feat(links): Copy Lotus Link permalinks, in-app recognition, /home redirect for joined rooms, via= alias, OIDC deep-link redirect (#130)

matrix.to cannot target this deployment (Cinny adapter hard-codes
app.cinny.in; web-instance[] is Element-only, allowlisted), so add a
"Copy Lotus Link" next to every Copy Link (message menu, space header
menu, sidebar space tab) producing https://<this origin>/home/<room>/<event>
?viaServers=… via plugins/lotus-permalink.ts. Lotus links in messages are
rewritten to their matrix.to form inside the HTML parser so they render as
room/event mentions and navigate in place.

/home/<room> for a joined room that belongs to a space or Direct now
redirects to its own route (was a preview card with a View button; also
the form matrix.to → Cinny links use). ?via= is accepted as an alias of
?viaServers= (what the matrix.to Cinny adapter emits). A deep link
visited while logged out is now honoured after an OIDC login: the OIDC
callback reloads at the app root, which discarded the stored path — the
index loader consumes it via the shared takeAfterLoginPath().

Verified end-to-end with Playwright on a local Synapse: logged-out cold
link → login → lands on the event under the space route; menu copies the
expected link; a pasted Lotus link renders as a mention and jumps in
place; both space menus copy the space link.

Closes #130

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/plugins/lotus-permalink.test.ts

@@ -0,0 +1,91 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  getLotusRoomPermalink,
+  getLotusSpacePermalink,
+  lotusPermalinkToMatrixTo,
+  parseLotusPermalink,
+} from './lotus-permalink';
+
+const BASE = 'https://chat.lotusguild.org/';
+
+test('builds room / event / space permalinks with encoded ids and viaServers', () => {
+  assert.equal(
+    getLotusRoomPermalink(BASE, '!abc:matrix.lotusguild.org', '$ev1', ['matrix.lotusguild.org']),
+    'https://chat.lotusguild.org/home/!abc%3Amatrix.lotusguild.org/%24ev1?viaServers=matrix.lotusguild.org',
+  );
+  assert.equal(
+    getLotusRoomPermalink(BASE, '#general:matrix.lotusguild.org'),
+    'https://chat.lotusguild.org/home/%23general%3Amatrix.lotusguild.org',
+  );
+  assert.equal(
+    getLotusSpacePermalink('https://chat.lotusguild.org', '#guild:matrix.lotusguild.org'),
+    'https://chat.lotusguild.org/%23guild%3Amatrix.lotusguild.org',
+  );
+});
+
+test('parses its own output back (encoded and decoded forms)', () => {
+  const link = getLotusRoomPermalink(BASE, '!abc:lotus', '$ev1', ['a.org', 'b.org']);
+  assert.deepEqual(parseLotusPermalink(BASE, link), {
+    roomIdOrAlias: '!abc:lotus',
+    eventId: '$ev1',
+    viaServers: ['a.org', 'b.org'],
+  });
+  assert.deepEqual(parseLotusPermalink(BASE, 'https://chat.lotusguild.org/home/!abc:lotus/$ev1'), {
+    roomIdOrAlias: '!abc:lotus',
+    eventId: '$ev1',
+    viaServers: undefined,
+  });
+  assert.deepEqual(parseLotusPermalink(BASE, 'https://chat.lotusguild.org/direct/!dm:lotus/'), {
+    roomIdOrAlias: '!dm:lotus',
+    viaServers: undefined,
+  });
+});
+
+test('space routes: lobby → the space, nested room → the room', () => {
+  assert.deepEqual(parseLotusPermalink(BASE, 'https://chat.lotusguild.org/%23guild%3Alotus/'), {
+    roomIdOrAlias: '#guild:lotus',
+    viaServers: undefined,
+  });
+  assert.deepEqual(
+    parseLotusPermalink(BASE, 'https://chat.lotusguild.org/%23guild%3Alotus/!room%3Alotus/%24e'),
+    { roomIdOrAlias: '!room:lotus', eventId: '$e', viaServers: undefined },
+  );
+});
+
+test('accepts the matrix.to Cinny adapter form (?via=a,b)', () => {
+  assert.deepEqual(
+    parseLotusPermalink(BASE, 'https://chat.lotusguild.org/home/!r:x?via=a.org,b.org'),
+    {
+      roomIdOrAlias: '!r:x',
+      viaServers: ['a.org', 'b.org'],
+    },
+  );
+});
+
+test('rejects other origins, non-room routes and malformed ids', () => {
+  assert.equal(parseLotusPermalink(BASE, 'https://app.cinny.in/home/!r:x'), undefined);
+  assert.equal(parseLotusPermalink(BASE, 'https://chat.lotusguild.org/home/settings'), undefined);
+  assert.equal(parseLotusPermalink(BASE, 'https://chat.lotusguild.org/explore/lotus'), undefined);
+  assert.equal(
+    parseLotusPermalink(BASE, 'https://chat.lotusguild.org/home/!r:x/notanevent'),
+    undefined,
+  );
+  assert.equal(
+    parseLotusPermalink(BASE, 'https://chat.lotusguild.org.evil.com/home/!r:x'),
+    undefined,
+  );
+  assert.equal(parseLotusPermalink(BASE, 'https://chat.lotusguild.org'), undefined);
+});
+
+test('rewrites to the matrix.to form the existing mention pipeline understands', () => {
+  assert.equal(
+    lotusPermalinkToMatrixTo(BASE, 'https://chat.lotusguild.org/home/!r:x/$e?viaServers=a.org'),
+    'https://matrix.to/#/!r:x/$e?via=a.org',
+  );
+  assert.equal(
+    lotusPermalinkToMatrixTo(BASE, 'https://chat.lotusguild.org/%23guild%3Ax/'),
+    'https://matrix.to/#/#guild:x',
+  );
+  assert.equal(lotusPermalinkToMatrixTo(BASE, 'https://example.org/home/!r:x'), undefined);
+});

