Split to smaller files (canonical#10)

lib/src/route.dart

@@ -0,0 +1,26 @@
+import 'package:flutter/widgets.dart';
+
+/// The signature of [WizardRoute.onNext] and [WizardRoute.onBack] callbacks.
+typedef WizardRouteCallback = String? Function(RouteSettings settings);
+
+class WizardRoute {
+  const WizardRoute({
+    required this.builder,
+    this.onNext,
+    this.onBack,
+  });
+
+  final WidgetBuilder builder;
+
+  /// The callback invoked when the next page is requested.
+  ///
+  /// If `onNext` is not specified or it returns `null`, the order is determined
+  /// from [routes].
+  final WizardRouteCallback? onNext;
+
+  /// The callback invoked when the previous page is requested.
+  ///
+  /// If `onBack` is not specified or it returns `null`, the order is determined
+  /// from [routes].
+  final WizardRouteCallback? onBack;
+}

lib/src/scope.dart

@@ -0,0 +1,141 @@
+import 'dart:async';
+
+import 'package:flutter/widgets.dart';
+import 'package:flow_builder/flow_builder.dart';
+
+import 'route.dart';
+import 'settings.dart';
+
+/// The scope of a wizard page.
+///
+/// Each page is enclosed by a `WizardScope` widget.
+class WizardScope extends StatefulWidget {
+  const WizardScope({
+    Key? key,
+    required int index,
+    required WizardRoute route,
+    required List<String> routes,
+  })  : _index = index,
+        _route = route,
+        _routes = routes,
+        super(key: key);
+
+  final int _index;
+  final WizardRoute _route;
+  final List<String> _routes;
+
+  @override
+  State<WizardScope> createState() => WizardScopeState();
+}
+
+/// The state of a `WizardScope`, accessed via `Wizard.of(context)`.
+class WizardScopeState extends State<WizardScope> {
+  /// Arguments passed from the previous page.
+  ///
+  /// ```dart
+  /// final something = Wizard.of(context).arguments as Something;
+  /// ```
+  Object? get arguments => ModalRoute.of(context)?.settings.arguments;
+
+  /// Requests the wizard to show the first page.
+  ///
+  /// ```dart
+  /// onPressed: Wizard.of(context).home
+  /// ```
+  void home() {
+    final routes = _getRoutes();
+    assert(routes.length > 1,
+        '`Wizard.home()` called from the first route ${routes.last.name}');
+
+    _updateRoutes((state) {
+      final copy = List<WizardRouteSettings>.of(state);
+      return copy..replaceRange(1, routes.length, []);
+    });
+  }
+
+  /// Requests the wizard to show the previous page. Optionally, `result` can be
+  /// returned to the previous page.
+  ///
+  /// ```dart
+  /// onPressed: Wizard.of(context).back
+  /// ```
+  void back<T extends Object?>([T? result]) {
+    final routes = _getRoutes();
+    assert(routes.length > 1,
+        '`Wizard.back()` called from the first route ${routes.last.name}');
+
+    // go back to a specific route, or pick the previous route on the list
+    final previous = widget._route.onBack?.call(routes.last);
+    if (previous != null) {
+      assert(widget._routes.contains(previous),
+          '`Wizard.routes` is missing route \'$previous\'.');
+    }
+
+    final start = previous != null
+        ? routes.lastIndexWhere((settings) => settings.name == previous) + 1
+        : routes.length - 1;
+
+    _updateRoutes((state) {
+      final copy = List<WizardRouteSettings>.of(state);
+      copy[start].result.complete(result);
+      return copy..replaceRange(start, routes.length, []);
+    });
+  }
+
+  /// Requests the wizard to show the next page. Optionally, `arguments` can be
+  /// passed to the next page.
+  ///
+  /// ```dart
+  /// onPressed: Wizard.of(context).next
+  /// ```
+  Future<T?> next<T extends Object?>({Object? arguments}) {
+    final routes = _getRoutes();
+    assert(routes.isNotEmpty, routes.length.toString());
+
+    final previous = routes.last.copyWith(arguments: arguments);
+
+    // advance to a specific route
+    String? onNext() => widget._route.onNext?.call(previous);
+
+    // pick the next route on the list
+    String nextRoute() {
+      final index = widget._routes.indexOf(previous.name!);
+      assert(index < widget._routes.length - 1,
+          '`Wizard.next()` called from the last route ${previous.name}.');
+      return widget._routes[index + 1];
+    }
+
+    final next = WizardRouteSettings<T?>(
+      name: onNext() ?? nextRoute(),
+      arguments: arguments,
+    );
+
+    assert(widget._routes.contains(next.name),
+        '`Wizard.routes` is missing route \'${next.name}\'.');
+
+    _updateRoutes((state) {
+      final copy = List<WizardRouteSettings>.of(state);
+      return copy..add(next);
+    });
+
+    return next.result.future;
+  }
+
+  List<WizardRouteSettings> _getRoutes() =>
+      context.flow<List<WizardRouteSettings>>().state;
+
+  void _updateRoutes(
+    List<WizardRouteSettings> Function(List<WizardRouteSettings>) callback,
+  ) {
+    context.flow<List<WizardRouteSettings>>().update(callback);
+  }
+
+  /// Returns `false` if the wizard page is the first page.
+  bool get hasPrevious => widget._index > 0;
+
+  /// Returns `false` if the wizard page is the last page.
+  bool get hasNext => widget._index < widget._routes.length - 1;
+
+  @override
+  Widget build(BuildContext context) => Builder(builder: widget._route.builder);
+}

