Make AccountsSettings and Persister more clear

InternalUtilities/Account.cs

@@ -0,0 +1,95 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using AudibleApi;
+using AudibleApi.Authorization;
+using Dinah.Core;
+using Newtonsoft.Json;
+
+namespace InternalUtilities
+{
+	public class Account : IUpdatable
+	{
+		public event EventHandler Updated;
+		private void update(object sender = null, EventArgs e = null)
+			=> Updated?.Invoke(this, new EventArgs());
+
+		// canonical. immutable. email or phone number
+		public string AccountId { get; }
+
+		// user-friendly, non-canonical name. mutable
+		private string _accountName;
+		public string AccountName
+		{
+			get => _accountName;
+			set
+			{
+				if (string.IsNullOrWhiteSpace(value))
+					return;
+				var v = value.Trim();
+				if (v == _accountName)
+					return;
+				_accountName = v;
+				update();
+			}
+		}
+
+		// whether to include this account when scanning libraries.
+		// technically this is an app setting; not an attribute of account. but since it's managed with accounts, it makes sense to put this exception-to-the-rule here
+		private bool _libraryScan = true;
+		public bool LibraryScan
+		{
+			get => _libraryScan;
+			set
+			{
+				if (value == _libraryScan)
+					return;
+				_libraryScan = value;
+				update();
+			}
+		}
+
+		private string _decryptKey = "";
+		public string DecryptKey
+		{
+			get => _decryptKey;
+			set
+			{
+				var v = (value ?? "").Trim();
+				if (v == _decryptKey)
+					return;
+				_decryptKey = v;
+				update();
+			}
+		}
+
+		private Identity _identity;
+		public Identity IdentityTokens
+		{
+			get => _identity;
+			set
+			{
+				if (_identity is null && value is null)
+					return;
+
+				if (_identity != null)
+					_identity.Updated -= update;
+
+				if (value != null)
+					value.Updated += update;
+
+				_identity = value;
+				update();
+			}
+		}
+
+		[JsonIgnore]
+		public Locale Locale => IdentityTokens?.Locale;
+
+		public Account(string accountId)
+		{
+			ArgumentValidator.EnsureNotNullOrWhiteSpace(accountId, nameof(accountId));
+			AccountId = accountId.Trim();
+		}
+	}
+}