Improve event route handling for legacy URLs

Replaces the redirect function with a beforeEnter guard to support old-style event URLs without repetitionId or tab. The new logic normalizes paths, distinguishes between repetitionId and tab segments, and ensures users are redirected to the correct route format, improving backward compatibility.

Author: neSpecc

src/router.ts

@@ -123,16 +123,79 @@ const router = createRouter({
                   path: 'event/:eventId/:repetitionId?',
                   name: 'event',
                   component: () => import(/* webpackChunkName: 'event-overview' */ './components/event/Layout.vue'),
-                  redirect: (to) => {
-                    const projectId = to.params.projectId as string;
-                    const eventId = to.params.eventId as string;
-                    const repetitionId = to.params.repetitionId as string | undefined;
+                  // eslint-disable-next-line jsdoc/require-param
+                  /**
+                   * Support old-style event urls:
+                   *  - without repetitionId
+                   *  - without tab
+                   */
+                  beforeEnter: (to, from, next) => {
+                    /**
+                     * Normalize path by removing trailing slashes
+                     */
+                    const normalizedPath = to.path.replace(/\/+$/, '');
 
-                    if (repetitionId !== undefined && repetitionId !== '') {
-                      return `/project/${projectId}/event/${eventId}/${repetitionId}/overview`;
+                    /**
+                     * Match the event route path pattern:
+                     * /project/:projectId/event/:eventId[/:repetitionId][/:tab]
+                     */
+                    const pathMatch = normalizedPath.match(
+                      /^\/project\/([^/]+)\/event\/([^/]+)(?:\/([^/]+))?(?:\/([^/]+))?$/
+                    );
+
+                    if (!pathMatch) {
+                      next();
+
+                      return;
+                    }
+
+                    const projectId = pathMatch[1];
+                    const eventId = pathMatch[2];
+                    const segment3 = pathMatch[3];
+                    const segment4 = pathMatch[4];
+                    const knownTabs = new Set(['overview', 'repetitions', 'daily', 'affected']);
+
+                    /**
+                     * Determine if segment3 is a tab name or a repetitionId
+                     */
+                    const isSegment3Tab = segment3 !== undefined && knownTabs.has(segment3);
+
+                    /**
+                     * Legacy format: /project/:projectId/event/:eventId/:tab
+                     * segment3 is a tab, segment4 is undefined
+                     */
+                    if (isSegment3Tab && segment4 === undefined) {
+                      next(`/project/${projectId}/event/${eventId}/${eventId}/${segment3}`);
+
+                      return;
+                    }
+
+                    /**
+                     * Normal format: /project/:projectId/event/:eventId/:repetitionId/:tab
+                     * segment3 is repetitionId, segment4 is tab
+                     */
+                    if (segment3 !== undefined && !isSegment3Tab && segment4 !== undefined) {
+                      /**
+                       * Already in correct format, continue
+                       */
+                      next();
+
+                      return;
+                    }
+
+                    /**
+                     * Missing tab: /project/:projectId/event/:eventId[/:repetitionId]
+                     * Redirect to overview
+                     */
+                    if (segment4 === undefined) {
+                      const repetitionId = segment3 && !isSegment3Tab ? segment3 : eventId;
+
+                      next(`/project/${projectId}/event/${eventId}/${repetitionId}/overview`);
+
+                      return;
                     }
 
-                    return `/project/${projectId}/event/${eventId}/${eventId}/overview`;
+                    next();
                   },
                   children: [
                     {