add basic feature flags api

posthog-v3/posthog-samples/posthog-android-sample/src/main/java/com/posthog/android/sample/MainActivity.kt

@@ -38,7 +38,10 @@ fun Greeting(name: String, modifier: Modifier = Modifier) {
         text = AnnotatedString("Hello $name!"),
         modifier = modifier,
         onClick = {
-            PostHog.capture("testEvent", mapOf("testProperty" to "testValue"))
+//            PostHog.capture("testEvent", mapOf("testProperty" to "testValue"))
+//            PostHog.reloadFeatureFlagsRequest()
+            // sessionRecording
+            PostHog.isFeatureEnabled("sessionRecording")
         },
     )
 }

posthog-v3/posthog/api/posthog.api

@@ -8,6 +8,9 @@ public final class com/posthog/PostHog {
 	public final fun close ()V
 	public final fun getAnonymousId ()Ljava/lang/String;
 	public final fun getDistinctId ()Ljava/lang/String;
+	public final fun isFeatureEnabled (Ljava/lang/String;Z)Z
+	public static synthetic fun isFeatureEnabled$default (Lcom/posthog/PostHog;Ljava/lang/String;ZILjava/lang/Object;)Z
+	public final fun reloadFeatureFlagsRequest ()V
 	public final fun screen (Ljava/lang/String;Ljava/util/Map;)V
 	public static synthetic fun screen$default (Lcom/posthog/PostHog;Ljava/lang/String;Ljava/util/Map;ILjava/lang/Object;)V
 	public final fun setup (Lcom/posthog/PostHogConfig;)V
@@ -17,24 +20,16 @@ public final class com/posthog/PostHog$Companion {
 	public final fun capture (Ljava/lang/String;Ljava/util/Map;)V
 	public static synthetic fun capture$default (Lcom/posthog/PostHog$Companion;Ljava/lang/String;Ljava/util/Map;ILjava/lang/Object;)V
 	public final fun close ()V
+	public final fun isFeatureEnabled (Ljava/lang/String;Z)Z
+	public static synthetic fun isFeatureEnabled$default (Lcom/posthog/PostHog$Companion;Ljava/lang/String;ZILjava/lang/Object;)Z
+	public final fun reloadFeatureFlagsRequest ()V
 	public final fun setup (Lcom/posthog/PostHogConfig;)V
 	public final fun with (Lcom/posthog/PostHogConfig;)Lcom/posthog/PostHog;
 }
 
 public final class com/posthog/PostHogConfig {
 	public fun <init> (Ljava/lang/String;Ljava/lang/String;ZIIIILcom/posthog/PostHogDataMode;)V
 	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;ZIIIILcom/posthog/PostHogDataMode;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
-	public final fun component1 ()Ljava/lang/String;
-	public final fun component2 ()Ljava/lang/String;
-	public final fun component3 ()Z
-	public final fun component4 ()I
-	public final fun component5 ()I
-	public final fun component6 ()I
-	public final fun component7 ()I
-	public final fun component8 ()Lcom/posthog/PostHogDataMode;
-	public final fun copy (Ljava/lang/String;Ljava/lang/String;ZIIIILcom/posthog/PostHogDataMode;)Lcom/posthog/PostHogConfig;
-	public static synthetic fun copy$default (Lcom/posthog/PostHogConfig;Ljava/lang/String;Ljava/lang/String;ZIIIILcom/posthog/PostHogDataMode;ILjava/lang/Object;)Lcom/posthog/PostHogConfig;
-	public fun equals (Ljava/lang/Object;)Z
 	public final fun getApiKey ()Ljava/lang/String;
 	public final fun getDataMode ()Lcom/posthog/PostHogDataMode;
 	public final fun getDebug ()Z
@@ -43,14 +38,12 @@ public final class com/posthog/PostHogConfig {
 	public final fun getHost ()Ljava/lang/String;
 	public final fun getMaxBatchSize ()I
 	public final fun getMaxQueueSize ()I
-	public fun hashCode ()I
 	public final fun setDataMode (Lcom/posthog/PostHogDataMode;)V
 	public final fun setDebug (Z)V
 	public final fun setFlushAt (I)V
 	public final fun setFlushIntervalSeconds (I)V
 	public final fun setMaxBatchSize (I)V
 	public final fun setMaxQueueSize (I)V
-	public fun toString ()Ljava/lang/String;
 }
 
