dirty: assets-controller

packages/assets-controllers/src/AssetsController/data-sources/AbstractDataSource.ts

@@ -0,0 +1,144 @@
+import type { ChainId, DataRequest, DataResponse } from '../types';
+
+// ============================================================================
+// DATA SOURCE BASE TYPES
+// ============================================================================
+
+/**
+ * Subscription request from AssetsController.
+ */
+export interface SubscriptionRequest {
+  request: DataRequest;
+  subscriptionId: string;
+  isUpdate: boolean;
+}
+
+/**
+ * Base state for all data sources.
+ */
+export interface DataSourceState {
+  /** Currently active chains (supported AND available) */
+  activeChains: ChainId[];
+}
+
+// ============================================================================
+// ABSTRACT DATA SOURCE
+// ============================================================================
+
+/**
+ * Abstract base class for data sources.
+ *
+ * Data sources communicate with AssetsController via Messenger:
+ * - Register actions that AssetsController can call
+ * - Publish events that AssetsController subscribes to
+ */
+export abstract class AbstractDataSource<
+  Name extends string,
+  State extends DataSourceState = DataSourceState,
+> {
+  protected readonly name: Name;
+  protected state: State;
+
+  /** Active subscriptions by ID */
+  protected readonly activeSubscriptions: Map<
+    string,
+    { cleanup: () => void; chains: ChainId[] }
+  > = new Map();
+
+  constructor(name: Name, initialState: State) {
+    this.name = name;
+    this.state = initialState;
+  }
+
+  /**
+   * Get the data source name/ID.
+   */
+  getName(): Name {
+    return this.name;
+  }
+
+  /**
+   * Get currently active chains (supported AND available).
+   */
+  async getActiveChains(): Promise<ChainId[]> {
+    return this.state.activeChains;
+  }
+
+  /**
+   * Subscribe to updates for the given request.
+   */
+  abstract subscribe(request: SubscriptionRequest): Promise<void>;
+
+  /**
+   * Unsubscribe from updates.
+   */
+  async unsubscribe(subscriptionId: string): Promise<void> {
+    const subscription = this.activeSubscriptions.get(subscriptionId);
+    if (subscription) {
+      subscription.cleanup();
+      this.activeSubscriptions.delete(subscriptionId);
+    }
+  }
+
+  /**
+   * Update active chains and notify listeners only if changed.
+   */
+  protected updateActiveChains(
+    chains: ChainId[],
+    publishEvent: (chains: ChainId[]) => void,
+  ): void {
+    const previousChains = new Set(this.state.activeChains);
+    const newChains = new Set(chains);
+
+    // Check if chains have actually changed
+    const hasChanges =
+      previousChains.size !== newChains.size ||
+      chains.some((chain) => !previousChains.has(chain));
+
+    // Always update state
+    this.state.activeChains = chains;
+
+    // Only publish event if there are actual changes
+    if (hasChanges) {
+      publishEvent(chains);
+    }
+  }
+
+  /**
+   * Add a chain to active chains.
+   */
+  protected addActiveChain(
+    chainId: ChainId,
+    publishEvent: (chains: ChainId[]) => void,
+  ): void {
+    if (!this.state.activeChains.includes(chainId)) {
+      this.state.activeChains = [...this.state.activeChains, chainId];
+      publishEvent(this.state.activeChains);
+    }
+  }
+
+  /**
+   * Remove a chain from active chains.
+   */
+  protected removeActiveChain(
+    chainId: ChainId,
+    publishEvent: (chains: ChainId[]) => void,
+  ): void {
+    if (this.state.activeChains.includes(chainId)) {
+      this.state.activeChains = this.state.activeChains.filter(
+        (c) => c !== chainId,
+      );
+      publishEvent(this.state.activeChains);
+    }
+  }
+
+  /**
+   * Destroy the data source and clean up resources.
+   */
+  destroy(): void {
+    for (const subscription of this.activeSubscriptions.values()) {
+      subscription.cleanup();
+    }
+    this.activeSubscriptions.clear();
+  }
+}