feat: integrate Pi backend and Pi Web

pi/packages/ai/src/auth/credential-store.ts

@@ -0,0 +1,51 @@
+import type { Credential, CredentialInfo, CredentialStore } from "./types.ts";
+
+/**
+ * Default in-memory credential store. Apps inject persistent stores.
+ * Keyed by `Provider.id`, one credential per provider; see `CredentialStore`.
+ * Writes are serialized per provider through a promise chain.
+ */
+export class InMemoryCredentialStore implements CredentialStore {
+	private credentials = new Map<string, Credential>();
+	private chains = new Map<string, Promise<unknown>>();
+
+	/** Serialize tasks per provider id. */
+	private enqueue<T>(providerId: string, task: () => Promise<T>): Promise<T> {
+		const previous = this.chains.get(providerId) ?? Promise.resolve();
+		const next = (async () => {
+			await previous.catch(() => {});
+			return task();
+		})();
+		this.chains.set(
+			providerId,
+			next.catch(() => {}),
+		);
+		return next;
+	}
+
+	async read(providerId: string): Promise<Credential | undefined> {
+		return this.credentials.get(providerId);
+	}
+
+	async list(): Promise<readonly CredentialInfo[]> {
+		return [...this.credentials].map(([providerId, credential]) => ({ providerId, type: credential.type }));
+	}
+
+	modify(
+		providerId: string,
+		fn: (current: Credential | undefined) => Promise<Credential | undefined>,
+	): Promise<Credential | undefined> {
+		return this.enqueue(providerId, async () => {
+			const current = this.credentials.get(providerId);
+			const next = await fn(current);
+			if (next !== undefined) this.credentials.set(providerId, next);
+			return next ?? current;
+		});
+	}
+
+	delete(providerId: string): Promise<void> {
+		return this.enqueue(providerId, async () => {
+			this.credentials.delete(providerId);
+		});
+	}
+}