Add a Checklist class

lib/core/checklist.dart

@@ -0,0 +1,101 @@
+import 'package:flutter/material.dart';
+import 'package:markdown/markdown.dart' as md;
+
+import 'package:gitjournal/core/note.dart';
+
+class ChecklistItem {
+  bool checked;
+  String text;
+  md.Element element;
+
+  ChecklistItem({
+    @required this.checked,
+    @required this.text,
+    @required this.element,
+  });
+
+  @override
+  String toString() => 'ChecklistItem: $checked $text';
+}
+
+class Checklist {
+  Note note;
+  List<ChecklistItem> items;
+
+  Checklist(this.note) {
+    items = ChecklistBuilder().parse(note.body);
+  }
+}
+
+/// Copied from flutter-markdown - cannot be merged as we added xUpperCase and changed the regexp
+/// Parse [task list items](https://github.github.com/gfm/#task-list-items-extension-).
+class TaskListSyntax extends md.InlineSyntax {
+  // FIXME: Waiting for dart-lang/markdown#269 to land
+  static final String _pattern = r'^ *\[([ xX])\] +(.*)$';
+
+  TaskListSyntax() : super(_pattern);
+
+  @override
+  bool onMatch(md.InlineParser parser, Match match) {
+    md.Element el = md.Element.withTag('input');
+    el.attributes['type'] = 'checkbox';
+    el.attributes['checked'] = '${match[1].trim().isNotEmpty}';
+    var m = match[1].trim();
+    if (m.isNotEmpty) {
+      el.attributes['xUpperCase'] = (m[0] == 'X').toString();
+    }
+    el.attributes['text'] = '${match[2]}';
+    parser.addNode(el);
+    return true;
+  }
+}
+
+class ChecklistBuilder implements md.NodeVisitor {
+  List<ChecklistItem> list;
+
+  @override
+  bool visitElementBefore(md.Element element) {
+    return true;
+  }
+
+  @override
+  void visitText(md.Text text) {}
+
+  @override
+  void visitElementAfter(md.Element element) {
+    final String tag = element.tag;
+
+    if (tag == 'input') {
+      var el = element;
+      if (el is md.Element && el.attributes['type'] == 'checkbox') {
+        bool val = el.attributes['checked'] != 'false';
+        var item = ChecklistItem(
+          checked: val,
+          text: el.attributes['text'],
+          element: el,
+        );
+        list.add(item);
+      }
+    }
+  }
+
+  List<ChecklistItem> build(List<md.Node> nodes) {
+    list = <ChecklistItem>[];
+    for (md.Node node in nodes) {
+      node.accept(this);
+    }
+
+    return list;
+  }
+
+  List<ChecklistItem> parse(String text) {
+    var doc = md.Document(
+      encodeHtml: false,
+      inlineSyntaxes: [TaskListSyntax()],
+      extensionSet: md.ExtensionSet.gitHubFlavored,
+    );
+
+    var nodes = doc.parseInline(text);
+    return build(nodes);
+  }
+}

test/checklist_test.dart

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+import 'dart:io';
+
+import 'package:gitjournal/core/checklist.dart';
+import 'package:gitjournal/core/note.dart';
+import 'package:gitjournal/core/notes_folder.dart';
+import 'package:path/path.dart' as p;
+import 'package:test/test.dart';
+
+void main() {
+  group('Note', () {
+    Directory tempDir;
+
+    setUpAll(() async {
+      tempDir = await Directory.systemTemp.createTemp('__notes_test__');
+    });
+
+    tearDownAll(() async {
+      tempDir.deleteSync(recursive: true);
+    });
+
+    test('Should parse simple checklists', () async {
+      var content = """---
+title: Foo
+modified: 2017-02-15T22:41:19+01:00
+---
+
+# Title 1
+
+How are you doing?
+
+[ ] item 1
+[x] item 2
+[X] item 3
+[ ] item 4
+
+Booga Wooga
+""";
+
+      var notePath = p.join(tempDir.path, "note.md");
+      File(notePath).writeAsString(content);
+
+      var parentFolder = NotesFolder(null, tempDir.path);
+      var note = Note(parentFolder, notePath);
+      await note.load();
+
+      var checklist = Checklist(note);
+      expect(checklist.items.length, equals(4));
+
+      expect(checklist.items[0].checked, false);
+      expect(checklist.items[1].checked, true);
+      expect(checklist.items[2].checked, true);
+      expect(checklist.items[3].checked, false);
+
+      expect(checklist.items[0].text, "item 1");
+      expect(checklist.items[1].text, "item 2");
+      expect(checklist.items[2].text, "item 3");
+      expect(checklist.items[3].text, "item 4");
+    });
+  });
+}