Anki template renderer abstraction (#1839)

* Add AnkiTemplateRenderer abstraction

* Move Anki-specific template functionality into AnkiTemplateRenderer

* Add documentation comments

4 files changed, 584 insertions, 515 deletions

diff --git a/ext/js/templates/sandbox/anki-template-renderer.js b/ext/js/templates/sandbox/anki-template-renderer.js
new file mode 100644
index 00000000..907ab0fa
--- /dev/null
+++ b/ext/js/templates/sandbox/anki-template-renderer.js
@@ -0,0 +1,555 @@
+/*
+ * Copyright (C) 2021  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/* global
+ * AnkiNoteDataCreator
+ * CssStyleApplier
+ * DictionaryDataUtil
+ * Handlebars
+ * JapaneseUtil
+ * StructuredContentGenerator
+ * TemplateRenderer
+ * TemplateRendererMediaProvider
+ */
+
+/**
+ * This class contains all Anki-specific template rendering functionality. It is built on
+ * the generic TemplateRenderer class and various other Anki-related classes.
+ */
+class AnkiTemplateRenderer {
+    /**
+     * Creates a new instance of the class.
+     */
+    constructor() {
+        this._cssStyleApplier = new CssStyleApplier('/data/structured-content-style.json');
+        this._japaneseUtil = new JapaneseUtil(null);
+        this._templateRenderer = new TemplateRenderer();
+        this._ankiNoteDataCreator = new AnkiNoteDataCreator(this._japaneseUtil);
+        this._mediaProvider = new TemplateRendererMediaProvider();
+        this._stateStack = null;
+        this._requirements = null;
+        this._cleanupCallbacks = null;
+        this._temporaryElement = null;
+    }
+
+    /**
+     * Gets the generic TemplateRenderer instance.
+     */
+    get templateRenderer() {
+        return this._templateRenderer;
+    }
+
+    /**
+     * Prepares the data that is necessary before the template renderer can be safely used.
+     */
+    async prepare() {
+        this._templateRenderer.registerHelpers([
+            ['dumpObject',       this._dumpObject.bind(this)],
+            ['furigana',         this._furigana.bind(this)],
+            ['furiganaPlain',    this._furiganaPlain.bind(this)],
+            ['kanjiLinks',       this._kanjiLinks.bind(this)],
+            ['multiLine',        this._multiLine.bind(this)],
+            ['sanitizeCssClass', this._sanitizeCssClass.bind(this)],
+            ['regexReplace',     this._regexReplace.bind(this)],
+            ['regexMatch',       this._regexMatch.bind(this)],
+            ['mergeTags',        this._mergeTags.bind(this)],
+            ['eachUpTo',         this._eachUpTo.bind(this)],
+            ['spread',           this._spread.bind(this)],
+            ['op',               this._op.bind(this)],
+            ['get',              this._get.bind(this)],
+            ['set',              this._set.bind(this)],
+            ['scope',            this._scope.bind(this)],
+            ['property',         this._property.bind(this)],
+            ['noop',             this._noop.bind(this)],
+            ['isMoraPitchHigh',  this._isMoraPitchHigh.bind(this)],
+            ['getKanaMorae',     this._getKanaMorae.bind(this)],
+            ['typeof',           this._getTypeof.bind(this)],
+            ['join',             this._join.bind(this)],
+            ['concat',           this._concat.bind(this)],
+            ['pitchCategories',  this._pitchCategories.bind(this)],
+            ['formatGlossary',   this._formatGlossary.bind(this)],
+            ['hasMedia',         this._hasMedia.bind(this)],
+            ['getMedia',         this._getMedia.bind(this)]
+        ]);
+        this._templateRenderer.registerDataType('ankiNote', {
+            modifier: ({marker, commonData}) => this._ankiNoteDataCreator.create(marker, commonData),
+            composeData: (marker, commonData) => ({marker, commonData})
+        });
+        this._templateRenderer.setRenderCallbacks(
+            this._onRenderSetup.bind(this),
+            this._onRenderCleanup.bind(this)
+        );
+        await this._cssStyleApplier.prepare();
+    }
+
+    // Private
+
+    _onRenderSetup() {
+        const requirements = [];
+        this._stateStack = [new Map()];
+        this._requirements = requirements;
+        this._mediaProvider.requirements = requirements;
+        this._cleanupCallbacks = [];
+        return {requirements};
+    }
+
+    _onRenderCleanup() {
+        for (const callback of this._cleanupCallbacks) { callback(); }
+        this._stateStack = null;
+        this._requirements = null;
+        this._mediaProvider.requirements = null;
+        this._cleanupCallbacks = null;
+    }
+
+    _escape(text) {
+        return Handlebars.Utils.escapeExpression(text);
+    }
+
+    // Template helpers
+
+    _dumpObject(context, options) {
+        const dump = JSON.stringify(options.fn(context), null, 4);
+        return this._escape(dump);
+    }
+
+    _furigana(context, ...args) {
+        const {expression, reading} = this._getFuriganaExpressionAndReading(context, ...args);
+        const segs = this._japaneseUtil.distributeFurigana(expression, reading);
+
+        let result = '';
+        for (const {text, reading: reading2} of segs) {
+            if (reading2.length > 0) {
+                result += `<ruby>${text}<rt>${reading2}</rt></ruby>`;
+            } else {
+                result += text;
+            }
+        }
+
+        return result;
+    }
+
+    _furiganaPlain(context, ...args) {
+        const {expression, reading} = this._getFuriganaExpressionAndReading(context, ...args);
+        const segs = this._japaneseUtil.distributeFurigana(expression, reading);
+
+        let result = '';
+        for (const {text, reading: reading2} of segs) {
+            if (reading2.length > 0) {
+                if (result.length > 0) { result += ' '; }
+                result += `${text}[${reading2}]`;
+            } else {
+                result += text;
+            }
+        }
+
+        return result;
+    }
+
+    _getFuriganaExpressionAndReading(context, ...args) {
+        const options = args[args.length - 1];
+        if (args.length >= 3) {
+            return {expression: args[0], reading: args[1]};
+        } else {
+            const {expression, reading} = options.fn(context);
+            return {expression, reading};
+        }
+    }
+
+    _kanjiLinks(context, options) {
+        const jp = this._japaneseUtil;
+        let result = '';
+        for (const c of options.fn(context)) {
+            if (jp.isCodePointKanji(c.codePointAt(0))) {
+                result += `<a href="#" class="kanji-link">${c}</a>`;
+            } else {
+                result += c;
+            }
+        }
+
+        return result;
