From 7c081ae7495d19ff50508ff69912417e7873551c Mon Sep 17 00:00:00 2001
From: whitlocktech <whitlocktech@gmail.com>
Date: Sat, 27 Jun 2026 11:25:15 -0500
Subject: [PATCH] Wiki Phase 3: internal links, backlinks, and tags

Connectivity phase of the wiki upgrade (see WIKI_UPGRADE.md).

Schema (additive new tables): wiki_tags, wiki_page_tags, wiki_links.

Internal links & backlinks:
- new wiki.links.js parses a saved body for /wiki/<slug> (and data-wiki-slug)
  targets; wiki_links is rebuilt on every save
- article shows a "Linked from" section (published backlinks) and renders
  links to non-existent pages as red links (server returns missing_links)
- editor gains an internal-link picker listing existing pages

Tags:
- pages accept a tags[] array; tags upsert on save, page tag-set is replaced,
  and orphaned tags are auto-pruned (on save and delete)
- public/admin list filter by ?tag=; /wiki/tags lists tags with published counts
- article shows tag chips; the index has a flat tag-filtered view; editor has a
  comma-separated tags field

Verified end-to-end: A->B backlink appears, red link detected, link index
rebuilds on edit, tag filtering + chips + pruning all work.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 WIKI_UPGRADE.md                               |   9 +-
 client/src/api/client.js                      |  10 +-
 client/src/components/RichTextEditor.jsx      |  48 ++++++-
 client/src/routes/admin/views/WikiEditor.jsx  |  29 ++++-
 client/src/routes/wiki/Wiki.jsx               |  74 +++++++----
 client/src/routes/wiki/WikiArticle.jsx        |  47 ++++++-
 client/src/styles/theme.css                   |  68 +++++++++-
 server/db/schema.sql                          |  24 ++++
 server/src/model/wiki/wiki.db.js              | 122 +++++++++++++++---
 server/src/model/wiki/wiki.links.js           |  15 +++
 server/src/model/wiki/wiki.model.js           |  96 +++++++++++---
 .../src/router/v1/admin/admin.controller.js   |  16 +++
 server/src/router/v1/admin/admin.routes.js    |   5 +
 .../src/router/v1/public/public.controller.js |  20 ++-
 server/src/router/v1/public/public.routes.js  |   3 +-
 15 files changed, 516 insertions(+), 70 deletions(-)
 create mode 100644 server/src/model/wiki/wiki.links.js

diff --git a/WIKI_UPGRADE.md b/WIKI_UPGRADE.md
index 3a95ffe..e66e0a4 100644
--- a/WIKI_UPGRADE.md
+++ b/WIKI_UPGRADE.md
@@ -309,10 +309,17 @@ phase if preferred). Do not merge a phase that hasn't been verified.
   `<script>` stripped); a toolbar edit (insert divider) saved and persisted. TipTap
   is code-split into its own chunk (lazy-loaded), keeping it off the public bundle.
 
-### Phase 3 — Connectivity
+### Phase 3 — Connectivity ✅
 - Internal `[[slug]]` links + red-link detection; `wiki_links` rebuild on save;
   backlinks on the article; tags + tag/category filtering.
 - **Exit check**: link page A→B, confirm B shows A under "Linked from"; tag filter works.
+- **Verified** (2026-06-27): internal links authored via an in-editor page picker
+  (links to `/wiki/<slug>`); A→B made B list A under "Linked from"; a link to a
+  non-existent page renders as a red link; removing the link on save cleared the
+  backlink (link index rebuilt). Tags upsert on save, filter via `?tag=` (chips +
+  flat index view), list with published counts, and orphan tags are auto-pruned.
+- Implementation note: links are plain anchors to `/wiki/<slug>` (the WYSIWYG fits
+  this better than `[[ ]]` syntax); the sanitizer also allows `data-wiki-slug`.
 
 ### Phase 4 — Discovery & trust
 - FULLTEXT search (public search box + admin filter); revision history list /
diff --git a/client/src/api/client.js b/client/src/api/client.js
index 7a523b5..45c5666 100644
--- a/client/src/api/client.js
+++ b/client/src/api/client.js
@@ -49,8 +49,15 @@ export const api = {
   status: () => req('/public/status'),
   posts: (category) => req(`/public/posts/${category}`),
   post: (category, idOrSlug) => req(`/public/posts/${category}/${idOrSlug}`),
-  wiki: (category) => req(`/public/wiki${category ? `?category=${encodeURIComponent(category)}` : ''}`),
+  wiki: (opts = {}) => {
+    const qs = new URLSearchParams()
+    if (opts.category) qs.set('category', opts.category)
+    if (opts.tag) qs.set('tag', opts.tag)
+    const s = qs.toString()
+    return req(`/public/wiki${s ? `?${s}` : ''}`)
+  },
   wikiCategories: () => req('/public/wiki/categories'),
+  wikiTags: () => req('/public/wiki/tags'),
   wikiPage: (slug) => req(`/public/wiki/${slug}`),
   contact: (payload) => req('/public/contact', { method: 'POST', body: payload }),
 
@@ -83,6 +90,7 @@ export const api = {
     publishWiki: (slug, published) =>
       req(`/admin/wiki/${slug}/publish`, { method: 'PATCH', body: { published } }),
     deleteWiki: (slug) => req(`/admin/wiki/${slug}`, { method: 'DELETE' }),
+    listWikiTags: () => req('/admin/wiki/tags'),
     listWikiCategories: () => req('/admin/wiki/categories'),
     createWikiCategory: (data) => req('/admin/wiki/categories', { method: 'POST', body: data }),
     updateWikiCategory: (id, data) =>
diff --git a/client/src/components/RichTextEditor.jsx b/client/src/components/RichTextEditor.jsx
index 77c7b2d..e9289f4 100644
--- a/client/src/components/RichTextEditor.jsx
+++ b/client/src/components/RichTextEditor.jsx
@@ -21,9 +21,15 @@ function Btn({ onClick, active, disabled, title, children }) {
   )
 }
 
