Play and delete a torrent that came as a folder of files (#158)

A torrent of several files is recorded as its folder. /media could not serve a folder, and the
reaper's remove_file failed on it, warned "could not delete" on every pass and freed nothing, so it
counted against the quota for good; Delete in the page failed the same way.

download::remove deletes a file or a whole folder, for the reaper and Delete alike, and the reaper
counts a folder by its recorded size, as a directory's own size is not its contents'.
download::playable answers the path itself, or for a folder the largest file in it, which is the
episode, and /media serves that.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/download.rs

@@ -207,6 +207,33 @@ pub async fn place(d: &Downloaded, dir: &Path) -> Result<PathBuf> {
     Ok(dest)
 }
 
+/// Deletes what an enclosure's path names: a file, or the folder a torrent of several files came
+/// down as. `remove_file` refused the folder, so the reaper warned on every pass and freed nothing,
+/// and Delete failed (#158).
+pub fn remove(path: &Path) -> std::io::Result<()> {
+    if path.is_dir() { std::fs::remove_dir_all(path) } else { std::fs::remove_file(path) }
+}
+
+/// The file to play for an enclosure's path: the path itself, or for a torrent of several files,
+/// the largest file in its folder, which is the episode (#158).
+pub fn playable(path: &Path) -> PathBuf {
+    fn largest(dir: &Path, best: &mut Option<(u64, PathBuf)>) {
+        let Ok(entries) = std::fs::read_dir(dir) else { return };
+        for e in entries.flatten() {
+            match e.metadata() {
+                Ok(m) if m.is_dir() => largest(&e.path(), best),
+                Ok(m) if best.as_ref().is_none_or(|(n, _)| m.len() > *n) => *best = Some((m.len(), e.path())),
+                _ => {}
+            }
+        }
+    }
+    let mut best = None;
+    if path.is_dir() {
+        largest(path, &mut best);
+    }
+    best.map_or_else(|| path.to_owned(), |(_, p)| p)
+}
+
 /// Advertised as a torrent, before spending any bandwidth on it.
 pub fn looks_like_torrent(url: &str, mime: Option<&str>) -> bool {
     mime.is_some_and(|m| m.to_ascii_lowercase().contains("torrent"))
@@ -415,6 +442,20 @@ mod tests {
         assert_eq!(folder_for(&cfg, "id", &f, None), "etc/Show");
     }
 
+    #[test]
+    fn a_torrent_folder_plays_its_largest_file_and_deletes_whole() {
+        let d = std::env::temp_dir().join(format!("ipx-torrent-test-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&d);
+        std::fs::create_dir_all(d.join("show/extras")).unwrap();
+        std::fs::write(d.join("show/cover.jpg"), [0; 10]).unwrap();
+        std::fs::write(d.join("show/extras/episode.mp3"), [0; 100]).unwrap();
+        assert_eq!(playable(&d.join("show")), d.join("show/extras/episode.mp3"));
+        assert_eq!(playable(&d.join("show/cover.jpg")), d.join("show/cover.jpg"), "a file is itself");
+        remove(&d.join("show")).unwrap();
+        assert!(!d.join("show").exists());
+        let _ = std::fs::remove_dir_all(&d);
+    }
+
     #[test]
     fn keyword_matching_is_or_across_keywords_and_and_within_one() {
         let kws = vec!["deep dive".to_string(), "interview".to_string()];