lib/src/settings.dart

@@ -0,0 +1,12 @@
+import 'dart:async';
+
+import 'package:flutter/widgets.dart';
+
+class WizardRouteSettings<T extends Object?> extends RouteSettings {
+  WizardRouteSettings({
+    String? name,
+    Object? arguments,
+  }) : super(name: name, arguments: arguments);
+
+  final result = Completer<T?>();
+}

lib/src/wizard.dart

@@ -1,33 +1,10 @@
-import 'dart:async';
-
 import 'package:collection/collection.dart';
 import 'package:flutter/material.dart';
 import 'package:flow_builder/flow_builder.dart';
 
-/// The signature of [WizardRoute.onNext] and [WizardRoute.onBack] callbacks.
-typedef WizardRouteCallback = String? Function(RouteSettings settings);
-
-class WizardRoute {
-  const WizardRoute({
-    required this.builder,
-    this.onNext,
-    this.onBack,
-  });
-
-  final WidgetBuilder builder;
-
-  /// The callback invoked when the next page is requested.
-  ///
-  /// If `onNext` is not specified or it returns `null`, the order is determined
-  /// from [routes].
-  final WizardRouteCallback? onNext;
-
-  /// The callback invoked when the previous page is requested.
-  ///
-  /// If `onBack` is not specified or it returns `null`, the order is determined
-  /// from [routes].
-  final WizardRouteCallback? onBack;
-}
+import 'route.dart';
+import 'scope.dart';
+import 'settings.dart';
 
 /// A wizard is a flow of steps that the user can navigate through.
 ///
@@ -199,19 +176,19 @@ class Wizard extends StatefulWidget {
 }
 
 class _WizardState extends State<Wizard> {
-  late List<_WizardRouteSettings> _routes;
+  late List<WizardRouteSettings> _routes;
 
   @override
   void initState() {
     super.initState();
-    _routes = <_WizardRouteSettings>[
-      _WizardRouteSettings(
+    _routes = <WizardRouteSettings>[
+      WizardRouteSettings(
           name: widget.initialRoute ?? widget.routes.keys.first),
     ];
   }
 
   Page _createPage(BuildContext context,
-      {required int index, required _WizardRouteSettings settings}) {
+      {required int index, required WizardRouteSettings settings}) {
     return MaterialPage(
       name: settings.name,
       arguments: settings.arguments,
@@ -226,7 +203,7 @@ class _WizardState extends State<Wizard> {
 