-export default function RichTextEditor({ value, onChange }) {
+function escapeHtml(s) {
+  return String(s).replace(/[&<>"]/g, (c) => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;' })[c])
+}
+
+export default function RichTextEditor({ value, onChange, pages = [] }) {
   const fileRef = useRef(null)
   const [uploading, setUploading] = useState(false)
+  const [linkMenu, setLinkMenu] = useState(false)
+  const [linkFilter, setLinkFilter] = useState('')
 
   const editor = useEditor({
     extensions: [
@@ -55,6 +61,17 @@ export default function RichTextEditor({ value, onChange }) {
     editor.chain().focus().extendMarkRange('link').setLink({ href: url }).run()
   }
 
+  function insertInternalLink(page) {
+    const { from, to } = editor.state.selection
+    if (from === to) {
+      editor.chain().focus().insertContent(`<a href="/wiki/${page.slug}">${escapeHtml(page.title)}</a> `).run()
+    } else {
+      editor.chain().focus().extendMarkRange('link').setLink({ href: `/wiki/${page.slug}` }).run()
+    }
+    setLinkMenu(false)
+    setLinkFilter('')
+  }
+
   async function onPickImage(e) {
     const file = e.target.files?.[0]
     e.target.value = '' // allow re-selecting the same file
@@ -109,6 +126,9 @@ export default function RichTextEditor({ value, onChange }) {
         <Btn title="Link" active={editor.isActive('link')} onClick={setLink}>
           🔗
         </Btn>
+        <Btn title="Link to another wiki page" disabled={pages.length === 0} onClick={() => setLinkMenu((v) => !v)}>
+          📄
+        </Btn>
         <Btn title="Insert image" disabled={uploading} onClick={() => fileRef.current?.click()}>
           {uploading ? '…' : '🖼'}
         </Btn>
@@ -121,6 +141,32 @@ export default function RichTextEditor({ value, onChange }) {
         </Btn>
       </div>
 
+      {linkMenu && (
+        <div className="rte-linkmenu">
+          <input
+            autoFocus
+            className="input"
+            placeholder="Filter pages…"
+            value={linkFilter}
+            onChange={(e) => setLinkFilter(e.target.value)}
+          />
+          <div className="rte-linkmenu-list">
+            {pages
+              .filter((p) => {
+                const q = linkFilter.trim().toLowerCase()
+                return !q || p.title.toLowerCase().includes(q) || p.slug.includes(q)
+              })
+              .slice(0, 30)
+              .map((p) => (
+                <button key={p.slug} type="button" className="rte-linkmenu-item" onClick={() => insertInternalLink(p)}>
+                  <span>{p.title}</span>
+                  <span className="rte-linkmenu-slug">/{p.slug}</span>
+                </button>
+              ))}
+          </div>
+        </div>
+      )}
+
       <EditorContent editor={editor} className="rte-content prose" />
       <input ref={fileRef} type="file" accept="image/*" onChange={onPickImage} hidden />
     </div>
diff --git a/client/src/routes/admin/views/WikiEditor.jsx b/client/src/routes/admin/views/WikiEditor.jsx
index f53d3f0..541c3d3 100644
--- a/client/src/routes/admin/views/WikiEditor.jsx
+++ b/client/src/routes/admin/views/WikiEditor.jsx
@@ -15,19 +15,25 @@ export default function WikiEditor({ slug, onClose, onSaved }) {
     excerpt: '',
     category_id: '',
     published: true,
+    tags: '',
   })
   const [categories, setCategories] = useState([])
+  const [pages, setPages] = useState([])
   const [loading, setLoading] = useState(isEdit)
   const [busy, setBusy] = useState(false)
   const [error, setError] = useState('')
 
-  // Categories for the dropdown (both new and edit).
+  // Categories (dropdown) + pages (internal-link picker), for both new and edit.
   useEffect(() => {
     let active = true
     api.admin
       .listWikiCategories()
       .then((cats) => active && setCategories(cats))
       .catch(() => {})
+    api.admin
+      .listWiki()
+      .then((list) => active && setPages(list.map((p) => ({ slug: p.slug, title: p.title }))))
+      .catch(() => {})
     return () => {
       active = false
     }
@@ -48,6 +54,7 @@ export default function WikiEditor({ slug, onClose, onSaved }) {
             excerpt: p.excerpt || '',
             category_id: p.category_id != null ? String(p.category_id) : '',
             published: Boolean(p.published),
+            tags: (p.tags || []).map((t) => t.label).join(', '),
           }),
       )
       .catch(() => active && setError('Could not load this page.'))
@@ -66,6 +73,10 @@ export default function WikiEditor({ slug, onClose, onSaved }) {
       excerpt: form.excerpt.trim(),
       category_id: form.category_id ? Number(form.category_id) : null,
       published: form.published,
+      tags: form.tags
+        .split(',')
+        .map((t) => t.trim())
+        .filter(Boolean),
     }
   }
 
