zebra-report: RemoteTileFSM — mirror

zebra-report/zebra-spaces.html

@@ -905,6 +905,72 @@ const subscribeSpec = {
   },
 };
 
+/* ==================================================================
+ * RemoteTileFSM — one instance per incoming screen / camera track from
+ * a remote publisher. Formalises the lifecycle that f71e9e7 patched
+ * imperatively (frozen-thumb after unshare):
+ *
+ *   inactive ──TRACK_ARRIVED──▶ receiving ──MUTED──▶ muted
+ *                                 ▲                    │
+ *                                 │ UNMUTED            │ PRUNE / ENDED
+ *                                 └────────────────────┤
+ *                                                      ▼
+ *                                                   removed
+ *
+ *   {receiving, muted} + ENDED → removed
+ *   * + LEFT → removed (peer-left wipes the tile from every state)
+ *
+ * MUTED is a debounce gate, not a deletion: if UNMUTED arrives within
+ * the runtime's debounce window (~1.5s) we stay receiving — the mute
+ * was a transient network blip. If PRUNE fires (debounce expired and
+ * still muted) the publisher really unshared and the tile dies.
+ * ENDED skips the debounce. removed is terminal — a new tile gets
+ * a fresh FSM. */
+const remoteTileSpec = {
+  initial: 'inactive',
+  context: { kind: '', pubHex: '', stream: null, lastError: null },
+  states: {
+    inactive: {
+      on: {
+        TRACK_ARRIVED: {
+          target: 'receiving',
+          action: (ctx, ev) => { if (ev.payload) ctx.stream = ev.payload.stream || ctx.stream; },
+        },
+        LEFT: 'removed',
+      },
+    },
+    receiving: {
+      on: {
+        MUTED:   'muted',
+        ENDED:   'removed',
+        LEFT:    'removed',
+        /* a fresh ontrack for the same pubHex+kind — publisher re-shared
+         * before our prune fired; keep the new stream and stay receiving */
+        TRACK_ARRIVED: {
+          target: 'receiving',
+          action: (ctx, ev) => { if (ev.payload && ev.payload.stream) ctx.stream = ev.payload.stream; },
+        },
+      },
+    },
+    muted: {
+      on: {
+        UNMUTED: 'receiving',
+        PRUNE:   'removed',
+        ENDED:   'removed',
+        LEFT:    'removed',
+        TRACK_ARRIVED: {
+          target: 'receiving',
+          action: (ctx, ev) => { if (ev.payload && ev.payload.stream) ctx.stream = ev.payload.stream; },
+        },
+      },
+    },
+    removed: {
+      entry: (ctx) => { ctx.stream = null; },
+      /* terminal — no outbound transitions */
+    },
+  },
+};
+
 /* ==================================================================
  * identity — ed25519 keypair, persisted in localStorage as JWK.
  *
@@ -2973,8 +3039,8 @@ logLine('', 'ready — pick a handle, type a rendezvous code, enter the space');
 
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