pkp · jyhein · Jan 9, 2025
diff --git a/pages/article/ArticleHandler.php b/pages/article/ArticleHandler.php
@@ -24,6 +24,7 @@
 use APP\observers\events\UsageEvent;
 use APP\payment\ojs\OJSCompletedPaymentDAO;
 use APP\payment\ojs\OJSPaymentManager;
+use APP\publication\Publication;
 use APP\security\authorization\OjsJournalMustPublishPolicy;
 use APP\submission\Submission;
 use APP\template\TemplateManager;
@@ -360,6 +361,12 @@ public function view($args, $request)
                 $templateMgr->assign('purchaseArticleEnabled', true);
             }
 
+            $templateMgr->assign('pubLocaleData', $this->getMultilingualMetadataOpts(
+                $publication,
+                $templateMgr->getTemplateVars('currentLocale'),
+                $templateMgr->getTemplateVars('activeTheme')->getOption('showMultilingualMetadata') ?: [],
+            ));
+
             if (!Hook::call('ArticleHandler::view', [&$request, &$issue, &$article, $publication])) {
                 $templateMgr->display('frontend/pages/article.tpl');
                 event(new UsageEvent(Application::ASSOC_TYPE_SUBMISSION, $context, $article, null, null, $this->issue));
@@ -617,4 +624,26 @@ public function userCanViewGalley($request, $articleId, $galleyId = null)
         }
         return true;
     }
+
+    /**
+     * Multilingual publication metadata for template:
+     * showMultilingualMetadataOpts - Show metadata in other languages: title (+ subtitle), keywords, abstract, etc.
+     */
+    protected function getMultilingualMetadataOpts(Publication $publication, string $currentUILocale, array $showMultilingualMetadataOpts): array
+    {
+        $langNames = collect($publication->getLanguageNames())
+            ->sortKeys();
+        $langs = $langNames->keys();
+        return [
+            'opts' => array_flip($showMultilingualMetadataOpts),
+            'localeNames' => $langNames,
+            'langAttrs' => $langNames->map(fn ($_, $l) => preg_replace(['/@.+$/', '/_/'], ['', '-'], $l))->toArray() /* remove @ and text after */,
+            'localeOrder' => collect($publication->getLocalePrecedence())
+                ->intersect($langs) /* remove locales not in publication's languages */
+                ->concat($langs)
+                ->unique()
+                ->values()
+                ->toArray(),
+        ];
+    }
 }
diff --git a/plugins/themes/default/DefaultThemePlugin.php b/plugins/themes/default/DefaultThemePlugin.php
@@ -124,6 +124,30 @@ public function init()
             'default' => 'none',
         ]);
 
+        $this->addOption('showMultilingualMetadata', 'FieldOptions', [
+            'label' => __('plugins.themes.default.option.metadata.label'),
+            'description' => __('plugins.themes.default.option.metadata.description'),
+            'options' => [
+                [
+                    'value' => 'title',
+                    'label' => __('submission.title'),
+                ],
+                [
+                    'value' => 'abstract',
+                    'label' => __('common.abstract'),
+                ],
+                [
+                    'value' => 'keywords',
+                    'label' => __('common.keywords'),
+                ],
+                [
+                    'value' => 'author',
+                    'label' => __('default.groups.name.author'),
+                ],
+            ],
+            'default' => [],
+        ]);
+
 
         // Load primary stylesheet
         $this->addStyle('stylesheet', 'styles/index.less');

diff --git a/plugins/themes/default/js/main.js b/plugins/themes/default/js/main.js
@@ -114,3 +114,177 @@
 	});
 
