engine/ Improve Readability and Maintainability of Data Purge Functio…

…n (purge()) (#2529)

* engine/#2528/improve readability of data purge function

* engine/#2528/spotless check

* Update engine/src/main/java/com/google/android/fhir/db/impl/DatabaseImpl.kt

* Run spotless

---------

Co-authored-by: Jing Tang <[email protected]>

engine/src/main/java/com/google/android/fhir/db/impl/DatabaseImpl.kt

@@ -386,26 +386,22 @@ internal class DatabaseImpl(
  override suspend fun purge(type: ResourceType, ids: Set<String>, forcePurge: Boolean) {
  db.withTransaction {
  ids.forEach { id ->
- // To check resource is present in DB else throw ResourceNotFoundException()
+ // 1. Verify resource presence:
  selectEntity(type, id)
- val localChangeEntityList = localChangeDao.getLocalChanges(type, id)
- // If local change is not available simply delete resource
- if (localChangeEntityList.isEmpty()) {
- resourceDao.deleteResource(resourceId = id, resourceType = type)
- } else {
- // local change is available with FORCE_PURGE the delete resource and discard changes from
- // localChangeEntity table
- if (forcePurge) {
- resourceDao.deleteResource(resourceId = id, resourceType = type)
- localChangeDao.discardLocalChanges(
- token = LocalChangeToken(localChangeEntityList.map { it.id }),
- )
- } else {
- // local change is available but FORCE_PURGE = false then throw exception
- throw IllegalStateException(
- "Resource with type $type and id $id has local changes, either sync with server or FORCE_PURGE required",
- )
- }
+
+ // 2. Check for local changes (which can only be cleared without syncing in FORCE_PURGE
+ // mode):
+ val localChanges = localChangeDao.getLocalChanges(type, id)
+ if (localChanges.isNotEmpty() && !forcePurge) {
+ throw IllegalStateException(
+ "Resource with type $type and id $id has local changes, either sync with server or FORCE_PURGE required",
+ )
+ }
+
+ // 3. Delete resource and discard local changes (if applicable):
+ resourceDao.deleteResource(id, type)
+ if (localChanges.isNotEmpty()) {
+ localChangeDao.discardLocalChanges(id, type)
  }
  }
  }