revert(audience-env): drop AudienceEnvironment enum per PR review

Addresses review feedback on #709 from @nattb8: avoid exposing a public
enum of environments and match the Web/Pixel SDK pattern.

Problems with the enum:
- Makes Dev a first-class, permanently-supported public choice that
  cannot be removed later without a breaking change.
- Forces every future backend addition onto the public enum surface.
- Diverges from @imtbl/audience, which has no enum.

This commit undoes the enum wiring and restores the key-prefix URL
derivation that existed before the PR. A follow-up commit adds an
optional BaseUrl override on AudienceConfig (Web SDK parity) so devs
who need Dev can point the SDK there directly.

- Delete AudienceEnvironment.cs.
- Constants: restore TestKeyPrefix and the
  MessagesUrl/ConsentUrl/DataUrl(string?) signatures.
- AudienceConfig: drop the Environment field.
- HttpTransport: drop the AudienceEnvironment ctor parameter; URL
  derives from publishableKey prefix.
- ImmutableAudience: remove the CurrentEnvironment getter and its
  cached backing field; revert DeleteData, SyncConsentToBackend, and
  Init to pass publishableKey into the URL helpers.
- Tests: remove the CurrentEnvironment_* cases and the per-env URL
  cases; restore the pre-PR test-key / prod-key URL assertions.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ImmutableJeffrey

src/Packages/Audience/Runtime/AudienceConfig.cs

@@ -10,10 +10,6 @@ public class AudienceConfig
         // Studio API key. Required — Init throws if null.
         public string? PublishableKey { get; set; }
 
-        // Target backend. Sandbox default prevents accidental production
-        // traffic; pin to Production explicitly when shipping to players.
-        public AudienceEnvironment Environment { get; set; } = AudienceEnvironment.Sandbox;
-
         // Initial consent level.
         public ConsentLevel Consent { get; set; } = ConsentLevel.None;
 

src/Packages/Audience/Runtime/AudienceEnvironment.cs

@@ -4,7 +4,7 @@ namespace Immutable.Audience
 {
     internal static class Constants
     {
-        internal const string DevBaseUrl = "https://api.dev.immutable.com";
+        internal const string TestKeyPrefix = "pk_imapik-test-";
         internal const string SandboxBaseUrl = "https://api.sandbox.immutable.com";
         internal const string ProductionBaseUrl = "https://api.immutable.com";
 
@@ -26,21 +26,14 @@ internal static class Constants
 
         internal const string PublishableKeyHeader = "x-immutable-publishable-key";
 
-        internal static string MessagesUrl(AudienceEnvironment environment) => BaseUrl(environment) + MessagesPath;
-        internal static string ConsentUrl(AudienceEnvironment environment) => BaseUrl(environment) + ConsentPath;
-        internal static string DataUrl(AudienceEnvironment environment) => BaseUrl(environment) + DataPath;
+        internal static string MessagesUrl(string? publishableKey) => BaseUrl(publishableKey) + MessagesPath;
+        internal static string ConsentUrl(string? publishableKey) => BaseUrl(publishableKey) + ConsentPath;
+        internal static string DataUrl(string? publishableKey) => BaseUrl(publishableKey) + DataPath;
 
-        internal static string BaseUrl(AudienceEnvironment environment) =>
-            environment switch
-            {
-                AudienceEnvironment.Dev => DevBaseUrl,
-                AudienceEnvironment.Sandbox => SandboxBaseUrl,
-                AudienceEnvironment.Production => ProductionBaseUrl,
-                // Defensive: a future enum addition we forget to wire up
-                // falls back to Sandbox so accidental production traffic
-                // is impossible without explicit opt-in.
-                _ => SandboxBaseUrl,
-            };
+        internal static string BaseUrl(string? publishableKey) =>
+            publishableKey != null && publishableKey.StartsWith(TestKeyPrefix)
+                ? SandboxBaseUrl
+                : ProductionBaseUrl;
     }
 
     // Message type values written to (and read back from) the "type" field.

src/Packages/Audience/Runtime/Core/Constants.cs

@@ -62,11 +62,6 @@ public static class ImmutableAudience
         // a prior session changed it.
         public static ConsentLevel CurrentConsent => _state.Level;
 
-        // Caches the last Init's env so a diagnostic HUD does not flicker
-        // to the Sandbox default when Shutdown clears _config.
-        public static AudienceEnvironment CurrentEnvironment => _currentEnvironment;
-        private static volatile AudienceEnvironment _currentEnvironment = AudienceEnvironment.Sandbox;
-
         public static string? UserId => _state.UserId;
 
         // Display-only — Reset and SetConsent(None) wipe it, so it is not
@@ -130,15 +125,14 @@ public static void Init(AudienceConfig config)
                 }
 