+    }
+
+    _stringToMultiLineHtml(string) {
+        return string.split('\n').join('<br>');
+    }
+
+    _multiLine(context, options) {
+        return this._stringToMultiLineHtml(options.fn(context));
+    }
+
+    _sanitizeCssClass(context, options) {
+        return options.fn(context).replace(/[^_a-z0-9\u00a0-\uffff]/ig, '_');
+    }
+
+    _regexReplace(context, ...args) {
+        // Usage:
+        // {{#regexReplace regex string [flags]}}content{{/regexReplace}}
+        // regex: regular expression string
+        // string: string to replace
+        // flags: optional flags for regular expression
+        //   e.g. "i" for case-insensitive, "g" for replace all
+        let value = args[args.length - 1].fn(context);
+        if (args.length >= 3) {
+            try {
+                const flags = args.length > 3 ? args[2] : 'g';
+                const regex = new RegExp(args[0], flags);
+                value = value.replace(regex, args[1]);
+            } catch (e) {
+                return `${e}`;
+            }
+        }
+        return value;
+    }
+
+    _regexMatch(context, ...args) {
+        // Usage:
+        // {{#regexMatch regex [flags]}}content{{/regexMatch}}
+        // regex: regular expression string
+        // flags: optional flags for regular expression
+        //   e.g. "i" for case-insensitive, "g" for match all
+        let value = args[args.length - 1].fn(context);
+        if (args.length >= 2) {
+            try {
+                const flags = args.length > 2 ? args[1] : '';
+                const regex = new RegExp(args[0], flags);
+                const parts = [];
+                value.replace(regex, (g0) => parts.push(g0));
+                value = parts.join('');
+            } catch (e) {
+                return `${e}`;
+            }
+        }
+        return value;
+    }
+
+    _mergeTags(context, object, isGroupMode, isMergeMode) {
+        const tagSources = [];
+        if (isGroupMode || isMergeMode) {
+            for (const definition of object.definitions) {
+                tagSources.push(definition.definitionTags);
+            }
+        } else {
+            tagSources.push(object.definitionTags);
+        }
+
+        const tags = new Set();
+        for (const tagSource of tagSources) {
+            if (!Array.isArray(tagSource)) { continue; }
+            for (const tag of tagSource) {
+                tags.add(tag.name);
+            }
+        }
+
+        return [...tags].join(', ');
+    }
+
+    _eachUpTo(context, iterable, maxCount, options) {
+        if (iterable) {
+            const results = [];
+            let any = false;
+            for (const entry of iterable) {
+                any = true;
+                if (results.length >= maxCount) { break; }
+                const processedEntry = options.fn(entry);
+                results.push(processedEntry);
+            }
+            if (any) {
+                return results.join('');
+            }
+        }
+        return options.inverse(context);
+    }
+
+    _spread(context, ...args) {
+        const result = [];
+        for (let i = 0, ii = args.length - 1; i < ii; ++i) {
+            try {
+                result.push(...args[i]);
+            } catch (e) {
+                // NOP
+            }
+        }
+        return result;
+    }
+
+    _op(context, ...args) {
+        switch (args.length) {
+            case 3: return this._evaluateUnaryExpression(args[0], args[1]);
+            case 4: return this._evaluateBinaryExpression(args[0], args[1], args[2]);
+            case 5: return this._evaluateTernaryExpression(args[0], args[1], args[2], args[3]);
+            default: return void 0;
+        }
+    }
+
+    _evaluateUnaryExpression(operator, operand1) {
+        switch (operator) {
+            case '+': return +operand1;
+            case '-': return -operand1;
+            case '~': return ~operand1;
+            case '!': return !operand1;
+            default: return void 0;
+        }
+    }
+
+    _evaluateBinaryExpression(operator, operand1, operand2) {
+        switch (operator) {
+            case '+': return operand1 + operand2;
+            case '-': return operand1 - operand2;
+            case '/': return operand1 / operand2;
+            case '*': return operand1 * operand2;
+            case '%': return operand1 % operand2;
+            case '**': return operand1 ** operand2;
+            case '==': return operand1 == operand2; // eslint-disable-line eqeqeq
+            case '!=': return operand1 != operand2; // eslint-disable-line eqeqeq
+            case '===': return operand1 === operand2;
+            case '!==': return operand1 !== operand2;
+            case '<':  return operand1 < operand2;
+            case '<=': return operand1 <= operand2;
+            case '>':  return operand1 > operand2;
+            case '>=': return operand1 >= operand2;
+            case '<<': return operand1 << operand2;
+            case '>>': return operand1 >> operand2;
+            case '>>>': return operand1 >>> operand2;
+            case '&': return operand1 & operand2;
+            case '|': return operand1 | operand2;
+            case '^': return operand1 ^ operand2;
+            case '&&': return operand1 && operand2;
+            case '||': return operand1 || operand2;
+            default: return void 0;
+        }
+    }
+
+    _evaluateTernaryExpression(operator, operand1, operand2, operand3) {
+        switch (operator) {
+            case '?:': return operand1 ? operand2 : operand3;
+            default: return void 0;
+        }
+    }
+
+    _get(context, key) {
+        const stateStack = this._stateStack;
+        for (let i = stateStack.length; --i >= 0;) {
+            const map = stateStack[i];
+            if (map.has(key)) {
+                return map.get(key);
+            }
+        }
+        return void 0;
+    }
+
+    _set(context, ...args) {
+        const stateStack = this._stateStack;
+        switch (args.length) {
+            case 2:
+                {
+                    const [key, options] = args;
+                    const value = options.fn(context);
+                    stateStack[stateStack.length - 1].set(key, value);
+                }
+                break;
+            case 3:
+                {
+                    const [key, value] = args;
+                    stateStack[stateStack.length - 1].set(key, value);
+                }
+                break;
+        }
+        return '';
+    }
+
+    _scope(context, options) {
+        const stateStack = this._stateStack;
+        try {
+            stateStack.push(new Map());
