fix: handle unavailable ai summary

Author: DIYgod

packages/internal/store/package.json

@@ -98,6 +98,7 @@
     }
   },
   "scripts": {
+    "test": "vitest run",
     "typecheck": "tsc --noEmit"
   },
   "peerDependencies": {

packages/internal/store/src/modules/summary/store.test.ts

@@ -0,0 +1,99 @@
+import { FollowAPIError } from "@follow-app/client-sdk"
+import { beforeEach, describe, expect, test, vi } from "vitest"
+
+import { apiContext } from "../../context"
+import type { FollowAPI } from "../../types"
+import { useEntryStore } from "../entry/store"
+import type { EntryModel } from "../entry/types"
+import { SummaryGeneratingStatus } from "./enum"
+import { summarySyncService, useSummaryStore } from "./store"
+import { getGenerateSummaryStatusId } from "./utils"
+
+const { insertSummaryMock } = vi.hoisted(() => ({
+  insertSummaryMock: vi.fn(),
+}))
+
+vi.mock("@follow/database/services/summary", () => ({
+  summaryService: {
+    getAllSummaries: vi.fn(),
+    insertSummary: insertSummaryMock,
+    reset: vi.fn(),
+  },
+}))
+
+const createEntry = (id: string): EntryModel => ({
+  id,
+  guid: `${id}-guid`,
+  insertedAt: new Date("2026-01-01T00:00:00.000Z"),
+  publishedAt: new Date("2026-01-01T00:00:00.000Z"),
+})
+
+describe("summarySyncService", () => {
+  const entryId = "entry-1"
+  const actionLanguage = "en"
+  const target = "content"
+  const summaryApiMock = vi.fn()
+
+  beforeEach(() => {
+    vi.clearAllMocks()
+
+    useEntryStore.setState({
+      data: {
+        [entryId]: createEntry(entryId),
+      },
+    })
+    useSummaryStore.setState({
+      data: {},
+      generatingStatus: {},
+    })
+    apiContext.provide({
+      ai: {
+        summary: summaryApiMock,
+      },
+    } as unknown as FollowAPI)
+  })
+
+  test.each([
+    { apiData: null, expected: null },
+    { apiData: "", expected: null },
+  ])(
+    "treats empty API summary data as unavailable instead of payment failure",
+    async ({ apiData, expected }) => {
+      summaryApiMock.mockResolvedValue({ data: apiData })
+
+      await expect(
+        summarySyncService.generateSummary({
+          entryId,
+          target,
+          actionLanguage,
+        }),
+      ).resolves.toBe(expected)
+
+      expect(insertSummaryMock).not.toHaveBeenCalled()
+      expect(
+        useSummaryStore.getState().generatingStatus[
+          getGenerateSummaryStatusId(entryId, actionLanguage, target)
+        ],
+      ).toBe(SummaryGeneratingStatus.Success)
+    },
+  )
+
+  test("keeps real API payment errors for the upgrade prompt", async () => {
+    const paymentError = new FollowAPIError("Payment required", 402)
+    summaryApiMock.mockRejectedValue(paymentError)
+
+    await expect(
+      summarySyncService.generateSummary({
+        entryId,
+        target,
+        actionLanguage,
+      }),
+    ).rejects.toBe(paymentError)
+
+    expect(
+      useSummaryStore.getState().generatingStatus[
+        getGenerateSummaryStatusId(entryId, actionLanguage, target)
+      ],
+    ).toBe(SummaryGeneratingStatus.Error)
+  })
+})

packages/internal/store/src/modules/summary/store.ts

@@ -2,7 +2,6 @@ import type { SummarySchema } from "@follow/database/schemas/types"
 import { summaryService } from "@follow/database/services/summary"
 import type { SupportedActionLanguage } from "@follow/shared"
 import { toApiSupportedActionLanguage } from "@follow/shared"
-import { FollowAPIError } from "@follow-app/client-sdk"
 
 import { api } from "../../context"
 import type { Hydratable, Resetable } from "../../lib/base"
@@ -139,7 +138,7 @@ class SummaryActions implements Resetable, Hydratable {
 export const summaryActions = new SummaryActions()
 
 class SummarySyncService {
-  private pendingPromises: Record<StatusID, Promise<string>> = {}
+  private pendingPromises: Record<StatusID, Promise<string | null>> = {}
 
   async generateSummary({
     entryId,
@@ -178,8 +177,14 @@ class SummarySyncService {
         target,
       })
       .then((summary) => {
-        if (!summary.data) {
-          throw new FollowAPIError("AI summary limit exceeded. Please try again later.", 402)
+        const generatedSummary = summary.data?.trim() ? summary.data : null
+
+        if (!generatedSummary) {
+          immerSet((state) => {
+            state.generatingStatus[statusID] = SummaryGeneratingStatus.Success
+          })
+
+          return null
         }
 
         immerSet((state) => {
@@ -190,18 +195,18 @@ class SummarySyncService {
           state.data[entryId][actionLanguage] = {
             summary:
               target === "content"
-                ? summary.data || ""
+                ? generatedSummary
                 : state.data[entryId]?.[actionLanguage]?.summary || "",
             readabilitySummary:
               target === "readabilityContent"
-                ? summary.data || ""
+                ? generatedSummary
                 : state.data[entryId]?.[actionLanguage]?.readabilitySummary || null,
             lastAccessed: Date.now(),
           }
           state.generatingStatus[statusID] = SummaryGeneratingStatus.Success
         })
 
-        return summary.data || ""
+        return generatedSummary
       })
       .catch((error) => {
         immerSet((state) => {

packages/internal/store/vitest.config.ts

@@ -0,0 +1,11 @@
+import { defineProject } from "vitest/config"
+
+export default defineProject({
+  test: {
+    environment: "node",
+  },
+  define: {
+    ELECTRON: "false",
+    APP_VERSION: JSON.stringify("0.0.0"),
+  },
+})