@@ -174,10 +185,24 @@ export default function WikiEditor({ slug, onClose, onSaved }) {
               placeholder="One-line summary shown on the wiki home."
             />
           </label>
+          <label>
+            <span className="field-label">Tags (comma-separated)</span>
+            <input
+              type="text"
+              value={form.tags}
+              onChange={set('tags')}
+              className="input"
+              placeholder="beginner, pvp, towns"
+            />
+          </label>
           <div>
             <span className="field-label">Body (use Heading 2 for table-of-contents sections)</span>
             <Suspense fallback={<span className="spin" />}>
-              <RichTextEditor value={form.body} onChange={(html) => setForm((f) => ({ ...f, body: html }))} />
+              <RichTextEditor
+                value={form.body}
+                onChange={(html) => setForm((f) => ({ ...f, body: html }))}
+                pages={pages.filter((p) => p.slug !== form.slug)}
+              />
             </Suspense>
           </div>
         </div>
diff --git a/client/src/routes/wiki/Wiki.jsx b/client/src/routes/wiki/Wiki.jsx
index 0c169f4..c43d51f 100644
--- a/client/src/routes/wiki/Wiki.jsx
+++ b/client/src/routes/wiki/Wiki.jsx
@@ -38,17 +38,22 @@ function PageCard({ page }) {
 export default function Wiki() {
   const [searchParams] = useSearchParams()
   const activeCategory = searchParams.get('category')
-  const { loading, error, data } = useAsync(() =>
-    Promise.all([api.wikiCategories(), api.wiki()]).then(([categories, pages]) => ({
-      categories,
-      pages,
-    })),
+  const activeTag = searchParams.get('tag')
+  // Tag view fetches a tag-filtered page list; otherwise all pages (grouped here).
+  const { loading, error, data } = useAsync(
+    () =>
+      Promise.all([api.wikiCategories(), api.wiki(activeTag ? { tag: activeTag } : {})]).then(
+        ([categories, pages]) => ({ categories, pages }),
+      ),
+    [activeTag],
   )
+
   const allSections = data ? groupByCategory(data.categories, data.pages) : []
   const sections = activeCategory
     ? allSections.filter((s) => s.slug === activeCategory)
     : allSections
   const hasPages = data && data.pages.length > 0
+  const filtered = Boolean(activeCategory || activeTag)
 
   return (
     <PublicLayout section="wiki">
@@ -61,39 +66,54 @@ export default function Wiki() {
         />
         {loading && <Loading />}
         {error && <ErrorState message="Could not load the wiki right now." />}
-        {!loading && !error && !hasPages && <EmptyState>No wiki pages yet.</EmptyState>}
+        {!loading && !error && !hasPages && !filtered && <EmptyState>No wiki pages yet.</EmptyState>}
 
-        {!loading && !error && activeCategory && (
+        {!loading && !error && filtered && (
           <p className="sans" style={{ margin: '0 0 8px', fontSize: '0.85rem' }}>
             <Link to="/wiki" style={{ color: 'var(--accent)', textDecoration: 'none' }}>
               ← All sections
             </Link>
+            {activeTag && <span className="muted"> · Tagged #{activeTag}</span>}
           </p>
         )}
-        {!loading && !error && hasPages && activeCategory && sections.length === 0 && (
-          <EmptyState>No pages in this section yet.</EmptyState>
-        )}
 
-        {sections.map((section) => (
-          <section key={section.id} style={{ marginTop: 36 }}>
-            <h2
-              className="display"
-              style={{ margin: '0 0 4px', fontSize: '1.5rem', color: 'var(--accent)' }}
-            >
-              {section.title}
-            </h2>
-            {section.description && (
-              <p className="muted" style={{ margin: '0 0 16px', fontSize: '0.95rem' }}>
-                {section.description}
-              </p>
-            )}
-            <div className="grid-4" style={{ marginTop: section.description ? 0 : 12 }}>
-              {section.pages.map((p) => (
+        {/* Tag view: a flat list of matching pages (tags cross categories). */}
+        {!loading && !error && activeTag &&
+          (data.pages.length === 0 ? (
+            <EmptyState>No pages with this tag.</EmptyState>
+          ) : (
+            <div className="grid-4" style={{ marginTop: 12 }}>
+              {data.pages.map((p) => (
                 <PageCard key={p.slug} page={p} />
               ))}
             </div>
-          </section>
-        ))}
+          ))}
+
+        {/* Category / full view: grouped sections. */}
+        {!loading && !error && !activeTag && hasPages && activeCategory && sections.length === 0 && (
+          <EmptyState>No pages in this section yet.</EmptyState>
+        )}
+        {!activeTag &&
+          sections.map((section) => (
+            <section key={section.id} style={{ marginTop: 36 }}>
+              <h2
+                className="display"
+                style={{ margin: '0 0 4px', fontSize: '1.5rem', color: 'var(--accent)' }}
+              >
+                {section.title}
+              </h2>
+              {section.description && (
+                <p className="muted" style={{ margin: '0 0 16px', fontSize: '0.95rem' }}>
+                  {section.description}
+                </p>
+              )}
+              <div className="grid-4" style={{ marginTop: section.description ? 0 : 12 }}>
+                {section.pages.map((p) => (
+                  <PageCard key={p.slug} page={p} />
+                ))}
+              </div>
+            </section>
+          ))}
       </div>
     </PublicLayout>
   )
diff --git a/client/src/routes/wiki/WikiArticle.jsx b/client/src/routes/wiki/WikiArticle.jsx
index 4d629e7..c4015fd 100644
--- a/client/src/routes/wiki/WikiArticle.jsx
+++ b/client/src/routes/wiki/WikiArticle.jsx
@@ -15,8 +15,9 @@ function slugify(text) {
 }
 
