yDnab-iOS/ydnab/Persistence.swift

//
//  Persistence.swift
//  ydnab
//
//  Created by Andrea Franceschini on 20/09/2020.
//

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 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
//    }()

    let container: NSPersistentContainer

    init(inMemory: Bool = false) {
        container = NSPersistentContainer(name: "ydnab")
        if inMemory {
            container.persistentStoreDescriptions.first!.url = URL(fileURLWithPath: "/dev/null")
        }
        container.loadPersistentStores { (storeDescription, error) in
            if let error = error as NSError? {
                /*
                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)")
            }
        }
    }
}