fix build, take 2

app/javascript/flavours/glitch/components/hashtag_bar.tsx

@@ -0,0 +1,234 @@
+import { useState, useCallback } from 'react';
+
+import { FormattedMessage } from 'react-intl';
+
+import { Link } from 'react-router-dom';
+
+import type { List, Record } from 'immutable';
+
+import { groupBy, minBy } from 'lodash';
+
+import { getStatusContent } from './status_content';
+
+// Fit on a single line on desktop
+const VISIBLE_HASHTAGS = 3;
+
+// Those types are not correct, they need to be replaced once this part of the state is typed
+export type TagLike = Record<{ name: string }>;
+export type StatusLike = Record<{
+  tags: List<TagLike>;
+  contentHTML: string;
+  media_attachments: List<unknown>;
+  spoiler_text?: string;
+}>;
+
+function normalizeHashtag(hashtag: string) {
+  return (
+    hashtag && hashtag.startsWith('#') ? hashtag.slice(1) : hashtag
+  ).normalize('NFKC');
+}
+
+function isNodeLinkHashtag(element: Node): element is HTMLLinkElement {
+  return (
+    element instanceof HTMLAnchorElement &&
+    // it may be a <a> starting with a hashtag
+    (element.textContent?.[0] === '#' ||
+      // or a #<a>
+      element.previousSibling?.textContent?.[
+        element.previousSibling.textContent.length - 1
+      ] === '#')
+  );
+}
+
+/**
+ * Removes duplicates from an hashtag list, case-insensitive, keeping only the best one
+ * "Best" here is defined by the one with the more casing difference (ie, the most camel-cased one)
+ * @param hashtags The list of hashtags
+ * @returns The input hashtags, but with only 1 occurence of each (case-insensitive)
+ */
+function uniqueHashtagsWithCaseHandling(hashtags: string[]) {
+  const groups = groupBy(hashtags, (tag) =>
+    tag.normalize('NFKD').toLowerCase(),
+  );
+
+  return Object.values(groups).map((tags) => {
+    if (tags.length === 1) return tags[0];
+
+    // The best match is the one where we have the less difference between upper and lower case letter count
+    const best = minBy(tags, (tag) => {
+      const upperCase = Array.from(tag).reduce(
+        (acc, char) => (acc += char.toUpperCase() === char ? 1 : 0),
+        0,
+      );
+
+      const lowerCase = tag.length - upperCase;
+
+      return Math.abs(lowerCase - upperCase);
+    });
+
+    return best ?? tags[0];
+  });
+}
+
+// Create the collator once, this is much more efficient
+const collator = new Intl.Collator(undefined, {
+  sensitivity: 'base', // we use this to emulate the ASCII folding done on the server-side, hopefuly more efficiently
+});
+
+function localeAwareInclude(collection: string[], value: string) {
+  const normalizedValue = value.normalize('NFKC');
+
+  return !!collection.find(
+    (item) => collator.compare(item.normalize('NFKC'), normalizedValue) === 0,
+  );
+}
+
+// We use an intermediate function here to make it easier to test
+export function computeHashtagBarForStatus(status: StatusLike): {
+  statusContentProps: { statusContent: string };
+  hashtagsInBar: string[];
+} {
+  let statusContent = getStatusContent(status);
+
+  const tagNames = status
+    .get('tags')
+    .map((tag) => tag.get('name'))
+    .toJS();
+
+  // this is returned if we stop the processing early, it does not change what is displayed
+  const defaultResult = {
+    statusContentProps: { statusContent },
+    hashtagsInBar: [],
+  };
+
+  // return early if this status does not have any tags
+  if (tagNames.length === 0) return defaultResult;
+
+  const template = document.createElement('template');
+  template.innerHTML = statusContent.trim();
+
+  const lastChild = template.content.lastChild;
+
+  if (!lastChild || lastChild.nodeType === Node.TEXT_NODE) return defaultResult;
+
+  template.content.removeChild(lastChild);
+  const contentWithoutLastLine = template;
+
+  // First, try to parse
+  const contentHashtags = Array.from(
+    contentWithoutLastLine.content.querySelectorAll<HTMLLinkElement>('a[href]'),
+  ).reduce<string[]>((result, link) => {