 public final class com/posthog/PostHogDataMode : java/lang/Enum {

posthog-v3/posthog/src/main/java/com/posthog/PostHog.kt

@@ -1,6 +1,7 @@
 package com.posthog
 
 import com.posthog.internal.PostHogApi
+import com.posthog.internal.PostHogFeatureFlags
 import com.posthog.internal.PostHogPrintLogger
 import com.posthog.internal.PostHogQueue
 import com.posthog.internal.PostHogSessionManager
@@ -15,6 +16,7 @@ public class PostHog {
     private var config: PostHogConfig? = null
     private var storage: PostHogStorage? = null
     private var sessionManager: PostHogSessionManager? = null
+    private var featureFlags: PostHogFeatureFlags? = null
     private var api: PostHogApi? = null
     private var queue: PostHogQueue? = null
 
@@ -36,14 +38,17 @@ public class PostHog {
             sessionManager = PostHogSessionManager(storage)
             val api = PostHogApi(config)
             val queue = PostHogQueue(config, storage, api)
+            val featureFlags = PostHogFeatureFlags(config, api)
 
             this.api = api
             this.storage = storage
             this.config = config
             this.queue = queue
+            this.featureFlags = featureFlags
             enabled = true
 
             queue.start()
+            loadFeatureFlagsRequest()
         }
     }
 
@@ -125,6 +130,25 @@ public class PostHog {
         capture("\$create_alias", properties = props)
     }
 
+    public fun reloadFeatureFlagsRequest() {
+        if (!isEnabled()) {
+            return
+        }
+        loadFeatureFlagsRequest()
+    }
+
+    private fun loadFeatureFlagsRequest() {
+        val map = mapOf<String, Any>()
+        featureFlags?.loadFeatureFlagsRequest(buildProperties(map))
+    }
+
+    public fun isFeatureEnabled(key: String, defaultValue: Boolean = false): Boolean {
+        if (!isEnabled()) {
+            return defaultValue
+        }
+        return featureFlags?.isFeatureEnabled(key, defaultValue) ?: defaultValue
+    }
+
     // TODO: groups, groupIdentify, group, feature flags, buildProperties (static context, dynamic context, distinct_id)
 
     private fun isEnabled(): Boolean {
@@ -156,6 +180,14 @@ public class PostHog {
             shared.capture(event, properties = properties)
         }
 
+        public fun reloadFeatureFlagsRequest() {
+            shared.reloadFeatureFlagsRequest()
+        }
+
+        public fun isFeatureEnabled(key: String, defaultValue: Boolean = false): Boolean {
+            return shared.isFeatureEnabled(key, defaultValue = defaultValue)
+        }
+
         // TODO: add other methods
     }
 }

posthog-v3/posthog/src/main/java/com/posthog/PostHogConfig.kt

@@ -2,7 +2,7 @@ package com.posthog
 
 import com.posthog.internal.PostHogLogger
 
-public data class PostHogConfig(
+public class PostHogConfig(
     // apiKey and host are immutable due to offline caching
     public val apiKey: String,
     public val host: String = "https://app.posthog.com",

posthog-v3/posthog/src/main/java/com/posthog/internal/PostHogApi.kt

@@ -20,11 +20,12 @@ internal class PostHogApi(private val config: PostHogConfig) {
     private val gson = GsonBuilder().apply {
         registerTypeAdapter(Date::class.java, GsonDateTypeAdapter(config))
     }.create()
-    private val gsonBodyType = object : TypeToken<PostHogBatchEvent>() {}.type
+    private val gsonBatchBodyType = object : TypeToken<PostHogBatchEvent>() {}.type
+    private val gsonDecideBodyType = object : TypeToken<Map<String, Any>>() {}.type
 