+            return options.fn(context);
+        } finally {
+            if (stateStack.length > 1) {
+                stateStack.pop();
+            }
+        }
+    }
+
+    _property(context, ...args) {
+        const ii = args.length - 1;
+        if (ii <= 0) { return void 0; }
+
+        try {
+            let value = args[0];
+            for (let i = 1; i < ii; ++i) {
+                value = value[args[i]];
+            }
+            return value;
+        } catch (e) {
+            return void 0;
+        }
+    }
+
+    _noop(context, options) {
+        return options.fn(context);
+    }
+
+    _isMoraPitchHigh(context, index, position) {
+        return this._japaneseUtil.isMoraPitchHigh(index, position);
+    }
+
+    _getKanaMorae(context, text) {
+        return this._japaneseUtil.getKanaMorae(`${text}`);
+    }
+
+    _getTypeof(context, ...args) {
+        const ii = args.length - 1;
+        const value = (ii > 0 ? args[0] : args[ii].fn(context));
+        return typeof value;
+    }
+
+    _join(context, ...args) {
+        return args.length > 1 ? args.slice(1, args.length - 1).flat().join(args[0]) : '';
+    }
+
+    _concat(context, ...args) {
+        let result = '';
+        for (let i = 0, ii = args.length - 1; i < ii; ++i) {
+            result += args[i];
+        }
+        return result;
+    }
+
+    _pitchCategories(context, data) {
+        const {pronunciations, headwords} = data.dictionaryEntry;
+        const categories = new Set();
+        for (const {headwordIndex, pitches} of pronunciations) {
+            const {reading, wordClasses} = headwords[headwordIndex];
+            const isVerbOrAdjective = DictionaryDataUtil.isNonNounVerbOrAdjective(wordClasses);
+            for (const {position} of pitches) {
+                const category = this._japaneseUtil.getPitchCategory(reading, position, isVerbOrAdjective);
+                if (category !== null) {
+                    categories.add(category);
+                }
+            }
+        }
+        return [...categories];
+    }
+
+    _getTemporaryElement() {
+        let element = this._temporaryElement;
+        if (element === null) {
+            element = document.createElement('div');
+            this._temporaryElement = element;
+        }
+        return element;
+    }
+
+    _getHtml(node) {
+        const container = this._getTemporaryElement();
+        container.appendChild(node);
+        this._normalizeHtml(container);
+        const result = container.innerHTML;
+        container.textContent = '';
+        return result;
+    }
+
+    _normalizeHtml(root) {
+        const {ELEMENT_NODE, TEXT_NODE} = Node;
+        const treeWalker = document.createTreeWalker(root, NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT);
+        const elements = [];
+        const textNodes = [];
+        while (true) {
+            const node = treeWalker.nextNode();
+            if (node === null) { break; }
+            switch (node.nodeType) {
+                case ELEMENT_NODE:
+                    elements.push(node);
+                    break;
+                case TEXT_NODE:
+                    textNodes.push(node);
+                    break;
+            }
+        }
+        this._cssStyleApplier.applyClassStyles(elements);
+        for (const element of elements) {
+            const {dataset} = element;
+            for (const key of Object.keys(dataset)) {
+                delete dataset[key];
+            }
+        }
+        for (const textNode of textNodes) {
+            this._replaceNewlines(textNode);
+        }
+    }
+
+    _replaceNewlines(textNode) {
+        const parts = textNode.nodeValue.split('\n');
+        if (parts.length <= 1) { return; }
+        const {parentNode} = textNode;
+        if (parentNode === null) { return; }
+        const fragment = document.createDocumentFragment();
+        for (let i = 0, ii = parts.length; i < ii; ++i) {
+            if (i > 0) { fragment.appendChild(document.createElement('br')); }
+            fragment.appendChild(document.createTextNode(parts[i]));
+        }
+        parentNode.replaceChild(fragment, textNode);
+    }
+
+    _createStructuredContentGenerator(data) {
+        const mediaLoader = {
+            loadMedia: async (path, dictionary, onLoad, onUnload) => {
+                const imageUrl = this._mediaProvider.getMedia(data, ['dictionaryMedia', path], {dictionary, format: 'fileName', default: null});
+                if (imageUrl !== null) {
+                    onLoad(imageUrl);
+                    this._cleanupCallbacks.push(() => onUnload(true));
+                }
+            }
+        };
+        return new StructuredContentGenerator(mediaLoader, document);
+    }
+
+    _formatGlossary(context, dictionary, options) {
+        const data = options.data.root;
+        const content = options.fn(context);
+        if (typeof content === 'string') { return this._stringToMultiLineHtml(this._escape(content)); }
+        if (!(typeof content === 'object' && content !== null)) { return ''; }
+        switch (content.type) {
+            case 'image': return this._formatGlossaryImage(content, dictionary, data);
+            case 'structured-content': return this._formatStructuredContent(content, dictionary, data);
+        }
+        return '';
+    }
+
+    _formatGlossaryImage(content, dictionary, data) {
+        const structuredContentGenerator = this._createStructuredContentGenerator(data);
+        const node = structuredContentGenerator.createDefinitionImage(content, dictionary);
+        return this._getHtml(node);
+    }
+
+    _formatStructuredContent(content, dictionary, data) {
+        const structuredContentGenerator = this._createStructuredContentGenerator(data);
+        const node = structuredContentGenerator.createStructuredContent(content.content, dictionary);
+        return node !== null ? this._getHtml(node) : '';
+    }
+
+    _hasMedia(context, ...args) {
+        const ii = args.length - 1;
+        const options = args[ii];
+        return this._mediaProvider.hasMedia(options.data.root, args.slice(0, ii), options.hash);
+    }
+
+    _getMedia(context, ...args) {
+        const ii = args.length - 1;
+        const options = args[ii];
+        return this._mediaProvider.getMedia(options.data.root, args.slice(0, ii), options.hash);
+    }
+}
diff --git a/ext/js/templates/sandbox/template-renderer-frame-main.js b/ext/js/templates/sandbox/template-renderer-frame-main.js
index bb9cac3a..15fe7781 100644
--- a/ext/js/templates/sandbox/template-renderer-frame-main.js
+++ b/ext/js/templates/sandbox/template-renderer-frame-main.js
@@ -16,23 +16,13 @@
  */
 
