layout and remote fix

src/lib/utils/layoutShell.test.ts

@@ -1,13 +1,15 @@
 /**
- * Regression tests for the app's fixed bottom-UI (mini player + bottom nav)
- * layout rules.
+ * Tests for the app's bottom-UI (mini player + bottom nav) visibility rules.
  *
- * The bug these guard against: on the library route the layout used to render
- * its OWN in-flow mini player while the root ALSO painted a fixed bottom nav on
- * top of it, and the library scroller only reserved 1rem — so the last row hid
- * behind the nav. The fix unified everything onto the root: the root owns the
- * single fixed bottom UI on every route/platform, and every scroll container
- * reserves the measured `bottomUiHeight`.
+ * The overlap bug these guard against: on the library page the last rows were
+ * hidden behind the bottom nav. It was caused by rendering the bottom UI as a
+ * FIXED overlay and trying to reserve its (async-measured, initially-0) height
+ * as padding. The fix renders the bottom UI as an in-flow flex child below the
+ * scroller, so overlap is structurally impossible — no measurement, no padding.
+ *
+ * These pure functions only decide *whether* each piece shows on a route. The
+ * structural guarantee (flex sibling below the scroller) is exercised by
+ * running the app, not by jsdom (which has no layout engine).
  *
  * TRACES: UR-005 | DR-009
  */
@@ -18,7 +20,6 @@ import {
   showGlobalMiniPlayer,
   routeOwnsLayout,
   showBottomUi,
-  reservedBottomPadding,
 } from "./layoutShell";
 
 const authed = (pathname: string) => ({ pathname, isAuthenticated: true });
@@ -44,15 +45,14 @@ describe("showGlobalMiniPlayer", () => {
     expect(showGlobalMiniPlayer({ pathname: "/settings" })).toBe(false);
   });
 
-  it("does NOT depend on platform or on /library — the root owns it everywhere", () => {
-    // The signature intentionally has no `isAndroid` input: the old bug was a
-    // platform/route split that let a second in-flow mini player exist.
+  it("does NOT depend on platform or on /library — one code path everywhere", () => {
+    // The old bug was a platform/route split that let a second mini player exist.
     expect(showGlobalMiniPlayer({ pathname: "/library" })).toBe(true);
   });
 });
 
 describe("showBottomNav", () => {
-  it("shows on authenticated content routes including library", () => {
+  it("shows on authenticated content routes including library and settings", () => {
     expect(showBottomNav(authed("/library"))).toBe(true);
     expect(showBottomNav(authed("/"))).toBe(true);
     expect(showBottomNav(authed("/settings"))).toBe(true);
@@ -69,64 +69,55 @@ describe("showBottomNav", () => {
 });
 
 describe("routeOwnsLayout", () => {
-  it("is true for library/settings/player/login (they manage their own scroll)", () => {
+  it("is true for library/player/login (they render their own flex column + BottomUi)", () => {
     expect(routeOwnsLayout({ pathname: "/library" })).toBe(true);
     expect(routeOwnsLayout({ pathname: "/library/abc" })).toBe(true);
-    expect(routeOwnsLayout({ pathname: "/settings" })).toBe(true);
     expect(routeOwnsLayout({ pathname: "/player/x" })).toBe(true);
     expect(routeOwnsLayout({ pathname: "/login" })).toBe(true);
   });
 
-  it("is false for routes that render into the root scroller", () => {
+  it("is false for routes that render into the root scroller (incl. settings)", () => {
+    // Settings has no +layout of its own; it must flow through the root scroller
+    // so the root's in-flow BottomUi renders below it (otherwise settings loses
+    // its nav, since the fixed-overlay nav no longer exists).
     expect(routeOwnsLayout({ pathname: "/" })).toBe(false);
     expect(routeOwnsLayout({ pathname: "/search" })).toBe(false);
     expect(routeOwnsLayout({ pathname: "/downloads" })).toBe(false);
+    expect(routeOwnsLayout({ pathname: "/settings" })).toBe(false);
   });
 });
 
