[AltStore] Refactors fetch apps logic to use Source model objects

AltStore/Model/Source.swift

@@ -0,0 +1,92 @@
+//
+//  Source.swift
+//  AltStore
+//
+//  Created by Riley Testut on 7/30/19.
+//  Copyright © 2019 Riley Testut. All rights reserved.
+//
+
+import CoreData
+
+extension Source
+{
+    static let altStoreIdentifier = "com.rileytestut.AltStore"
+}
+
+@objc(Source)
+class Source: NSManagedObject, Fetchable, Decodable
+{
+    /* Properties */
+    @NSManaged var name: String
+    @NSManaged var identifier: String
+    @NSManaged var sourceURL: URL
+    
+    /* Relationships */
+    @objc(apps) @NSManaged private(set) var _apps: NSOrderedSet
+    
+    @nonobjc var apps: [App] {
+        get {
+            return self._apps.array as! [App]
+        }
+        set {
+            self._apps = NSOrderedSet(array: newValue)
+        }
+    }
+    
+    private enum CodingKeys: String, CodingKey
+    {
+        case name
+        case identifier
+        case sourceURL
+        case apps
+    }
+    
+    private override init(entity: NSEntityDescription, insertInto context: NSManagedObjectContext?)
+    {
+        super.init(entity: entity, insertInto: context)
+    }
+    
+    required init(from decoder: Decoder) throws
+    {
+        guard let context = decoder.managedObjectContext else { preconditionFailure("Decoder must have non-nil NSManagedObjectContext.") }
+        
+        super.init(entity: Source.entity(), insertInto: nil)
+        
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+        self.name = try container.decode(String.self, forKey: .name)
+        self.identifier = try container.decode(String.self, forKey: .identifier)
+        self.sourceURL = try container.decode(URL.self, forKey: .sourceURL)
+        
+        let apps = try container.decodeIfPresent([App].self, forKey: .apps) ?? []
+        for (index, app) in apps.enumerated()
+        {
+            app.sortIndex = Int32(index)
+        }
+        
+        context.insert(self)
+        
+        // Must assign after we're inserted into context.
+        self._apps = NSMutableOrderedSet(array: apps)
+        
+        print("Downloaded Order:", self.apps.map { $0.bundleIdentifier })
+    }
+}
+
+extension Source
+{
+    class func makeAltStoreSource(in context: NSManagedObjectContext) -> Source
+    {
+        let source = Source(context: context)
+        source.name = "AltStore"
+        source.identifier = Source.altStoreIdentifier
+        source.sourceURL = URL(string: "https://www.dropbox.com/s/6qi1vt6hsi88lv6/Apps-Dev.json?dl=1")!
+        
+        return source
+    }
+    
+    class func fetchAltStoreSource(in context: NSManagedObjectContext) -> Source?
+    {
+        let source = Source.first(satisfying: NSPredicate(format: "%K == %@", #keyPath(Source.identifier), Source.altStoreIdentifier), in: context)
+        return source
+    }
+}