Code review cleanup: cache placement/adjacency, drop dead code

- Cache choosePlacement and adjacentTile results per (id,dir); invalidate
  on addTile. Avoids O(n^3) placement scoring on every pointermove.
- setCurrent now re-renders only affected navs (prev + new) instead of
  refreshAllNav; remove refreshAllNav entirely.
- Add pointercancel handler so interrupted touch/trackpad gestures don't
  leave a stuck drag.
- Remove dead code: placeRect, photoConnections + /api/photo route and
  THUMBS const on server, dangling info var in pointerup.
- Trim .gitignore, remove .DS_Store, bump cache-bust to ?v=20.

4 files changed, 29 insertions, 113 deletions

diff --git a/.gitignore b/.gitignore
index fd3dbb5..6659201 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,36 +1,4 @@
-# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
-
-# dependencies
-/node_modules
-/.pnp
-.pnp.js
-.yarn/install-state.gz
-
-# testing
-/coverage
-
-# next.js
-/.next/
-/out/
-
-# production
-/build
-
-# misc
+node_modules/
 .DS_Store
-*.pem
-
-# debug
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
-
-# local env files
-.env*.local
-
-# vercel
-.vercel
-
-# typescript
-*.tsbuildinfo
-next-env.d.ts
+*.log
+.env*
diff --git a/public/app.js b/public/app.js
index 800a822..95f64d4 100644
--- a/public/app.js
+++ b/public/app.js
@@ -155,11 +155,6 @@ function bestPlacement(w, h, from, dir) {
   return best ? { rect: best, cost: bestCost } : null
 }
 
-function placeRect(w, h, from, dir) {
-  const p = bestPlacement(w, h, from, dir)
-  return p ? p.rect : null
-}
-
 function addTile(info, rect) {
   const el = document.createElement("div")
   el.className = "tile"
@@ -177,18 +172,22 @@ function addTile(info, rect) {
   requestAnimationFrame(() => el.classList.add("lock"))
   tiles.set(info.id, { el, info, rect })
   rectOf.set(info.id, rect)
+  placementCache.clear()
+  adjacencyCache.clear()
   renderNav(info.id)
   return el
 }
 
 function setCurrent(id, rect) {
+  const prevId = cur && cur.id
   for (const t of tiles.values()) t.el.classList.remove("current")
   cur = { id, rect }
   tiles.get(id).el.classList.add("current")
   if (!userZoomed) scale = worldScale()
   center()
   getExits(id)
-  refreshAllNav()
+  if (prevId && prevId !== id) renderNav(prevId)
+  renderNav(id)
 }
 
 function renderNav(id) {
@@ -223,10 +222,6 @@ function renderNav(id) {
   t.el.appendChild(nav)
 }
 
-function refreshAllNav() {
-  for (const id of tiles.keys()) if (exitsCache.has(id)) renderNav(id)
-}
-
 async function getExits(id) {
   if (exitsCache.has(id)) return exitsCache.get(id)
   if (exitPending.has(id)) return exitPending.get(id)
@@ -251,7 +246,12 @@ async function getExits(id) {
   return p
 }
 
+const placementCache = new Map()
+const adjacencyCache = new Map()
+
 function choosePlacement(id, dir) {
+  const key = id + ":" + dir
+  if (placementCache.has(key)) return placementCache.get(key)
   const exits = exitsCache.get(id)
   const ex = exits && exits.find((e) => e.dir === dir)
   if (!ex) return null
@@ -290,10 +290,14 @@ function choosePlacement(id, dir) {
   const best = scored[0]
   const next = ex.next && !rectOf.has(ex.next.id) ? scored.find((s) => s.id === ex.next.id) : null
   const chosen = next && next.cost - best.cost <= FIT_TOLERANCE ? next : best
-  return { id: chosen.id, info: chosen.info, rect: chosen.rect }
+  const out = { id: chosen.id, info: chosen.info, rect: chosen.rect }
+  placementCache.set(key, out)
+  return out
 }
 
 function adjacentTile(id, dir) {
+  const key = id + ":" + dir
+  if (adjacencyCache.has(key)) return adjacencyCache.get(key)
   const r = tiles.get(id).rect
   let best = null
   let bestDist = Infinity
@@ -311,7 +315,9 @@ function adjacentTile(id, dir) {
       : Math.abs(q.y + q.h / 2 - (r.y + r.h / 2))
     if (d < bestDist) { bestDist = d; best = t }
   }
-  return best ? best.info.id : null
+  const out = best ? best.info.id : null
+  adjacencyCache.set(key, out)
+  return out
 }
 
 function traverseFrom(id, dir) {
@@ -326,7 +332,6 @@ function traverseFrom(id, dir) {
   hideGhost()
   addTile(chosen.info, chosen.rect)
   setCurrent(chosen.id, chosen.rect)
-  refreshAllNav()
   refreshAllZones()
 }
 
