Good stuff

server-rs/src/data/travel_time.rs

@@ -66,24 +66,41 @@ impl LruCache {
     }
 }
 
+/// Strip a numeric prefix like "000000-" from a filename stem.
+/// "000000-bank-tube-station" → "bank-tube-station"
+fn strip_numeric_prefix(stem: &str) -> &str {
+    if let Some(pos) = stem.find('-') {
+        if stem[..pos].chars().all(|ch| ch.is_ascii_digit()) {
+            return &stem[pos + 1..];
+        }
+    }
+    stem
+}
+
 /// Manages on-demand loading and caching of precomputed travel time parquet files.
 ///
-/// Directory structure: `{base_dir}/{mode}/{slug}.parquet`
+/// Directory structure: `{base_dir}/{mode}/{NNNNNN-slug}.parquet`
+/// Files have a numeric prefix for uniqueness; lookups use the stripped slug.
 /// Each parquet file has columns: `pcds` (String), `travel_minutes` (Int16).
 pub struct TravelTimeStore {
     base_dir: PathBuf,
     /// Available transport modes (subdirectory names, e.g., "bicycle")
     pub available_modes: Vec<String>,
-    /// mode → set of destination slugs (filenames without .parquet)
+    /// mode → set of destination slugs (numeric prefix stripped)
     pub destinations: FxHashMap<String, FxHashSet<String>>,
+    /// (mode, stripped_slug) → full filename stem (with numeric prefix)
+    slug_to_file: FxHashMap<(String, String), String>,
     cache: Mutex<LruCache>,
 }
 
 impl TravelTimeStore {
     /// Scan the travel-times directory to discover available modes and destinations.
+    /// Filename stems have a numeric prefix (e.g., "000000-bank-tube-station") which
+    /// is stripped for slug lookups but preserved for file loading.
     pub fn load(base_dir: &Path, cache_capacity: usize) -> anyhow::Result<Self> {
         let mut available_modes = Vec::new();
         let mut destinations: FxHashMap<String, FxHashSet<String>> = FxHashMap::default();
+        let mut slug_to_file: FxHashMap<(String, String), String> = FxHashMap::default();
 
         for entry in std::fs::read_dir(base_dir)
             .with_context(|| format!("Failed to read travel-times dir: {}", base_dir.display()))?
@@ -103,7 +120,12 @@ impl TravelTimeStore {
                 let file_name = file_entry.file_name();
                 let file_name = file_name.to_string_lossy();
                 if file_name.ends_with(".parquet") {
-                    let slug = file_name.trim_end_matches(".parquet").to_string();
+                    let file_stem = file_name.trim_end_matches(".parquet");
+                    let slug = strip_numeric_prefix(file_stem).to_string();
+                    slug_to_file.insert(
+                        (mode.clone(), slug.clone()),
+                        file_stem.to_string(),
+                    );
                     slugs.insert(slug);
                 }
             }
@@ -125,6 +147,7 @@ impl TravelTimeStore {
             base_dir: base_dir.to_path_buf(),
             available_modes,
             destinations,
+            slug_to_file,
             cache: Mutex::new(LruCache::new(cache_capacity)),
         })
     }
@@ -142,11 +165,16 @@ impl TravelTimeStore {
             }
         }
 
-        // Load from file (no lock held — harmless if two threads load the same file)
+        // Resolve slug to actual filename (may have numeric prefix)
+        let file_stem = self
+            .slug_to_file
+            .get(&key)
+            .map(|val| val.as_str())
+            .unwrap_or(slug);
         let path = self
             .base_dir
             .join(mode)
-            .join(format!("{}.parquet", slug));
+            .join(format!("{}.parquet", file_stem));
         if !path.exists() {
             bail!("Travel time file not found: {}", path.display());
         }
@@ -233,18 +261,15 @@ mod tests {
     #[test]
     fn slugify_basic() {
         assert_eq!(slugify("Abbey Hey"), "abbey-hey");
-        assert_eq!(slugify("Abbots Bickington"), "abbots-bickington");
         assert_eq!(slugify("London"), "london");
     }
 
     #[test]
-    fn slugify_special_chars() {
-        assert_eq!(slugify("A'Bhuaile Ghlas"), "a-bhuaile-ghlas");
-    }
-
-    #[test]
-    fn slugify_edges() {
-        assert_eq!(slugify(" Hello "), "hello");
-        assert_eq!(slugify("Abbey"), "abbey");
+    fn strip_numeric_prefix_basic() {
+        assert_eq!(strip_numeric_prefix("000000-bank-tube-station"), "bank-tube-station");
+        assert_eq!(strip_numeric_prefix("000123-abbey-hey"), "abbey-hey");
+        assert_eq!(strip_numeric_prefix("bank-tube-station"), "bank-tube-station");
+        assert_eq!(strip_numeric_prefix("london"), "london");
     }
 }
+