 // Parse the stored body HTML: sanitize (defense in depth — the server also
-// sanitizes on save), then assign ids to <h2> headings and collect a TOC.
-function buildArticle(body) {
+// sanitizes on save), assign ids to <h2> headings and collect a TOC, and mark
+// internal links to pages that don't exist as "red links".
+function buildArticle(body, missing) {
   if (!body) return { html: '', toc: [] }
   if (typeof window === 'undefined' || !window.DOMParser) return { html: '', toc: [] }
   const safe = DOMPurify.sanitize(body)
@@ -27,13 +28,22 @@ function buildArticle(body) {
     h.id = id
     toc.push({ id, label: h.textContent })
   })
+  doc.querySelectorAll('a[href^="/wiki/"]').forEach((a) => {
+    const target = a.getAttribute('href').replace(/^\/wiki\//, '').replace(/[#?].*$/, '')
+    a.removeAttribute('target') // internal links stay in-app
+    if (missing.has(target)) {
+      a.classList.add('wiki-red-link')
+      a.setAttribute('title', 'This page does not exist yet')
+    }
+  })
   return { html: doc.body.innerHTML, toc }
 }
 
 export default function WikiArticle() {
   const { slug } = useParams()
   const { loading, error, data: page } = useAsync(() => api.wikiPage(slug), [slug])
-  const { html, toc } = useMemo(() => buildArticle(page?.body), [page])
+  const missing = useMemo(() => new Set(page?.missing_links || []), [page])
+  const { html, toc } = useMemo(() => buildArticle(page?.body, missing), [page, missing])
 
   return (
     <PublicLayout section="wiki">
@@ -100,6 +110,15 @@ export default function WikiArticle() {
               <p className="sans" style={{ margin: '18px 0 0', color: 'var(--dim)', fontSize: '0.78rem', letterSpacing: '0.04em' }}>
                 Last updated {longDate(page.updated_at) || '—'}
               </p>
+              {page.tags && page.tags.length > 0 && (
+                <div style={{ display: 'flex', flexWrap: 'wrap', gap: 8, marginTop: 14 }}>
+                  {page.tags.map((t) => (
+                    <Link key={t.slug} to={`/wiki?tag=${t.slug}`} className="wiki-tag">
+                      #{t.label}
+                    </Link>
+                  ))}
+                </div>
+              )}
               <div style={{ height: 1, background: 'var(--line)', margin: '30px 0' }} />
               {html ? (
                 <div className="prose" dangerouslySetInnerHTML={{ __html: html }} />
@@ -107,6 +126,28 @@ export default function WikiArticle() {
                 <p className="muted">This page has no content yet.</p>
               )}
 
+              {page.backlinks && page.backlinks.length > 0 && (
+                <section
+                  style={{ marginTop: 40, borderTop: '1px solid var(--line)', paddingTop: 22 }}
+                >
+                  <p
+                    className="sans"
+                    style={{ margin: '0 0 12px', color: 'var(--accent)', fontSize: '0.66rem', fontWeight: 700, letterSpacing: '0.14em', textTransform: 'uppercase' }}
+                  >
+                    Linked from
+                  </p>
+                  <ul style={{ margin: 0, paddingLeft: 18, fontFamily: 'var(--sans)', fontSize: '0.92rem' }}>
+                    {page.backlinks.map((b) => (
+                      <li key={b.slug} style={{ marginBottom: 6 }}>
+                        <Link to={`/wiki/${b.slug}`} style={{ color: 'var(--accent)', textDecoration: 'none' }}>
+                          {b.title}
+                        </Link>
+                      </li>
+                    ))}
+                  </ul>
+                </section>
+              )}
+
               <nav style={{ display: 'flex', justifyContent: 'flex-start', marginTop: 40 }}>
                 <Link to="/wiki" className="pill">
                   ← All wiki pages
diff --git a/client/src/styles/theme.css b/client/src/styles/theme.css
index d91c188..96c2991 100644
--- a/client/src/styles/theme.css
+++ b/client/src/styles/theme.css
@@ -314,10 +314,10 @@ button[disabled] {
 
 /* ===== Rich text editor (TipTap) ===== */
 .rte {
+  position: relative;
   border: 1px solid var(--line);
   border-radius: 8px;
   background: var(--bg);
-  overflow: hidden;
 }
 .rte:focus-within {
   border-color: var(--accent);
@@ -380,6 +380,72 @@ button[disabled] {
   color: var(--dim);
   pointer-events: none;
 }
+/* Internal-link picker popover */
+.rte-linkmenu {
+  position: absolute;
+  z-index: 20;
+  top: 50px;
+  left: 10px;
+  width: min(360px, calc(100% - 20px));
+  padding: 10px;
+  border: 1px solid var(--line);
+  border-radius: 8px;
+  background: var(--panel-a);
+  box-shadow: var(--shadow-card);
+}
+.rte-linkmenu-list {
+  margin-top: 8px;
+  max-height: 220px;
+  overflow-y: auto;
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+}
+.rte-linkmenu-item {
+  display: flex;
+  justify-content: space-between;
+  align-items: baseline;
+  gap: 12px;
+  padding: 7px 9px;
+  border: none;
+  border-radius: 6px;
+  background: transparent;
+  color: var(--text);
+  font-family: var(--sans);
+  font-size: 0.88rem;
+  text-align: left;
+  cursor: pointer;
+}
+.rte-linkmenu-item:hover {
+  background: var(--blue);
+  color: var(--ink);
+}
+.rte-linkmenu-slug {
+  color: var(--dim);
+  font-family: ui-monospace, Menlo, monospace;
+  font-size: 0.76rem;
+}
+
+/* ===== Wiki connectivity (tags + red links) ===== */
+.wiki-tag {
+  display: inline-block;
+  padding: 3px 10px;
+  border: 1px solid var(--line);
+  border-radius: 999px;
+  background: rgba(127, 153, 189, 0.1);
+  color: var(--accent);
+  font-family: var(--sans);
+  font-size: 0.78rem;
+  text-decoration: none;
+}
+.wiki-tag:hover {
+  border-color: var(--accent);
+  background: var(--blue);
+}
+.prose a.wiki-red-link {
+  color: #d98b84;
+  border-bottom: 1px dotted #d98b84;
+}
 
