Internalize all IM channel implementations

plugin-src/host/channels/feishu/credential-store.mjs

@@ -0,0 +1,84 @@
+/**
+ * Credential references owned by the Feishu Host plugin.  They deliberately
+ * use DSH's credential provider instead of plugin settings, so the browser's
+ * configuration plane can only observe configured/source metadata.
+ */
+export const FEISHU_APP_ID_REF = 'DSH_FEISHU_APP_ID';
+export const FEISHU_APP_SECRET_REF = 'DSH_FEISHU_APP_SECRET';
+
+function assertNonEmptyString(value, label) {
+  if (typeof value !== 'string' || value.length === 0) {
+    throw new TypeError(`${label} must be a non-empty string`);
+  }
+  return value;
+}
+
+async function restore(provider, ref, previous) {
+  try {
+    if (previous?.value) await provider.set(ref, previous.value);
+    else await provider.unset(ref);
+  } catch {
+    // Preserve the original write failure.  The provider remains the source
+    // of truth and will report the partial state through describe().
+  }
+}
+
+/**
+ * Adapt the real DSH `ctx.credentials` seam to the small interface consumed
+ * by the Feishu controller.  Secret values only travel Host-to-Host here.
+ *
+ * @param {{resolve(Function), describe(Function), set(Function), unset(Function)}} provider
+ * @param {{appIdRef?: string, appSecretRef?: string}} options
+ */
+export function createDshCredentialStore(provider, options = {}) {
+  if (!provider
+    || typeof provider.resolve !== 'function'
+    || typeof provider.describe !== 'function'
+    || typeof provider.set !== 'function'
+    || typeof provider.unset !== 'function') {
+    throw new TypeError('A DSH credential provider is required');
+  }
+
+  const appIdRef = options.appIdRef ?? FEISHU_APP_ID_REF;
+  const appSecretRef = options.appSecretRef ?? FEISHU_APP_SECRET_REF;
+
+  return Object.freeze({
+    async save({ appId, appSecret }) {
+      const nextId = assertNonEmptyString(appId, 'Feishu App ID');
+      const nextSecret = assertNonEmptyString(appSecret, 'Feishu App Secret');
+      const [previousId, previousSecret] = await Promise.all([
+        provider.resolve(appIdRef),
+        provider.resolve(appSecretRef),
+      ]);
+
+      try {
+        // Store the secret first.  An App ID without its matching secret must
+        // never be treated as a usable integration.
+        await provider.set(appSecretRef, nextSecret);
+        await provider.set(appIdRef, nextId);
+      } catch {
+        await restore(provider, appSecretRef, previousSecret);
+        await restore(provider, appIdRef, previousId);
+        throw new Error('Unable to store the Feishu credentials.');
+      }
+    },
+
+    async clear() {
+      const outcomes = await Promise.allSettled([
+        provider.unset(appIdRef),
+        provider.unset(appSecretRef),
+      ]);
+      if (outcomes.some((outcome) => outcome.status === 'rejected')) {
+        throw new Error('Unable to remove the Feishu credentials.');
+      }
+    },
+
+    async configured() {
+      const [appId, appSecret] = await Promise.all([
+        provider.describe(appIdRef),
+        provider.describe(appSecretRef),
+      ]);
+      return appId.configured === true && appSecret.configured === true;
+    },
+  });
+}