fix(config): attempt to deserialize deep directory structure before flat

This meant that if you had set the directory structure, than it would
always deserialize as "Flat".
We also migrate the newly migrated media to the deep directory structure,
if configured.

src/config/mod.rs

@@ -527,8 +527,8 @@ impl Default for DirectoryStructure {
 #[derive(Deserialize)]
 #[serde(untagged)]
 enum ShadowDirectoryStructure {
-    Flat {},
     Deep { length: NonZeroU8, depth: NonZeroU8 },
+    Flat {},
 }
 
 impl TryFrom<ShadowDirectoryStructure> for DirectoryStructure {

src/database/mod.rs

@@ -459,7 +459,7 @@ impl KeyValueDatabase {
         }
 
         // If the database has any data, perform data migrations before starting
-        let latest_database_version = 17;
+        let latest_database_version = 18;
 
         if services().users.count()? > 0 {
             // MIGRATIONS
@@ -1050,9 +1050,44 @@ impl KeyValueDatabase {
                         return Err(e);
                     }
                 }
-                services().globals.bump_database_version(17)?;
+                services().globals.bump_database_version(18)?;
 
-                warn!("Migration: 16 -> 17 finished");
+                warn!("Migration: 16 -> 18 finished");
+            }
+
+            if services().globals.database_version()? < 18 {
+                if let crate::config::MediaBackendConfig::FileSystem {
+                    path,
+                    directory_structure: crate::config::DirectoryStructure::Deep { length, depth },
+                } = &services().globals.config.media.backend
+                {
+                    for file in fs::read_dir(path)
+                        .unwrap()
+                        .filter_map(Result::ok)
+                        .filter(|entry| {
+                            entry.file_name().len() == 64
+                                && entry.path().parent().and_then(|parent| parent.to_str())
+                                    == Some(path.as_str())
+                        })
+                    {
+                        tokio::fs::rename(
+                            file.path(),
+                            services().globals.get_media_path(
+                                path.as_str(),
+                                &crate::config::DirectoryStructure::Deep {
+                                    length: *length,
+                                    depth: *depth,
+                                },
+                                file.file_name().to_str().unwrap(),
+                            )?,
+                        )
+                        .await?;
+                    }
+                }
+
+                services().globals.bump_database_version(18)?;
+
+                warn!("Migration: 17 -> 18 finished");
             }
 
             assert_eq!(