src/app/plugins/lotus-permalink.ts

@@ -0,0 +1,109 @@
+import { getHomeRoomPath, getSpacePath, withSearchParam } from '../pages/pathUtils';
+import { _RoomSearchParams } from '../pages/paths';
+import { MatrixToRoom, MatrixToRoomEvent } from './matrix-to';
+
+/**
+ * [Gitea #130] Direct Lotus permalinks.
+ *
+ * `matrix.to` cannot be pointed at this deployment (its Cinny adapter is
+ * hard-coded to app.cinny.in and `web-instance[]` only works for Element), so
+ * next to every "Copy Link" there is a "Copy Lotus Link" that yields
+ * `https://<this deployment>/home/<room>/<event>?viaServers=…` — the same
+ * routes the app already serves cold (logged-out → login → back to the room).
+ *
+ * `baseUrl` is `getOriginBaseUrl(hashRouter)` so the result is right for any
+ * deployment and for the hash-router config.
+ */
+
+const trimSlash = (s: string): string => s.replace(/\/+$/, '');
+
+const withVia = (path: string, viaServers?: string[]): string =>
+  viaServers && viaServers.length > 0
+    ? withSearchParam<_RoomSearchParams>(path, { viaServers: viaServers.join(',') })
+    : path;
+
+export const getLotusRoomPermalink = (
+  baseUrl: string,
+  roomIdOrAlias: string,
+  eventId?: string,
+  viaServers?: string[],
+): string => `${trimSlash(baseUrl)}${withVia(getHomeRoomPath(roomIdOrAlias, eventId), viaServers)}`;
+
+export const getLotusSpacePermalink = (
+  baseUrl: string,
+  spaceIdOrAlias: string,
+  viaServers?: string[],
+): string => `${trimSlash(baseUrl)}${withVia(getSpacePath(spaceIdOrAlias), viaServers)}`;
+
+const tryDecode = (value: string): string => {
+  try {
+    return decodeURIComponent(value);
+  } catch {
+    return value;
+  }
+};
+
+const isRoomIdOrAlias = (s: string): boolean => /^[!#][^/\s]+:[^/\s]+$/.test(s);
+const isEventId = (s: string): boolean => /^\$[^/\s]+$/.test(s);
+
+/**
+ * Parse a link into the same shape the matrix.to parsers return, when it
+ * points at THIS deployment's room/space routes:
+ *
+ *   <base>/home/<room>/<event>?viaServers=a,b
+ *   <base>/direct/<room>/<event>
+ *   <base>/<space>/                      (space lobby)
+ *   <base>/<space>/<room>/<event>        (room inside a space → the room)
+ *
+ * Anything else — settings pages, explore, a different origin — is undefined.
+ * `via` is accepted as an alias of `viaServers` because the matrix.to Cinny
+ * adapter emits it.
+ */
+export const parseLotusPermalink = (
+  baseUrl: string,
+  href: string,
+): MatrixToRoom | MatrixToRoomEvent | undefined => {
+  const base = trimSlash(baseUrl);
+  if (!href.startsWith(`${base}/`)) return undefined;
+  const rest = href.slice(base.length);
+  let url: URL;
+  try {
+    url = new URL(rest, 'http://lotus.invalid');
+  } catch {
+    return undefined;
+  }
+  const segments = url.pathname
+    .split('/')
+    .filter((s) => s.length > 0)
+    .map(tryDecode);
+  const via = [...url.searchParams.getAll('viaServers'), ...url.searchParams.getAll('via')]
+    .flatMap((v) => v.split(','))
+    .map((v) => v.trim())
+    .filter((v) => v.length > 0);
+  const viaServers = via.length > 0 ? via : undefined;
+
+  let roomIdOrAlias: string | undefined;
+  let eventId: string | undefined;
+
+  if (segments[0] === 'home' || segments[0] === 'direct') {
+    [, roomIdOrAlias, eventId] = segments;
+  } else if (segments[0] && isRoomIdOrAlias(segments[0])) {
+    // /<space>/ or /<space>/<room>/<event>
+    roomIdOrAlias = segments[1] && isRoomIdOrAlias(segments[1]) ? segments[1] : segments[0];
+    if (segments[1] && isRoomIdOrAlias(segments[1])) [, , eventId] = segments;
+  }
+
+  if (!roomIdOrAlias || !isRoomIdOrAlias(roomIdOrAlias)) return undefined;
+  if (eventId !== undefined && !isEventId(eventId)) return undefined;
+  return eventId ? { roomIdOrAlias, eventId, viaServers } : { roomIdOrAlias, viaServers };
+};
+
+/** Rewrite a Lotus permalink as the matrix.to link the rest of the app already understands. */
+export const lotusPermalinkToMatrixTo = (baseUrl: string, href: string): string | undefined => {
+  const parsed = parseLotusPermalink(baseUrl, href);
+  if (!parsed) return undefined;
+  const fragment =
+    'eventId' in parsed ? `${parsed.roomIdOrAlias}/${parsed.eventId}` : parsed.roomIdOrAlias;
+  const query = parsed.viaServers ? `?${parsed.viaServers.map((s) => `via=${s}`).join('&')}` : '';
+  return `https://matrix.to/#/${fragment}${query}`;
+};

