# Programme Sidebar and Course Integration Design

## Goal

Publish the substantive Computer Science course material from `origin/isaacs-changes` without merging that branch's broken file moves, empty placeholders, malformed description, content duplication, or archive deletion. Reorganize bachelor navigation so readers can switch between Computer Science and Data Science & AI while global wiki resources remain available.

## Source and scope

The source branch is `origin/isaacs-changes` at commit `d5d6730`. It diverged from `main` at `c590f77` and must not be merged or cherry-picked wholesale.

Publish these five substantive Computer Science pages from the branch after normalizing them to current repository conventions:

- Introduction to Computer Science
- Computer Architecture
- Algorithmic Design
- Databases
- Statistics

Also expose these seven courses in both bachelor programmes:

- Discrete Mathematics
- Procedural Programming
- Calculus
- Logic
- Objects in Programming
- Data Structures and Algorithms
- Linear Algebra

The branch's copies of those seven pages are byte-identical. Their common body content therefore has one source, while each programme receives its own public route and frontmatter wrapper.

Do not publish:

- `computer-science/course-description.md`, which lacks frontmatter and contains duplicate `#Hello` headings;
- any of the 30 Computer Science Year 2 and Year 3 `Empty Page` placeholders;
- duplicate full copies of identical shared-course bodies; or
- the branch deletion of `previous-exams-and-documents.md`.

No other `origin/isaacs-changes` change is in scope.

## Public route model

Use programme-specific routes:

- `/computer-science/`
- `/computer-science/year-1/`
- `/computer-science/year-1/period-N/<course>/`
- `/data-science-and-ai/`
- `/data-science-and-ai/year-N/`
- `/data-science-and-ai/year-N/block-N/<course>/`

The period/block naming follows each source programme's existing terminology. Do not rewrite course URLs to imply the two curricula have identical structures.

Move the current DSAI pages from `/bachelor/...` to `/data-science-and-ai/...`. Preserve every previous `/bachelor/...` URL with a permanent redirect to its exact DSAI replacement, including overview, year, project, honours, thesis, study-abroad, and course routes. Internal wiki links and the sidebar should use the new canonical URLs after migration.

The five newly recovered Computer Science pages live only under Computer Science routes. Empty later-year Computer Science routes are not created.

## Shared-course content model

Store the common body of each of the seven identical courses as a non-published MDX partial outside the `docs` collection. Create a thin MDX page at each programme-specific route with:

- programme-appropriate title and description frontmatter;
- the standard historical-information caution;
- an import of the shared body partial; and
- an optional programme-specific notes section when verified differences exist.

The shared partial contains no page-level frontmatter, H1 heading, or historical caution. This prevents duplicate rendered titles and notices.

If a shared course later diverges, keep both public routes stable. Replace or extend only that programme wrapper; the other programme continues using the shared partial. Do not encode programme identity in the shared source.

## Programme overview pages

Create a clean Computer Science overview and Year 1 overview using only verified descriptions and links. Do not reuse or repair the malformed branch course-description text by inference.

Retitle and relocate the existing bachelor overview pages as Data Science & AI. Preserve their historical warning and current external Maastricht University guidance.

## Sidebar interaction

Add a small route-aware programme switch above the course-navigation portion of Starlight's global sidebar:

- **Computer Science**
- **Data Science & AI**

The switch uses ordinary links, works without client JavaScript, is keyboard accessible, and marks the active programme with `aria-current`. It renders inside the existing Starlight sidebar on desktop and in the existing mobile navigation.

Use Starlight's supported `Sidebar` component override to prepend the switch while reusing the default `Sidebar` component. Use Starlight route-data middleware to filter the detailed bachelor course tree to the active programme.

Programme selection is derived from the current route and is never stored in cookies or local storage:

- Computer Science routes activate Computer Science navigation.
- Data Science & AI routes and redirected legacy bachelor routes activate DSAI navigation.
- Global pages show neither option as active and show compact links to both programme overviews instead of a detailed bachelor tree.

When a reader uses the switch from one of the seven shared-course routes, link to the paired route in the other programme. From a programme-specific course without an equivalent, link to the other programme's Year 1 overview. From other programme pages, link to the other programme overview.

The rest of the global navigation remains available in both programme contexts:

- Home
- About Incognito
- Previous exams and documents
- Master AI
- Master DSDM
- Useful Information and all its current child pages

The programme switch changes only the detailed bachelor-course portion. It must not hide the master programmes or Useful Information.

## Navigation data boundaries

Keep navigation definitions as focused data structures:

- one Computer Science course tree;
- one Data Science & AI course tree;
- one global navigation section;
- one explicit map of paired shared-course routes; and
- one pure function that selects the active programme and switch destinations from a route ID.

The route middleware consumes those structures and assigns the final Starlight sidebar. The component override only renders the switch and delegates the link tree to Starlight's default component; it does not duplicate sidebar filtering logic.

## Migration records and provenance

Update the migration manifest, migration report, supplemental-content registry, and sidebar tests in lockstep with the route moves and new pages.

- Existing DSAI content retains its existing source provenance while its destination changes.
- The five new Computer Science pages record their `wiki.msvincognito.nl` source URLs and `2026-08-02` capture provenance.
- Shared programme wrappers record which source page supplied the common body.
- Redirects are documented as compatibility routes, not duplicate published content.

The audit must continue to reject undeclared published Markdown/MDX files and any reintroduction of the excluded placeholder or malformed pages.

## Accessibility and responsive behavior

- Use a labelled navigation region for the programme switch.
- Expose the current programme with both visual styling and `aria-current="page"`.
- Keep touch targets at least as large as existing Starlight sidebar links.
- Preserve Starlight's default sidebar persistence, focus behavior, and mobile menu footer by wrapping rather than copying the default component.
- Ensure long programme labels wrap without horizontal scrolling at narrow widths.

## Testing and verification

Add focused automated coverage for:

- exact inclusion of the five substantive Computer Science pages;
- exclusion of the malformed description and all empty placeholders;
- one shared source body for each identical course and two programme-specific public routes;
- programme-specific content overrides remaining possible;
- complete old `/bachelor/...` to new DSAI redirect coverage;
- route-to-programme detection and paired-course switch destinations;
- route middleware retaining global navigation and showing only the active detailed bachelor tree;
- accessible programme switch markup and active state;
- sidebar visibility on Computer Science, DSAI, master, and Useful Information pages;
- updated manifest, report, and supplemental registry consistency; and
- absence of duplicate H1 headings, broken internal links, and unpublished-source leakage.

Run focused red/green tests first, then the full `npm run verify` workflow. Build once at `/` and once with a non-root `BASE` to cover canonical links, redirects, the sidebar override, and mobile-compatible output.

## References

- [Starlight Sidebar override](https://starlight.astro.build/reference/overrides/#sidebar)
- [Starlight component overrides](https://starlight.astro.build/guides/overriding-components/)
- [Starlight route-data middleware](https://starlight.astro.build/guides/route-data/#customizing-route-data)
- [Starlight sidebar configuration](https://starlight.astro.build/guides/sidebar/)