Core Data helper

CoreDataHelper.swift

//
//  CoreData.swift
//  Themez (iOS)
//
//  Created by yepz on 09/02/23.
//

import Foundation
import CoreData

public class CoreDataHelper {
    // Singleton Instance
    public static let shared = CoreDataHelper()

    // Context from persistentContainer
    lazy var context = persistentContainer.viewContext

    // Persistent Container
    lazy var persistentContainer: NSPersistentContainer = {
        let container = NSPersistentContainer(name: "ThemezData")
        container.loadPersistentStores(completionHandler: { (_, error) in
            if let error = error as NSError? {
                fatalError("Unresolved error \(error), \(error.userInfo)")
            }
        })
        return container
    }()

    var url: URL? {
        persistentContainer.viewContext.persistentStoreCoordinator?.persistentStores.first?.url
    }
    
    public func getStoredSize(forPersistentContainerUrl storeUrl: URL) -> CGFloat {
        do {
            let size = try Data(contentsOf: storeUrl)
            if size.count < 1 {
                printd(type: .warning, message: "Size can't be determined")
                return 0
            }
            let bcf = ByteCountFormatter()
            bcf.allowedUnits = [.useKB, .useMB] // optional: restricts the units to MB only
            bcf.countStyle = .file
    
            let sizeString = bcf.string(fromByteCount: Int64(size.count))
            let countString = "\(sizeString.components(separatedBy: " ").first ?? "")"
            guard let count = NumberFormatter().number(from: countString) else {
                return 0
            }
            let storedSize = CGFloat(truncating: count)
            printd(type: .success, message: "get size \(storedSize)")
            return storedSize
        } catch {
            printd(type: .error, message: error.localizedDescription)
            return 0
        }
    }

    // Save Context
    public func saveContext() {
        let context = persistentContainer.viewContext
        if context.hasChanges {
            do {
                try context.save()
            } catch {
                let nserror = error as NSError
                fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
            }
        }
    }

    // Fetch All Items
    public func fetchAllItems() -> [NSManagedObject] {
        let request = NSFetchRequest<NSManagedObject>(entityName: "Item")
        do {
            let items = try context.fetch(request)
            return items
        } catch let error as NSError {
            print("Could not fetch. \(error), \(error.userInfo)")
            return []
        }
    }

    // Filter by Name
    public func filterByName(name: String) -> NSManagedObject? {
        let request = NSFetchRequest<NSManagedObject>(entityName: "Item")
        request.predicate = NSPredicate(format: "name == %@", name)
        do {
            let items = try context.fetch(request)
            if items.count > 0 {
                return items[0]
            } else {
                return nil
            }
        } catch let error as NSError {
            print("Could not fetch. \(error), \(error.userInfo)")
            return nil
        }
    }

    // Delete Object Model
    public func deleteObject(object: NSManagedObject) {
        context.delete(object)
        saveContext()
    }

}