feat: support multiple video selection

tests/unit/video_state.rs

@@ -1394,3 +1394,58 @@ fn youtube_v1_reports_keep_canonical_urls_and_unknown_field_tolerance() {
     assert!(state.poll_progress().unwrap());
     assert!(state.is_watched(&video.id));
 }
+
+#[test]
+fn player_launch_rejects_invalid_and_duplicate_batch_identities_before_creating_sessions() {
+    use crate::youtube::PlayerLaunch;
+    use std::ffi::OsStr;
+
+    let directory = TestDirectory::new();
+    let mut state = State::open(&directory.config()).unwrap();
+    for id in [
+        "",
+        "--help",
+        "jNQXAC9IVRw&list=other",
+        "日本語",
+        "miruro:opaque_Show-1:0",
+        "miruro:opaque_Show-1:01",
+        "miruro:opaque_Show-1:2147483648",
+        "miruro:../other:1",
+        "miruro:opaque_Show-1:1&ep=2",
+        "miruro-series:opaque_Show-1",
+    ] {
+        let mut invalid_video = video();
+        invalid_video.id = id.into();
+        assert!(matches!(
+            PlayerLaunch::start(&[video(), invalid_video], OsStr::new("terebi"), &mut state),
+            Err(error) if error.kind() == io::ErrorKind::InvalidInput
+        ));
+    }
+    for videos in [vec![], vec![video(), video()]] {
+        assert!(matches!(
+            PlayerLaunch::start(&videos, OsStr::new("terebi"), &mut state),
+            Err(error) if error.kind() == io::ErrorKind::InvalidInput
+        ));
+    }
+    assert!(!state.sessions.exists());
+    assert!(state.streams.is_empty());
+}
+
+#[test]
+fn progress_batch_prevalidates_snapshots_and_session_capacity() {
+    let directory = TestDirectory::new();
+    let mut state = State::open(&directory.config()).unwrap();
+    let mut invalid_video = miruro_video(2);
+    invalid_video.title = "invalid\nmetadata".into();
+    assert!(state.progress_files(&[video(), invalid_video]).is_err());
+    assert!(!state.sessions.exists());
+    assert!(state.streams.is_empty());
+    for _ in 0..MAX_STREAMS - 1 {
+        state
+            .streams
+            .push(ProgressStream::new(directory.0.join("unused.jsonl")));
+    }
+    assert!(state.progress_files(&[video(), miruro_video(2)]).is_err());
+    assert!(!state.sessions.exists());
+    assert_eq!(state.streams.len(), MAX_STREAMS - 1);
+}