Use a general approach to show tooltip, fix temporary tooltip bug (#23574)

## TLDR

* Improve performance: lazy creating the tippy instances.
* Transparently support all "tooltip" elements, no need to call
`initTooltip` again and again.
* Fix a temporary tooltip re-entrance bug, which causes showing temp
content forever.
* Upgrade vue3-calendar-heatmap to 2.0.2 with lazy tippy init
(initHeatmap time decreases from 100ms to 50ms)

## Details

### The performance

Creating a lot of tippy tooltip instances is expensive. This PR doesn't
create all tippy tooltip instances, instead, it only adds "mouseover"
event listener to necessary elements, and then switches to the tippy
tooltip

### The general approach for all tooltips

Before, dynamically generated tooltips need to be called with
`initTooltip`.

After, use MutationObserver to:

* Attach the event listeners to newly created tooltip elements, work for
Vue (easier than before)
* Catch changed attributes and update the tooltip content (better than
before)

It does help a lot, eg:

https://github.com/go-gitea/gitea/blob/1a4efa0ee9a49d48549be7479a46be133b9bc260/web_src/js/components/PullRequestMergeForm.vue#L33-L36

### Temporary tooltip re-entrance bug

To reproduce, on try.gitea.io, click the "copy clone url" quickly, then
the tooltip will be "Copied!" forever.

After this PR, with the help of `attachTippyTooltip`, the tooltip
content could be reset to the default correctly.

### Other changes

* `data-tooltip-content` is preferred from now on, the old
`data-content` may cause conflicts with other modules.
* `data-placement` was only used for tooltip, so it's renamed to
`data-tooltip-placement`, and removed from `createTippy`.

1 files changed, 97 insertions, 20 deletions

diff --git a/web_src/js/modules/tippy.js b/web_src/js/modules/tippy.js
index 4872608ecd..98d0ff84b6 100644
--- a/web_src/js/modules/tippy.js
+++ b/web_src/js/modules/tippy.js
@@ -3,7 +3,6 @@ import tippy from 'tippy.js';
 export function createTippy(target, opts = {}) {
   const instance = tippy(target, {
     appendTo: document.body,
-    placement: target.getAttribute('data-placement') || 'top-start',
     animation: false,
     allowHTML: false,
     hideOnClick: false,
@@ -25,38 +24,116 @@ export function createTippy(target, opts = {}) {
   return instance;
 }
 
-export function initTooltip(el, props = {}) {
-  const content = el.getAttribute('data-content') || props.content;
+/**
+ * Attach a tooltip tippy to the given target element.
+ * If the target element already has a tooltip tippy attached, the tooltip will be updated with the new content.
+ * If the target element has no content, then no tooltip will be attached, and it returns null.
+ *
+ * Note: "tooltip" doesn't equal to "tippy". "tooltip" means a auto-popup content, it just uses tippy as the implementation.
+ *
+ * @param target {HTMLElement}
+ * @param content {null|string}
+ * @returns {null|tippy}
+ */
+function attachTooltip(target, content = null) {
+  content = content ?? getTooltipContent(target);
   if (!content) return null;
-  if (!el.hasAttribute('aria-label')) el.setAttribute('aria-label', content);
-  return createTippy(el, {
+
+  const props = {
     content,
     delay: 100,
     role: 'tooltip',
-    ...(el.getAttribute('data-tooltip-interactive') === 'true' ? {interactive: true} : {}),
-    ...props,
-  });
-}
+    placement: target.getAttribute('data-tooltip-placement') || 'top-start',
+    ...(target.getAttribute('data-tooltip-interactive') === 'true' ? {interactive: true} : {}),
+  };
 
-export function showTemporaryTooltip(target, content) {
-  let tippy, oldContent;
-  if (target._tippy) {
-    tippy = target._tippy;
-    oldContent = tippy.props.content;
+  if (!target._tippy) {
+    createTippy(target, props);
   } else {
-    tippy = initTooltip(target, {content});
+    target._tippy.setProps(props);
+  }
+  return target._tippy;
+}
+
+/**
+ * Creating tooltip tippy instance is expensive, so we only create it when the user hovers over the element
+ * According to https://www.w3.org/TR/DOM-Level-3-Events/#events-mouseevent-event-order , mouseover event is fired before mouseenter event
+ * Some old browsers like Pale Moon doesn't support "mouseenter(capture)"
+ * The tippy by default uses "mouseenter" event to show, so we use "mouseover" event to switch to tippy
+ * @param e {Event}
+ */
+function lazyTooltipOnMouseHover(e) {
+  e.target.removeEventListener('mouseover', lazyTooltipOnMouseHover, true);
+  attachTooltip(this);
+}
+
+function getTooltipContent(target) {
+  // prefer to always use the "[data-tooltip-content]" attribute
+  // for backward compatibility, we also support the ".tooltip[data-content]" attribute
+  // in next PR, refactor all the ".tooltip[data-content]" to "[data-tooltip-content]"
+  let content = target.getAttribute('data-tooltip-content');
+  if (!content && target.classList.contains('tooltip')) {
+    content = target.getAttribute('data-content');
+  }
+  return content;
+}
+
+/**
+ * Activate the tooltip for all children elements
+ * And if the element has no aria-label, use the tooltip content as aria-label
+ * @param target {HTMLElement}
+ */
+function attachChildrenLazyTooltip(target) {
+  // the selector must match the logic in getTippyTooltipContent
+  for (const el of target.querySelectorAll('[data-tooltip-content], .tooltip[data-content]')) {
+    el.addEventListener('mouseover', lazyTooltipOnMouseHover, true);
+
+    // meanwhile, if the element has no aria-label, use the tooltip content as aria-label
+    if (!el.hasAttribute('aria-label')) {
+      const content = getTooltipContent(el);
+      if (content) {
+        el.setAttribute('aria-label', content);
+      }
+    }
   }
+}
 
+export function initGlobalTooltips() {
+  // use MutationObserver to detect new elements added to the DOM, or attributes changed
+  const observer = new MutationObserver((mutationList) => {
+    for (const mutation of mutationList) {
+      if (mutation.type === 'childList') {
+        // mainly for Vue components and AJAX rendered elements
+        for (const el of mutation.addedNodes) {
+          // handle all "tooltip" elements in added nodes which have 'querySelectorAll' method, skip non-related nodes (eg: "#text")
+          if ('querySelectorAll' in el) {
+            attachChildrenLazyTooltip(el);
+          }
+        }
+      } else if (mutation.type === 'attributes') {
+        // sync the tooltip content if the attributes change
+        attachTooltip(mutation.target);
+      }
+    }
+  });
+  observer.observe(document, {
+    subtree: true,
+    childList: true,
+    attributeFilter: ['data-tooltip-content', 'data-content'],
+  });
+
+  attachChildrenLazyTooltip(document.documentElement);
+}
+
+export function showTemporaryTooltip(target, content) {
+  const tippy = target._tippy ?? attachTooltip(target, content);
   tippy.setContent(content);
   if (!tippy.state.isShown) tippy.show();
   tippy.setProps({
     onHidden: (tippy) => {
-      if (oldContent) {
-        tippy.setContent(oldContent);
-        tippy.setProps({onHidden: undefined});
-      } else {
+      // reset the default tooltip content, if no default, then this temporary tooltip could be destroyed
+      if (!attachTooltip(target)) {
         tippy.destroy();
-        // after destroy, the `_tippy` is detached, it can't do "setProps (etc...)" anymore
       }
     },
   });