 /* globals
- * AnkiNoteDataCreator
- * CssStyleApplier
- * JapaneseUtil
- * TemplateRenderer
+ * AnkiTemplateRenderer
  * TemplateRendererFrameApi
  */
 
 (async () => {
-    const cssStyleApplier = new CssStyleApplier('/data/structured-content-style.json');
-    await cssStyleApplier.prepare();
-    const japaneseUtil = new JapaneseUtil(null);
-    const templateRenderer = new TemplateRenderer(japaneseUtil, cssStyleApplier);
-    const ankiNoteDataCreator = new AnkiNoteDataCreator(japaneseUtil);
-    templateRenderer.registerDataType('ankiNote', {
-        modifier: ({marker, commonData}) => ankiNoteDataCreator.create(marker, commonData),
-        composeData: (marker, commonData) => ({marker, commonData})
-    });
-    const templateRendererFrameApi = new TemplateRendererFrameApi(templateRenderer);
+    const ankiTemplateRenderer = new AnkiTemplateRenderer();
+    await ankiTemplateRenderer.prepare();
+    const templateRendererFrameApi = new TemplateRendererFrameApi(ankiTemplateRenderer.templateRenderer);
     templateRendererFrameApi.prepare();
 })();
diff --git a/ext/js/templates/sandbox/template-renderer.js b/ext/js/templates/sandbox/template-renderer.js
index 02471c97..adb6733a 100644
--- a/ext/js/templates/sandbox/template-renderer.js
+++ b/ext/js/templates/sandbox/template-renderer.js
@@ -16,31 +16,34 @@
  */
 
