fix(query): Remove duplicated rows when datasets shared Publicly in the hub page

amber/src/main/scala/org/apache/texera/web/resource/dashboard/DatasetSearchQueryBuilder.scala

@@ -66,31 +66,39 @@ object DatasetSearchQueryBuilder extends SearchQueryBuilder with LazyLogging {
       params: DashboardResource.SearchQueryParams,
       includePublic: Boolean = false
   ): TableLike[_] = {
+    // Case 1: if `uid` is (set) and `includePublic` is false
+    // -> return ONLY datasets that given `uid` has explicit access to.
+    // Case 2: if `uid` is (null) and `includePublic` is true
+    // -> return ONLY datasets that are public
+    // Case 3 (DUPLICATE ROWS): if `uid` is (set) and `includePublic` is true
+    // -> Intersection of datasets that are public and explicitly shared with user is returned
+    // Case 4: if `uid` is (null) and `includePublic` is false
+    // -> return public datasets by default as user might not be logged in
     val baseJoin = DATASET
-      .leftJoin(DATASET_USER_ACCESS)
-      .on(DATASET_USER_ACCESS.DID.eq(DATASET.DID))
-      .leftJoin(USER)
-      .on(USER.UID.eq(DATASET.OWNER_UID))
+       .leftJoin(DATASET_USER_ACCESS)
+       .on(DATASET_USER_ACCESS.DID.eq(DATASET.DID))
+       .and(if (uid == null) DSL.falseCondition() else DATASET_USER_ACCESS.UID.eq(uid))
+       .leftJoin(USER)
+       .on(USER.UID.eq(DATASET.OWNER_UID))
 
-    // Default condition starts as true, ensuring all datasets are selected initially.
-    var condition: Condition = DSL.trueCondition()
-
-    if (uid == null) {
-      // If `uid` is null, the user is not logged in or performing a public search
-      // We only select datasets marked as public
-      condition = DATASET.IS_PUBLIC.eq(true)
-    } else {
-      // When `uid` is present, we add a condition to only include datasets with direct user access.
-      val userAccessCondition = DATASET_USER_ACCESS.UID.eq(uid)
-
-      if (includePublic) {
-        // If `includePublic` is true, we extend visibility to public datasets as well.
-        condition = userAccessCondition.or(DATASET.IS_PUBLIC.eq(true))
-      } else {
-        condition = userAccessCondition
+    // Set the `condition` where clause here
+    val condition: Condition =
+      if (uid == null) {
+        // Case 2 and 4
+        // Get all the public datasets by default
+          DATASET.IS_PUBLIC.eq(true)
+      } else { 
+          if(includePublic) {
+          // Case 3
+          // Get all the datasets that `uid` has access to and the public datasets
+            DATASET.IS_PUBLIC.eq(true).or(DATASET_USER_ACCESS.UID.isNotNull)
+          } else{
+          // Case 1
+          // If `includePublic` is false get only user accessible datasets
+            DATASET_USER_ACCESS.UID.isNotNull
+          }
       }
-    }
-    baseJoin.where(condition)
+     baseJoin.where(condition)
   }
 
   override protected def constructWhereClause(
@@ -140,7 +148,9 @@ object DatasetSearchQueryBuilder extends SearchQueryBuilder with LazyLogging {
     val dd = DashboardDataset(
       dataset,
       owner.getEmail,
-      record.get(DATASET_USER_ACCESS.PRIVILEGE, classOf[PrivilegeEnum]),
+      Option(record.get(
+        DATASET_USER_ACCESS.PRIVILEGE, classOf[PrivilegeEnum]
+      )).getOrElse(PrivilegeEnum.NONE),
       dataset.getOwnerUid == uid,
       size
     )