1 files changed, 42 insertions, 0 deletions
diff --git a/Map/Data/Persistence.swift b/Map/Data/Persistence.swift
new file mode 100644
index 0000000..1eb09e8
--- /dev/null
+++ b/Map/Data/Persistence.swift
@@ -0,0 +1,42 @@
+import CoreData
+
+struct PersistenceController {
+  static let shared = PersistenceController()
+
+  static var preview: PersistenceController = {
+    let result = PersistenceController(inMemory: true)
+    let viewContext = result.container.viewContext
+    for _ in 0..<10 {
+      let newMap = Map(context: viewContext)
+      newMap.uuid = UUID()
+      newMap.createdAt = Date()
+      newMap.title = "Map \(newMap.createdAt!.format())"
+      newMap.content = ""
+    }
+    do {
+      try viewContext.save()
+    } catch {
+      let nsError = error as NSError
+      fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
+    }
+    return result
+  }()
+
+  let container: NSPersistentCloudKitContainer
+
+  init(inMemory: Bool = false) {
+    container = NSPersistentCloudKitContainer(name: "Map")
+
+    container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
+    container.viewContext.automaticallyMergesChangesFromParent = true
+
+    if inMemory {
+      container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null")
+    }
+    container.loadPersistentStores(completionHandler: { (storeDescription, error) in
+      if let error = error as NSError? {
+        fatalError("Unresolved error \(error), \(error.userInfo)")
+      }
+    })
+  }
+}