fix image model alias compatibility

tests/unit/api-config/model-selection-alias.test.ts

@@ -0,0 +1,88 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const prismaMock = vi.hoisted(() => ({
+  userPreference: {
+    findUnique: vi.fn<(...args: unknown[]) => Promise<{ customModels: string; customProviders: string | null } | null>>(async () => null),
+  },
+}))
+
+vi.mock('@/lib/prisma', () => ({
+  prisma: prismaMock,
+}))
+
+import { resolveModelSelection } from '@/lib/api-config'
+
+const compatImageTemplate = {
+  version: 1 as const,
+  mediaType: 'image' as const,
+  mode: 'sync' as const,
+  create: {
+    method: 'POST' as const,
+    path: '/images/generations',
+    contentType: 'application/json' as const,
+    bodyTemplate: {
+      model: '{{model}}',
+      prompt: '{{prompt}}',
+    },
+  },
+  response: {
+    outputUrlPath: '$.data[0].url',
+    errorPath: '$.error.message',
+  },
+}
+
+describe('api-config image model alias resolution', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  it('matches a preview image model when the caller still uses the legacy model id', async () => {
+    prismaMock.userPreference.findUnique.mockResolvedValueOnce({
+      customProviders: null,
+      customModels: JSON.stringify([
+        {
+          modelId: 'gemini-3.1-flash-image-preview',
+          modelKey: 'openai-compatible:oa-1::gemini-3.1-flash-image-preview',
+          name: 'Nano Banana 2',
+          type: 'image',
+          provider: 'openai-compatible:oa-1',
+          compatMediaTemplate: compatImageTemplate,
+        },
+      ]),
+    })
+
+    const selection = await resolveModelSelection(
+      'user-1',
+      'openai-compatible:oa-1::gemini-3.1-flash-image',
+      'image',
+    )
+
+    expect(selection.modelId).toBe('gemini-3.1-flash-image-preview')
+    expect(selection.modelKey).toBe('openai-compatible:oa-1::gemini-3.1-flash-image-preview')
+  })
+
+  it('matches a legacy image model when the caller already uses the preview model id', async () => {
+    prismaMock.userPreference.findUnique.mockResolvedValueOnce({
+      customProviders: null,
+      customModels: JSON.stringify([
+        {
+          modelId: 'gemini-3.1-flash-image',
+          modelKey: 'openai-compatible:oa-1::gemini-3.1-flash-image',
+          name: 'Nano Banana 2',
+          type: 'image',
+          provider: 'openai-compatible:oa-1',
+          compatMediaTemplate: compatImageTemplate,
+        },
+      ]),
+    })
+
+    const selection = await resolveModelSelection(
+      'user-1',
+      'openai-compatible:oa-1::gemini-3.1-flash-image-preview',
+      'image',
+    )
+
+    expect(selection.modelId).toBe('gemini-3.1-flash-image')
+    expect(selection.modelKey).toBe('openai-compatible:oa-1::gemini-3.1-flash-image')
+  })
+})