create: disable shot counts an engine cannot produce

create.html

@@ -151,6 +151,9 @@ function modelOf(id) {
   return null;
 }
 function shotSeconds() { return (MODEL && MODEL.shot_seconds) || 8; }
+// Some engines cap total length: extension stops at 40s, so 6 shots is not
+// available there. Grey it out rather than let the server silently clamp.
+function maxShots() { return (MODEL && MODEL.max_shots) || 0; }
 
 (async function loadFormats() {
   var r = await api("camera_presets", {});
@@ -210,9 +213,25 @@ function paintModel() {
   var el = document.getElementById("modelnote");
   el.textContent = MODEL ? (MODEL.shot_seconds + "s per shot. " + (MODEL.note || "")) : "";
   var chips = document.querySelectorAll("#len .chip");
+  var cap = maxShots();
   for (var i = 0; i < chips.length; i++) {
     var nshots = parseInt(chips[i].getAttribute("data-v"), 10);
-    chips[i].textContent = nshots + " shots · " + (nshots * shotSeconds()) + "s";
+    var over = cap && nshots > cap;
+    chips[i].textContent = nshots + " shots · " + (nshots * shotSeconds()) + "s"
+      + (over ? " — too long for this engine" : "");
+    chips[i].style.opacity = over ? "0.4" : "";
+    chips[i].style.pointerEvents = over ? "none" : "";
+    // If the disabled one was selected, fall back to the largest that fits.
+    if (over && chips[i].classList.contains("on")) {
+      chips[i].classList.remove("on");
+      for (var j = i - 1; j >= 0; j--) {
+        if (!chips[j].style.pointerEvents) {
+          chips[j].classList.add("on");
+          segments = parseInt(chips[j].getAttribute("data-v"), 10);
+          break;
+        }
+      }
+    }
   }
   document.getElementById("lenhint").textContent =
     "The piece is written as one continuous monologue, then cut into "