-describe("layout invariant: a reservation owner exists wherever bottom UI shows", () => {
-  // The core anti-regression check. Every route falls into exactly one of two
-  // reservation regimes:
-  //   - route owns its layout  -> the route's own scroller reserves bottomUiHeight
-  //   - route does NOT own it   -> the root scroller reserves bottomUiHeight
-  // The bug was that the library route was implicitly a THIRD regime: it owned
-  // its layout, showed a fixed nav from the root, but reserved only 1rem. That
-  // can't recur now because library both owns its layout (so it reserves
-  // internally) and the mini player is root-owned (no second in-flow bar).
+describe("structural invariant: every route that shows bottom UI has a scroller above it", () => {
+  // With the in-flow model, "the bottom UI is a flex sibling below a scroller"
+  // must hold on every route where it shows. That scroller is provided by
+  // exactly one owner:
+  //   - routeOwnsLayout === true  -> the route's own column (header + main + BottomUi)
+  //   - routeOwnsLayout === false -> the root column (scroller + BottomUi)
+  // The forbidden state — bottom UI shows but no owning column renders a
+  // scroller + BottomUi pair — cannot occur because the two branches are total.
   const routes = ["/", "/search", "/downloads", "/library", "/library/abc", "/settings"];
 
   for (const pathname of routes) {
-    it(`${pathname}: exactly one reservation owner`, () => {
-      if (!showBottomUi(authed(pathname))) return; // no bottom UI -> nothing to reserve
-      // Ownership is a total boolean, so exactly one regime always applies —
-      // there is no route that shows bottom UI with no reservation owner.
+    it(`${pathname}: bottom UI shows and has a defined layout owner`, () => {
+      expect(showBottomUi(authed(pathname))).toBe(true);
       expect(typeof routeOwnsLayout({ pathname })).toBe("boolean");
     });
   }
 
-  it("library shows bottom UI AND owns its layout, so it reserves internally", () => {
-    // Directly pins the regression: library must NOT rely on the root scroller
-    // (it has none — the root gives owning routes a clipped, non-scrolling box).
+  it("library owns its layout, so it renders its own in-flow BottomUi", () => {
+    // Directly pins the original regression: library must render BottomUi inside
+    // its own column (the root gives owning routes a clipped, non-scrolling box).
     expect(showBottomUi(authed("/library"))).toBe(true);
     expect(routeOwnsLayout({ pathname: "/library" })).toBe(true);
   });
-});
 
-describe("reservedBottomPadding", () => {
-  it("returns an exact px fit when no extra room requested", () => {
-    expect(reservedBottomPadding(120)).toBe("120px");
+  it("settings does NOT own its layout, so the root scroller + BottomUi cover it", () => {
+    expect(showBottomUi(authed("/settings"))).toBe(true);
+    expect(routeOwnsLayout({ pathname: "/settings" })).toBe(false);
   });
 
-  it("adds breathing room via calc for layout-owning routes", () => {
-    expect(reservedBottomPadding(120, 1)).toBe("calc(120px + 1rem)");
-  });
-
-  it("never returns negative padding", () => {
-    expect(reservedBottomPadding(-50)).toBe("0px");
-    expect(reservedBottomPadding(-50, 1)).toBe("calc(0px + 1rem)");
-  });
-
-  it("reserves 1rem-only when the bottom UI is collapsed to 0 (nothing playing, nav-only measured elsewhere)", () => {
-    expect(reservedBottomPadding(0, 1)).toBe("calc(0px + 1rem)");
+  it("the full-screen player shows no bottom UI and owns its layout", () => {
+    expect(showBottomUi(authed("/player/x"))).toBe(false);
+    expect(routeOwnsLayout({ pathname: "/player/x" })).toBe(true);
   });
 });