1 files changed, 23 insertions, 0 deletions
diff --git a/src/TextViewport/Viewport/Position.hs b/src/TextViewport/Viewport/Position.hs
new file mode 100644
index 0000000..149fc9e
--- /dev/null
+++ b/src/TextViewport/Viewport/Position.hs
@@ -0,0 +1,23 @@
+module TextViewport.Viewport.Position where
+
+import TextViewport.Render.RenderedBuffer (RenderedBuffer)
+import TextViewport.Render.RenderedBuffer qualified as RenderedBuffer
+import TextViewport.Render.RenderedLine qualified as RenderedLine
+import TextViewport.Viewport.Viewport (Viewport)
+import TextViewport.Viewport.Viewport qualified as Viewport
+
+lookupPosition
+  :: Int
+  -> Int
+  -> Viewport
+  -> RenderedBuffer
+  -> Maybe (Int, Int)
+lookupPosition x y vp rb =
+  let allLines = RenderedBuffer.flatten rb
+      idx      = Viewport.vpOffset vp + y
+  in case drop idx allLines of
+       (rl:_) ->
+         let charIx = RenderedLine.rlCharStart rl + x
+         in Just (RenderedLine.rlItemIx rl, charIx)
+       [] -> Nothing
+