Refactor storage model to work with native Realm

ios/App/Shared/models/local/LocalFile.swift

@@ -0,0 +1,73 @@
+//
+//  LocalFile.swift
+//  App
+//
+//  Created by Ron Heft on 8/16/22.
+//
+
+import Foundation
+import RealmSwift
+
+class LocalFile: Object, Codable {
+    @Persisted(primaryKey: true) var id: String = UUID().uuidString
+    @Persisted var filename: String?
+    @Persisted var _contentUrl: String = ""
+    @Persisted var mimeType: String?
+    @Persisted var size: Int = 0
+
+    var contentUrl: String { AbsDownloader.itemDownloadFolder(path: _contentUrl)!.absoluteString }
+    var contentPath: URL { AbsDownloader.itemDownloadFolder(path: _contentUrl)! }
+    var basePath: String? { self.filename }
+    
+    private enum CodingKeys : String, CodingKey {
+        case id, filename, contentUrl, mimeType, size, basePath
+    }
+    
+    override init() {
+        super.init()
+    }
+    
+    required init(from decoder: Decoder) throws {
+        let values = try decoder.container(keyedBy: CodingKeys.self)
+        id = try values.decode(String.self, forKey: .id)
+        filename = try? values.decode(String.self, forKey: .filename)
+        mimeType = try? values.decode(String.self, forKey: .mimeType)
+        size = try values.decode(Int.self, forKey: .size)
+    }
+
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encode(id, forKey: .id)
+        try container.encode(filename, forKey: .filename)
+        try container.encode(contentUrl, forKey: .contentUrl)
+        try container.encode(mimeType, forKey: .mimeType)
+        try container.encode(size, forKey: .size)
+        try container.encode(basePath, forKey: .basePath)
+    }
+}
+
+extension LocalFile {
+    convenience init(_ libraryItemId: String, _ filename: String, _ mimeType: String, _ localUrl: String, fileSize: Int) {
+        self.init()
+        
+        self.id = "\(libraryItemId)_\(filename.toBase64())"
+        self.filename = filename
+        self.mimeType = mimeType
+        self._contentUrl = localUrl
+        self.size = fileSize
+    }
+    
+    var absolutePath: String {
+        return AbsDownloader.itemDownloadFolder(path: self._contentUrl)?.absoluteString ?? ""
+    }
+    
+    func isAudioFile() -> Bool {
+        switch self.mimeType {
+            case "application/octet-stream",
+                "video/mp4":
+                return true
+            default:
+                return self.mimeType?.starts(with: "audio") ?? false
+        }
+    }
+}