bugfix product options and variants

src/lib/components/single-product.svelte

@@ -1,21 +1,62 @@
 <script lang="ts">
     import { cart } from '$lib/stores/cart';
-    import type { MedusaProduct, MedusaVariant } from '$lib/types/medusa';
+    import type { MedusaProduct, MedusaVariant, MedusaOptionValue } from '$lib/types/medusa';
 
     export let product: MedusaProduct;
     let selectedVariant: MedusaVariant = product.variants[0];
     let currentImageIndex = 0;
     let cartButton: HTMLDivElement;
     let isSticky = false;
+    let selectedOptions = new Map<string, string>();
+
+    // Initialize selected options from the first variant
+    $: if (product.variants.length > 0) {
+        selectedOptions = new Map(
+            product.variants[0].options.map(opt => [opt.option_id, opt.value])
+        );
+    }
 
     function handleScroll() {
         if (!cartButton) return;
         isSticky = window.scrollY + window.innerHeight < cartButton.offsetTop;
     }
 
-    function handleVariantChange(variantId: string) {
-        const variant = product.variants.find((v: MedusaVariant) => v.id === variantId);
-        if (variant) selectedVariant = variant;
+    function handleOptionChange(optionId: string, value: string) {
+        selectedOptions.set(optionId, value);
+        
+        // Find the variant that matches all selected options
+        const matchingVariant = product.variants.find(variant => 
+            variant.options.every(opt => 
+                selectedOptions.get(opt.option_id) === opt.value
+            )
+        );
+
+        if (matchingVariant) {
+            selectedVariant = matchingVariant;
+        }
+    }
+
+    // Get available values for an option based on other selected options
+    function getAvailableValues(optionId: string) {
+        const otherSelectedOptions = new Map(selectedOptions);
+        otherSelectedOptions.delete(optionId);
+
+        return product.options
+            .find(opt => opt.id === optionId)
+            ?.values.filter(value => {
+                // Check if this value is available in any variant with current selections
+                return product.variants.some(variant => 
+                    variant.options.some(opt => 
+                        opt.option_id === optionId && 
+                        opt.value === value.value &&
+                        // Check if other selected options match
+                        variant.options.every(opt => 
+                            opt.option_id === optionId || 
+                            otherSelectedOptions.get(opt.option_id) === opt.value
+                        )
+                    )
+                );
+            }) || [];
     }
 </script>
 
@@ -52,17 +93,17 @@
 
         {#each product.options as option}
             <div>
-                <label class="label" for={`option-${option.title}`}>
+                <label class="label" for={`option-${option.id}`}>
                     <span class="label-text">{option.title}</span>
                 </label>
                 <select 
-                    id={`option-${option.title}`}
+                    id={`option-${option.id}`}
                     class="select select-bordered w-full"
-                    value={selectedVariant.id}
-                    on:change={(e) => handleVariantChange((e.target as HTMLSelectElement).value)}
+                    value={selectedOptions.get(option.id)}
+                    on:change={(e) => handleOptionChange(option.id, (e.target as HTMLSelectElement).value)}
                 >
-                    {#each option.values as value}
-                        <option value={product.variants.find(v => v.options[0].value === value.value)?.id}>
+                    {#each getAvailableValues(option.id) as value}
+                        <option value={value.value}>
                             {value.value}
                         </option>
                     {/each}