 /* ===== Admin tables ===== */
 .adm-table {
diff --git a/server/db/schema.sql b/server/db/schema.sql
index d2bb3a0..8ac3084 100644
--- a/server/db/schema.sql
+++ b/server/db/schema.sql
@@ -58,6 +58,30 @@ CREATE TABLE IF NOT EXISTS wiki_pages (
   FULLTEXT INDEX idx_wiki_search (title, body)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
+-- Wiki tags (many-to-many with pages).
+CREATE TABLE IF NOT EXISTS wiki_tags (
+  id    INT AUTO_INCREMENT PRIMARY KEY,
+  slug  VARCHAR(120) NOT NULL UNIQUE,
+  label VARCHAR(120) NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+CREATE TABLE IF NOT EXISTS wiki_page_tags (
+  page_id INT NOT NULL,
+  tag_id  INT NOT NULL,
+  PRIMARY KEY (page_id, tag_id),
+  CONSTRAINT fk_wpt_page FOREIGN KEY (page_id) REFERENCES wiki_pages(id) ON DELETE CASCADE,
+  CONSTRAINT fk_wpt_tag  FOREIGN KEY (tag_id)  REFERENCES wiki_tags(id)  ON DELETE CASCADE
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+-- Internal-link index, rebuilt on each save. target_slug may point at a page
+-- that does not exist yet (a "red link").
+CREATE TABLE IF NOT EXISTS wiki_links (
+  source_page_id INT NOT NULL,
+  target_slug    VARCHAR(120) NOT NULL,
+  CONSTRAINT fk_wiki_links_src FOREIGN KEY (source_page_id) REFERENCES wiki_pages(id) ON DELETE CASCADE,
+  INDEX idx_wiki_links_target (target_slug)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
 CREATE TABLE IF NOT EXISTS settings (
   `key`      VARCHAR(64) PRIMARY KEY,
   value      TEXT NULL,
diff --git a/server/src/model/wiki/wiki.db.js b/server/src/model/wiki/wiki.db.js
index 541e111..f5f8c55 100644
--- a/server/src/model/wiki/wiki.db.js
+++ b/server/src/model/wiki/wiki.db.js
@@ -14,22 +14,15 @@ const SUMMARY_COLS =
 const FROM = 'FROM wiki_pages p LEFT JOIN wiki_categories c ON c.id = p.category_id'
 const ORDER = 'ORDER BY p.sort_order ASC, p.title ASC'
 
-// ── Page reads ─────────────────────────────────────────────────────────
-// Published summaries (public). Optional category filter by id.
-async function listPublishedSummaries(categoryId = null) {
-  if (categoryId != null) {
-    return query(
-      `SELECT ${SUMMARY_COLS} ${FROM} WHERE p.published = 1 AND p.category_id = ? ${ORDER}`,
-      [categoryId],
-    )
-  }
-  return query(`SELECT ${SUMMARY_COLS} ${FROM} WHERE p.published = 1 ${ORDER}`)
-}
-
-// All summaries (admin), with optional category / status filters.
-async function listAllSummaries({ categoryId = null, published = null } = {}) {
+// Shared summary query builder with optional category / tag / status filters.
+function buildSummaryQuery({ categoryId = null, tagId = null, published = null }) {
+  const joins = []
   const where = []
   const params = []
+  if (tagId != null) {
+    joins.push('JOIN wiki_page_tags pt ON pt.page_id = p.id AND pt.tag_id = ?')
+    params.push(tagId)
+  }
   if (categoryId != null) {
     where.push('p.category_id = ?')
     params.push(categoryId)
@@ -39,7 +32,22 @@ async function listAllSummaries({ categoryId = null, published = null } = {}) {
     params.push(published ? 1 : 0)
   }
   const clause = where.length ? `WHERE ${where.join(' AND ')}` : ''
-  return query(`SELECT ${SUMMARY_COLS} ${FROM} ${clause} ${ORDER}`, params)
+  return {
+    sql: `SELECT ${SUMMARY_COLS} ${FROM} ${joins.join(' ')} ${clause} ${ORDER}`,
+    params,
+  }
+}
+
+// Published summaries (public). Optional category / tag filters.
+async function listPublishedSummaries({ categoryId = null, tagId = null } = {}) {
+  const { sql, params } = buildSummaryQuery({ categoryId, tagId, published: true })
+  return query(sql, params)
+}
+
+// All summaries (admin), with optional category / tag / status filters.
+async function listAllSummaries({ categoryId = null, tagId = null, published = null } = {}) {
+  const { sql, params } = buildSummaryQuery({ categoryId, tagId, published })
+  return query(sql, params)
 }
 
 async function findBySlug(slug) {
@@ -151,6 +159,80 @@ async function deleteCategory(id) {
   return query('DELETE FROM wiki_categories WHERE id = ?', [id])
 }
 
