Use PostModel for parent page in EditPostRepository

Instead of using another page model class (ParentPage), we should leverage the
existing PostModel object, simplifying the logic and keeping things consistent.

Author: thomashorta

WordPress/src/main/java/org/wordpress/android/ui/posts/EditPostRepository.kt

@@ -98,7 +98,7 @@ class EditPostRepository
         get() = post!!.tagNameList
     val dateLocallyChanged: String
         get() = post!!.dateLocallyChanged
-    private var parent: ParentPage = ParentPage(0L, EMPTY_STRING)
+    private var parent: PostModel? = null
 
     private var locked = false
 
@@ -237,27 +237,19 @@ class EditPostRepository
 
     fun getParentTitle(site: SiteModel): String {
         // update parent local field if parent ID of current post has changed
-        if (parent.id != post?.parentId) {
+        if (parent?.remotePostId != post?.parentId) {
             runBlocking {
-                val parentId = post?.parentId ?: 0L
-                val parentTitle = parentId
-                        .takeUnless { it == 0L }
-                        ?.let { postStore.getPostByRemotePostId(it, site)?.title }
-                        ?: EMPTY_STRING
-                parent = ParentPage(parentId, parentTitle)
+                parent = post?.parentId
+                        ?.takeUnless { it == 0L }
+                        ?.let { postStore.getPostByRemotePostId(it, site) }
             }
         }
 
-        return parent.title
+        return parent?.title ?: EMPTY_STRING
     }
 
     sealed class UpdatePostResult {
         object Updated : UpdatePostResult()
         object NoChanges : UpdatePostResult()
     }
-
-    private data class ParentPage(
-        val id: Long,
-        val title: String,
-    )
 }

WordPress/src/test/java/org/wordpress/android/ui/posts/EditPostRepositoryTest.kt

@@ -581,7 +581,10 @@ class EditPostRepositoryTest {
         val site = SiteModel()
 
         val parentTitle = "Parent"
-        val parentPost = PostModel().apply { setTitle(parentTitle) }
+        val parentPost = PostModel().apply {
+            setRemotePostId(parentId)
+            setTitle(parentTitle)
+        }
 
         whenever(postStore.getPostByRemotePostId(remoteId, site)).thenReturn(post)
         whenever(postStore.getPostByRemotePostId(parentId, site)).thenReturn(parentPost)