Add belt reader building

src/js/game/systems/belt_reader.js

@@ -0,0 +1,40 @@
+import { GameSystemWithFilter } from "../game_system_with_filter";
+import { BeltReaderComponent } from "../components/belt_reader";
+import { globalConfig } from "../../core/config";
+import { BOOL_TRUE_SINGLETON, BOOL_FALSE_SINGLETON } from "../items/boolean_item";
+
+export class BeltReaderSystem extends GameSystemWithFilter {
+    constructor(root) {
+        super(root, [BeltReaderComponent]);
+    }
+
+    update() {
+        const now = this.root.time.now();
+        const minimumTime = now - globalConfig.readerAnalyzeIntervalSeconds;
+        const minimumTimeForThroughput = now - 1;
+        for (let i = 0; i < this.allEntities.length; ++i) {
+            const entity = this.allEntities[i];
+
+            const readerComp = entity.components.BeltReader;
+            const pinsComp = entity.components.WiredPins;
+
+            // Remove outdated items
+            while (readerComp.lastItemTimes[0] < minimumTime) {
+                readerComp.lastItemTimes.shift();
+            }
+
+            pinsComp.slots[1].value = readerComp.lastItem;
+            pinsComp.slots[0].value =
+                (readerComp.lastItemTimes[readerComp.lastItemTimes.length - 1] || 0) >
+                minimumTimeForThroughput
+                    ? BOOL_TRUE_SINGLETON
+                    : BOOL_FALSE_SINGLETON;
+
+            if (now - readerComp.lastThroughputComputation > 0.5) {
+                readerComp.lastThroughputComputation = now;
+                readerComp.lastThroughput =
+                    readerComp.lastItemTimes.length / globalConfig.readerAnalyzeIntervalSeconds;
+            }
+        }
+    }
+}