1 files changed, 37 insertions, 0 deletions
diff --git a/app/Patch.hs b/app/Patch.hs
new file mode 100644
index 0000000..f1c547a
--- /dev/null
+++ b/app/Patch.hs
@@ -0,0 +1,37 @@
+module Patch
+  ( Patch,
+    parse,
+    render,
+  )
+where
+
+import Control.Exception (throw)
+import Data.Text qualified as T
+import Exception qualified as E
+import Prettyprinter (pretty)
+import Prettyprinter qualified as P
+import Prettyprinter.Render.Terminal qualified as P
+import Text.Diff.Parse qualified as D
+import Text.Diff.Parse.Types qualified as D
+
+newtype Patch = Patch
+  { fileDeltas :: D.FileDeltas
+  }
+  deriving (Show)
+
+parse :: T.Text -> Patch
+parse = either (throw . E.InvalidDiff) Patch . D.parseDiff
+
+render :: Patch -> P.Doc P.AnsiStyle
+render (Patch {..}) =
+  P.vsep $ map prettyFileDelta fileDeltas
+  where
+    prettyFileDelta (D.FileDelta {..}) = prettyContent fileDeltaContent
+    prettyContent D.Binary = P.emptyDoc
+    prettyContent (D.Hunks hunks) = P.vsep (map prettyHunk hunks)
+    prettyHunk (D.Hunk {..}) = P.vsep $ map prettyLine hunkLines
+    prettyLine (D.Line {..}) =
+      case lineAnnotation of
+        D.Added -> P.annotate (P.color P.Green) $ P.pretty ("+" :: T.Text) <> pretty lineContent
+        D.Removed -> P.annotate (P.color P.Red) $ P.pretty ("-" :: T.Text) <> pretty lineContent
+        D.Context -> P.annotate (P.color P.White) $ P.pretty (" " :: T.Text) <> pretty lineContent