From af667970e49f27761bd0e3a8dcdf17d6d02f4897 Mon Sep 17 00:00:00 2001
From: Rainnny7 <braydonrainnny@gmail.com>
Date: Wed, 18 Sep 2024 00:07:12 -0400
Subject: [PATCH] Feature flag impl

---
 .../java/cc/pulseapp/api/model/Feature.java   | 46 ++++++++++++++
 .../cc/pulseapp/api/service/FlagsService.java | 61 +++++++++++++++++++
 2 files changed, 107 insertions(+)
 create mode 100644 src/main/java/cc/pulseapp/api/model/Feature.java
 create mode 100644 src/main/java/cc/pulseapp/api/service/FlagsService.java

diff --git a/src/main/java/cc/pulseapp/api/model/Feature.java b/src/main/java/cc/pulseapp/api/model/Feature.java
new file mode 100644
index 0000000..ea91a1a
--- /dev/null
+++ b/src/main/java/cc/pulseapp/api/model/Feature.java
@@ -0,0 +1,46 @@
+package cc.pulseapp.api.model;
+
+import lombok.*;
+
+/**
+ * A feature flag.
+ *
+ * @author Braydon
+ */
+@RequiredArgsConstructor @Getter @ToString
+public enum Feature {
+    USER_REGISTRATION_ENABLED("user-registration"),
+    ORG_CREATION_ENABLED("org-creation");
+
+    public static final Feature[] VALUES = values();
+
+    /**
+     * The name of this feature.
+     */
+    @NonNull private final String id;
+
+    /**
+     * Whether this feature is enabled.
+     */
+    @Setter private boolean enabled;
+
+    /**
+     * The value of this feature, if any.
+     */
+    @Setter private Object value;
+
+    /**
+     * Get a feature by its id.
+     *
+     * @param id the feature id
+     * @return the feature, null if none
+     */
+    public static Feature getById(@NonNull String id) {
+        for (Feature feature : VALUES) {
+            if (feature.getId().equals(id)) {
+                return feature;
+            }
+        }
+        return null;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/cc/pulseapp/api/service/FlagsService.java b/src/main/java/cc/pulseapp/api/service/FlagsService.java
new file mode 100644
index 0000000..00e21aa
--- /dev/null
+++ b/src/main/java/cc/pulseapp/api/service/FlagsService.java
@@ -0,0 +1,61 @@
+package cc.pulseapp.api.service;
+
+import cc.pulseapp.api.model.Feature;
+import com.flagsmith.FlagsmithClient;
+import com.flagsmith.models.BaseFlag;
+import jakarta.annotation.PostConstruct;
+import lombok.SneakyThrows;
+import lombok.extern.log4j.Log4j2;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * This service is responsible for
+ * fetching remote feature flags.
+ *
+ * @author Braydon
+ */
+@Service @Log4j2(topic = "Flags")
+public final class FlagsService {
+    private static final long FETCH_INTERVAL = TimeUnit.SECONDS.toMillis(30L);
+
+    @Value("${flagsmith.api-url}")
+    private String apiUrl;
+
+    @Value("${flagsmith.api-key}")
+    private String apiKey;
+
+    /**
+     * The Flagsmith client.
+     */
+    private FlagsmithClient client;
+
+    @PostConstruct
+    public void onInitialize() {
+        client = FlagsmithClient.newBuilder()
+                .withApiUrl(apiUrl)
+                .setApiKey(apiKey)
+                .build();
+
+        // Schedule a task to fetch all flags
+        new Timer().scheduleAtFixedRate(new TimerTask() {
+            @Override @SneakyThrows
+            public void run() {
+                for (BaseFlag flag : client.getEnvironmentFlags().getAllFlags()) {
+                    Feature feature = Feature.getById(flag.getFeatureName());
+                    if (feature == null) {
+                        continue;
+                    }
+                    Object value = flag.getValue();
+                    feature.setEnabled(flag.getEnabled());
+                    feature.setValue(value instanceof String stringedValue && (stringedValue.isBlank()) ? null : value);
+                }
+                log.info("Fetched new flags (:");
+            }
+        }, 0L, FETCH_INTERVAL);
+    }
+}
\ No newline at end of file