+// ── Tags ───────────────────────────────────────────────────────────────
+async function listTags() {
+  return query(
+    `SELECT t.id, t.slug, t.label,
+       (SELECT COUNT(*) FROM wiki_page_tags pt
+          JOIN wiki_pages p ON p.id = pt.page_id
+          WHERE pt.tag_id = t.id AND p.published = 1) AS published_count
+     FROM wiki_tags t ORDER BY t.label ASC`,
+  )
+}
+
+async function findTagBySlug(slug) {
+  const rows = await query('SELECT id, slug, label FROM wiki_tags WHERE slug = ? LIMIT 1', [slug])
+  return rows[0] || null
+}
+
+async function getTagsForPage(pageId) {
+  return query(
+    'SELECT t.slug, t.label FROM wiki_tags t ' +
+      'JOIN wiki_page_tags pt ON pt.tag_id = t.id WHERE pt.page_id = ? ORDER BY t.label ASC',
+    [pageId],
+  )
+}
+
+async function upsertTag(slug, label) {
+  await query('INSERT INTO wiki_tags (slug, label) VALUES (?, ?) ON DUPLICATE KEY UPDATE label = VALUES(label)', [
+    slug,
+    label,
+  ])
+  const rows = await query('SELECT id FROM wiki_tags WHERE slug = ? LIMIT 1', [slug])
+  return rows[0].id
+}
+
+async function setPageTags(pageId, tagIds) {
+  await query('DELETE FROM wiki_page_tags WHERE page_id = ?', [pageId])
+  for (const tagId of tagIds) {
+    await query('INSERT IGNORE INTO wiki_page_tags (page_id, tag_id) VALUES (?, ?)', [pageId, tagId])
+  }
+}
+
+// Drop tags no longer attached to any page (keeps the tag list tidy).
+async function deleteOrphanTags() {
+  return query('DELETE FROM wiki_tags WHERE id NOT IN (SELECT tag_id FROM wiki_page_tags)')
+}
+
+// ── Internal links / backlinks ─────────────────────────────────────────
+async function clearLinks(pageId) {
+  return query('DELETE FROM wiki_links WHERE source_page_id = ?', [pageId])
+}
+
+async function insertLink(pageId, targetSlug) {
+  return query('INSERT INTO wiki_links (source_page_id, target_slug) VALUES (?, ?)', [pageId, targetSlug])
+}
+
+// Pages that link TO targetSlug (excludes the page linking to itself).
+async function getBacklinks(targetSlug, { publishedOnly = true } = {}) {
+  const pub = publishedOnly ? 'AND p.published = 1' : ''
+  return query(
+    `SELECT DISTINCT p.slug, p.title FROM wiki_links l
+       JOIN wiki_pages p ON p.id = l.source_page_id
+     WHERE l.target_slug = ? AND p.slug <> ? ${pub}
+     ORDER BY p.title ASC`,
+    [targetSlug, targetSlug],
+  )
+}
+
+// Of the given slugs, which actually exist (for red-link detection).
+async function getExistingSlugs(slugs) {
+  if (!slugs || slugs.length === 0) return new Set()
+  const placeholders = slugs.map(() => '?').join(',')
+  const rows = await query(`SELECT slug FROM wiki_pages WHERE slug IN (${placeholders})`, slugs)
+  return new Set(rows.map((r) => r.slug))
+}
+
 // ── Seeding (idempotent) ───────────────────────────────────────────────
 async function seedDefault(slug, title, body) {
   await query('INSERT IGNORE INTO wiki_pages (slug, title, body) VALUES (?, ?, ?)', [
@@ -191,6 +273,16 @@ module.exports = {
   insertCategory,
   updateCategory,
   deleteCategory,
+  listTags,
+  findTagBySlug,
+  getTagsForPage,
+  upsertTag,
+  setPageTags,
+  deleteOrphanTags,
+  clearLinks,
+  insertLink,
+  getBacklinks,
+  getExistingSlugs,
   seedDefault,
   seedDefaultCategory,
   assignCategoryBySlug,
diff --git a/server/src/model/wiki/wiki.links.js b/server/src/model/wiki/wiki.links.js
new file mode 100644
index 0000000..b88a492
--- /dev/null
+++ b/server/src/model/wiki/wiki.links.js
@@ -0,0 +1,15 @@
+// Extract internal wiki-link targets from a saved (already sanitized) body.
+// Internal links are anchors to /wiki/<slug> or elements carrying a
+// data-wiki-slug attribute. Returns a de-duplicated array of slugs.
+function extractTargets(html) {
+  if (!html) return []
+  const targets = new Set()
+  const hrefRe = /href="\/wiki\/([a-z0-9-]+)"/g
+  const dataRe = /data-wiki-slug="([a-z0-9-]+)"/g
+  let m
+  while ((m = hrefRe.exec(html))) targets.add(m[1])
+  while ((m = dataRe.exec(html))) targets.add(m[1])
+  return [...targets]
+}
+
+module.exports = { extractTargets }
diff --git a/server/src/model/wiki/wiki.model.js b/server/src/model/wiki/wiki.model.js
index 5620364..fe56a17 100644
--- a/server/src/model/wiki/wiki.model.js
+++ b/server/src/model/wiki/wiki.model.js
@@ -1,45 +1,97 @@
 const wikiDb = require('./wiki.db')
 const { cleanBody } = require('../../utils/sanitizeHtml')
+const { extractTargets } = require('./wiki.links')
+
+function slugifyTag(label) {
+  return String(label)
+    .toLowerCase()
+    .trim()
+    .replace(/[^a-z0-9]+/g, '-')
+    .replace(/(^-|-$)/g, '')
+}
+
+// Upsert each label into wiki_tags and set the page's tag set exactly.
+async function syncTags(pageId, tags) {
+  const ids = []
+  const seen = new Set()
+  for (const raw of tags) {
+    const label = String(raw).trim()
+    if (!label) continue
+    const slug = slugifyTag(label)
+    if (!slug || seen.has(slug)) continue
+    seen.add(slug)
+    ids.push(await wikiDb.upsertTag(slug, label))
+  }
+  await wikiDb.setPageTags(pageId, ids)
+  await wikiDb.deleteOrphanTags()
+}
+
+// Rebuild the page's outgoing internal-link rows from its (sanitized) body.
+async function rebuildLinks(pageId, html) {
+  await wikiDb.clearLinks(pageId)
+  for (const target of extractTargets(html)) {
+    await wikiDb.insertLink(pageId, target)
+  }
+}
 
