fix(api): preserve import result contracts

Map data-directory import lock conflicts to HTTP 409 across REST import paths and report stream duplicate counts from the dedicated diagnostics field.

apps/desktop/main/api/routes/import-helpers.test.ts

@@ -0,0 +1,44 @@
+import assert from 'node:assert/strict'
+import test from 'node:test'
+import { IMPORT_IN_PROGRESS_ERROR_KEY } from '@openchatlab/node-runtime/src/import/import-lock'
+import { ApiErrorCode } from '../errors'
+import { apiErrorFromImportResult, batchFromStreamDiagnostics } from './import-helpers'
+
+test('maps an import lock result to the documented 409 API error', () => {
+  const error = apiErrorFromImportResult(IMPORT_IN_PROGRESS_ERROR_KEY, 'Import failed')
+
+  assert.equal(error.code, ApiErrorCode.IMPORT_IN_PROGRESS)
+  assert.equal(error.statusCode, 409)
+})
+
+test('keeps ordinary import failures as IMPORT_FAILED', () => {
+  const error = apiErrorFromImportResult('database write failed', 'Import failed')
+
+  assert.equal(error.code, ApiErrorCode.IMPORT_FAILED)
+  assert.equal(error.statusCode, 500)
+  assert.equal(error.message, 'database write failed')
+})
+
+test('maps stream duplicate and invalid-row counts to their distinct API fields', () => {
+  assert.deepEqual(
+    batchFromStreamDiagnostics({
+      logFile: null,
+      detectedFormat: 'fixture',
+      messagesReceived: 12,
+      messagesWritten: 7,
+      duplicateCount: 3,
+      messagesSkipped: 2,
+      skipReasons: {
+        noSenderId: 1,
+        noAccountName: 0,
+        invalidTimestamp: 1,
+        noType: 0,
+      },
+    }),
+    {
+      receivedCount: 12,
+      writtenCount: 7,
+      duplicateCount: 3,
+    }
+  )
+})

apps/desktop/main/api/routes/import-helpers.ts

@@ -0,0 +1,22 @@
+import { IMPORT_IN_PROGRESS_ERROR_KEY } from '@openchatlab/node-runtime/src/import/import-lock'
+import type { ImportDiagnostics } from '@openchatlab/node-runtime/src/import/streaming-importer'
+import { importFailed, importInProgress, type ApiError } from '../errors'
+
+export function apiErrorFromImportResult(error: string | undefined, fallbackMessage: string): ApiError {
+  return error === IMPORT_IN_PROGRESS_ERROR_KEY ? importInProgress() : importFailed(error || fallbackMessage)
+}
+
+export function batchFromStreamDiagnostics(diagnostics: ImportDiagnostics | undefined):
+  | {
+      receivedCount: number
+      writtenCount: number
+      duplicateCount: number
+    }
+  | undefined {
+  if (!diagnostics) return undefined
+  return {
+    receivedCount: diagnostics.messagesReceived,
+    writtenCount: diagnostics.messagesWritten,
+    duplicateCount: diagnostics.duplicateCount,
+  }
+}

apps/desktop/main/api/routes/import.ts

@@ -33,6 +33,7 @@ import {
   errorResponse,
 } from '../errors'
 import { apiLogger } from '../logger'
+import { apiErrorFromImportResult, batchFromStreamDiagnostics } from './import-helpers'
 
 // Per-session lock: different sessionIds can import in parallel.
 const isImporting = new Set<string>()
@@ -280,7 +281,7 @@ async function handleUnifiedImport(request: FastifyRequest, reply: FastifyReply,
         reply.send(responsePayload)
       } else {
         idempotencyFail(cacheKey)
-        const err = importFailed(result.error || 'Incremental import failed')
+        const err = apiErrorFromImportResult(result.error, 'Incremental import failed')
         reply.code(err.statusCode).send(errorResponse(err))
       }
     } else {
@@ -308,20 +309,14 @@ async function handleUnifiedImport(request: FastifyRequest, reply: FastifyReply,
         const responsePayload = successResponse({
           sessionId: result.sessionId,
           created: true,
-          batch: diag
-            ? {
-                receivedCount: diag.messagesReceived,
-                writtenCount: diag.messagesWritten,
-                duplicateCount: diag.messagesSkipped,
-              }
-            : undefined,
+          batch: batchFromStreamDiagnostics(diag),
           session: sessionInfo,
         })
         idempotencySuccess(cacheKey, responsePayload)
         reply.send(responsePayload)
       } else {
         idempotencyFail(cacheKey)
-        const err = importFailed(result.error || 'Import failed')
+        const err = apiErrorFromImportResult(result.error, 'Import failed')
         reply.code(err.statusCode).send(errorResponse(err))
       }
     }
@@ -401,7 +396,7 @@ async function handleLegacyImport(request: FastifyRequest, reply: FastifyReply,
           })
         )
       } else {
-        const err = importFailed(result.error || 'Incremental import failed')
+        const err = apiErrorFromImportResult(result.error, 'Incremental import failed')
         reply.code(err.statusCode).send(errorResponse(err))
       }
     } else {
@@ -416,7 +411,7 @@ async function handleLegacyImport(request: FastifyRequest, reply: FastifyReply,
           })
         )
       } else {
-        const err = importFailed(result.error || 'Import failed')
+        const err = apiErrorFromImportResult(result.error, 'Import failed')
         reply.code(err.statusCode).send(errorResponse(err))
       }
     }