+    if (isNodeLinkHashtag(link)) {
+      if (link.textContent) result.push(normalizeHashtag(link.textContent));
+    }
+    return result;
+  }, []);
+
+  // Now we parse the last line, and try to see if it only contains hashtags
+  const lastLineHashtags: string[] = [];
+  // try to see if the last line is only hashtags
+  let onlyHashtags = true;
+
+  const normalizedTagNames = tagNames.map((tag) => tag.normalize('NFKC'));
+
+  Array.from(lastChild.childNodes).forEach((node) => {
+    if (isNodeLinkHashtag(node) && node.textContent) {
+      const normalized = normalizeHashtag(node.textContent);
+
+      if (!localeAwareInclude(normalizedTagNames, normalized)) {
+        // stop here, this is not a real hashtag, so consider it as text
+        onlyHashtags = false;
+        return;
+      }
+
+      if (!localeAwareInclude(contentHashtags, normalized))
+        // only add it if it does not appear in the rest of the content
+        lastLineHashtags.push(normalized);
+    } else if (node.nodeType !== Node.TEXT_NODE || node.nodeValue?.trim()) {
+      // not a space
+      onlyHashtags = false;
+    }
+  });
+
+  const hashtagsInBar = tagNames.filter((tag) => {
+    const normalizedTag = tag.normalize('NFKC');
+    // the tag does not appear at all in the status content, it is an out-of-band tag
+    return (
+      !localeAwareInclude(contentHashtags, normalizedTag) &&
+      !localeAwareInclude(lastLineHashtags, normalizedTag)
+    );
+  });
+
+  const isOnlyOneLine = contentWithoutLastLine.content.childElementCount === 0;
+  const hasMedia = status.get('media_attachments').size > 0;
+  const hasSpoiler = !!status.get('spoiler_text');
+
+  // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition -- due to https://github.com/microsoft/TypeScript/issues/9998
+  if (onlyHashtags && ((hasMedia && !hasSpoiler) || !isOnlyOneLine)) {
+    // if the last line only contains hashtags, and we either:
+    // - have other content in the status
+    // - dont have other content, but a media and no CW. If it has a CW, then we do not remove the content to avoid having an empty content behind the CW button
+    statusContent = contentWithoutLastLine.innerHTML;
+    // and add the tags to the bar
+    hashtagsInBar.push(...lastLineHashtags);
+  }
+
+  return {
+    statusContentProps: { statusContent },
+    hashtagsInBar: uniqueHashtagsWithCaseHandling(hashtagsInBar),
+  };
+}
+
+/**
+ *  This function will process a status to, at the same time (avoiding parsing it twice):
+ * - build the HashtagBar for this status
+ * - remove the last-line hashtags from the status content
+ * @param status The status to process
+ * @returns Props to be passed to the <StatusContent> component, and the hashtagBar to render
+ */
+export function getHashtagBarForStatus(status: StatusLike) {
+  const { statusContentProps, hashtagsInBar } =
+    computeHashtagBarForStatus(status);
+
+  return {
+    statusContentProps,
+    hashtagBar: <HashtagBar hashtags={hashtagsInBar} />,
+  };
+}
+
+const HashtagBar: React.FC<{
+  hashtags: string[];
+}> = ({ hashtags }) => {
+  const [expanded, setExpanded] = useState(false);
+  const handleClick = useCallback(() => {
+    setExpanded(true);
+  }, []);
+
+  if (hashtags.length === 0) {
+    return null;
+  }
+
+  const revealedHashtags = expanded
+    ? hashtags
+    : hashtags.slice(0, VISIBLE_HASHTAGS);
+
+  return (
+    <div className='hashtag-bar'>
+      {revealedHashtags.map((hashtag) => (
+        <Link key={hashtag} to={`/tags/${hashtag}`}>
+          #<span>{hashtag}</span>
+        </Link>
+      ))}
+
+      {!expanded && hashtags.length > VISIBLE_HASHTAGS && (
+        <button className='link-button' onClick={handleClick}>
+          <FormattedMessage
+            id='hashtags.and_other'
+            defaultMessage='…and {count, plural, other {# more}}'
+            values={{ count: hashtags.length - VISIBLE_HASHTAGS }}
+          />
+        </button>
+      )}
+    </div>
+  );
+};