inject host time into datastream wasm rules engine (SCHY-471)

src/main/java/com/schematic/api/datastream/WasmRulesEngine.java

@@ -52,6 +52,7 @@ public class WasmRulesEngine implements RulesEngine {
     private ExportFunction allocFn;
     private ExportFunction deallocFn;
     private ExportFunction checkFlagFn;
+    private ExportFunction setTimeFn;
     private ExportFunction getResultJsonFn;
     private ExportFunction getResultJsonLengthFn;
 
@@ -106,6 +107,15 @@ public synchronized void initialize() {
             allocFn = instance.export("alloc");
             deallocFn = instance.export("dealloc");
             checkFlagFn = instance.export("checkFlagCombined");
+            // Optional: feed the wasm the current wall-clock time before each
+            // check. The raw wasm has no clock under Chicory (SCHY-471); without
+            // it, metric-period reset timestamps are omitted. Absent on older
+            // wasm builds, so resolve it defensively.
+            try {
+                setTimeFn = instance.export("setCurrentTimeMillis");
+            } catch (Exception e) {
+                setTimeFn = null;
+            }
             getResultJsonFn = instance.export("getResultJson");
             getResultJsonLengthFn = instance.export("getResultJsonLength");
 
@@ -197,6 +207,12 @@ private synchronized String callWasm(String inputJson) {
         try {
             memory.write(ptr, data);
 
+            // Supply the host's current time so the engine can compute
+            // metric-period reset timestamps (SCHY-471). No-op on older wasm.
+            if (setTimeFn != null) {
+                setTimeFn.apply(System.currentTimeMillis());
+            }
+
             long[] checkResult = checkFlagFn.apply(ptr, length);
             int resultLen = (int) checkResult[0];
 

src/test/java/com/schematic/api/datastream/WasmRulesEngineClockTest.java

@@ -0,0 +1,83 @@
+package com.schematic.api.datastream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.schematic.api.core.ObjectMappers;
+import com.schematic.api.types.RulesengineCheckFlagResult;
+import com.schematic.api.types.RulesengineCompany;
+import com.schematic.api.types.RulesengineFlag;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Regression for SCHY-471.
+ *
+ * <p>A company-override entitlement rule whose metric condition uses a
+ * calendar/billing metric period drives the engine into the metric-period-reset
+ * code path, which needs a wall clock. On the raw {@code wasm32-unknown-unknown}
+ * build that path used to trap ({@code wasm unreachable}) under the Chicory
+ * runtime; the flag then wrongly fell back to its default value for a company
+ * that is legitimately entitled. The host now injects the current time via
+ * {@code setCurrentTimeMillis} so this path evaluates cleanly.
+ */
+class WasmRulesEngineClockTest {
+
+    private static WasmRulesEngine engine;
+
+    @BeforeAll
+    static void setUp() {
+        engine = new WasmRulesEngine(null);
+        engine.initialize();
+    }
+
+    private static final String FLAG_JSON = "{"
+            + "\"id\":\"flag1\",\"key\":\"mcp-access\",\"account_id\":\"acc_1\","
+            + "\"environment_id\":\"env_1\",\"default_value\":false,\"rules\":[]}";
+
+    // Usage 40 < allocation 100, so the company override grants the feature.
+    private static final String COMPANY_JSON = "{"
+            + "\"id\":\"co_entitled\",\"account_id\":\"acc_1\",\"environment_id\":\"env_1\","
+            + "\"keys\":{\"id\":\"co_entitled\"},"
+            + "\"metrics\":[{\"account_id\":\"acc_1\",\"environment_id\":\"env_1\",\"company_id\":\"co_entitled\","
+            + "\"event_subtype\":\"api-calls\",\"period\":\"current_month\",\"month_reset\":\"billing_cycle\","
+            + "\"value\":40,\"created_at\":\"2023-01-01T00:00:00Z\"}],"
+            + "\"rules\":[{\"id\":\"rule_override\",\"flag_id\":\"flag1\",\"account_id\":\"acc_1\","
+            + "\"environment_id\":\"env_1\",\"name\":\"Company Override\",\"rule_type\":\"company_override\","
+            + "\"priority\":0,\"value\":true,\"condition_groups\":[],\"conditions\":["
+            + "{\"id\":\"cond_company\",\"account_id\":\"acc_1\",\"environment_id\":\"env_1\","
+            + "\"condition_type\":\"company\",\"operator\":\"eq\",\"resource_ids\":[\"co_entitled\"],\"trait_value\":\"\"},"
+            + "{\"id\":\"cond_metric\",\"account_id\":\"acc_1\",\"environment_id\":\"env_1\","
+            + "\"condition_type\":\"metric\",\"operator\":\"lt\",\"event_subtype\":\"api-calls\",\"metric_value\":100,"
+            + "\"metric_period\":\"current_month\",\"metric_period_month_reset\":\"billing_cycle\",\"trait_value\":\"100\"}"
+            + "]}]}";
+
+    private static RulesengineFlag flag() throws Exception {
+        return ObjectMappers.JSON_MAPPER.readValue(FLAG_JSON, RulesengineFlag.class);
+    }
+
+    private static RulesengineCompany entitledCompany() throws Exception {
+        return ObjectMappers.JSON_MAPPER.readValue(COMPANY_JSON, RulesengineCompany.class);
+    }
+
+    @Test
+    void billingMetricOverride_evaluatesWithoutTrapping() throws Exception {
+        // Must not throw (the bug surfaced as a Chicory trap from checkFlagCombined).
+        RulesengineCheckFlagResult result = engine.checkFlag(flag(), entitledCompany(), null);
+
+        // The override grants the feature; a fallback to default_value would be false.
+        assertTrue(result.getValue(), "company override should grant the flag, not fall back to default false");
+        assertTrue(
+                result.getReason().toLowerCase().contains("override"),
+                "expected an override match reason, got: " + result.getReason());
+    }
+
+    @Test
+    void billingMetricOverride_populatesResetAt() throws Exception {
+        RulesengineCheckFlagResult result = engine.checkFlag(flag(), entitledCompany(), null);
+
+        // setCurrentTimeMillis lets the engine compute the next reset boundary.
+        assertTrue(
+                result.getFeatureUsageResetAt().isPresent(),
+                "reset-at should be computed from the injected host time");
+    }
+}