                 _config = config;
-                _currentEnvironment = config.Environment;
                 Log.Enabled = config.Debug;
                 // Persisted consent overrides the config default (prior downgrade survives restart).
                 var initialLevel = ConsentStore.Load(config.PersistentDataPath) ?? config.Consent;
                 _state = new ConsentState(initialLevel, null);
 
                 _store = new DiskStore(config.PersistentDataPath);
                 _queue = new EventQueue(_store, config.FlushIntervalSeconds, config.FlushSize);
-                _transport = new HttpTransport(_store, config.PublishableKey, config.Environment, config.OnError, config.HttpHandler);
+                _transport = new HttpTransport(_store, config.PublishableKey, config.OnError, config.HttpHandler);
                 _controlClient = config.HttpHandler != null
                     ? new HttpClient(config.HttpHandler, disposeHandler: false)
                     : new HttpClient();
@@ -394,7 +388,7 @@ public static Task DeleteData(string? userId = null)
                 query = "anonymousId=" + Uri.EscapeDataString(anonymousId);
             }
 
-            var url = Constants.DataUrl(config.Environment) + "?" + query;
+            var url = Constants.DataUrl(config.PublishableKey) + "?" + query;
             var onError = config.OnError;
             var publishableKey = config.PublishableKey;
             var cancellationToken = _shutdownCancellationSource?.Token ?? CancellationToken.None;
@@ -556,7 +550,7 @@ private static void SyncConsentToBackend(AudienceConfig config, ConsentLevel lev
             var client = _controlClient;
             if (client == null) return;
 
-            var url = Constants.ConsentUrl(config.Environment);
+            var url = Constants.ConsentUrl(config.PublishableKey);
             var publishableKey = config.PublishableKey;
             var onError = config.OnError;
             var cancellationToken = _shutdownCancellationSource?.Token ?? CancellationToken.None;
@@ -771,9 +765,6 @@ internal static void ResetState()
                 // Defensive: Shutdown nulls _session too, but a future refactor
                 // that bails before that null must not leak a stale Session.
                 _session = null;
-                // Reset the env cache so test isolation and domain-reload
-                // both start from Sandbox; a subsequent Init overwrites it.
-                _currentEnvironment = AudienceEnvironment.Sandbox;
                 Identity.ClearCache();
             }
         }

src/Packages/Audience/Runtime/ImmutableAudience.cs

@@ -28,21 +28,18 @@ internal sealed class HttpTransport : IDisposable
 
         // store: source of event batches.
         // publishableKey: sent as x-immutable-publishable-key on every request.
-        // environment: which backend to send to. Defaults to Sandbox so
-        //   tests and ad-hoc construction cannot accidentally hit production.
         // onError: optional failure callback. Exceptions thrown inside it are caught.
         // handler / getUtcNow: test seams; null for production use.
         internal HttpTransport(
             DiskStore store,
             string publishableKey,
-            AudienceEnvironment environment = AudienceEnvironment.Sandbox,
             Action<AudienceError>? onError = null,
             HttpMessageHandler? handler = null,
             Func<DateTime>? getUtcNow = null)
         {
             _store = store ?? throw new ArgumentNullException(nameof(store));
             _publishableKey = publishableKey ?? throw new ArgumentNullException(nameof(publishableKey));
-            _url = Constants.MessagesUrl(environment);
+            _url = Constants.MessagesUrl(publishableKey);
             _onError = onError;
             // disposeHandler: false so the consumer can reuse their handler
             // across Init/Shutdown cycles (matches _controlClient's policy).

src/Packages/Audience/Runtime/Transport/HttpTransport.cs

@@ -42,7 +42,7 @@ public void SetConsent_FiresPut_WithExpectedBodyShape()
             var put = WaitForPut(handler);
             var body = JsonReader.DeserializeObject(put.Body);
 
-            Assert.AreEqual(Constants.ConsentUrl(AudienceEnvironment.Sandbox), put.Url);
+            Assert.AreEqual(Constants.ConsentUrl("pk_imapik-test-key1"), put.Url);
             Assert.AreEqual("full", body["status"]);
             Assert.AreEqual(Constants.ConsentSource, body["source"]);
             Assert.IsTrue(body.ContainsKey("anonymousId"));

src/Packages/Audience/Tests/Runtime/ConsentSyncTests.cs

@@ -6,32 +6,6 @@ namespace Immutable.Audience.Tests
     [TestFixture]
     internal class ConstantsTests
     {
-        // -----------------------------------------------------------------
-        // BaseUrl per environment
-        // -----------------------------------------------------------------
-
-        [Test]
-        public void BaseUrl_Dev_ReturnsDevHost()
-        {
-            Assert.AreEqual(Constants.DevBaseUrl, Constants.BaseUrl(AudienceEnvironment.Dev));
-        }
-
-        [Test]
-        public void BaseUrl_Sandbox_ReturnsSandboxHost()
-        {
-            Assert.AreEqual(Constants.SandboxBaseUrl, Constants.BaseUrl(AudienceEnvironment.Sandbox));
-        }
-
-        [Test]
-        public void BaseUrl_Production_ReturnsProductionHost()
-        {
-            Assert.AreEqual(Constants.ProductionBaseUrl, Constants.BaseUrl(AudienceEnvironment.Production));
-        }
-
-        // -----------------------------------------------------------------
-        // Library version
-        // -----------------------------------------------------------------
-
         [Test]
         public void LibraryVersion_MatchesPackageJson()
         {

