3
--- /dev/null
+++ b/ext/js/dictionary/dictionary-worker-media-loader.js
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2021-2022  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/>.
+ */
+
+import {generateId} from '../core.js';
+import {ExtensionError} from '../core/extension-error.js';
+
+/**
+ * Class used for loading and validating media from a worker thread
+ * during the dictionary import process.
+ */
+export class DictionaryWorkerMediaLoader {
+    /**
+     * Creates a new instance of the media loader.
+     */
+    constructor() {
+        /** @type {Map<string, {resolve: (result: import('dictionary-worker-media-loader').ImageDetails) => void, reject: (reason?: import('core').RejectionReason) => void}>} */
+        this._requests = new Map();
+    }
+
+    /**
+     * Handles a response message posted to the worker thread.
+     * @param {import('dictionary-worker-media-loader').HandleMessageParams} params Details of the response.
+     */
+    handleMessage(params) {
+        const {id} = params;
+        const request = this._requests.get(id);
+        if (typeof request === 'undefined') { return; }
+        this._requests.delete(id);
+        const {error} = params;
+        if (typeof error !== 'undefined') {
+            request.reject(ExtensionError.deserialize(error));
+        } else {
+            request.resolve(params.result);
+        }
+    }
+
+    /** @type {import('dictionary-importer-media-loader').GetImageDetailsFunction} */
+    getImageDetails(content, mediaType) {
+        return new Promise((resolve, reject) => {
+            const id = generateId(16);
+            this._requests.set(id, {resolve, reject});
+            // This is executed in a Worker context, so the self needs to be force cast
+            /** @type {Worker} */ (/** @type {unknown} */ (self)).postMessage({
+                action: 'getImageDetails',
+                params: {id, content, mediaType}
+            }, [content]);
+        });
+    }
+}
diff --git a/ext/js/dictionary/dictionary-worker.js b/ext/js/dictionary/dictionary-worker.js
new file mode 100644
index 00000000..669c65ac
--- /dev/null
+++ b/ext/js/dictionary/dictionary-worker.js
@@ -0,0 +1,206 @@
+/*
+ * Copyright (C) 2023  Yomitan Authors
+ * Copyright (C) 2021-2022  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/>.
+ */
+
+import {ExtensionError} from '../core/extension-error.js';
+import {DictionaryImporterMediaLoader} from './dictionary-importer-media-loader.js';
+
+export class DictionaryWorker {
+    constructor() {
+        /** @type {DictionaryImporterMediaLoader} */
+        this._dictionaryImporterMediaLoader = new DictionaryImporterMediaLoader();
+    }
+
+    /**
+     * @param {ArrayBuffer} archiveContent
+     * @param {import('dictionary-importer').ImportDetails} details
+     * @param {?import('dictionary-worker').ImportProgressCallback} onProgress
+     * @returns {Promise<import('dictionary-importer').ImportResult>}
+     */
+    importDictionary(archiveContent, details, onProgress) {
+        return this._invoke(
+            'importDictionary',
+            {details, archiveContent},
+            [archiveContent],
+            onProgress,
+            this._formatImportDictionaryResult.bind(this)
+        );
+    }
+
+    /**
+     * @param {string} dictionaryTitle
+     * @param {?import('dictionary-worker').DeleteProgressCallback} onProgress
+     * @returns {Promise<void>}
+     */
+    deleteDictionary(dictionaryTitle, onProgress) {
+        return this._invoke('deleteDictionary', {dictionaryTitle}, [], onProgress, null);
+    }
+
+    /**
+     * @param {string[]} dictionaryNames
+     * @param {boolean} getTotal
+     * @returns {Promise<import('dictionary-database').DictionaryCounts>}
+     */
+    getDictionaryCounts(dictionaryNames, getTotal) {
+        return this._invoke('getDictionaryCounts', {dictionaryNames, getTotal}, [], null, null);
+    }
+
+    // Private
+
+    /**
+     * @template [TParams=import('core').SerializableObject]
+     * @template [TResponseRaw=unknown]
+     * @template [TResponse=unknown]
+     * @param {string} action
+     * @param {TParams} params
+     * @param {Transferable[]} transfer
+     * @param {?(arg: import('core').SafeAny) => void} onProgress
+     * @param {?(result: TResponseRaw) => TResponse} formatResult
+     */
+    _invoke(action, params, transfer, onProgress, formatResult) {
+        return new Promise((resolve, reject) => {
+            const worker = new Worker('/js/dictionary/dictionary-worker-main.js', {type: 'module'});
+            /** @type {import('dictionary-worker').InvokeDetails<TResponseRaw, TResponse>} */
+            const details = {
+                complete: false,
+                worker,
+                resolve,
+                reject,
+                onMessage: null,
+                onProgress,
+                formatResult
+            };
+            // Ugly typecast below due to not being able to explicitly state the template types
