From 6c6f401e3e5ba30de54be4a03c22732c85f47df8 Mon Sep 17 00:00:00 2001
From: Maurice Parker <mo@vincode.io>
Date: Sat, 9 May 2020 19:36:03 -0500
Subject: [PATCH] Change to save new records only if there isn't already a
 server side record

---
 .../CloudKitArticleStatusUpdate.swift         |  5 ++
 .../CloudKit/CloudKitArticlesZone.swift       | 15 +++-
 .../Account/CloudKit/CloudKitZone.swift       | 74 +++++++++++++++++++
 3 files changed, 92 insertions(+), 2 deletions(-)

diff --git a/Frameworks/Account/CloudKit/CloudKitArticleStatusUpdate.swift b/Frameworks/Account/CloudKit/CloudKitArticleStatusUpdate.swift
index 851fb3c54..65048cb9d 100644
--- a/Frameworks/Account/CloudKit/CloudKitArticleStatusUpdate.swift
+++ b/Frameworks/Account/CloudKit/CloudKitArticleStatusUpdate.swift
@@ -14,6 +14,7 @@ struct CloudKitArticleStatusUpdate {
 	
 	enum Record {
 		case all
+		case new
 		case statusOnly
 		case delete
 	}
@@ -27,6 +28,10 @@ struct CloudKitArticleStatusUpdate {
 			return .delete
 		}
 		
+		if statuses.count == 1, statuses.first!.key == .new {
+			return .new
+		}
+		
 		if let article = article {
 			if article.status.read == false || article.status.starred == true {
 				return .all
diff --git a/Frameworks/Account/CloudKit/CloudKitArticlesZone.swift b/Frameworks/Account/CloudKit/CloudKitArticlesZone.swift
index 8c84e556d..6db210674 100644
--- a/Frameworks/Account/CloudKit/CloudKitArticlesZone.swift
+++ b/Frameworks/Account/CloudKit/CloudKitArticlesZone.swift
@@ -111,6 +111,7 @@ final class CloudKitArticlesZone: CloudKitZone {
 		}
 		
 		var modifyRecords = [CKRecord]()
+		var newRecords = [CKRecord]()
 		var deleteRecordIDs = [CKRecord.ID]()
 		
 		for statusUpdate in statusUpdates {
@@ -118,6 +119,9 @@ final class CloudKitArticlesZone: CloudKitZone {
 			case .all:
 				modifyRecords.append(makeStatusRecord(statusUpdate))
 				modifyRecords.append(makeArticleRecord(statusUpdate.article!))
+			case .new:
+				newRecords.append(makeStatusRecord(statusUpdate))
+				newRecords.append(makeArticleRecord(statusUpdate.article!))
 			case .delete:
 				deleteRecordIDs.append(CKRecord.ID(recordName: statusID(statusUpdate.articleID), zoneID: Self.zoneID))
 			case .statusOnly:
@@ -126,10 +130,17 @@ final class CloudKitArticlesZone: CloudKitZone {
 			}
 		}
 		
-		self.modify(recordsToSave: modifyRecords, recordIDsToDelete: deleteRecordIDs) { result in
+		modify(recordsToSave: modifyRecords, recordIDsToDelete: deleteRecordIDs) { result in
 			switch result {
 			case .success:
-				completion(.success(()))
+				self.saveIfNew(newRecords) { result in
+					switch result {
+					case .success:
+						completion(.success(()))
+					case .failure(let error):
+						completion(.failure(error))
+					}
+				}
 			case .failure(let error):
 				self.handleModifyArticlesError(error, statusUpdates: statusUpdates, completion: completion)
 			}
diff --git a/Frameworks/Account/CloudKit/CloudKitZone.swift b/Frameworks/Account/CloudKit/CloudKitZone.swift
index af8f91e1f..2fda15212 100644
--- a/Frameworks/Account/CloudKit/CloudKitZone.swift
+++ b/Frameworks/Account/CloudKit/CloudKitZone.swift
@@ -234,6 +234,80 @@ extension CloudKitZone {
 		modify(recordsToSave: records, recordIDsToDelete: [], completion: completion)
 	}
 	
+	/// Saves or modifies the records as long as they are unchanged relative to the local version
+	func saveIfNew(_ records: [CKRecord], completion: @escaping (Result<Void, Error>) -> Void) {
+		let op = CKModifyRecordsOperation(recordsToSave: records, recordIDsToDelete: [CKRecord.ID]())
+		op.savePolicy = .ifServerRecordUnchanged
+		op.isAtomic = false
+		
+		op.modifyRecordsCompletionBlock = { [weak self] (_, _, error) in
+			
+			guard let self = self else { return }
+			
+			switch CloudKitZoneResult.resolve(error) {
+			case .success, .partialFailure:
+				DispatchQueue.main.async {
+					completion(.success(()))
+				}
+				
+			case .zoneNotFound:
+				self.createZoneRecord() { result in
+					switch result {
+					case .success:
+						self.saveIfNew(records, completion: completion)
+					case .failure(let error):
+						DispatchQueue.main.async {
+							completion(.failure(error))
+						}
+					}
+				}
+				
+			case .userDeletedZone:
+				DispatchQueue.main.async {
+					completion(.failure(CloudKitZoneError.userDeletedZone))
+				}
+				
+			case .retry(let timeToWait):
+				self.retryIfPossible(after: timeToWait) {
+					self.saveIfNew(records, completion: completion)
+				}
+				
+			case .limitExceeded:
+
+				let chunkedRecords = records.chunked(into: 300)
+
+				let group = DispatchGroup()
+				var errorOccurred = false
+
+				for chunk in chunkedRecords {
+					group.enter()
+					self.saveIfNew(chunk) { result in
+						if case .failure(let error) = result {
+							os_log(.error, log: self.log, "%@ zone modify records error: %@", Self.zoneID.zoneName, error.localizedDescription)
+							errorOccurred = true
+						}
+						group.leave()
+					}
+				}
+				
+				group.notify(queue: DispatchQueue.main) {
+					if errorOccurred {
+						completion(.failure(CloudKitZoneError.unknown))
+					} else {
+						completion(.success(()))
+					}
+				}
+				
+			default:
+				DispatchQueue.main.async {
+					completion(.failure(CloudKitError(error!)))
+				}
+			}
+		}
+
+		database?.add(op)
+	}
+
 	/// Save the CKSubscription
 	func save(_ subscription: CKSubscription, completion: @escaping (Result<CKSubscription, Error>) -> Void) {
 		database?.save(subscription) { [weak self] savedSubscription, error in