 /* global
- * DictionaryDataUtil
  * Handlebars
- * StructuredContentGenerator
- * TemplateRendererMediaProvider
  */
 
 class TemplateRenderer {
-    constructor(japaneseUtil, cssStyleApplier) {
-        this._japaneseUtil = japaneseUtil;
-        this._cssStyleApplier = cssStyleApplier;
-        this._mediaProvider = new TemplateRendererMediaProvider();
+    constructor() {
         this._cache = new Map();
         this._cacheMaxSize = 5;
-        this._helpersRegistered = false;
-        this._stateStack = null;
         this._dataTypes = new Map();
-        this._requirements = null;
-        this._cleanupCallbacks = null;
-        this._temporaryElement = null;
+        this._renderSetup = null;
+        this._renderCleanup = null;
+    }
+
+    registerHelpers(helpers) {
+        Handlebars.partials = Handlebars.templates;
+        for (const [name, helper] of helpers) {
+            this._registerHelper(name, helper);
+        }
     }
 
     registerDataType(name, {modifier=null, composeData=null}) {
         this._dataTypes.set(name, {modifier, composeData});
     }
 
+    setRenderCallbacks(setup, cleanup) {
+        this._renderSetup = setup;
+        this._renderCleanup = cleanup;
+    }
+
     render(template, data, type) {
         const instance = this._getTemplateInstance(template);
         data = this._getModifiedData(data, void 0, type);
@@ -75,10 +78,6 @@ class TemplateRenderer {
     // Private
 
     _getTemplateInstance(template) {
-        if (!this._helpersRegistered) {
-            this._registerHelpers();
-        }
-
         const cache = this._cache;
         let instance = cache.get(template);
         if (typeof instance === 'undefined') {
@@ -91,22 +90,18 @@ class TemplateRenderer {
     }
 
     _renderTemplate(instance, data) {
-        const cleanupCallbacks = [];
-        const requirements = [];
+        const renderSetup = this._renderSetup;
+        const renderCleanup = this._renderCleanup;
+        let result;
+        let additions1;
+        let additions2;
         try {
-            this._stateStack = [new Map()];
-            this._requirements = requirements;
-            this._mediaProvider.requirements = requirements;
-            this._cleanupCallbacks = cleanupCallbacks;
-            const result = instance(data).trim();
-            return {result, requirements};
+            additions1 = (typeof renderSetup === 'function' ? renderSetup(data) : null);
+            result = instance(data).trim();
         } finally {
-            for (const callback of cleanupCallbacks) { callback(); }
-            this._stateStack = null;
-            this._requirements = null;
-            this._mediaProvider.requirements = null;
-            this._cleanupCallbacks = null;
+            additions2 = (typeof renderCleanup === 'function' ? renderCleanup(data) : null);
         }
+        return Object.assign({result}, additions1, additions2);
     }
 
     _getModifiedData(data, commonData, type) {
@@ -139,482 +134,10 @@ class TemplateRenderer {
         }
     }
 
