editor: remember last-used tool

Resolves #370

lib/components/canvas/tools/_tool.dart

@@ -1,10 +1,33 @@
-
 import 'package:flutter/material.dart';
+import 'package:saber/data/prefs.dart';
 
-class Tool {
+abstract class Tool {
   @protected
   @visibleForTesting
   const Tool();
 
-  static const Tool textEditing = Tool();
+  /// An identifier for the tool,
+  /// used to save the last-used tool in [Prefs.lastTool].
+  ToolId get toolId;
+
+  static const Tool textEditing = _TextEditingTool();
+}
+
+class _TextEditingTool extends Tool {
+  const _TextEditingTool();
+
+  @override
+  ToolId get toolId => ToolId.textEditing;
+}
+
+enum ToolId {
+  fountainPen('fountainPen'),
+  ballpointPen('ballpointPen'),
+  highlighter('Highlighter'),
+  eraser('Eraser'),
+  select('Select'),
+  textEditing('TextEditingTool');
+
+  final String id;
+  const ToolId(this.id);
 }

lib/components/canvas/tools/eraser.dart

@@ -18,6 +18,9 @@ class Eraser extends Tool {
     this.size = 10
   });
 
+  @override
+  ToolId get toolId => ToolId.eraser;
+
   /// Returns the indices of any [strokes] that are close to the given [eraserPos].
   List<int> checkForOverlappingStrokes(Offset eraserPos, List<Stroke> strokes) {
     final List<int> indices = [];

lib/components/canvas/tools/highlighter.dart

@@ -1,6 +1,6 @@
-
 import 'package:flutter/material.dart';
 import 'package:font_awesome_flutter/font_awesome_flutter.dart';
+import 'package:saber/components/canvas/tools/_tool.dart';
 import 'package:saber/components/canvas/tools/pen.dart';
 import 'package:saber/data/prefs.dart';
 import 'package:saber/i18n/strings.g.dart';
@@ -12,6 +12,7 @@ class Highlighter extends Pen {
     sizeMax: 100,
     sizeStep: 10,
     icon: highlighterIcon,
+    toolId: ToolId.highlighter,
   ) {
     strokeProperties = Prefs.lastHighlighterProperties.value;
   }

lib/components/canvas/tools/pen.dart

@@ -18,6 +18,7 @@ class Pen extends Tool {
     required this.sizeMax,
     required this.sizeStep,
     required this.icon,
+    required this.toolId,
   });
 
   Pen.fountainPen() :
@@ -26,19 +27,25 @@ class Pen extends Tool {
         sizeMax = 25,
         sizeStep = 1,
         icon = fountainPenIcon,
-        strokeProperties = Prefs.lastFountainPenProperties.value;
+        strokeProperties = Prefs.lastFountainPenProperties.value,
+        toolId = ToolId.fountainPen;
 
   Pen.ballpointPen() :
         name = t.editor.pens.ballpointPen,
         sizeMin = 1,
         sizeMax = 25,
         sizeStep = 1,
         icon = ballpointPenIcon,
-        strokeProperties = Prefs.lastBallpointPenProperties.value;
+        strokeProperties = Prefs.lastBallpointPenProperties.value,
+        toolId = ToolId.ballpointPen;
 
   final String name;
   final double sizeMin, sizeMax, sizeStep;
   final IconData icon;
+
+  @override
+  final ToolId toolId;
+
   static const IconData fountainPenIcon = FontAwesomeIcons.penFancy;
   static const IconData ballpointPenIcon = FontAwesomeIcons.pen;
 

lib/components/canvas/tools/select.dart

@@ -13,6 +13,9 @@ class Select extends Tool {
   SelectResult selectResult = SelectResult(-1, const [], Path());
   bool doneSelecting = false;
 
