Client consent screen

config/src/main/java/dev/faststats/config/SimpleConfig.java

@@ -9,9 +9,9 @@
 import org.jspecify.annotations.Nullable;
 
 import java.io.IOException;
-import java.io.OutputStreamWriter;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.Objects;
 import java.util.Properties;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -21,15 +21,7 @@
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 @ApiStatus.Internal
-public record SimpleConfig(
-        UUID serverId,
-        boolean enabled,
-        boolean additionalMetrics,
-        boolean debug,
-        boolean submitMetrics,
-        boolean errorTracking,
-        boolean firstRun
-) implements Config {
+public final class SimpleConfig implements Config {
     private static final int CONFIG_VERSION = 2;
 
     private static final String COMMENT = """
@@ -58,7 +50,86 @@
             Learn more at: https://faststats.dev/info
 
             Since this is your first start with FastStats, submission will not start
-            until you restart the server to allow you to opt out if you prefer.""";
+            until after a restart, to allow you to opt out if you prefer.""";
+
+    private final Path file;
+    private final UUID serverId;
+    private final boolean debug;
+    private final boolean firstRun;
+    private volatile boolean additionalMetrics;
+    private volatile boolean enabled;
+    private volatile boolean errorTracking;
+    private volatile boolean submitMetrics;
+
+    public SimpleConfig(
+            final Path file,
+            final UUID serverId,
+            final boolean enabled,
+            final boolean additionalMetrics,
+            final boolean debug,
+            final boolean submitMetrics,
+            final boolean errorTracking,
+            final boolean firstRun
+    ) {
+        this.file = file;
+        this.serverId = serverId;
+        this.enabled = enabled;
+        this.additionalMetrics = additionalMetrics;
+        this.debug = debug;
+        this.submitMetrics = submitMetrics;
+        this.errorTracking = errorTracking;
+        this.firstRun = firstRun;
+    }
+
+    @Override
+    public UUID serverId() {
+        return serverId;
+    }
+
+    @Override
+    public boolean enabled() {
+        return enabled;
+    }
+
+    public void enabled(final boolean enabled) {
+        this.enabled = enabled;
+    }
+
+    @Override
+    public boolean additionalMetrics() {
+        return additionalMetrics;
+    }
+
+    public void additionalMetrics(final boolean additionalMetrics) {
+        this.additionalMetrics = additionalMetrics;
+    }
+
+    @Override
+    public boolean debug() {
+        return debug;
+    }
+
+    @Override
+    public boolean submitMetrics() {
+        return submitMetrics;
+    }
+
+    public void submitMetrics(final boolean submitMetrics) {
+        this.submitMetrics = submitMetrics;
+    }
+
+    @Override
+    public boolean errorTracking() {
+        return errorTracking;
+    }
+
+    public void errorTracking(final boolean errorTracking) {
+        this.errorTracking = errorTracking;
+    }
+
+    public boolean firstRun() {
+        return firstRun;
+    }
 
     @Contract(mutates = "io")
     public static SimpleConfig read(final Path file, final LoggerFactory factory) throws RuntimeException {
@@ -91,8 +162,7 @@
             if (configVersion != null && configVersion < CONFIG_VERSION)
                 logger.info("Updating config version from %s to %s", configVersion, CONFIG_VERSION);
             Files.createDirectories(file.getParent());
-            try (final var out = Files.newOutputStream(file);
-                 final var writer = new OutputStreamWriter(out, UTF_8)) {
+            try (final var writer = Files.newBufferedWriter(file, UTF_8)) {
                 final var store = new Properties();
 
                 store.setProperty("enabled", Boolean.toString(enabled));
@@ -112,6 +182,7 @@
         }
 
         return new SimpleConfig(
+                file,
                 serverId,
                 enabled && enabledFlag,
                 enabled && enabledFlag && additionalMetrics,
@@ -122,6 +193,23 @@
         );
     }
 
