Viewing threads as a tree, not flattened

I couldn't tell who was replying to whom, so I thought I'd give a shot at implementing a tree of threads, instead of a flattened list, with only the root distinguishable from the rest.

brutaldon/threadtree.py

@@ -0,0 +1,54 @@
+def maketree(descendants):
+    lookup = {(descendant.id, descendant) for descendant in descendants}
+    replies = {}
+    roots = set()
+    for descendant in descendants:
+        if not descendant.in_reply_to_id:
+            roots.add(descendant.id)
+        if descendant.in_reply_to_id in replies:
+            reps = replies[descendant.in_reply_to_id]
+            reps.add(descendant.id)
+        else:
+            reps = set()
+            replies[descendant.in_reply_to_id] = set([descendant.id])
+    seen = set()
+    def onelevel(reps):
+        for rep in reps:
+            if rep in seen: continue
+            seen.add(rep)
+            subreps = replies.get(rep)
+            if subreps:
+                yield lookup[rep], onelevel(subreps)
+            else:
+                yield lookup[rep], ()
+    for root in roots:
+        seen.add(root)
+        reps = replies.get(root)
+        if reps:
+            yield lookup[root], onelevel(reps)
+        else:
+            yield lookup[root], ()
+# returns (status, gen[(status, gen[(status, ...), (status, ())]), ...])
+
+# django can't do recursion well so we'll turn the tree
+# ((A, (B, C)))
+# into
+# (in, in, A, in, B, C, out, out, out)
+class OPERATION: pass
+IN = OPERATION()
+OUT = OPERATION()
+class POST(OPERATION):
+    post = None
+    def __init__(self, post):
+        self.post = post
+
+def unmaketree(tree):
+    for post, children in tree:
+        yield POST(post)
+        if children:
+            yield IN
+            yield from unmaketree(children)
+            yield OUT
+
+def threadtree(descendants):
+    return unmaketree(maketree(descendants))

brutaldon/views.py

@@ -687,6 +687,10 @@ def thread(request, id):
     notifications = _notes_count(account, mastodon)
     filters = get_filters(mastodon, context="thread")
 
+    import pprint
+    pprint.pprint(context)
+    raise SystemExit(23)
+
     # Apply filters
     descendants = [
         x for x in context.descendants if not toot_matches_filters(x, filters)
@@ -699,7 +703,7 @@ def thread(request, id):
             "context": context,
             "toot": toot,
             "root": root,
-            "descendants": descendants,
+            "descendants": unmaketree(maketree(descendants)),
             "own_acct": request.session["active_user"],
             "notifications": notifications,
             "preferences": account.preferences,