Extract & add test

backend/sync_server/src/utils.rs

@@ -1,3 +1,5 @@
+use regex::Regex;
+
 /// Sanitize the document's path to allow all clients to create the same path in
 /// their filesystem. If we didn't do this server-side, client's would need to
 /// deal with mapping invalid names to valid ones and then back.
@@ -21,6 +23,45 @@ pub fn sanitize_path(path: &str) -> String {
         .join("/")
 }
 
+pub fn deduped_file_paths(path: &str) -> impl Iterator<Item = String> {
+    let mut path_parts = path.split('/').collect::<Vec<_>>();
+    let file_name = path_parts.pop().unwrap().to_owned();
+
+    let mut directory = path_parts.join("/");
+    if !directory.is_empty() {
+        directory.push('/');
+    }
+
+    let name_parts = file_name.rsplitn(2, '.').collect::<Vec<_>>();
+    let mut reverse_parts = name_parts.into_iter().rev();
+    let (stem, extension) = match (reverse_parts.next(), reverse_parts.next()) {
+        (Some(stem), maybe_extension) => (
+            stem.to_owned(),
+            maybe_extension
+                .map(|ext| format!(".{ext}"))
+                .unwrap_or_default(),
+        ),
+        _ => unreachable!("Path must have at least one part"),
+    };
+
+    let regex = Regex::new(r" \((\d+)\)$").unwrap();
+    let start_number = regex
+        .captures(&stem)
+        .and_then(|caps| caps.get(1))
+        .and_then(|m| m.as_str().parse::<u32>().ok())
+        .unwrap_or(0);
+
+    let clean_stem = regex.replace(&stem, "").to_string();
+
+    (start_number..).map(move |dedup_number| {
+        if dedup_number == 0 {
+            format!("{directory}{clean_stem}{extension}")
+        } else {
+            format!("{directory}{clean_stem} ({dedup_number}){extension}")
+        }
+    })
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -30,4 +71,47 @@ mod test {
         assert_eq!(sanitize_path("/my/path/what?"), "/my/path/what");
         assert_eq!(sanitize_path("/my/path/\\\\:?"), "/my/path/_");
     }
+
+    #[test]
+    fn test_deduped_file_paths() {
+        let mut deduped = deduped_file_paths("file.txt");
+        assert_eq!(deduped.next(), Some("file.txt".to_owned()));
+        assert_eq!(deduped.next(), Some("file (1).txt".to_owned()));
+        assert_eq!(deduped.next(), Some("file (2).txt".to_owned()));
+
+        let mut deduped = deduped_file_paths("file");
+        assert_eq!(deduped.next(), Some("file".to_owned()));
+        assert_eq!(deduped.next(), Some("file (1)".to_owned()));
+        assert_eq!(deduped.next(), Some("file (2)".to_owned()));
+
+        let mut deduped = deduped_file_paths("file (51).md");
+        assert_eq!(deduped.next(), Some("file (51).md".to_owned()));
+        assert_eq!(deduped.next(), Some("file (52).md".to_owned()));
+        assert_eq!(deduped.next(), Some("file (53).md".to_owned()));
+
+        let mut deduped = deduped_file_paths("file (5)");
+        assert_eq!(deduped.next(), Some("file (5)".to_owned()));
+        assert_eq!(deduped.next(), Some("file (6)".to_owned()));
+        assert_eq!(deduped.next(), Some("file (7)".to_owned()));
+
+        let mut deduped = deduped_file_paths("my/path.with.dots/file (5).md");
+        assert_eq!(
+            deduped.next(),
+            Some("my/path.with.dots/file (5).md".to_owned())
+        );
+        assert_eq!(
+            deduped.next(),
+            Some("my/path.with.dots/file (6).md".to_owned())
+        );
+
+        let mut deduped = deduped_file_paths("my/path.with.dots/file (5)");
+        assert_eq!(
+            deduped.next(),
+            Some("my/path.with.dots/file (5)".to_owned())
+        );
+        assert_eq!(
+            deduped.next(),
+            Some("my/path.with.dots/file (6)".to_owned())
+        );
+    }
 }