src/app/plugins/react-custom-html-parser.tsx

@@ -23,6 +23,7 @@ import Linkify from 'linkify-react';
 import { ErrorBoundary } from 'react-error-boundary';
 import { ChildNode } from 'domhandler';
 import { stripTrackingParams } from '../utils/urlTracking';
+import { lotusPermalinkToMatrixTo } from './lotus-permalink';
 import * as css from '../styles/CustomHtml.css';
 import {
   getMxIdLocalPart,
@@ -118,6 +119,22 @@ export const setStripTrackingOnRender = (enabled: boolean): void => {
 const cleanHref = (href: string): string =>
   stripTrackingOnRender ? stripTrackingParams(href) : href;
 
+// [Gitea #130] Links to THIS deployment's room routes render and click like
+// matrix.to links. The base is set once from the client config
+// (ClientNonUIFeatures) because this module has no access to hooks.
+let lotusPermalinkBase: string | undefined;
+export const setLotusPermalinkBase = (baseUrl: string | undefined): void => {
+  lotusPermalinkBase = baseUrl;
+};
+/**
+ * The matrix.to form of `href` when it is a matrix.to link or a Lotus
+ * permalink; undefined for every other link.
+ */
+export const toMatrixToHref = (href: string): string | undefined => {
+  if (testMatrixTo(href)) return href;
+  return lotusPermalinkBase ? lotusPermalinkToMatrixTo(lotusPermalinkBase, href) : undefined;
+};
+
 export const LINKIFY_OPTS: LinkifyOpts = {
   attributes: {
     target: '_blank',
@@ -235,8 +252,10 @@ export const factoryRenderLinkifyWithMention = (
     attributes,
     content,
   }) => {
-    if (tagName === 'a' && testMatrixTo(tryDecodeURIComponent(attributes.href))) {
-      const mention = mentionRender(tryDecodeURIComponent(attributes.href));
+    const matrixHref =
+      tagName === 'a' ? toMatrixToHref(tryDecodeURIComponent(attributes.href)) : undefined;
+    if (matrixHref) {
+      const mention = mentionRender(matrixHref);
       if (mention) return mention;
     }
 
@@ -559,7 +578,9 @@ export const getReactCustomHtmlParser = (
           }
         }
 
-        if (name === 'a' && testMatrixTo(tryDecodeURIComponent(String(props.href)))) {
+        const matrixHref =
+          name === 'a' ? toMatrixToHref(tryDecodeURIComponent(String(props.href))) : undefined;
+        if (matrixHref) {
           const content = children.find((child) => !(child instanceof DOMText))
             ? undefined
             : children.map((c) => (c instanceof DOMText ? c.data : '')).join();
@@ -567,7 +588,7 @@ export const getReactCustomHtmlParser = (
           const mention = renderMatrixMention(
             mx,
             roomId,
-            tryDecodeURIComponent(String(props.href)),
+            matrixHref,
             makeMentionCustomProps(params.handleMentionClick, content),
           );