   @override
   Widget build(BuildContext context) {
-    return FlowBuilder<List<_WizardRouteSettings>>(
+    return FlowBuilder<List<WizardRouteSettings>>(
       state: _routes,
       onGeneratePages: (state, __) {
         _routes = state;
@@ -239,146 +216,3 @@ class _WizardState extends State<Wizard> {
     );
   }
 }
-
-/// The scope of a wizard page.
-///
-/// Each page is enclosed by a `WizardScope` widget.
-class WizardScope extends StatefulWidget {
-  const WizardScope({
-    Key? key,
-    required int index,
-    required WizardRoute route,
-    required List<String> routes,
-  })  : _index = index,
-        _route = route,
-        _routes = routes,
-        super(key: key);
-
-  final int _index;
-  final WizardRoute _route;
-  final List<String> _routes;
-
-  @override
-  State<WizardScope> createState() => WizardScopeState();
-}
-
-/// The state of a `WizardScope`, accessed via `Wizard.of(context)`.
-class WizardScopeState extends State<WizardScope> {
-  /// Arguments passed from the previous page.
-  ///
-  /// ```dart
-  /// final something = Wizard.of(context).arguments as Something;
-  /// ```
-  Object? get arguments => ModalRoute.of(context)?.settings.arguments;
-
-  /// Requests the wizard to show the first page.
-  ///
-  /// ```dart
-  /// onPressed: Wizard.of(context).home
-  /// ```
-  void home() {
-    final routes = _getRoutes();
-    assert(routes.length > 1,
-        '`Wizard.home()` called from the first route ${routes.last.name}');
-
-    _updateRoutes((state) {
-      final copy = List<_WizardRouteSettings>.of(state);
-      return copy..replaceRange(1, routes.length, []);
-    });
-  }
-
-  /// Requests the wizard to show the previous page. Optionally, `result` can be
-  /// returned to the previous page.
-  ///
-  /// ```dart
-  /// onPressed: Wizard.of(context).back
-  /// ```
-  void back<T extends Object?>([T? result]) {
-    final routes = _getRoutes();
-    assert(routes.length > 1,
-        '`Wizard.back()` called from the first route ${routes.last.name}');
-
-    // go back to a specific route, or pick the previous route on the list
-    final previous = widget._route.onBack?.call(routes.last);
-    if (previous != null) {
-      assert(widget._routes.contains(previous),
-          '`Wizard.routes` is missing route \'$previous\'.');
-    }
-
-    final start = previous != null
-        ? routes.lastIndexWhere((settings) => settings.name == previous) + 1
-        : routes.length - 1;
-
-    _updateRoutes((state) {
-      final copy = List<_WizardRouteSettings>.of(state);
-      copy[start].result.complete(result);
-      return copy..replaceRange(start, routes.length, []);
-    });
-  }
-
-  /// Requests the wizard to show the next page. Optionally, `arguments` can be
-  /// passed to the next page.
-  ///
-  /// ```dart
-  /// onPressed: Wizard.of(context).next
-  /// ```
-  Future<T?> next<T extends Object?>({Object? arguments}) {
-    final routes = _getRoutes();
-    assert(routes.isNotEmpty, routes.length.toString());
-
-    final previous = routes.last.copyWith(arguments: arguments);
-
-    // advance to a specific route
-    String? onNext() => widget._route.onNext?.call(previous);
-
-    // pick the next route on the list
-    String nextRoute() {
-      final index = widget._routes.indexOf(previous.name!);
-      assert(index < widget._routes.length - 1,
-          '`Wizard.next()` called from the last route ${previous.name}.');
-      return widget._routes[index + 1];
-    }
-
-    final next = _WizardRouteSettings<T?>(
-      name: onNext() ?? nextRoute(),
-      arguments: arguments,
-    );
-
-    assert(widget._routes.contains(next.name),
-        '`Wizard.routes` is missing route \'${next.name}\'.');
-
-    _updateRoutes((state) {
-      final copy = List<_WizardRouteSettings>.of(state);
-      return copy..add(next);
-    });
-
-    return next.result.future;
-  }
-
-  List<_WizardRouteSettings> _getRoutes() =>
-      context.flow<List<_WizardRouteSettings>>().state;
-
-  void _updateRoutes(
-    List<_WizardRouteSettings> Function(List<_WizardRouteSettings>) callback,
-  ) {
-    context.flow<List<_WizardRouteSettings>>().update(callback);
-  }
-
-  /// Returns `false` if the wizard page is the first page.
-  bool get hasPrevious => widget._index > 0;
-
-  /// Returns `false` if the wizard page is the last page.
-  bool get hasNext => widget._index < widget._routes.length - 1;
-
-  @override
-  Widget build(BuildContext context) => Builder(builder: widget._route.builder);
-}
-
-class _WizardRouteSettings<T extends Object?> extends RouteSettings {
-  _WizardRouteSettings({
-    String? name,
-    Object? arguments,
-  }) : super(name: name, arguments: arguments);
-
-  final result = Completer<T?>();
-}