 // ── Pages ──────────────────────────────────────────────────────────────
-async function listPublished(categoryId = null) {
-  return wikiDb.listPublishedSummaries(categoryId)
+async function listPublished(filters = {}) {
+  return wikiDb.listPublishedSummaries(filters)
 }
 
 async function listAll(filters = {}) {
   return wikiDb.listAllSummaries(filters)
 }
 
+// Admin detail: page + its tags.
 async function getBySlug(slug) {
-  return wikiDb.findBySlug(slug)
+  const page = await wikiDb.findBySlug(slug)
+  if (!page) return null
+  page.tags = await wikiDb.getTagsForPage(page.id)
+  return page
 }
 
+// Public detail: page + tags + backlinks + missing (red) link targets.
 async function getPublishedBySlug(slug) {
-  return wikiDb.findPublishedBySlug(slug)
+  const page = await wikiDb.findPublishedBySlug(slug)
+  if (!page) return null
+  page.tags = await wikiDb.getTagsForPage(page.id)
+  page.backlinks = await wikiDb.getBacklinks(slug, { publishedOnly: true })
+  const targets = extractTargets(page.body)
+  const existing = await wikiDb.getExistingSlugs(targets)
+  page.missing_links = targets.filter((t) => !existing.has(t))
+  return page
 }
 
-async function create({ slug, title, body, excerpt, categoryId, published, updatedBy }) {
+async function create({ slug, title, body, excerpt, categoryId, published, updatedBy, tags }) {
+  const clean = cleanBody(body)
   await wikiDb.insert({
     slug,
     title,
-    body: cleanBody(body),
+    body: clean,
     excerpt: excerpt || null,
     categoryId: categoryId ?? null,
-    published: published !== false, // default published unless explicitly false
+    published: published !== false,
     updatedBy,
   })
-  return wikiDb.findBySlug(slug)
+  const page = await wikiDb.findBySlug(slug)
+  if (Array.isArray(tags)) await syncTags(page.id, tags)
+  await rebuildLinks(page.id, clean)
+  return getBySlug(slug)
 }
 
-// Partial update — only keys present in `input` are written. Body is sanitized;
-// published_at is stamped the first time a page goes live.
+// Partial update — only keys present in `input` are written.
 async function update(slug, input) {
   const current = await wikiDb.findBySlug(slug)
   if (!current) return null
 
   const fields = { updated_by: input.updatedBy ?? null }
+  let cleanForLinks = null
   if ('title' in input) fields.title = input.title
-  if ('body' in input) fields.body = cleanBody(input.body)
+  if ('body' in input) {
+    fields.body = cleanBody(input.body)
+    cleanForLinks = fields.body
+  }
   if ('excerpt' in input) fields.excerpt = input.excerpt || null
   if ('categoryId' in input) fields.category_id = input.categoryId ?? null
   if ('published' in input) {
@@ -48,7 +100,9 @@ async function update(slug, input) {
   }
 
   await wikiDb.updateBySlug(slug, fields)
-  return wikiDb.findBySlug(slug)
+  if (Array.isArray(input.tags)) await syncTags(current.id, input.tags)
+  if (cleanForLinks != null) await rebuildLinks(current.id, cleanForLinks)
+  return getBySlug(slug)
 }
 
 async function setPublished(slug, published) {
@@ -57,11 +111,22 @@ async function setPublished(slug, published) {
   const fields = { published: published ? 1 : 0 }
   if (published && !current.published_at) fields.published_at = new Date()
   await wikiDb.updateBySlug(slug, fields)
-  return wikiDb.findBySlug(slug)
+  return getBySlug(slug)
 }
 
 async function remove(slug) {
-  return wikiDb.deleteBySlug(slug)
+  const res = await wikiDb.deleteBySlug(slug)
+  await wikiDb.deleteOrphanTags() // page_tags cascade on delete; drop now-empty tags
+  return res
+}
+
+// ── Tags ───────────────────────────────────────────────────────────────
+async function listTags() {
+  return wikiDb.listTags()
+}
+
+async function getTagBySlug(slug) {
+  return wikiDb.findTagBySlug(slug)
 }
 
 // ── Categories ─────────────────────────────────────────────────────────
@@ -97,7 +162,6 @@ async function removeCategory(id) {
 }
 
 module.exports = {
-  list: listPublished, // back-compat alias (old callers expected published list)
   listPublished,
   listAll,
   getBySlug,
@@ -106,6 +170,8 @@ module.exports = {
   update,
   setPublished,
   remove,
+  listTags,
+  getTagBySlug,
   listCategories,
   getCategoryBySlug,
   getCategoryById,
diff --git a/server/src/router/v1/admin/admin.controller.js b/server/src/router/v1/admin/admin.controller.js
index 6b38247..1dcbc7c 100644
--- a/server/src/router/v1/admin/admin.controller.js
+++ b/server/src/router/v1/admin/admin.controller.js
@@ -177,6 +177,10 @@ async function listWiki(req, res) {
       const category = await wiki.getCategoryBySlug(req.query.category)
       filters.categoryId = category ? category.id : -1 // unknown → match nothing
     }
+    if (req.query.tag) {
+      const tag = await wiki.getTagBySlug(req.query.tag)
+      filters.tagId = tag ? tag.id : -1 // unknown → match nothing
+    }
     if (req.query.status === 'draft') filters.published = false
     if (req.query.status === 'published') filters.published = true
     return res.json(await wiki.listAll(filters))
@@ -221,6 +225,7 @@ async function createWiki(req, res) {
       excerpt: req.body.excerpt || null,
       categoryId: cat.value,
       published: req.body.published !== false,
+      tags: Array.isArray(req.body.tags) ? req.body.tags : undefined,
       updatedBy: req.user.id,
     })
     await activity.log({ req, action: 'wiki.create', detail: { slug: page.slug } })
@@ -241,6 +246,7 @@ async function updateWiki(req, res) {
     if ('body' in req.body) input.body = req.body.body || null
     if ('excerpt' in req.body) input.excerpt = req.body.excerpt || null
     if ('published' in req.body) input.published = Boolean(req.body.published)
+    if ('tags' in req.body) input.tags = Array.isArray(req.body.tags) ? req.body.tags : []
     if ('category_id' in req.body) {
       const cat = await resolveCategoryId(req.body)
       if (!cat.ok) return res.status(400).json({ message: 'Unknown category' })
@@ -282,6 +288,15 @@ async function deleteWiki(req, res) {
   }
 }
 