src/Packages/Audience/Tests/Runtime/ConstantsTests.cs

@@ -80,53 +80,6 @@ public void Initialized_FlipsAroundInitAndShutdown()
                 "Initialized should flip back to false after Shutdown");
         }
 
-        [Test]
-        public void CurrentEnvironment_DefaultsToSandbox()
-        {
-            // MakeConfig() leaves Environment unset, which means
-            // AudienceConfig's Sandbox default applies.
-            ImmutableAudience.Init(MakeConfig());
-            Assert.AreEqual(AudienceEnvironment.Sandbox,
-                ImmutableAudience.CurrentEnvironment);
-        }
-
-        [Test]
-        public void CurrentEnvironment_ExplicitDev_PassesThrough()
-        {
-            var config = MakeConfig();
-            config.Environment = AudienceEnvironment.Dev;
-            ImmutableAudience.Init(config);
-            Assert.AreEqual(AudienceEnvironment.Dev,
-                ImmutableAudience.CurrentEnvironment);
-        }
-
-        [Test]
-        public void CurrentEnvironment_BeforeInit_ReturnsSandbox()
-        {
-            // Pre-Init there is no config to read. Returning Sandbox
-            // matches the AudienceConfig default so UI never shows a
-            // separate "(uninitialised)" sentinel for this row.
-            Assert.AreEqual(AudienceEnvironment.Sandbox,
-                ImmutableAudience.CurrentEnvironment);
-        }
-
-        [Test]
-        public void CurrentEnvironment_SurvivesShutdown()
-        {
-            // A diagnostic HUD running in Production must not flicker to
-            // Sandbox when the SDK tears down. CurrentEnvironment caches
-            // the last Init's env so it keeps reporting the same value
-            // after Shutdown clears _config.
-            var config = MakeConfig();
-            config.Environment = AudienceEnvironment.Production;
-            ImmutableAudience.Init(config);
-            ImmutableAudience.Shutdown();
-
-            Assert.AreEqual(AudienceEnvironment.Production,
-                ImmutableAudience.CurrentEnvironment,
-                "CurrentEnvironment should retain the last Init's value after Shutdown");
-        }
-
         [Test]
         public void CurrentConsent_ReflectsLatestSetConsent()
         {

src/Packages/Audience/Tests/Runtime/ImmutableAudienceTests.cs

@@ -123,7 +123,7 @@ public async Task SendBatchAsync_200_SendsPlainJsonPayloadWithoutContentEncoding
 #endif
 
         [Test]
-        public async Task SendBatchAsync_DefaultEnvironment_HitsSandbox()
+        public async Task SendBatchAsync_200_UsesCorrectUrlForTestKey()
         {
             _store.Write("{\"type\":\"track\"}");
 
@@ -138,31 +138,14 @@ public async Task SendBatchAsync_DefaultEnvironment_HitsSandbox()
         }
 
         [Test]
-        public async Task SendBatchAsync_ExplicitDev_HitsDev()
+        public async Task SendBatchAsync_200_UsesCorrectUrlForProdKey()
         {
             _store.Write("{\"type\":\"track\"}");
 
             HttpRequestMessage captured = null;
             var handler = new MockHandler(HttpStatusCode.OK, "{\"accepted\":1,\"rejected\":0}",
                 onRequest: req => captured = req);
-            using var transport = new HttpTransport(_store, "pk_imapik-test-key1",
-                environment: AudienceEnvironment.Dev, handler: handler);
-
-            await transport.SendBatchAsync();
-
-            StringAssert.StartsWith(Constants.DevBaseUrl, captured.RequestUri.ToString());
-        }
-
-        [Test]
-        public async Task SendBatchAsync_ExplicitProduction_HitsProduction()
-        {
-            _store.Write("{\"type\":\"track\"}");
-
-            HttpRequestMessage captured = null;
-            var handler = new MockHandler(HttpStatusCode.OK, "{\"accepted\":1,\"rejected\":0}",
-                onRequest: req => captured = req);
-            using var transport = new HttpTransport(_store, "pk_imapik-test-key1",
-                environment: AudienceEnvironment.Production, handler: handler);
+            using var transport = new HttpTransport(_store, "pk_imapik-prodkey", handler: handler);
 
             await transport.SendBatchAsync();