     fun batch(events: List<PostHogEvent>) {
         val batch = PostHogBatchEvent(config.apiKey, events)
-        val json = gson.toJson(batch, gsonBodyType)
+        val json = gson.toJson(batch, gsonBatchBodyType)
 //        """
 // {
 //  "api_key": "_6SG-F7I1vCuZ-HdJL3VZQqjBlaSb1_20hDPwqMNnGI",
@@ -50,7 +51,7 @@ internal class PostHogApi(private val config: PostHogConfig) {
             .build()
 
         client.newCall(request).execute().use {
-            if (!it.isSuccessful) throw PostHogApiError(it.code, it.message)
+            if (!it.isSuccessful) throw PostHogApiError(it.code, it.message, body = it.body)
 //            """
 // {
 //  "status": 1
@@ -59,5 +60,63 @@ internal class PostHogApi(private val config: PostHogConfig) {
         }
     }
 
-    // TODO: decide, get APIs
+    fun decide(properties: Map<String, Any>): Map<String, Any>? {
+        val map = mutableMapOf<String, Any>()
+        map.putAll(properties)
+        map["api_key"] = config.apiKey
+
+        val json = gson.toJson(map, gsonDecideBodyType)
+//        """
+// {
+//  "distinct_id": "1fc77c1a-5f98-43b3-bb77-7a2dd15fd13a",
+//  "api_key": "_6SG-F7I1vCuZ-HdJL3VZQqjBlaSb1_20hDPwqMNnGI"
+// }
+//        """.trimIndent()
+        val body = json.toRequestBody(mediaType)
+
+        val request = Request.Builder()
+            .url("${config.host}/decide/?v=3")
+            .header("User-Agent", config.userAgent)
+            .post(body)
+            .build()
+
+        client.newCall(request).execute().use {
+            if (!it.isSuccessful) throw PostHogApiError(it.code, it.message, body = it.body)
+
+            it.body?.let { body ->
+                return gson.fromJson(body.string(), gsonDecideBodyType)
+            }
+            return null
+        }
+//            """
+// {
+//  "config": {
+//    "enable_collect_everything": true
+//  },
+//  "toolbarParams": {},
+//  "isAuthenticated": false,
+//  "supportedCompression": [
+//    "gzip",
+//    "gzip-js"
+//  ],
+//  "featureFlags": {
+//    "4535-funnel-bar-viz": true
+//  },
+//  "sessionRecording": false,
+//  "errorsWhileComputingFlags": false,
+//  "featureFlagPayloads": {},
+//  "capturePerformance": true,
+//  "autocapture_opt_out": false,
+//  "autocaptureExceptions": false,
+//  "siteApps": [
+//    {
+//      "id": 21039,
+//      "url": "/site_app/21039/EOsOSePYNyTzHkZ3f4mjrjUap8Hy8o2vUTAc6v1ZMFP/576ac89bc8aed72a21d9b19221c2c626/"
+//    }
+//  ]
+// }
+//            """.trimIndent()
+    }
+
+    // TODO: get APIs
 }

posthog-v3/posthog/src/main/java/com/posthog/internal/PostHogApiError.kt

@@ -1,6 +1,11 @@
 package com.posthog.internal
 
+import okhttp3.ResponseBody
 import java.lang.RuntimeException
 
 // TODO: rete limit will be part of response in the future
-internal data class PostHogApiError(val statusCode: Int, override val message: String) : RuntimeException(message)
+internal class PostHogApiError(
+    val statusCode: Int,
+    override val message: String,
+    body: ResponseBody? = null,
+) : RuntimeException(message)

