refactor(tts): derive save filename from URL path only

packages/tts/src/index.test.ts

@@ -43,26 +43,12 @@ describe('fetchModFileFromUrl', () => {
 });
 
 describe('getFileName', () => {
-  it('parses a quoted content-disposition filename', () => {
-    expect(
-      getFileName('https://example.com/save', 'attachment; filename="mod.json"'),
-    ).toBe('mod.json');
-  });
-
-  it('parses an unquoted filename', () => {
-    expect(
-      getFileName('https://example.com/save', 'attachment; filename=mod.json'),
-    ).toBe('mod.json');
-  });
-
-  it('falls back to the URL path when there is no disposition', () => {
-    expect(getFileName('https://example.com/files/mod.json', null)).toBe(
-      'mod.json',
-    );
+  it('derives the filename from the URL path', () => {
+    expect(getFileName('https://example.com/files/mod.json')).toBe('mod.json');
   });
 
   it('falls back to a default when the URL has no path', () => {
-    expect(getFileName('https://example.com', null)).toBe('save.json');
+    expect(getFileName('https://example.com')).toBe('save.json');
   });
 });
 

packages/tts/src/index.ts

@@ -47,17 +47,12 @@ export async function fetchModFromUrl(fileUrl: string): Promise<TTSMod> {
 }
 
 /**
- * Derive a filename from a `content-disposition` header.
- * Parses `filename="..."`; falls back to the URL path, then a default.
+ * Derive a filename for a downloaded save from its URL path, falling back to
+ * a default when the URL has no path segment. The upstream `content-disposition`
+ * header is intentionally ignored: Steam save URLs are extension-less and
+ * rarely carry a useful filename, so the URL path is the reliable source.
  */
-export function getFileName(url: string, disposition: string | null): string {
-  if (disposition) {
-    const match = disposition.match(/filename\*?=(?:"([^"]*)"|([^;\s]*))/i);
-    const name = match?.[1] ?? match?.[2];
-    if (name) {
-      return name;
-    }
-  }
+export function getFileName(url: string): string {
   return new URL(url).pathname.split('/').pop() || 'save.json';
 }
 
@@ -81,7 +76,7 @@ export async function fetchModFileFromUrl(
   fileUrl: string,
 ): Promise<{ data: ArrayBuffer; filename: string }> {
   const data = await downloadSave(fileUrl);
-  const filename = getFileName(fileUrl, null);
+  const filename = getFileName(fileUrl);
   return { data, filename };
 }