save discount profile is now working perfectly well

src/controllers/admin_products.rs

@@ -432,6 +432,62 @@ fn percent_off(regular_cents: i64, sale_cents: i64) -> i64 {
     off.round() as i64
 }
 
+/// Preview the effective prices that the submitted (unsaved) checkbox set would
+/// produce, without persisting anything. Returns OOB `<span>`s that htmx swaps
+/// into the effective-price column so the admin sees the effect before Save.
+#[debug_handler]
+async fn profiles_preview(
+    auth: auth::JWT,
+    jar: CookieJar,
+    ViewEngine(v): ViewEngine<TeraView>,
+    Query(params): Query<HashMap<String, String>>,
+    State(ctx): State<AppContext>,
+    body: String,
+) -> Result<Response> {
+    guard::current_admin(auth, &ctx).await?;
+    let audience = read_audience(&params);
+
+    let profile_ids: Vec<i32> = form_urlencoded::parse(body.as_bytes())
+        .filter(|(k, _)| k == "profile_ids")
+        .filter_map(|(_, value)| value.parse::<i32>().ok())
+        .collect();
+
+    let all_categories = categories::Entity::find()
+        .order_by_asc(categories::Column::Position)
+        .order_by_asc(categories::Column::Name)
+        .all(&ctx.db)
+        .await?;
+    let list = products::Entity::find()
+        .order_by_desc(products::Column::CreatedAt)
+        .all(&ctx.db)
+        .await?;
+    let effective =
+        pricing::audience_price_many_preview(&ctx, &list, audience, profile_ids).await?;
+
+    let selected_category = params.get("category").map(String::as_str).unwrap_or("all");
+    let filter = view::category_filter_ids(&all_categories, selected_category);
+
+    let mut rows = Vec::new();
+    for (product, priced) in list.iter().zip(effective.iter()) {
+        if !view::category_filter_keep(&filter, product.category_id) {
+            continue;
+        }
+        rows.push(json!({
+            "id": product.id,
+            "currency": product.currency,
+            "effective_price": format_price(priced.price_cents),
+            "effective_reduced": priced.is_reduced(),
+            "effective_percent_off": percent_off(product.price_cents, priced.price_cents),
+        }));
+    }
+
+    format::view(
+        &v,
+        "admin/catalog/_price_preview.html",
+        json!({ "products": rows, "lang": current_lang(&jar) }),
+    )
+}
+
 /// Replace the profiles applied to this audience with the submitted checkbox set
 /// (`profile_ids`, a repeated field parsed directly from the body).
 #[debug_handler]
@@ -631,6 +687,10 @@ pub fn routes() -> Routes {
             post(create).layer(image_limit.clone()),
         )
         .add("/admin/catalog/products/profiles", post(sync_profiles))
+        .add(
+            "/admin/catalog/products/profiles/preview",
+            post(profiles_preview),
+        )
         .add("/admin/catalog/products/{id}/edit", get(edit))
         .add(
             "/admin/catalog/products/{id}",