+  @override
+  ToolId get toolId => ToolId.select;
+
   void unselect() {
     doneSelecting = false;
     selectResult.pageIndex = -1;

lib/data/prefs.dart

@@ -6,6 +6,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:nextcloud/nextcloud.dart' show NextcloudProvisioningApiUserDetails_Quota;
 import 'package:saber/components/canvas/_canvas_background_painter.dart';
+import 'package:saber/components/canvas/tools/_tool.dart';
 import 'package:saber/components/canvas/tools/stroke_properties.dart';
 import 'package:saber/data/flavor_config.dart';
 import 'package:saber/data/nextcloud/nextcloud_client_extension.dart';
@@ -67,6 +68,7 @@ abstract class Prefs {
   static late final PlainPref<List<String>> recentColorsChronological;
   static late final PlainPref<List<String>> recentColorsPositioned;
 
+  static late final PlainPref<ToolId> lastTool;
   static late final PlainPref<StrokeProperties>
       lastFountainPenProperties,
       lastBallpointPenProperties,
@@ -127,6 +129,7 @@ abstract class Prefs {
     recentColorsChronological = PlainPref('recentColorsChronological', []);
     recentColorsPositioned = PlainPref('recentColorsPositioned', [], historicalKeys: ['recentColors']);
 
+    lastTool = PlainPref('lastTool', ToolId.fountainPen);
     lastFountainPenProperties = PlainPref('lastFountainPenProperties', StrokeProperties.fountainPen, deprecatedKeys: ['lastPenColor']);
     lastBallpointPenProperties = PlainPref('lastBallpointPenProperties', StrokeProperties.ballpointPen);
     lastHighlighterProperties = PlainPref('lastHighlighterProperties', StrokeProperties.highlighter, deprecatedKeys: ['lastHighlighterColor']);
@@ -257,6 +260,7 @@ class PlainPref<T> extends IPref<T> {
         || T == typeOf<Queue<String>>()
         || T == StrokeProperties || T == typeOf<Quota?>()
         || T == AxisDirection || T == ThemeMode || T == TargetPlatform
+        || T == ToolId
     );
   }
 
@@ -322,6 +326,8 @@ class PlainPref<T> extends IPref<T> {
         return await _prefs!.setInt(key, (value as ThemeMode).index);
       } else if (T == TargetPlatform) {
         return await _prefs!.setInt(key, (value as TargetPlatform).index);
+      } else if (T == ToolId) {
+        return await _prefs!.setString(key, (value as ToolId).id);
       } else {
         return await _prefs!.setString(key, value as String);
       }
@@ -367,6 +373,12 @@ class PlainPref<T> extends IPref<T> {
         if (index == null) return null;
         if (index == -1) return defaultTargetPlatform as T?;
         return TargetPlatform.values[index] as T?;
+      } else if (T == ToolId) {
+        String id = _prefs!.getString(key)!;
+        return ToolId.values
+            .cast<ToolId?>()
+            .firstWhere((toolId) => toolId?.id == id, orElse: () => null)
+            as T?;
       } else {
         return _prefs!.get(key) as T?;
       }

lib/pages/editor/editor.dart

@@ -67,7 +67,33 @@ class EditorState extends State<Editor> {
 
   late bool needsNaming = widget.needsNaming && Prefs.editorPromptRename.value;
 
-  Tool currentTool = Pen.currentPen;
+  late Tool _currentTool = () {
+    switch (Prefs.lastTool.value) {
+      case ToolId.fountainPen:
+        if (Pen.currentPen.toolId != Prefs.lastTool.value) {
+          Pen.currentPen = Pen.fountainPen();
+        }
+        return Pen.currentPen;
+      case ToolId.ballpointPen:
+        if (Pen.currentPen.toolId != Prefs.lastTool.value) {
+          Pen.currentPen = Pen.ballpointPen();
+        }
+        return Pen.currentPen;
+      case ToolId.highlighter:
+        return Highlighter.currentHighlighter;
+      case ToolId.eraser:
+        return Eraser();
+      case ToolId.select:
+        return Select.currentSelect;
+      case ToolId.textEditing:
+        return Tool.textEditing;
+    }
+  }();
+  Tool get currentTool => _currentTool;
+  set currentTool(Tool tool) {
+    _currentTool = tool;
+    Prefs.lastTool.value = tool.toolId;
+  }
 
   /// Whether the note has changed since it was last saved
   bool _hasEdited = false;