1 files changed, 206 insertions, 0 deletions
diff --git a/ext/js/templates/template-renderer.js b/ext/js/templates/template-renderer.js
new file mode 100644
index 00000000..7bb93aa2
--- /dev/null
+++ b/ext/js/templates/template-renderer.js
@@ -0,0 +1,206 @@
+/*
+ * Copyright (C) 2023-2024  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 {Handlebars} from '../../lib/handlebars.js';
+import {ExtensionError} from '../core/extension-error.js';
+
+export class TemplateRenderer {
+    constructor() {
+        /** @type {Map<string, import('handlebars').TemplateDelegate<import('anki-templates').NoteData>>} */
+        this._cache = new Map();
+        /** @type {number} */
+        this._cacheMaxSize = 5;
+        /** @type {Map<import('anki-templates').RenderMode, import('template-renderer').DataType>} */
+        this._dataTypes = new Map();
+        /** @type {?((noteData: import('anki-templates').NoteData) => import('template-renderer').SetupCallbackResult)} */
+        this._renderSetup = null;
+        /** @type {?((noteData: import('anki-templates').NoteData) => import('template-renderer').CleanupCallbackResult)} */
+        this._renderCleanup = null;
+    }
+
+    /**
+     * @param {import('template-renderer').HelperFunctionsDescriptor} helpers
+     */
+    registerHelpers(helpers) {
+        for (const [name, helper] of helpers) {
+            this._registerHelper(name, helper);
+        }
+    }
+
+    /**
+     * @param {import('anki-templates').RenderMode} name
+     * @param {import('template-renderer').DataType} details
+     */
+    registerDataType(name, {modifier, composeData}) {
+        this._dataTypes.set(name, {modifier, composeData});
+    }
+
+    /**
+     * @param {?((noteData: import('anki-templates').NoteData) => import('template-renderer').SetupCallbackResult)} setup
+     * @param {?((noteData: import('anki-templates').NoteData) => import('template-renderer').CleanupCallbackResult)} cleanup
+     */
+    setRenderCallbacks(setup, cleanup) {
+        this._renderSetup = setup;
+        this._renderCleanup = cleanup;
+    }
+
+    /**
+     * @param {string} template
+     * @param {import('template-renderer').PartialOrCompositeRenderData} data
+     * @param {import('anki-templates').RenderMode} type
+     * @returns {import('template-renderer').RenderResult}
+     */
+    render(template, data, type) {
+        const instance = this._getTemplateInstance(template);
+        const modifiedData = this._getModifiedData(data, void 0, type);
+        return this._renderTemplate(instance, modifiedData);
+    }
+
+    /**
+     * @param {import('template-renderer').RenderMultiItem[]} items
+     * @returns {import('core').Response<import('template-renderer').RenderResult>[]}
+     */
+    renderMulti(items) {
+        /** @type {import('core').Response<import('template-renderer').RenderResult>[]} */
+        const results = [];
+        for (const {template, templateItems} of items) {
+            const instance = this._getTemplateInstance(template);
+            for (const {type, commonData, datas} of templateItems) {
+                for (const data of datas) {
+                    let result;
+                    try {
+                        const data2 = this._getModifiedData(data, commonData, type);
+                        const renderResult = this._renderTemplate(instance, data2);
+                        result = {result: renderResult};
+                    } catch (error) {
+                        result = {error: ExtensionError.serialize(error)};
+                    }
+                    results.push(result);
+                }
+            }
+        }
+        return results;
+    }
+
+    /**
+     * @param {import('template-renderer').CompositeRenderData} data
+     * @param {import('anki-templates').RenderMode} type
+     * @returns {import('anki-templates').NoteData}
+     */
+    getModifiedData(data, type) {
+        return this._getModifiedData(data, void 0, type);
+    }
+
+    // Private
+
+    /**
+     * @param {string} template
+     * @returns {import('handlebars').TemplateDelegate<import('anki-templates').NoteData>}
+     */
+    _getTemplateInstance(template) {
+        const cache = this._cache;
+        let instance = cache.get(template);
+        if (typeof instance === 'undefined') {
+            this._updateCacheSize(this._cacheMaxSize - 1);
+            instance = /** @type {import('handlebars').TemplateDelegate<import('anki-templates').NoteData>} */ (Handlebars.compileAST(template));
+            cache.set(template, instance);
+        }
+
+        return instance;
+    }
+
+    /**
+     * @param {import('handlebars').TemplateDelegate<import('anki-templates').NoteData>} instance
+     * @param {import('anki-templates').NoteData} data
+     * @returns {import('template-renderer').RenderResult}
+     */
+    _renderTemplate(instance, data) {
+        const renderSetup = this._renderSetup;
+        const renderCleanup = this._renderCleanup;
+        /** @type {string} */
+        let result;
+        /** @type {?import('template-renderer').SetupCallbackResult} */
+        let additions1;
+        /** @type {?import('template-renderer').CleanupCallbackResult} */
+        let additions2;
+        try {
+            additions1 = (typeof renderSetup === 'function' ? renderSetup(data) : null);
+            result = instance(data).replace(/^\n+|\n+$/g, '');
+        } finally {
+            additions2 = (typeof renderCleanup === 'function' ? renderCleanup(data) : null);
+        }
+        return /** @type {import('template-renderer').RenderResult} */ (Object.assign({result}, additions1, additions2));
+    }
+
+    /**
+     * @param {import('template-renderer').PartialOrCompositeRenderData} data
+     * @param {import('anki-note-builder').CommonData|undefined} commonData
+     * @param {import('anki-templates').RenderMode} type
+     * @returns {import('anki-templates').NoteData}
+     * @throws {Error}
+     */
+    _getModifiedData(data, commonData, type) {
+        if (typeof type === 'string') {
+            const typeInfo = this._dataTypes.get(type);
+            if (typeof typeInfo !== 'undefined') {
+                if (typeof commonData !== 'undefined') {
+                    const {composeData} = typeInfo;
+                    data = composeData(data, commonData);
+                } else if (typeof data.commonData === 'undefined') {
+                    throw new Error('Incomplete data');
+                }
+                const {modifier} = typeInfo;
+                return modifier(/** @type {import('template-renderer').CompositeRenderData} */ (data));
+            }
+        }
+        throw new Error(`Invalid type: ${type}`);
+    }
+
+    /**
+     * @param {number} maxSize
+     */
+    _updateCacheSize(maxSize) {
+        const cache = this._cache;
+        let removeCount = cache.size - maxSize;
+        if (removeCount <= 0) { return; }
+
+        for (const key of cache.keys()) {
+            cache.delete(key);
+            if (--removeCount <= 0) { break; }
+        }
+    }
+
+    /**
+     * @param {string} name
+     * @param {import('template-renderer').HelperFunction} helper
+     */
+    _registerHelper(name, helper) {
+        /**
+         * @this {unknown}
+         * @param {unknown[]} args
+         * @returns {unknown}
+         */
+        function wrapper(...args) {
+            const argCountM1 = Math.max(0, args.length - 1);
+            const options = /** @type {import('handlebars').HelperOptions} */ (args[argCountM1]);
+            args.length = argCountM1;
+            return helper(args, this, options);
+        }
+        Handlebars.registerHelper(name, wrapper);
+    }
+}