Create the beginning of a DB backup system.

lib/models/database_backup.dart

@@ -0,0 +1,57 @@
+// Local
+import '/models/expense.dart';
+import '/models/income.dart';
+import '/models/asset.dart';
+import '/db.dart';
+
+/// TODO:
+/// - Test the JSON data to ensure it's formed properly.
+/// - Enable the functions for income and assets once they are implemented.
+/// - Create a method (factory?) to load JSON data and delete/insert the data.
+
+class DatabaseBackup {
+  List<Expense> expenseTable = [];
+  List<Income> incomeTable = [];
+  List<Asset> assetTable = [];
+
+  void loadTables() async {
+    expenseTable = await DatabaseHelper.instance.getExpenses();
+    //incomeTable = await DatabaseHelper.instance.getIncomes();
+    //assetTable = await DatabaseHelper.instance.getAssets();
+  }
+
+  Map<String, dynamic> toMap() {
+    loadTables(); // TODO: Do we somehow need to wait for this to finish?
+    return {
+      'expense_table': [
+        for (Expense e in expenseTable)
+          {
+            'id': e.id,
+            'name': e.name,
+            'cost': e.amount,
+            'frequency': e.frequency.title,
+            'description': e.description,
+          },
+      ],
+      'income_table': [
+        for (Income i in incomeTable)
+          {
+            'id': i.id,
+            'name': i.name,
+            'revenue': i.amount,
+            'frequency': i.frequency.title,
+            'description': i.description,
+          },
+      ],
+      'asset_table': [
+        for (Asset a in assetTable)
+          {
+            'id': a.id,
+            'name': a.name,
+            'amount': a.amount,
+            'description': a.description,
+          },
+      ],
+    };
+  }
+}