feat(downloads): reuse unfinished filename matches

Fixes #26

src/utils/downloads.test.ts

@@ -1,6 +1,11 @@
 import { describe, expect, it } from 'vitest';
 import type { DownloadItem } from '../bindings/DownloadItem';
-import { redactDownloadForPersistence, resolveDownloadConnections } from './downloads';
+import {
+  downloadFileNamesMatch,
+  downloadMediaKindsMatch,
+  redactDownloadForPersistence,
+  resolveDownloadConnections
+} from './downloads';
 
 const item = (status: DownloadItem['status']): DownloadItem => ({
   id: 'download-1',
@@ -56,3 +61,28 @@ describe('download connection resolution', () => {
     expect(resolveDownloadConnections(Number.NaN, 8)).toBe(8);
   });
 });
+
+describe('download filename matching', () => {
+  it('matches case and path spelling while preserving the actual filename', () => {
+    expect(downloadFileNamesMatch(
+      'Media\\Example.Show.S01E01.MKV',
+      'example.show.s01e01.mkv'
+    )).toBe(true);
+  });
+
+  it('does not collapse distinct extensions or names', () => {
+    expect(downloadFileNamesMatch('example.zip', 'example.tar')).toBe(false);
+    expect(downloadFileNamesMatch('example-1.zip', 'example.zip')).toBe(false);
+  });
+
+  it('does not auto-match weak metadata fallback names', () => {
+    expect(downloadFileNamesMatch('download', 'download')).toBe(false);
+    expect(downloadFileNamesMatch('identifier', 'IDENTIFIER')).toBe(false);
+    expect(downloadFileNamesMatch('real-file.bin', 'real-file.bin')).toBe(true);
+  });
+
+  it('treats omitted media flags as ordinary downloads', () => {
+    expect(downloadMediaKindsMatch(undefined, false)).toBe(true);
+    expect(downloadMediaKindsMatch(undefined, true)).toBe(false);
+  });
+});

src/utils/downloads.ts

@@ -132,6 +132,29 @@ export const canonicalizeDownloadFileName = (fileName: string): string => {
   return sanitized && sanitized !== '.' && sanitized !== '..' ? sanitized : 'download';
 };
 
+/**
+ * Compare metadata-derived names without allowing path spelling or case to
+ * turn the same download into a second queue entry. Keep the extension and
+ * the rest of the name intact: URL query strings are not part of this value.
+ */
+export const normalizeDownloadFileNameForMatch = (fileName: string): string =>
+  canonicalizeDownloadFileName(fileName).normalize('NFKC').toLowerCase();
+
+export const downloadMediaKindsMatch = (
+  left: boolean | undefined,
+  right: boolean | undefined
+): boolean => Boolean(left) === Boolean(right);
+
+const WEAK_DOWNLOAD_FILE_NAMES = new Set(['download', 'identifier', 'view', 'uc']);
+
+export const downloadFileNamesMatch = (left: string, right: string): boolean => {
+  const normalizedLeft = normalizeDownloadFileNameForMatch(left);
+  const normalizedRight = normalizeDownloadFileNameForMatch(right);
+  return !WEAK_DOWNLOAD_FILE_NAMES.has(normalizedLeft)
+    && !WEAK_DOWNLOAD_FILE_NAMES.has(normalizedRight)
+    && normalizedLeft === normalizedRight;
+};
+
 export const isMediaUrl = (rawUrl: string): boolean => {
   try {
     const url = new URL(rawUrl);