now products have different options, like different parameters

src/controllers/shop.rs

@@ -9,22 +9,40 @@ use serde_json::json;
 use crate::{
     controllers::i18n::current_lang,
     shared::{guard, pricing},
-    models::{categories, product_images, products, users},
+    models::{categories, product_images, product_variants, products, users},
     views::shop as view,
 };
 
-/// Shape a list of products into card rows for `user` (None = public), pricing
-/// each via [`pricing::price_many`] and loading its primary image.
+/// Shape a list of products into card rows for `user` (None = public). Each card
+/// shows the resolved price of the product's representative (first) variant; the
+/// `variant_count` lets the template render "from {price}" for multi-variant
+/// products. Products with no variants are skipped (not purchasable).
 async fn product_rows(
     ctx: &AppContext,
     user: Option<&users::Model>,
     list: Vec<products::Model>,
 ) -> Result<Vec<serde_json::Value>> {
-    let priced = pricing::price_many(ctx, &list, user).await?;
-    let mut rows = Vec::with_capacity(list.len());
-    for (product, priced) in list.iter().zip(priced.iter()) {
+    let ids: Vec<i32> = list.iter().map(|p| p.id).collect();
+    let grouped = product_variants::Entity::grouped_for_products(&ctx.db, &ids).await?;
+
+    // Representative (first) variant per product, in list order, dropping any
+    // product that has no variants.
+    let mut entries: Vec<(&products::Model, product_variants::Model, usize)> = Vec::new();
+    for product in &list {
+        if let Some(variants) = grouped.get(&product.id) {
+            if let Some(first) = variants.first() {
+                entries.push((product, first.clone(), variants.len()));
+            }
+        }
+    }
+
+    let reps: Vec<product_variants::Model> = entries.iter().map(|(_, v, _)| v.clone()).collect();
+    let priced = pricing::price_variants(ctx, &reps, user).await?;
+
+    let mut rows = Vec::with_capacity(entries.len());
+    for ((product, rep, count), priced) in entries.iter().zip(priced.iter()) {
         let image = product_images::first_for(ctx, product.id).await?;
-        rows.push(view::product_card(product, priced, image, None));
+        rows.push(view::product_card(product, rep, priced, *count, image, None));
     }
     Ok(rows)
 }
@@ -121,13 +139,44 @@ async fn show(
     };
 
     let user = guard::current_user(&ctx, &jar).await;
-    let priced = pricing::price_for(&ctx, &product, user.as_ref()).await?;
+    let variants = product_variants::Entity::for_product(&ctx.db, product.id).await?;
+    let variant_prices = pricing::price_variants(&ctx, &variants, user.as_ref()).await?;
+    let options: Vec<serde_json::Value> = variants
+        .iter()
+        .zip(variant_prices.iter())
+        .map(|(variant, priced)| view::variant_option(variant, priced))
+        .collect();
+    // The card header uses the representative (first) variant for its headline
+    // price; the picker below lets the customer switch.
+    let representative = variants.first();
+    let priced = variant_prices.first().copied();
+    let card = match (representative, priced) {
+        (Some(rep), Some(priced)) => view::product_card(
+            &product,
+            rep,
+            &priced,
+            variants.len(),
+            None,
+            category.as_ref().map(|c| c.name.clone()),
+        ),
+        // A product with no variants isn't purchasable; show it without a price.
+        _ => serde_json::json!({
+            "id": product.id,
+            "name": product.name,
+            "slug": product.slug,
+            "description": product.description,
+            "currency": product.currency,
+            "variant_count": 0,
+            "has_options": false,
+        }),
+    };
     let c = guard::chrome_from(&ctx, user.as_ref());
     format::view(
         &v,
         "shop/show.html",
         json!({
-            "product": view::product_card(&product, &priced, None, category.as_ref().map(|c| c.name.clone())),
+            "product": card,
+            "variants": options,
             "images": images.iter().map(|i| i.image_id.clone()).collect::<Vec<_>>(),
             "category": category,
             "logged_in_admin": c.logged_in_admin,