-    _registerHelpers() {
-        Handlebars.partials = Handlebars.templates;
-
-        const helpers = [
-            ['dumpObject',       this._dumpObject.bind(this)],
-            ['furigana',         this._furigana.bind(this)],
-            ['furiganaPlain',    this._furiganaPlain.bind(this)],
-            ['kanjiLinks',       this._kanjiLinks.bind(this)],
-            ['multiLine',        this._multiLine.bind(this)],
-            ['sanitizeCssClass', this._sanitizeCssClass.bind(this)],
-            ['regexReplace',     this._regexReplace.bind(this)],
-            ['regexMatch',       this._regexMatch.bind(this)],
-            ['mergeTags',        this._mergeTags.bind(this)],
-            ['eachUpTo',         this._eachUpTo.bind(this)],
-            ['spread',           this._spread.bind(this)],
-            ['op',               this._op.bind(this)],
-            ['get',              this._get.bind(this)],
-            ['set',              this._set.bind(this)],
-            ['scope',            this._scope.bind(this)],
-            ['property',         this._property.bind(this)],
-            ['noop',             this._noop.bind(this)],
-            ['isMoraPitchHigh',  this._isMoraPitchHigh.bind(this)],
-            ['getKanaMorae',     this._getKanaMorae.bind(this)],
-            ['typeof',           this._getTypeof.bind(this)],
-            ['join',             this._join.bind(this)],
-            ['concat',           this._concat.bind(this)],
-            ['pitchCategories',  this._pitchCategories.bind(this)],
-            ['formatGlossary',   this._formatGlossary.bind(this)],
-            ['hasMedia',         this._hasMedia.bind(this)],
-            ['getMedia',         this._getMedia.bind(this)]
-        ];
-
-        for (const [name, helper] of helpers) {
-            this._registerHelper(name, helper);
-        }
-
-        this._helpersRegistered = true;
-    }
-
     _registerHelper(name, helper) {
         function wrapper(...args) {
             return helper(this, ...args);
         }
         Handlebars.registerHelper(name, wrapper);
     }
-
-    _escape(text) {
-        return Handlebars.Utils.escapeExpression(text);
-    }
-
-    _dumpObject(context, options) {
-        const dump = JSON.stringify(options.fn(context), null, 4);
-        return this._escape(dump);
-    }
-
-    _furigana(context, ...args) {
-        const {expression, reading} = this._getFuriganaExpressionAndReading(context, ...args);
-        const segs = this._japaneseUtil.distributeFurigana(expression, reading);
-
-        let result = '';
-        for (const {text, reading: reading2} of segs) {
-            if (reading2.length > 0) {
-                result += `<ruby>${text}<rt>${reading2}</rt></ruby>`;
-            } else {
-                result += text;
-            }
-        }
-
-        return result;
-    }
-
-    _furiganaPlain(context, ...args) {
-        const {expression, reading} = this._getFuriganaExpressionAndReading(context, ...args);
-        const segs = this._japaneseUtil.distributeFurigana(expression, reading);
-
-        let result = '';
-        for (const {text, reading: reading2} of segs) {
-            if (reading2.length > 0) {
-                if (result.length > 0) { result += ' '; }
-                result += `${text}[${reading2}]`;
-            } else {
-                result += text;
-            }
-        }
-
-        return result;
-    }
-
-    _getFuriganaExpressionAndReading(context, ...args) {
-        const options = args[args.length - 1];
-        if (args.length >= 3) {
-            return {expression: args[0], reading: args[1]};
-        } else {
-            const {expression, reading} = options.fn(context);
-            return {expression, reading};
-        }
-    }
-
-    _kanjiLinks(context, options) {
-        const jp = this._japaneseUtil;
-        let result = '';
-        for (const c of options.fn(context)) {
-            if (jp.isCodePointKanji(c.codePointAt(0))) {
-                result += `<a href="#" class="kanji-link">${c}</a>`;
-            } else {
-                result += c;
-            }
-        }
-
-        return result;
-    }
-
-    _stringToMultiLineHtml(string) {
-        return string.split('\n').join('<br>');
-    }
-
-    _multiLine(context, options) {
-        return this._stringToMultiLineHtml(options.fn(context));
-    }
-
-    _sanitizeCssClass(context, options) {
-        return options.fn(context).replace(/[^_a-z0-9\u00a0-\uffff]/ig, '_');
-    }
-
-    _regexReplace(context, ...args) {
-        // Usage:
-        // {{#regexReplace regex string [flags]}}content{{/regexReplace}}
-        // regex: regular expression string
-        // string: string to replace
-        // flags: optional flags for regular expression
-        //   e.g. "i" for case-insensitive, "g" for replace all
-        let value = args[args.length - 1].fn(context);
-        if (args.length >= 3) {
-            try {
-                const flags = args.length > 3 ? args[2] : 'g';
-                const regex = new RegExp(args[0], flags);
-                value = value.replace(regex, args[1]);
-            } catch (e) {
-                return `${e}`;
-            }
-        }
-        return value;
-    }
-
-    _regexMatch(context, ...args) {
-        // Usage:
-        // {{#regexMatch regex [flags]}}content{{/regexMatch}}
-        // regex: regular expression string
-        // flags: optional flags for regular expression
-        //   e.g. "i" for case-insensitive, "g" for match all
-        let value = args[args.length - 1].fn(context);
-        if (args.length >= 2) {
-            try {
-                const flags = args.length > 2 ? args[1] : '';
-                const regex = new RegExp(args[0], flags);
-                const parts = [];
-                value.replace(regex, (g0) => parts.push(g0));
-                value = parts.join('');
-            } catch (e) {