 })(jQuery);
+
+/**
+ * Create language buttons to show multilingual metadata
+ * [data-pkp-switcher-data]: Publication data for the switchers to control
+ * [data-pkp-switcher]: Switchers' containers
+ */
+(() => {
+	function createSwitcher(switcherContainer, data, localeOrder, localeNames) {
+		// Get all locales for the switcher from the data
+		const locales = Object.keys(Object.assign({}, ...Object.values(data)));
+		// The initially selected locale
+		let selectedLocale = null;
+		// Create and sort to alphabetical order
+		const buttons = localeOrder
+			.map((locale) => {
+				if (locales.indexOf(locale) === -1) {
+					return null;
+				}
+				if (!selectedLocale) {
+					selectedLocale = locale;
+				}
+
+				const isSelectedLocale = locale === selectedLocale;
+				const button = document.createElement('button');
+
+				button.type = 'button';
+				button.classList.add('pkpBadge', 'pkpBadge--button');
+				button.value = locale;
+				button.tabIndex = '-1';
+				button.role = 'option';
+				button.ariaHidden = `${!isSelectedLocale}`;
+				button.textContent = localeNames[locale];
+				if (isSelectedLocale) {
+					button.ariaPressed = 'false';
+					button.ariaCurrent = 'true';
+					button.tabIndex = '0';
+				}
+				return button;
+			})
+			.filter((btn) => btn)
+			.sort((a, b) => a.value.localeCompare(b.value));
+
+		// If only one button, set it disabled
+		if (buttons.length === 1) {
+			buttons[0].disabled = true;
+		}
+
+		buttons.forEach((btn, i) => {
+			switcherContainer.appendChild(btn);
+		});
+
+		return buttons;
+	}
+
+	/**
+	 * Sync data in elements to match the selected locale 
+	 */
+	function syncDataElContents(locale, propsData, langAttrs) {
+		for (prop in propsData.data) {
+			propsData.dataEls[prop].lang = langAttrs[locale];
+			propsData.dataEls[prop].innerHTML = propsData.data[prop][locale] ?? '';
+		}
+	}
+
+	/**
+	 * Toggle visibility of the buttons
+	 * setValue == true => aria-hidden == true, aria-expanded == false
+	 */
+	function setVisibility(switcherContainer, buttons, currentSelected, setValue) {
+		// Toggle switcher container's listbox/none-role
+		// Listbox when buttons visible and none when hidden
+		switcherContainer.role = setValue ? 'none' : 'listbox';
+		currentSelected.btn.ariaPressed = `${!setValue}`;
+		buttons.forEach((btn) => {
+			if (btn !== currentSelected.btn) {
+				btn.ariaHidden = `${setValue}`;
+			}
+		});
+		switcherContainer.ariaExpanded = `${!setValue}`;
+	}
+
+	function setSwitcher(propsData, switcherContainer, localeOrder, localeNames, langAttrs) {
+		// Create buttons and append them to the switcher container
+		const buttons = createSwitcher(switcherContainer, propsData.data, localeOrder, localeNames);
+		const currentSelected = {btn: switcherContainer.querySelector('[tabindex="0"]')};
+		const focused = {btn: currentSelected.btn};
+
+		// Sync contents in data elements to match the selected locale (currentSelected.btn.value)
+		syncDataElContents(currentSelected.btn.value, propsData, langAttrs);
+
+		// Do not add listeners if just one button, it is disabled
+		if (buttons.length < 2) {
+			return;
+		}
+
+		// New button switches language and syncs data contents. Same button hides buttons.
+		switcherContainer.addEventListener('click', (evt) => {
+			const newSelectedBtn = evt.target;
+			if (newSelectedBtn.type === 'button') {
+				if (newSelectedBtn !== currentSelected.btn) {
+					syncDataElContents(newSelectedBtn.value, propsData, langAttrs);
+					// Aria
+					currentSelected.btn.ariaCurrent = null;
+					newSelectedBtn.ariaCurrent = 'true';
+					currentSelected.btn.ariaPressed = null;
+					newSelectedBtn.ariaPressed = 'true';
+					// Tab index
+					currentSelected.btn.tabIndex = '-1';
+					newSelectedBtn.tabIndex = '0';
+					// Update current and focused button
+					currentSelected.btn = focused.btn = newSelectedBtn;
+					focused.btn.focus();
+				} else {
+					setVisibility(switcherContainer, buttons, currentSelected, switcherContainer.ariaExpanded === 'true');
+				}
+			}
+		});
+
+		// Hide buttons when focus out
+		switcherContainer.addEventListener('focusout', (evt) => {
+			// For safari losing button focus
+			if (evt.target.parentElement === switcherContainer && switcherContainer.ariaExpanded === 'true') {
+				focused.btn.focus();
+			}
+			if (!evt.relatedTarget || evt.relatedTarget && evt.relatedTarget.parentElement !== switcherContainer) {
+				setVisibility(switcherContainer, buttons, currentSelected, 'true');
+			}
+		});
+
+		// Arrow keys left and right cycles button focus when buttons visible. Set focused button.
+		switcherContainer.addEventListener("keydown", (evt) => {
+			if (switcherContainer.ariaExpanded === 'true' && evt.target.type === 'button' && (evt.key === "ArrowRight" || evt.key === "ArrowLeft")) {
+				focused.btn = (evt.key === "ArrowRight")
+					? (focused.btn.nextElementSibling ?? buttons[0])
+					: (focused.btn.previousElementSibling ?? buttons[buttons.length - 1]);
+				focused.btn.focus();
+			}
+		});
+	}
+
+	/**
+	 * Set all multilingual data and elements for the switchers
+	 */
+	function setSwitchersData(dataEls, pubLocaleData) {
+		const propsData = {};
+		dataEls.forEach((dataEl) => {
+			const propName = dataEl.getAttribute('data-pkp-switcher-data');
+			const switcherName = pubLocaleData[propName].switcher;
+			if (!propsData[switcherName]) {
+				propsData[switcherName] = {data: [], dataEls: []};
+			}
+			propsData[switcherName].data[propName] = pubLocaleData[propName].data;
+			propsData[switcherName].dataEls[propName] = dataEl;
+		});
+		return propsData;
+	}
+
+	(() => {
+		const switcherContainers = document.querySelectorAll('[data-pkp-switcher]');
+
+		if (!switcherContainers.length) return;
+
+		const pubLocaleData = JSON.parse(pubLocaleDataJson);
+		const switchersDataEls = document.querySelectorAll('[data-pkp-switcher-data]');
+		const switchersData = setSwitchersData(switchersDataEls, pubLocaleData);
+		// Create and set switchers, and sync data on the page
+		switcherContainers.forEach((switcherContainer) => {
+			const switcherName = switcherContainer.getAttribute('data-pkp-switcher');
+			if (switchersData[switcherName]) {
+				setSwitcher(switchersData[switcherName], switcherContainer, pubLocaleData.localeOrder, pubLocaleData.localeNames, pubLocaleData.langAttrs);
+			}
+		});
+	})();
+})();
diff --git a/plugins/themes/default/locale/en/locale.po b/plugins/themes/default/locale/en/locale.po
@@ -98,3 +98,21 @@ msgstr "Next slide"
 
