From 712ea2994d5797a1febac3303c4eb43c9a54de07 Mon Sep 17 00:00:00 2001
From: krawieck <fil.krawczyk@gmail.com>
Date: Mon, 31 Aug 2020 01:46:47 +0200
Subject: [PATCH] Add CommentTree #16

`CommentTree` transforms `List` of `CommentView`s into a tree-like structure
---
 lib/widgets/comment_tree.dart | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 lib/widgets/comment_tree.dart

diff --git a/lib/widgets/comment_tree.dart b/lib/widgets/comment_tree.dart
new file mode 100644
index 0000000..d0da0da
--- /dev/null
+++ b/lib/widgets/comment_tree.dart
@@ -0,0 +1,33 @@
+import 'package:lemmy_api_client/lemmy_api_client.dart';
+
+class CommentTree {
+  CommentView comment;
+  List<CommentTree> children;
+
+  CommentTree(this.comment, [this.children]) {
+    children ??= [];
+  }
+
+  static List<CommentTree> fromList(List<CommentView> comments) {
+    CommentTree gatherChildren(CommentTree parent) {
+      for (var el in comments) {
+        if (el.parentId == parent.comment.id) {
+          parent.children.add(gatherChildren(CommentTree(el)));
+        }
+      }
+      return parent;
+    }
+
+    var parents = <CommentTree>[];
+
+    // first pass to get all the parents
+    for (var i = 0; i < comments.length; i++) {
+      if (comments[i].parentId == null) {
+        parents.add(CommentTree(comments[i]));
+      }
+    }
+
+    var result = parents.map(gatherChildren).toList();
+    return result;
+  }
+}