Add empty-dirs verb to find movie directories with no movies.

src/lib.rs

@@ -1,5 +1,6 @@
 use std::cmp::Ordering;
 use std::collections::HashMap;
+use std::collections::HashSet;
 use std::env;
 use std::ffi::OsStr;
 use std::fmt;
@@ -678,6 +679,28 @@ impl MovieLibrary {
         Ok(serde_json::from_reader(r)
             .context(format!("serde_json::from_reader {}", path.display()))?)
     }
+
+    pub fn empty_dirs(&self) -> Result<Vec<String>, Error> {
+        let mut all_dirs = HashSet::new();
+        let root_len = self.root.len() + 1; // +1 for trailing slash
+        for de in Path::new(&self.root).read_dir()? {
+            let de = de?;
+            if de.metadata()?.is_dir() {
+                let path = de.path().to_string_lossy().to_string();
+                all_dirs.insert(path[root_len..].to_string());
+            }
+        }
+        for path in self.videos()?.keys() {
+            let dir = match path.find("/") {
+                Some(idx) => path[..idx].to_string(),
+                None => path.to_string(),
+            };
+            all_dirs.remove(&dir);
+        }
+        let mut empty_dirs: Vec<_> = all_dirs.into_iter().collect();
+        empty_dirs.sort();
+        Ok(empty_dirs)
+    }
 }
 
 #[cfg(test)]

src/main.rs

@@ -171,6 +171,8 @@ enum Command {
         about = "Write full metadata files and update compact file on changes"
     )]
     UpdateAndCompactMetadata,
+    #[structopt(about = "Print directories with no movie files in them")]
+    EmptyDirs,
 }
 
 #[derive(StructOpt)]
@@ -248,6 +250,16 @@ fn main() -> Result<(), Box<dyn Error>> {
             lib.update_metadata()?;
             lib.compact_metadata()?;
         }
+        Command::EmptyDirs => {
+            let lib = MovieLibrary::new(MOVIE_DIR);
+            let dirs = lib.empty_dirs()?;
+            if !dirs.is_empty() {
+                println!("Empty directories:");
+                for d in dirs {
+                    println!("  {}", d);
+                }
+            }
+        }
     }
     Ok(())
 }