import: Tip what string cannot be imported

src/ui/flutter_app/lib/l10n/intl_de.arb

@@ -220,6 +220,10 @@
   "@gameImported": {
     "description": "Game imported from clipboard."
   },
+  "cannotImport": "Kann nicht importieren",
+  "@cannotImport": {
+    "description": "Cannot import"
+  },
   "startRecording": "Starte die Aufnahme",
   "@startRecording": {
     "description": "Start recording"

src/ui/flutter_app/lib/l10n/intl_en.arb

@@ -220,6 +220,10 @@
   "@gameImported": {
     "description": "Game imported from clipboard."
   },
+  "cannotImport": "Cannot import",
+  "@cannotImport": {
+    "description": "Cannot import"
+  },
   "startRecording": "Start recording",
   "@startRecording": {
     "description": "Start recording"

src/ui/flutter_app/lib/l10n/intl_fa.arb

@@ -220,6 +220,10 @@
   "@gameImported": {
     "description": "Game imported from clipboard."
   },
+  "cannotImport": "وارد کردن امکان پذیر نیست",
+  "@cannotImport": {
+    "description": "Cannot import"
+  },
   "startRecording": "شروع به ضبط کنید",
   "@startRecording": {
     "description": "Start recording"

src/ui/flutter_app/lib/l10n/intl_zh.arb

@@ -55,6 +55,7 @@
   "importGame": "导入棋局",
   "exportGame": "导出棋局",
   "gameImported": "棋谱已从剪贴板导入",
+  "cannotImport": "无法导入",
   "startRecording": "开始录制",
   "recording": "录制中...",
   "stopRecording": "停止录制",

src/ui/flutter_app/lib/mill/recorder.dart

@@ -66,7 +66,7 @@ class GameRecorder {
     return move;
   }
 
-  void import(String moveList) {
+  String import(String moveList) {
     List<Move> newHistory = [];
     List<String> list = moveList.toLowerCase().replaceAll('\n', ' ').split(' ');
 
@@ -78,26 +78,41 @@ class GameRecorder {
           String m1 = parseNotation(i.substring(0, 2));
           if (m1 != "") {
             newHistory.add(Move(m1));
+          } else {
+            print("Cannot import $i");
+            return i;
           }
           String m2 = parseNotation(i.substring(2));
           if (m2 != "") {
             newHistory.add(Move(m2));
+          } else {
+            print("Cannot import $i");
+            return i;
           }
         } else if (i.length == 8 && i[2] == '-' && i[5] == 'x') {
           // "a1-b2xc3"
           String m1 = parseNotation(i.substring(0, 5));
           if (m1 != "") {
             newHistory.add(Move(m1));
+          } else {
+            print("Cannot import $i");
+            return i;
           }
           String m2 = parseNotation(i.substring(5));
           if (m2 != "") {
             newHistory.add(Move(m2));
+          } else {
+            print("Cannot import $i");
+            return i;
           }
         } else {
           // no x
           String m = parseNotation(i);
           if (m != "") {
             newHistory.add(Move(m));
+          } else {
+            print("Cannot import $i");
+            return i;
           }
         }
       }
@@ -106,6 +121,8 @@ class GameRecorder {
     if (newHistory.length > 0) {
       setHistory(newHistory);
     }
+
+    return "";
   }
 
   void jumpToHead() {

src/ui/flutter_app/lib/widgets/game_page.dart

@@ -565,7 +565,13 @@ class _GamePageState extends State<GamePage>
 
     await onTakeBackAllButtonPressed(pop: false);
     await Game.instance.position.recorder.clear();
-    await Game.instance.position.recorder.import(text);
+    var importFailedStr = await Game.instance.position.recorder.import(text);
+
+    if (importFailedStr != "") {
+      showTip(S.of(context).cannotImport + " " + importFailedStr);
+      return;
+    }
+
     await onStepForwardAllButtonPressed(pop: false);
 
     showTip(S.of(context).gameImported);