[CDX-380] Add support for variationId param in RecommendationsRequest (#183)

* [CDX-380] Add support for variationId param in RecommendationsRequest

* add validation for items size

* change validation, update test

* move expression

* lint

* Addresss comments

---------

Co-authored-by: Enes Kutay SEZEN <eneskutaysezen@gmail.com>

Author: quiteeasy

constructorio-client/src/main/java/io/constructor/client/ConstructorIO.java

@@ -1811,6 +1811,17 @@ public String recommendationsAsJSON(RecommendationsRequest req, UserInfo userInf
                 }
             }
 
+            if (StringUtils.isNotBlank(req.getVariationId())) {
+                if (req.getItemIds() == null || req.getItemIds().size() != 1) {
+                    throw new IllegalArgumentException(
+                            "variationId requires exactly one itemId to be specified");
+                }
+                url =
+                        url.newBuilder()
+                                .addQueryParameter("variation_id", req.getVariationId())
+                                .build();
+            }
+
             if (StringUtils.isNotBlank(req.getTerm())) {
                 url = url.newBuilder().addQueryParameter("term", req.getTerm()).build();
             }

constructorio-client/src/main/java/io/constructor/client/RecommendationsRequest.java

@@ -12,6 +12,7 @@ public class RecommendationsRequest {
     private String term;
     private int numResults;
     private List<String> itemIds;
+    private String variationId;
     private Map<String, List<String>> facets;
     private String section;
     private String preFilterExpression;
@@ -32,6 +33,7 @@ public RecommendationsRequest(String podId) throws IllegalArgumentException {
         this.podId = podId;
         this.numResults = 10;
         this.itemIds = null;
+        this.variationId = null;
         this.term = null;
         this.section = "Products";
         this.variationsMap = null;
@@ -97,6 +99,22 @@ public List<String> getItemIds() {
         return itemIds;
     }
 
+    /**
+     * @param variationId the variation id to set. Can be used with exactly one item_id specified in
+     *     the request. Applicable for alternative_items, complementary_items, and bundles pod
+     *     types.
+     */
+    public void setVariationId(String variationId) {
+        this.variationId = variationId;
+    }
+
+    /**
+     * @return the variation id
+     */
+    public String getVariationId() {
+        return variationId;
+    }
+
     /**
      * @param section the section to set
      */

constructorio-client/src/test/java/io/constructor/client/ConstructorIORecommendationsTest.java

@@ -29,6 +29,47 @@ public void getRecommendationsShouldReturnAResultWithSingleItemId() throws Excep
         assertTrue("recommendation result id exists", response.getResultId() != null);
     }
 
+    @Test
+    public void getRecommendationsShouldReturnAResultWithItemIdAndVariationId() throws Exception {
+        ConstructorIO constructor = new ConstructorIO("", apiKey, true, null);
+        UserInfo userInfo = new UserInfo(3, "c62a-2a09-faie");
+        RecommendationsRequest request = new RecommendationsRequest("item_page_1");
+        request.setItemIds(Arrays.asList("power_drill"));
+        request.setVariationId("power_drill_variation");
+        RecommendationsResponse response = constructor.recommendations(request, userInfo);
+        assertEquals(
+                "variation_id in request should match the variationId set",
+                "power_drill_variation",
+                response.getRequest().get("variation_id"));
+        assertTrue("recommendation results exist", response.getResponse().getResults().size() >= 0);
+        assertTrue("recommendation result id exists", response.getResultId() != null);
+    }
+
+    @Test
+    public void getRecommendationsShouldErrorWithVariationIdAndNoItemIds() throws Exception {
+        ConstructorIO constructor = new ConstructorIO("", apiKey, true, null);
+        UserInfo userInfo = new UserInfo(3, "c62a-2a09-faie");
+        RecommendationsRequest request = new RecommendationsRequest("item_page_1");
+        request.setVariationId("power_drill_variation");
+
+        thrown.expect(ConstructorException.class);
+        thrown.expectMessage("variationId requires exactly one itemId to be specified");
+        constructor.recommendations(request, userInfo);
+    }
+
+    @Test
+    public void getRecommendationsShouldErrorWithVariationIdAndMultipleItemIds() throws Exception {
+        ConstructorIO constructor = new ConstructorIO("", apiKey, true, null);
+        UserInfo userInfo = new UserInfo(3, "c62a-2a09-faie");
+        RecommendationsRequest request = new RecommendationsRequest("item_page_1");
+        request.setItemIds(Arrays.asList("power_drill", "drill"));
+        request.setVariationId("power_drill_variation");
+
+        thrown.expect(ConstructorException.class);
+        thrown.expectMessage("variationId requires exactly one itemId to be specified");
+        constructor.recommendations(request, userInfo);
+    }
+
     @Test
     public void getRecommendationsShouldReturnAResultWithMultipleItemIds() throws Exception {
         ConstructorIO constructor = new ConstructorIO("", apiKey, true, null);

constructorio-client/src/test/java/io/constructor/client/RecommendationsRequestTest.java

@@ -35,6 +35,7 @@ public void newShouldReturnDefaultProperties() throws Exception {
         assertEquals(request.getPodId(), podId);
         assertEquals(request.getNumResults(), 10);
         assertNull(request.getItemIds());
+        assertNull(request.getVariationId());
         assertNull(request.getTerm());
         assertEquals(request.getSection(), "Products");
         assertEquals(request.getFacets().size(), 0);
@@ -53,7 +54,8 @@ public void settersShouldSet() throws Exception {
 
         request.setPodId("zero_results_1");
         request.setNumResults(3);
-        request.setItemIds(Arrays.asList("1", "2", "3"));
+        request.setItemIds(Arrays.asList("1"));
+        request.setVariationId("variation-1");
         request.setSection("Search Suggestions");
         request.setFacets(facets);
         request.setTerm(term);
@@ -62,6 +64,8 @@ public void settersShouldSet() throws Exception {
 
         assertEquals(request.getPodId(), "zero_results_1");
         assertEquals(request.getNumResults(), 3);
+        assertEquals(request.getItemIds(), Arrays.asList("1"));
+        assertEquals(request.getVariationId(), "variation-1");
         assertEquals(request.getSection(), "Search Suggestions");
         assertEquals(request.getFacets(), facets);
         assertEquals(request.getTerm(), term);