From ae28d79b46b8d20113faafcae30e4ab5cd93ffb5 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Tue, 11 Feb 2020 12:59:36 +0000
Subject: [PATCH] Scroll so editor cursor is always visible

This took a bit to figure out. Also, this is the only point in this project
where I use lenses.
---
 package.yaml                    | 1 +
 src/Forest/Client/NodeEditor.hs | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/package.yaml b/package.yaml
index 63b9343..459cc1a 100644
--- a/package.yaml
+++ b/package.yaml
@@ -18,6 +18,7 @@ dependencies:
 - async
 - brick
 - containers
+- microlens
 - optparse-applicative
 - text
 - text-zipper
diff --git a/src/Forest/Client/NodeEditor.hs b/src/Forest/Client/NodeEditor.hs
index 202b2c6..aefa448 100644
--- a/src/Forest/Client/NodeEditor.hs
+++ b/src/Forest/Client/NodeEditor.hs
@@ -15,6 +15,7 @@ import           Brick.Widgets.Edit
 import qualified Data.Text                  as T
 import           Data.Text.Zipper
 import qualified Graphics.Vty               as Vty
+import           Lens.Micro
 
 import           Forest.Client.ResourceName
 
@@ -52,8 +53,13 @@ handleNodeEditorEvent event ne = do
   pure ne{neEditor = newEditor}
 
 renderNodeEditor :: NodeEditor -> Widget ResourceName
-renderNodeEditor ne = vLimit height $ renderEditor renderFunc True $ neEditor ne
+renderNodeEditor ne = makeVisible $ vLimit height $ renderEditor renderFunc True ed
   where
+    ed = neEditor ne
+
     height = length $ getCurrentText ne
     renderFunc :: [T.Text] -> Widget ResourceName
     renderFunc = vBox . map (\t -> if T.null t then txt " " else txt t)
+
+    (row, col) = cursorPosition $ ed ^. editContentsL
+    makeVisible = visibleRegion (Location (col, row)) (1, 1)