Merge pull request #16373 from [BEAM-13515] [Playground] Hiding lines in an example that are not necessary

Alexandr Zhuravlev · web-flow · commit f31cad083986 · 2022-01-19T16:43:16.000-08:00
* [BEAM-13515] Implemented structure of initial scroll in CodeField * [BEAM-13515] Changed scroll mechanics * [BEAM-13515] Moved values to consts, changed quotes to single * [BEAM-13515] Changed RegExp for Java, moved RegExp strings to consts * [BEAM-13515] Clarified variable declaration
diff --git a/playground/frontend/lib/modules/editor/components/editor_textarea.dart b/playground/frontend/lib/modules/editor/components/editor_textarea.dart
@@ -31,6 +31,15 @@ import 'package:playground/modules/examples/models/example_model.dart';
 import 'package:playground/modules/sdk/models/sdk.dart';
 import 'package:provider/provider.dart';
 
+const kNumberOfStringsToSkip = 16;
+const kJavaRegExp = r'import\s[A-z.0-9]*\;\n\n[(\/\*\*)|(public)|(class)]';
+const kPythonRegExp = r'[^\S\r\n](import|as)[^\S\r\n][A-z]*\n\n';
+const kGoRegExp = r'[^\S\r\n]+\'
+    r'"'
+    r'.*'
+    r'"'
+    r'\n\)\n\n';
+
 class EditorTextArea extends StatefulWidget {
   final SDK sdk;
   final ExampleModel? example;
@@ -51,6 +60,7 @@ class EditorTextArea extends StatefulWidget {
 
 class _EditorTextAreaState extends State<EditorTextArea> {
   CodeController? _codeController;
+  var focusNode = FocusNode();
 
   @override
   void initState() {
@@ -71,13 +81,17 @@ class _EditorTextAreaState extends State<EditorTextArea> {
       },
       webSpaceFix: false,
     );
+
+    _setTextScrolling();
+
     super.didChangeDependencies();
   }
 
   @override
   void dispose() {
     super.dispose();
     _codeController?.dispose();
+    focusNode.dispose();
   }
 
   @override
@@ -90,6 +104,7 @@ class _EditorTextAreaState extends State<EditorTextArea> {
       readOnly: widget.enabled,
       label: AppLocalizations.of(context)!.codeTextArea,
       child: CodeField(
+        focusNode: focusNode,
         enabled: widget.enabled,
         controller: _codeController!,
         textStyle: getCodeFontStyle(
@@ -105,6 +120,50 @@ class _EditorTextAreaState extends State<EditorTextArea> {
     );
   }
 
+  _setTextScrolling() {
+    focusNode.requestFocus();
+    if (_codeController!.text.isNotEmpty) {
+      _codeController!.selection = TextSelection.fromPosition(
+        TextPosition(offset: _findOffset()),
+      );
+    }
+  }
+
+  _findOffset() {
+    return _codeController!.text.indexOf(
+      _skipStrings(kNumberOfStringsToSkip),
+      _getPositionAfterImportsAndLicenses(widget.sdk),
+    );
+  }
+
+  String _skipStrings(int qntOfStrings) {
+    List<String> strings = _codeController!.text
+        .substring(_getPositionAfterImportsAndLicenses(widget.sdk))
+        .split('\n');
+    String result =
+        strings.length > qntOfStrings ? strings[qntOfStrings] : strings.last;
+    if (result == '') {
+      return _skipStrings(qntOfStrings - 1);
+    } else {
+      return result;
+    }
+  }
+
+  int _getPositionAfterImportsAndLicenses(SDK sdk) {
+    switch (sdk) {
+      case SDK.java:
+        return _codeController!.text.lastIndexOf(RegExp(kJavaRegExp));
+      case SDK.python:
+        return _codeController!.text.lastIndexOf(RegExp(kPythonRegExp));
+      case SDK.go:
+        return _codeController!.text.lastIndexOf(RegExp(kGoRegExp));
+      case SDK.scio:
+        return _codeController!.text.indexOf(
+          _codeController!.text.split('\n')[0],
+        );
+    }
+  }
+
   _getLanguageFromSdk() {
     switch (widget.sdk) {
       case SDK.java:
