Persistence.swift

//
//  Persistence.swift
//  Flips
//
//  Created by Jordan Foster on 3/17/21.
//

import CoreData

struct PersistenceController {
	static let shared = PersistenceController()
	
	/* Haven't learned yet
	 *
	static var preview: PersistenceController = {
		let result = PersistenceController(inMemory: true)
		let viewContext = result.container.viewContext
		for _ in 0..<10 {
			let newItem = Item(context: viewContext)
			newItem.timestamp = Date()
		}
		do {
			try viewContext.save()
		} catch {
			// Replace this implementation with code to handle the error appropriately.
			// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
			let nsError = error as NSError
			fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
		}
		return result
	}()
	 *
	 * Haven't learned yet */
	
	let container: NSPersistentContainer
	
	init(inMemory: Bool = false) {
		container = NSPersistentContainer(name: "Flips")
		if inMemory {
			container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null")
		}
		container.loadPersistentStores(completionHandler: { (storeDescription, error) in
			if let error = error as NSError? {
				// Replace this implementation with code to handle the error appropriately.
				// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
				
				/*
				Typical reasons for an error here include:
				* The parent directory does not exist, cannot be created, or disallows writing.
				* The persistent store is not accessible, due to permissions or data protection when the device is locked.
				* The device is out of space.
				* The store could not be migrated to the current model version.
				Check the error message to determine what the actual problem was.
				*/
				fatalError("Unresolved error \(error), \(error.userInfo)")
			}
		})
	}
}