posthog-v3/posthog/src/main/java/com/posthog/internal/PostHogFeatureFlags.kt

@@ -0,0 +1,58 @@
+package com.posthog.internal
+
+import com.posthog.PostHogConfig
+import java.util.concurrent.Executors
+import java.util.concurrent.atomic.AtomicBoolean
+
+internal class PostHogFeatureFlags(private val config: PostHogConfig, private val api: PostHogApi) {
+    private val executor = Executors.newSingleThreadScheduledExecutor(PostHogThreadFactory("PostHogDecideThread"))
+
+    private var isLoadingFeatureFlags = AtomicBoolean(false)
+
+    private val featureFlagsLock = Any()
+
+    private var featureFlags: Map<String, Any>? = null
+
+    @Volatile
+    private var isFeatureFlagsLoaded = false
+
+    fun loadFeatureFlagsRequest(properties: Map<String, Any>) {
+        executor.execute {
+            if (isLoadingFeatureFlags.getAndSet(true)) {
+                config.logger?.log("Feature flags are being loaded already.")
+                return@execute
+            }
+
+            try {
+                val featureFlags = api.decide(properties)
+
+                synchronized(featureFlagsLock) {
+                    this.featureFlags = featureFlags
+                }
+
+                isFeatureFlagsLoaded = true
+            } catch (e: Throwable) {
+                config.logger?.log("Loading feature flags failed: $e")
+            }
+
+            isLoadingFeatureFlags.set(false)
+        }
+    }
+
+    fun isFeatureEnabled(key: String, defaultValue: Boolean = false): Boolean {
+        if (!isFeatureFlagsLoaded) {
+            return defaultValue
+        }
+        val value: Any?
+
+        synchronized(featureFlagsLock) {
+            value = featureFlags?.get(key)
+        }
+
+        return if (value is Boolean) {
+            value
+        } else {
+            defaultValue
+        }
+    }
+}

posthog-v3/posthog/src/main/java/com/posthog/internal/PostHogQueue.kt

@@ -25,12 +25,11 @@ internal class PostHogQueue(private val config: PostHogConfig, private val stora
     private var timerTask: TimerTask? = null
 
     // https://github.com/square/tape/blob/master/tape/src/main/java/com/squareup/tape2/QueueFile.java
-    @Volatile
     private var isFlushing = AtomicBoolean(false)
 
     private val delay: Long get() = (config.flushIntervalSeconds * 1000).toLong()
 
-    private val executor = Executors.newSingleThreadScheduledExecutor(PostHogThreadFactory())
+    private val executor = Executors.newSingleThreadScheduledExecutor(PostHogThreadFactory("PostHogBatchThread"))
 
 //    init {
     // TOOD: load deque from disk
@@ -112,8 +111,7 @@ internal class PostHogQueue(private val config: PostHogConfig, private val stora
 
     fun start() {
         synchronized(timerLock) {
-            timerTask?.cancel()
-            timer?.cancel()
+            stopTimer()
             val timer = Timer(true)
             val timerTask = timer.schedule(delay, delay) {
                 // early check to avoid more checks when its already flushing
@@ -128,9 +126,14 @@ internal class PostHogQueue(private val config: PostHogConfig, private val stora
         }
     }
 
+    private fun stopTimer() {
+        timerTask?.cancel()
+        timer?.cancel()
+    }
+
     fun stop() {
         synchronized(timerLock) {
-            timer?.cancel()
+            stopTimer()
         }
     }
 }

posthog-v3/posthog/src/main/java/com/posthog/internal/PostHogThreadFactory.kt

@@ -2,11 +2,11 @@ package com.posthog.internal
 
 import java.util.concurrent.ThreadFactory
 
-internal class PostHogThreadFactory : ThreadFactory {
+internal class PostHogThreadFactory(private val threadName: String) : ThreadFactory {
     override fun newThread(runnable: Runnable): Thread {
         return Thread(runnable).apply {
             isDaemon = true
-            name = "PostHogThreadFactory"
+            name = threadName
         }
     }
 }