+// ── Wiki tags ──────────────────────────────────────────────────────────
+async function listWikiTags(req, res) {
+  try {
+    return res.json(await wiki.listTags())
+  } catch (err) {
+    return res.status(500).json({ message: 'Internal Server Error' })
+  }
+}
+
 // ── Wiki categories ────────────────────────────────────────────────────
 async function listWikiCategories(req, res) {
   try {
@@ -473,6 +488,7 @@ module.exports = {
   updateWiki,
   publishWiki,
   deleteWiki,
+  listWikiTags,
   listWikiCategories,
   createWikiCategory,
   updateWikiCategory,
diff --git a/server/src/router/v1/admin/admin.routes.js b/server/src/router/v1/admin/admin.routes.js
index 03543e2..734ca2a 100644
--- a/server/src/router/v1/admin/admin.routes.js
+++ b/server/src/router/v1/admin/admin.routes.js
@@ -90,6 +90,9 @@ adminRouter.put(
 )
 adminRouter.delete('/wiki/categories/:id', param('id').isInt(), validate, ctrl.deleteWikiCategory)
 
+// ── Wiki tags ──────────────────────────────────────────────────────────
+adminRouter.get('/wiki/tags', ctrl.listWikiTags)
+
 // ── Wiki pages ─────────────────────────────────────────────────────────
 adminRouter.get('/wiki', ctrl.listWiki)
 adminRouter.post(
@@ -99,6 +102,7 @@ adminRouter.post(
   body('excerpt').optional({ values: 'falsy' }).isString().isLength({ max: 400 }),
   body('category_id').optional({ values: 'null' }).isInt(),
   body('published').optional().isBoolean(),
+  body('tags').optional().isArray(),
   validate,
   ctrl.createWiki,
 )
@@ -109,6 +113,7 @@ adminRouter.put(
   body('excerpt').optional({ values: 'falsy' }).isString().isLength({ max: 400 }),
   body('category_id').optional({ values: 'null' }).isInt(),
   body('published').optional().isBoolean(),
+  body('tags').optional().isArray(),
   validate,
   ctrl.updateWiki,
 )
diff --git a/server/src/router/v1/public/public.controller.js b/server/src/router/v1/public/public.controller.js
index 2ed525a..a3c8ef3 100644
--- a/server/src/router/v1/public/public.controller.js
+++ b/server/src/router/v1/public/public.controller.js
@@ -58,15 +58,28 @@ async function getWikiCategories(req, res) {
   }
 }
 
+async function getWikiTags(req, res) {
+  try {
+    return res.json(await wiki.listTags())
+  } catch (err) {
+    return res.status(500).json({ message: 'Internal Server Error' })
+  }
+}
+
 async function getWikiList(req, res) {
   try {
-    let categoryId = null
+    const filters = {}
     if (req.query.category) {
       const category = await wiki.getCategoryBySlug(req.query.category)
       if (!category) return res.json([]) // unknown category → no pages
-      categoryId = category.id
+      filters.categoryId = category.id
     }
-    return res.json(await wiki.listPublished(categoryId))
+    if (req.query.tag) {
+      const tag = await wiki.getTagBySlug(req.query.tag)
+      if (!tag) return res.json([]) // unknown tag → no pages
+      filters.tagId = tag.id
+    }
+    return res.json(await wiki.listPublished(filters))
   } catch (err) {
     return res.status(500).json({ message: 'Internal Server Error' })
   }
@@ -100,6 +113,7 @@ module.exports = {
   getPosts,
   getPost,
   getWikiCategories,
+  getWikiTags,
   getWikiList,
   getWikiPage,
   contact,
diff --git a/server/src/router/v1/public/public.routes.js b/server/src/router/v1/public/public.routes.js
index 7798ee3..1ebb85c 100644
--- a/server/src/router/v1/public/public.routes.js
+++ b/server/src/router/v1/public/public.routes.js
@@ -25,8 +25,9 @@ publicRouter.post(
 publicRouter.get('/posts/:category', siteMode, ctrl.getPosts)
 publicRouter.get('/posts/:category/:idOrSlug', siteMode, ctrl.getPost)
 publicRouter.get('/wiki', siteMode, ctrl.getWikiList)
-// Static path must precede the :slug route so it isn't captured as a slug.
+// Static paths must precede the :slug route so they aren't captured as a slug.
 publicRouter.get('/wiki/categories', siteMode, ctrl.getWikiCategories)
+publicRouter.get('/wiki/tags', siteMode, ctrl.getWikiTags)
 publicRouter.get('/wiki/:slug', siteMode, ctrl.getWikiPage)
 
 module.exports = publicRouter