@@ -448,11 +453,16 @@ stage.addEventListener("pointerup", (e) => {
   world.style.transition = ""
   if (wasDrag || !tile) return
   const id = Number(tile.dataset.id)
-  const info = tiles.get(id).info
   if (cur && cur.id === id) return
   setCurrent(id, tiles.get(id).rect)
 })
 
+stage.addEventListener("pointercancel", () => {
+  if (!drag) return
+  drag = null
+  world.style.transition = ""
+})
+
 let zoomTimer = 0
 stage.addEventListener("wheel", (e) => {
   e.preventDefault()
diff --git a/public/index.html b/public/index.html
index ee844d7..4c13a5a 100644
--- a/public/index.html
+++ b/public/index.html
@@ -5,7 +5,7 @@
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="color-scheme" content="dark">
   <title>pathways</title>
-  <link rel="stylesheet" href="/app.css?v=19">
+  <link rel="stylesheet" href="/app.css?v=20">
 </head>
 <body>
   <main id="stage">
@@ -16,6 +16,6 @@
     <p>four paths, one per direction. walk them.</p>
     <button id="start">start</button>
   </div>
-  <script src="/app.js?v=19"></script>
+  <script src="/app.js?v=20"></script>
 </body>
 </html>
diff --git a/server.mjs b/server.mjs
index f03eace..5ae51a0 100644
--- a/server.mjs
+++ b/server.mjs
@@ -14,7 +14,6 @@ const DB = {
 }
 
 const PORT = Number(process.env.PORT || 3100)
-const THUMBS = process.env.THUMBS_ROOT || "/srv/photoprism/storage/cache/thumbnails"
 const PUBLIC = join(process.cwd(), "public")
 const MIN_PATH = 3
 
@@ -182,61 +181,6 @@ function json(res, code, data) {
   res.end(JSON.stringify(data))
 }
 
-async function photoConnections(id) {
-  const [ph] = await pool.query(
-    `SELECT p.id, p.photo_title, p.photo_year, p.photo_month, p.photo_day,
-            f.file_hash, f.file_width, f.file_height
-       FROM photos p
-       JOIN files f ON f.photo_id = p.id AND f.file_primary = 1 AND f.file_missing = 0
-      WHERE p.id = ?`,
-    [id]
-  )
-  if (ph.length === 0) return null
-  const p = ph[0]
-  const conns = []
-
-  const [labels] = await pool.query(
-    `SELECT l.label_name AS name, COUNT(*) AS n
-       FROM photos_labels pl JOIN labels l ON l.id = pl.label_id
-      WHERE pl.photo_id = ? GROUP BY pl.label_id`,
-    [id]
-  )
-  const [keywords] = await pool.query(
-    `SELECT kw.keyword AS name, COUNT(*) AS n
-       FROM photos_keywords pk JOIN keywords kw ON kw.id = pk.keyword_id
-      WHERE pk.photo_id = ? GROUP BY pk.keyword_id`,
-    [id]
-  )
-  const [camera] = await pool.query(
-    `SELECT CONCAT(c.camera_make, ' ', c.camera_model) AS name, COUNT(*) AS n
-       FROM photos p JOIN cameras c ON c.id = p.camera_id WHERE p.id = ?`,
-    [id]
-  )
-  const [lens] = await pool.query(
-    `SELECT l.lens_model AS name, COUNT(*) AS n
-       FROM photos p JOIN lenses l ON l.id = p.lens_id WHERE p.id = ?`,
-    [id]
-  )
-
-  for (const r of labels) conns.push({ type: "label", name: r.name, n: r.n })
-  for (const r of keywords) conns.push({ type: "keyword", name: r.name, n: r.n })
-  for (const r of camera) conns.push({ type: "camera", name: r.name, n: r.n })
-  for (const r of lens) conns.push({ type: "lens", name: r.name, n: r.n })
-
-  return {
-    photo: {
-      id: p.id,
-      thumb: thumb(p.file_hash),
-      full: thumb(p.file_hash, BIG_SIZE),
-      title: p.photo_title || "",
-      date: p.photo_year ? `${p.photo_year}-${String(p.photo_month || 1).padStart(2, "0")}-${String(p.photo_day || 1).padStart(2, "0")}` : "",
-      w: p.file_width || 0,
-      h: p.file_height || 0,
-    },
-    connections: conns,
-  }
-}
-
 const server = http.createServer(async (req, res) => {
   const url = new URL(req.url, `http://${req.headers.host || "localhost"}`)
   const path = url.pathname
@@ -268,12 +212,6 @@ const server = http.createServer(async (req, res) => {
         photos,
       })
     }
-    const photoMatch = path.match(/^\/api\/photo\/(\d+)$/)
-    if (photoMatch) {
-      const data = await photoConnections(Number(photoMatch[1]))
-      if (!data) return json(res, 404, { error: "not found" })
-      return json(res, 200, data)
-    }
     if (path === "/api/health") return json(res, 200, { ok: true })
 
     if (path === "/" || path === "") {