+    @Contract(mutates = "io")
+    public void persist() throws RuntimeException {
+        final var properties = readOrEmpty(file);
+        if (properties == null) throw new IllegalStateException("Metrics config has not been initialized");
+
+        properties.setProperty("enabled", Boolean.toString(enabled()));
+        properties.setProperty("submitAdditionalMetrics", Boolean.toString(additionalMetrics()));
+        properties.setProperty("submitErrors", Boolean.toString(errorTracking()));
+        properties.setProperty("submitMetrics", Boolean.toString(submitMetrics()));
+
+        try (final var writer = Files.newBufferedWriter(file, UTF_8)) {
+            properties.store(writer, COMMENT);
+        } catch (final IOException e) {
+            throw new RuntimeException("Failed to save metrics config", e);
+        }
+    }
+
     // fixme: this code sucks ass
     @Contract(value = "_, _, _, !null, _, _-> !null")
     private static <T> @Nullable T parse(
@@ -180,4 +268,33 @@
         }
         return true;
     }
+
+    @Override
+    public boolean equals(final Object object) {
+        if (this == object) return true;
+        if (!(object instanceof final SimpleConfig that)) return false;
+        return enabled == that.enabled
+                && additionalMetrics == that.additionalMetrics
+                && debug == that.debug
+                && submitMetrics == that.submitMetrics
+                && errorTracking == that.errorTracking
+                && firstRun == that.firstRun
+                && Objects.equals(serverId, that.serverId);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(serverId, enabled, additionalMetrics, debug, submitMetrics, errorTracking, firstRun);
+    }
+
+    @Override
+    public String toString() {
+        return "SimpleConfig[serverId=" + serverId
+                + ", enabled=" + enabled
+                + ", additionalMetrics=" + additionalMetrics
+                + ", debug=" + debug
+                + ", submitMetrics=" + submitMetrics
+                + ", errorTracking=" + errorTracking
+                + ", firstRun=" + firstRun + ']';
+    }
 }

core/src/main/java/dev/faststats/FastStatsRegistration.java

@@ -0,0 +1,22 @@
+package dev.faststats;
+
+import java.util.Set;
+
+/**
+ * A non-sensitive description of a live FastStats consumer.
+ *
+ * @since 0.29.2
+ */
+public record FastStatsRegistration(
+        String projectName,
+        String sdkName,
+        String sdkVersion,
+        boolean metrics,
+        boolean errorTracking,
+        boolean featureFlags,
+        Set<String> additionalMetrics
+) {
+    public FastStatsRegistration {
+        additionalMetrics = Set.copyOf(additionalMetrics);
+    }
+}

core/src/main/java/dev/faststats/FastStatsRegistry.java

@@ -0,0 +1,78 @@
+package dev.faststats;
+
+import org.jetbrains.annotations.Contract;
+import org.jspecify.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.IdentityHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Registry of contexts that opt into live onboarding lifecycle updates.
+ *
+ * @since 0.29.2
+ */
+public final class FastStatsRegistry {
+    private static final FastStatsRegistry INSTANCE = new FastStatsRegistry();
+
+    private final Map<SimpleContext, Entry> contexts = new IdentityHashMap<>();
+    private @Nullable Config config;
+
+    private FastStatsRegistry() {
+    }
+
+    @Contract(pure = true)
+    public static FastStatsRegistry instance() {
+        return INSTANCE;
+    }
+
+    /** Registers a context and the shared mutable configuration used by its platform. */
+    public synchronized void register(final SimpleContext context) {
+        if (this.config == null) this.config = context.getConfig();
+        contexts.put(context, new Entry(context, context.registration()));
+    }
+
+    /** Removes a context when its platform lifecycle ends. */
+    public synchronized void unregister(final SimpleContext context) {
+        contexts.remove(context);
+        if (contexts.isEmpty()) config = null;
+    }
+
+    /** Returns a snapshot of every registered FastStats consumer. */
+    public synchronized List<FastStatsRegistration> registrations() {
+        return contexts.values().stream().map(Entry::registration).toList();
+    }
+
+    /** Enables submission for all contexts using the shared configuration. */
+    public void start() {
+        final var config = config();
+        for (final var entry : entries()) {
+            entry.context().startSubmissions(config);
+        }
+    }
+
+    /** Disables submission for all contexts using the shared configuration. */
+    public void shutdown() {
+        final var config = config();
+        for (final var entry : entries()) {
+            entry.context().stopSubmissions(config);
+        }
+    }
+
+    private synchronized List<Entry> entries() {
+        return new ArrayList<>(contexts.values());
+    }
+
+    public synchronized Config config() {
+        final var config = this.config;
+        if (config == null) throw new IllegalStateException("No FastStats contexts are registered");
+        return config;
+    }
+
+    private record Entry(
+            SimpleContext context,
+            FastStatsRegistration registration
+    ) {
+    }
+}