-                return `${e}`;
-            }
-        }
-        return value;
-    }
-
-    _mergeTags(context, object, isGroupMode, isMergeMode) {
-        const tagSources = [];
-        if (isGroupMode || isMergeMode) {
-            for (const definition of object.definitions) {
-                tagSources.push(definition.definitionTags);
-            }
-        } else {
-            tagSources.push(object.definitionTags);
-        }
-
-        const tags = new Set();
-        for (const tagSource of tagSources) {
-            if (!Array.isArray(tagSource)) { continue; }
-            for (const tag of tagSource) {
-                tags.add(tag.name);
-            }
-        }
-
-        return [...tags].join(', ');
-    }
-
-    _eachUpTo(context, iterable, maxCount, options) {
-        if (iterable) {
-            const results = [];
-            let any = false;
-            for (const entry of iterable) {
-                any = true;
-                if (results.length >= maxCount) { break; }
-                const processedEntry = options.fn(entry);
-                results.push(processedEntry);
-            }
-            if (any) {
-                return results.join('');
-            }
-        }
-        return options.inverse(context);
-    }
-
-    _spread(context, ...args) {
-        const result = [];
-        for (let i = 0, ii = args.length - 1; i < ii; ++i) {
-            try {
-                result.push(...args[i]);
-            } catch (e) {
-                // NOP
-            }
-        }
-        return result;
-    }
-
-    _op(context, ...args) {
-        switch (args.length) {
-            case 3: return this._evaluateUnaryExpression(args[0], args[1]);
-            case 4: return this._evaluateBinaryExpression(args[0], args[1], args[2]);
-            case 5: return this._evaluateTernaryExpression(args[0], args[1], args[2], args[3]);
-            default: return void 0;
-        }
-    }
-
-    _evaluateUnaryExpression(operator, operand1) {
-        switch (operator) {
-            case '+': return +operand1;
-            case '-': return -operand1;
-            case '~': return ~operand1;
-            case '!': return !operand1;
-            default: return void 0;
-        }
-    }
-
-    _evaluateBinaryExpression(operator, operand1, operand2) {
-        switch (operator) {
-            case '+': return operand1 + operand2;
-            case '-': return operand1 - operand2;
-            case '/': return operand1 / operand2;
-            case '*': return operand1 * operand2;
-            case '%': return operand1 % operand2;
-            case '**': return operand1 ** operand2;
-            case '==': return operand1 == operand2; // eslint-disable-line eqeqeq
-            case '!=': return operand1 != operand2; // eslint-disable-line eqeqeq
-            case '===': return operand1 === operand2;
-            case '!==': return operand1 !== operand2;
-            case '<':  return operand1 < operand2;
-            case '<=': return operand1 <= operand2;
-            case '>':  return operand1 > operand2;
-            case '>=': return operand1 >= operand2;
-            case '<<': return operand1 << operand2;
-            case '>>': return operand1 >> operand2;
-            case '>>>': return operand1 >>> operand2;
-            case '&': return operand1 & operand2;
-            case '|': return operand1 | operand2;
-            case '^': return operand1 ^ operand2;
-            case '&&': return operand1 && operand2;
-            case '||': return operand1 || operand2;
-            default: return void 0;
-        }
-    }
-
-    _evaluateTernaryExpression(operator, operand1, operand2, operand3) {
-        switch (operator) {
-            case '?:': return operand1 ? operand2 : operand3;
-            default: return void 0;
-        }
-    }
-
-    _get(context, key) {
-        for (let i = this._stateStack.length; --i >= 0;) {
-            const map = this._stateStack[i];
-            if (map.has(key)) {
-                return map.get(key);
-            }
-        }
-        return void 0;
-    }
-
-    _set(context, ...args) {
-        switch (args.length) {
-            case 2:
-                {
-                    const [key, options] = args;
-                    const value = options.fn(context);
-                    this._stateStack[this._stateStack.length - 1].set(key, value);
-                }
-                break;
-            case 3:
-                {
-                    const [key, value] = args;
-                    this._stateStack[this._stateStack.length - 1].set(key, value);
-                }
-                break;
-        }
-        return '';
-    }
-
-    _scope(context, options) {
-        try {
-            this._stateStack.push(new Map());
-            return options.fn(context);
-        } finally {
-            if (this._stateStack.length > 1) {
-                this._stateStack.pop();
-            }
-        }
-    }
-
-    _property(context, ...args) {
-        const ii = args.length - 1;
-        if (ii <= 0) { return void 0; }
-
-        try {
-            let value = args[0];
-            for (let i = 1; i < ii; ++i) {
-                value = value[args[i]];
-            }
-            return value;
-        } catch (e) {
-            return void 0;
-        }
-    }
-
-    _noop(context, options) {
-        return options.fn(context);
-    }
-
-    _isMoraPitchHigh(context, index, position) {
-        return this._japaneseUtil.isMoraPitchHigh(index, position);
-    }
-
-    _getKanaMorae(context, text) {
-        return this._japaneseUtil.getKanaMorae(`${text}`);
-    }
-
-    _getTypeof(context, ...args) {
-        const ii = args.length - 1;
-        const value = (ii > 0 ? args[0] : args[ii].fn(context));
-        return typeof value;
-    }
-
-    _join(context, ...args) {
-        return args.length > 1 ? args.slice(1, args.length - 1).flat().join(args[0]) : '';
