Collection of realm operations. Requires ResultsExtension.swift

RealmService.swift

import RealmSwift

internal struct RealmService {
    
    private static var realm: Realm? {
        do {
            return try Realm()
        } catch let error as NSError {
            print(error)
            return nil
        }
    }
    
    // MARK: - Add operations
    internal static func add<T: Object>(object: T) {
        guard let realm = realm else { return }
        do {
            try realm.write({
                realm.add(object)
            })
        } catch {
            showError()
        }
    }
    
    internal static func add<T: Object>(array: [T]) {
        guard let realm = realm else { return }
        do {
            try realm.write({
                realm.add(array)
            })
        } catch {
            showError()
        }
    }
    
    // MARK: - Get operations
    internal static func get<T: Object>(objectsOfInstanceType instanceType: T.Type, withPredicate predicate: NSPredicate? = nil) -> Results<T>? {
        guard let realm = realm else { return nil }
        var objects = realm.objects(instanceType)
        if let predicate = predicate {
            objects = objects.filter(predicate)
        }
        guard !objects.isEmpty else { return nil }
        return objects
    }
    
    internal static func get<T: Object>(arrayOfInstanceType instanceType: T.Type, withPredicate predicate: NSPredicate? = nil) -> [T]? {
        guard let objects = get(objectsOfInstanceType: instanceType, withPredicate: predicate) else { return nil }
        return objects.toArray()
    }
    
    // MARK: - Remove operations
    internal static func remove<T: Object>(object: T) {
        guard let realm = realm else { return }
        realm.beginWrite()
        realm.delete(object)
        commitWrite(inRealm: realm)
    }
    
    internal static func remove<T: Object>(objectsOfInstanceType instanceType: T.Type) {
        guard let realm = realm else { return }
        let objects = realm.objects(instanceType)
        realm.beginWrite()
        realm.delete(objects)
        commitWrite(inRealm: realm)
    }
    
    // MARK: - Operations
    internal static func areObjectsAvailable<T: Object>(ofInstanceType instanceType: T.Type, withPredicate predicate: NSPredicate) -> Bool {
        guard let _ = get(objectsOfInstanceType: instanceType, withPredicate: predicate) else { return false }
        return true
    }
    
    // MARK: - Helpers
    private static func commitWrite(inRealm realm: Realm) {
        do {
            try realm.commitWrite()
        } catch {
            showError()
        }
    }
    
    private static func showError() {
        print("Realm Error")
    }
    
}