+            /** @type {(event: MessageEvent<import('dictionary-worker').MessageData<TResponseRaw>>) => void} */
+            const onMessage = /** @type {(details: import('dictionary-worker').InvokeDetails<TResponseRaw, TResponse>, event: MessageEvent<import('dictionary-worker').MessageData<TResponseRaw>>) => void} */ (this._onMessage).bind(this, details);
+            details.onMessage = onMessage;
+            worker.addEventListener('message', onMessage);
+            worker.postMessage({action, params}, transfer);
+        });
+    }
+
+    /**
+     * @template [TResponseRaw=unknown]
+     * @template [TResponse=unknown]
+     * @param {import('dictionary-worker').InvokeDetails<TResponseRaw, TResponse>} details
+     * @param {MessageEvent<import('dictionary-worker').MessageData<TResponseRaw>>} event
+     */
+    _onMessage(details, event) {
+        if (details.complete) { return; }
+        const {action, params} = event.data;
+        switch (action) {
+            case 'complete':
+                {
+                    const {worker, resolve, reject, onMessage, formatResult} = details;
+                    if (worker === null || onMessage === null || resolve === null || reject === null) { return; }
+                    details.complete = true;
+                    details.worker = null;
+                    details.resolve = null;
+                    details.reject = null;
+                    details.onMessage = null;
+                    details.onProgress = null;
+                    details.formatResult = null;
+                    worker.removeEventListener('message', onMessage);
+                    worker.terminate();
+                    this._onMessageComplete(params, resolve, reject, formatResult);
+                }
+                break;
+            case 'progress':
+                this._onMessageProgress(params, details.onProgress);
+                break;
+            case 'getImageDetails':
+                {
+                    const {worker} = details;
+                    if (worker === null) { return; }
+                    this._onMessageGetImageDetails(params, worker);
+                }
+                break;
+        }
+    }
+
+    /**
+     * @template [TResponseRaw=unknown]
+     * @template [TResponse=unknown]
+     * @param {import('dictionary-worker').MessageCompleteParams<TResponseRaw>} params
+     * @param {(result: TResponse) => void} resolve
+     * @param {(reason?: import('core').RejectionReason) => void} reject
+     * @param {?(result: TResponseRaw) => TResponse} formatResult
+     */
+    _onMessageComplete(params, resolve, reject, formatResult) {
+        const {error} = params;
+        if (typeof error !== 'undefined') {
+            reject(ExtensionError.deserialize(error));
+        } else {
+            const {result} = params;
+            if (typeof formatResult === 'function') {
+                let result2;
+                try {
+                    result2 = formatResult(result);
+                } catch (e) {
+                    reject(e);
+                    return;
+                }
+                resolve(result2);
+            } else {
+                // If formatResult is not provided, the response is assumed to be the same type
+                // For some reason, eslint thinks the TResponse type is undefined
+                // eslint-disable-next-line jsdoc/no-undefined-types
+                resolve(/** @type {TResponse} */ (/** @type {unknown} */ (result)));
+            }
+        }
+    }
+
+    /**
+     * @param {import('dictionary-worker').MessageProgressParams} params
+     * @param {?(...args: unknown[]) => void} onProgress
+     */
+    _onMessageProgress(params, onProgress) {
+        if (typeof onProgress !== 'function') { return; }
+        const {args} = params;
+        onProgress(...args);
+    }
+
+    /**
+     * @param {import('dictionary-worker').MessageGetImageDetailsParams} params
+     * @param {Worker} worker
+     */
+    async _onMessageGetImageDetails(params, worker) {
+        const {id, content, mediaType} = params;
+        /** @type {Transferable[]} */
+        const transfer = [];
+        let response;
+        try {
+            const result = await this._dictionaryImporterMediaLoader.getImageDetails(content, mediaType, transfer);
+            response = {id, result};
+        } catch (e) {
+            response = {id, error: ExtensionError.serialize(e)};
+        }
+        worker.postMessage({action: 'getImageDetails.response', params: response}, transfer);
+    }
+
+    /**
+     * @param {import('dictionary-worker').MessageCompleteResultSerialized} response
+     * @returns {import('dictionary-worker').MessageCompleteResult}
+     */
+    _formatImportDictionaryResult(response) {
+        const {result, errors} = response;
+        return {
+            result,
+            errors: errors.map((error) => ExtensionError.deserialize(error))
+        };
+    }
+}