-    }
-
-    _concat(context, ...args) {
-        let result = '';
-        for (let i = 0, ii = args.length - 1; i < ii; ++i) {
-            result += args[i];
-        }
-        return result;
-    }
-
-    _pitchCategories(context, data) {
-        const {pronunciations, headwords} = data.dictionaryEntry;
-        const categories = new Set();
-        for (const {headwordIndex, pitches} of pronunciations) {
-            const {reading, wordClasses} = headwords[headwordIndex];
-            const isVerbOrAdjective = DictionaryDataUtil.isNonNounVerbOrAdjective(wordClasses);
-            for (const {position} of pitches) {
-                const category = this._japaneseUtil.getPitchCategory(reading, position, isVerbOrAdjective);
-                if (category !== null) {
-                    categories.add(category);
-                }
-            }
-        }
-        return [...categories];
-    }
-
-    _getTemporaryElement() {
-        let element = this._temporaryElement;
-        if (element === null) {
-            element = document.createElement('div');
-            this._temporaryElement = element;
-        }
-        return element;
-    }
-
-    _getHtml(node) {
-        const container = this._getTemporaryElement();
-        container.appendChild(node);
-        this._normalizeHtml(container);
-        const result = container.innerHTML;
-        container.textContent = '';
-        return result;
-    }
-
-    _normalizeHtml(root) {
-        const {ELEMENT_NODE, TEXT_NODE} = Node;
-        const treeWalker = document.createTreeWalker(root, NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_TEXT);
-        const elements = [];
-        const textNodes = [];
-        while (true) {
-            const node = treeWalker.nextNode();
-            if (node === null) { break; }
-            switch (node.nodeType) {
-                case ELEMENT_NODE:
-                    elements.push(node);
-                    break;
-                case TEXT_NODE:
-                    textNodes.push(node);
-                    break;
-            }
-        }
-        this._cssStyleApplier.applyClassStyles(elements);
-        for (const element of elements) {
-            const {dataset} = element;
-            for (const key of Object.keys(dataset)) {
-                delete dataset[key];
-            }
-        }
-        for (const textNode of textNodes) {
-            this._replaceNewlines(textNode);
-        }
-    }
-
-    _replaceNewlines(textNode) {
-        const parts = textNode.nodeValue.split('\n');
-        if (parts.length <= 1) { return; }
-        const {parentNode} = textNode;
-        if (parentNode === null) { return; }
-        const fragment = document.createDocumentFragment();
-        for (let i = 0, ii = parts.length; i < ii; ++i) {
-            if (i > 0) { fragment.appendChild(document.createElement('br')); }
-            fragment.appendChild(document.createTextNode(parts[i]));
-        }
-        parentNode.replaceChild(fragment, textNode);
-    }
-
-    _createStructuredContentGenerator(data) {
-        const mediaLoader = {
-            loadMedia: async (path, dictionary, onLoad, onUnload) => {
-                const imageUrl = this._mediaProvider.getMedia(data, ['dictionaryMedia', path], {dictionary, format: 'fileName', default: null});
-                if (imageUrl !== null) {
-                    onLoad(imageUrl);
-                    this._cleanupCallbacks.push(() => onUnload(true));
-                }
-            }
-        };
-        return new StructuredContentGenerator(mediaLoader, document);
-    }
-
-    _formatGlossary(context, dictionary, options) {
-        const data = options.data.root;
-        const content = options.fn(context);
-        if (typeof content === 'string') { return this._stringToMultiLineHtml(this._escape(content)); }
-        if (!(typeof content === 'object' && content !== null)) { return ''; }
-        switch (content.type) {
-            case 'image': return this._formatGlossaryImage(content, dictionary, data);
-            case 'structured-content': return this._formatStructuredContent(content, dictionary, data);
-        }
-        return '';
-    }
-
-    _formatGlossaryImage(content, dictionary, data) {
-        const structuredContentGenerator = this._createStructuredContentGenerator(data);
-        const node = structuredContentGenerator.createDefinitionImage(content, dictionary);
-        return this._getHtml(node);
-    }
-
-    _formatStructuredContent(content, dictionary, data) {
-        const structuredContentGenerator = this._createStructuredContentGenerator(data);
-        const node = structuredContentGenerator.createStructuredContent(content.content, dictionary);
-        return node !== null ? this._getHtml(node) : '';
-    }
-
-    _hasMedia(context, ...args) {
-        const ii = args.length - 1;
-        const options = args[ii];
-        return this._mediaProvider.hasMedia(options.data.root, args.slice(0, ii), options.hash);
-    }
-
-    _getMedia(context, ...args) {
-        const ii = args.length - 1;
-        const options = args[ii];
-        return this._mediaProvider.getMedia(options.data.root, args.slice(0, ii), options.hash);
-    }
 }
diff --git a/ext/template-renderer.html b/ext/template-renderer.html
index 9e0769f9..2db61d05 100644
--- a/ext/template-renderer.html
+++ b/ext/template-renderer.html
@@ -22,6 +22,7 @@
 <script src="/js/dom/sandbox/css-style-applier.js"></script>
 <script src="/js/language/sandbox/dictionary-data-util.js"></script>
 <script src="/js/language/sandbox/japanese-util.js"></script>
+<script src="/js/templates/sandbox/anki-template-renderer.js"></script>
 <script src="/js/templates/sandbox/template-renderer.js"></script>
 <script src="/js/templates/sandbox/template-renderer-frame-api.js"></script>
 <script src="/js/templates/sandbox/template-renderer-media-provider.js"></script>