fix(downloads): distinguish missing Xtream seasons

libs/portal/xtream/feature/src/lib/serial-details/xtream-series-download.adapter.spec.ts

@@ -123,6 +123,10 @@ describe('createXtreamSeriesDownloadAdapter', () => {
             episode({ season: 0, episode_num: 0 }),
             '4'
         );
+        const stringSpecials = adapter.createCandidate(
+            episode({ season: '0' as unknown as number }),
+            '4'
+        );
         const fromSeasonKey = adapter.createCandidate(
             episode({ season: Number.NaN }),
             '0'
@@ -135,6 +139,9 @@ describe('createXtreamSeriesDownloadAdapter', () => {
         expect(specials?.identity).toEqual(
             expect.objectContaining({ seasonNumber: 0, episodeNumber: 1 })
         );
+        expect(stringSpecials?.identity).toEqual(
+            expect.objectContaining({ seasonNumber: 0, episodeNumber: 3 })
+        );
         expect(fromSeasonKey?.identity).toEqual(
             expect.objectContaining({ seasonNumber: 0, episodeNumber: 3 })
         );
@@ -148,6 +155,20 @@ describe('createXtreamSeriesDownloadAdapter', () => {
         );
     });
 
+    it.each([null, '', '   '] as const)(
+        'uses the season key for a missing runtime season value %p',
+        (season) => {
+            const adapter = createXtreamSeriesDownloadAdapter(OPTIONS);
+
+            expect(
+                adapter.createCandidate(
+                    episode({ season: season as unknown as number }),
+                    '2'
+                )?.identity
+            ).toEqual(expect.objectContaining({ seasonNumber: 2 }));
+        }
+    );
+
     it('preserves raw Xtream path concatenation and the mp4 extension fallback', async () => {
         const adapter = createXtreamSeriesDownloadAdapter({
             ...OPTIONS,

libs/portal/xtream/feature/src/lib/serial-details/xtream-series-download.adapter.ts

@@ -35,12 +35,13 @@ function downloadSeasonNumber(
     value: unknown,
     fallbackSeasonKey: string | undefined
 ): number | null {
-    const parsed = Number(value);
-    if (Number.isSafeInteger(parsed)) {
-        return parsed >= 0 ? parsed : null;
-    }
-    if (value != null && !(typeof value === 'number' && Number.isNaN(value))) {
-        return null;
+    const isMissing =
+        value == null ||
+        (typeof value === 'string' && value.trim() === '') ||
+        (typeof value === 'number' && Number.isNaN(value));
+    if (!isMissing) {
+        const parsed = Number(value);
+        return Number.isSafeInteger(parsed) && parsed >= 0 ? parsed : null;
     }
 
     const normalizedFallback = fallbackSeasonKey?.trim();