 msgid "plugins.themes.default.prevSlide"
 msgstr "Previous slide"
+
+msgid "plugins.themes.default.option.metadata.label"
+msgstr "Show article metadata on the article landing page"
+
+msgid "plugins.themes.default.option.metadata.description"
+msgstr "Select the article metadata to show in other languages."
+
+msgid "plugins.themes.default.languageSwitcher.ariaDescription.titles"
+msgstr "The article title and subtitle languages:"
+
+msgid "plugins.themes.default.languageSwitcher.ariaDescription.author"
+msgstr "The author's affiliation languages:"
+
+msgid "plugins.themes.default.languageSwitcher.ariaDescription.keywords"
+msgstr "The keywords languages:"
+
+msgid "plugins.themes.default.languageSwitcher.ariaDescription.abstract"
+msgstr "The abstract languages:"
diff --git a/plugins/themes/default/styles/objects/article_details.less b/plugins/themes/default/styles/objects/article_details.less
@@ -61,11 +61,16 @@
 				font-weight: @bold;
 			}
 
-			&.doi .label,
-			&.keywords .label {
+			&.doi .label {
 				display: inline;
 				font-size: @font-base;
 			}
+
+			&.keywords .label,
+			&.abstract .label {
+				display: inline-flex;
+				font-size: @font-base;
+			}
 		}
 
 		.sub_item {
@@ -281,6 +286,71 @@
 		}
 	}
 
+	/**
+	 * Language switcher
+	*/
+
+	.pkpBadge {
+		padding: 0.25em 1em;
+		font-size: @font-tiny;
+		font-weight: @normal;
+		line-height: 1.5em;
+		border: 1px solid @bg-border-color-light;
+		border-radius: 1.2em;
+		color: @text;
+	}
+
+	.pkpBadge--button {
+		background: inherit;
+		text-decoration: none;
+		cursor: pointer;
+
+		&:hover {
+			border-color: @text;
+			outline: 0;
+		}
+		&:disabled,
+		&:disabled:hover {
+			color: #fff;
+			background: @bg-dark;
+			border-color: @bg-dark;
+			cursor: not-allowed;
+		}
+	}
+
+	[data-pkp-switcher] [tabindex="0"] {
+		font-weight: @bold;
+	}
+
+	[data-pkp-switcher],
+	[data-pkp-switcher] * {
+		display: inline-flex;
+	}
+
+	[data-pkp-switcher] [aria-hidden="true"] {
+		display: none;
+	}
+
+	[data-pkp-switcher] [aria-hidden="false"] {
+		animation: fadeIn 0.7s ease-in-out;
+
+		@keyframes fadeIn {
+			0% {
+				display: none;
+				opacity: 0;
+			}
+
+			1% {
+				display: inline-flex;
+				opacity: 0;
+			}
+
+			100% {
+				opacity: 1;
+			}
+		}
+	}
+
 	@media(min-width: @screen-phone) {
 
 		.entry_details {
@@ -315,8 +385,7 @@
 				font-weight: @bold;
 			}
 
-			&.doi .label,
-			&.keywords .label {
+			&.doi .label {
 				display: inline;
 				font-size: @font-base;
 			}