better project structure

src/shared/slug.rs

@@ -0,0 +1,38 @@
+//! URL slug helpers shared by the catalog admin (products and categories).
+
+use loco_rs::prelude::*;
+
+/// Lowercase a string and collapse every run of non-alphanumeric characters
+/// into a single dash, trimming dashes from the ends.
+pub fn slugify(value: &str) -> String {
+    let mut slug = String::new();
+    let mut last_was_dash = false;
+    for ch in value.chars().flat_map(char::to_lowercase) {
+        if ch.is_ascii_alphanumeric() {
+            slug.push(ch);
+            last_was_dash = false;
+        } else if !last_was_dash && !slug.is_empty() {
+            slug.push('-');
+            last_was_dash = true;
+        }
+    }
+    slug.trim_matches('-').to_string()
+}
+
+/// Find the first slug that does not already exist, appending `-2`, `-3`, … to
+/// `base` until `exists` reports the candidate as free. An empty `base` falls
+/// back to `"item"`.
+pub async fn unique_slug<F, Fut>(base: &str, mut exists: F) -> Result<String>
+where
+    F: FnMut(String) -> Fut,
+    Fut: std::future::Future<Output = Result<bool>>,
+{
+    let base = if base.is_empty() { "item" } else { base };
+    let mut slug = base.to_string();
+    let mut suffix = 2;
+    while exists(slug.clone()).await? {
+        slug = format!("{base}-{suffix}");
+        suffix += 1;
+    }
+    Ok(slug)
+}