progress on visual. still some bugs

lib/HunkView.ml

@@ -2,12 +2,8 @@ open Nottui
 module W = Nottui_widgets
 
 (* Constants and Formatting Functions *)
-let added_marker (content : Ui.t) : Ui.t =
-  Ui.hcat [ W.string "+" ~attr:Notty.A.(fg green); content ]
-
-let removed_marker (content : Ui.t) : Ui.t =
-  Ui.hcat [ W.string "-" ~attr:Notty.A.(fg red); content ]
-
+let added_marker (content : Ui.t) : Ui.t = Ui.hcat [ W.string "+"; content ]
+let removed_marker (content : Ui.t) : Ui.t = Ui.hcat [ W.string "-"; content ]
 let unchanged_marker (content : Ui.t) : Ui.t = Ui.hcat [ W.string " "; content ]
 
 (* Types *)
@@ -117,13 +113,7 @@ let render_diff_line (mine_num : int) (their_num : int)
     (content : WordDiff.word list) (mode : rendering_mode) : Ui.t =
   let line_number = render_line_number mine_num their_num diff_type in
   let content_ui = render_word_diff content diff_type mode in
-  let marker =
-    match diff_type with
-    | `Added -> added_marker
-    | `Removed -> removed_marker
-    | `Unchanged -> unchanged_marker
-  in
-  Ui.hcat [ line_number; marker content_ui ]
+  Ui.hcat [ line_number; content_ui ]
 
 let render_hunk_lines (hunk_lines : WordDiff.line_content Patch.line list)
     (mode : rendering_mode) : Ui.t =

lib/WordDiff.ml

@@ -1,7 +1,11 @@
 type word = Unchanged of string | Changed of string
 type line_content = word list
 
-let string_to_words s = Array.of_list (String.split_on_char ' ' s)
+let string_arr_to_words s = Array.of_list (String.split_on_char ' ' s)
+
+let string_to_words s =
+  s |> String.trim |> String.split_on_char ' ' |> List.filter (fun s -> s <> "")
+
 let longest xs ys = if List.length xs > List.length ys then xs else ys
 
 let lcs xs' ys' =
@@ -44,8 +48,8 @@ let edit_distance (type a) (compare : a -> a -> bool) (s : a array)
   edit_distance_helper (Array.length s) (Array.length t)
 
 let diff_words (s1 : string) (s2 : string) : line_content * line_content =
-  let words1 = Array.to_list (string_to_words s1) in
-  let words2 = Array.to_list (string_to_words s2) in
+  let words1 = Array.to_list (string_arr_to_words s1) in
+  let words2 = Array.to_list (string_arr_to_words s2) in
   let common = lcs words1 words2 in
 
   let rec construct_diff w1 w2 lcs acc_mine acc_their =
@@ -77,11 +81,49 @@ let diff_words (s1 : string) (s2 : string) : line_content * line_content =
 
   construct_diff words1 words2 common [] []
 
+let string_similarity s1 s2 =
+  let a1 = string_to_words s1 |> Array.of_list in
+  let a2 = string_to_words s2 |> Array.of_list in
+  let distance = edit_distance (=) a1 a2 in
+  let max_length = max (Array.length a1) (Array.length a2) in
+  1.0 -. (float_of_int distance /. float_of_int max_length)
+
+let pair_lines mine their =
+  let similarity_threshold = 0.5 in
+  let rec pair acc mine their =
+    match mine, their with
+    | [], [] -> List.rev acc
+    | [], t::ts -> pair ((("", t) :: acc)) [] ts
+    | m::ms, [] -> pair (((m, "") :: acc)) ms []
+    | m::ms, t::ts ->
+        let similarity = string_similarity m t in
+        if similarity > similarity_threshold then
+          pair ((m, t) :: acc) ms ts
+        else
+          let (best_m, best_t) = 
+            List.fold_left (fun (bm, bt) cur_t ->
+              let sim = string_similarity m cur_t in
+              if sim > similarity_threshold then (Some m, Some cur_t) else (bm, bt)
+            ) (None, None) their
+          in
+          match best_m, best_t with
+          | Some bm, Some bt ->
+              pair ((bm, bt) :: acc) ms (List.filter ((<>) bt) their)
+          | _ -> pair ((m, "") :: acc) ms their
+  in
+  pair [] mine their
+
 let compute (block : string Block.t) : line_content Block.t =
   match block with
-  | Block.Common line -> Block.Common [ Unchanged line ]
+  | Block.Common line -> Block.Common [Unchanged line]
   | Block.Changed { mine; their; order } ->
-      let mine_str = String.concat " " mine in
-      let their_str = String.concat " " their in
-      let mine_words, their_words = diff_words mine_str their_str in
-      Block.Changed { mine = [ mine_words ]; their = [ their_words ]; order }
+      let paired_lines = pair_lines mine their in
+      let mine_content, their_content = 
+        List.split (List.map (fun (m, t) -> 
+          let m_words, t_words = diff_words m t in
+          (m_words, t_words)
+        ) paired_lines)
+      in
+      let mine_content = List.filter (fun l -> l <> []) mine_content in
+      let their_content = List.filter (fun l -> l <> []) their_content in
+      Block.Changed { mine = mine_content; their = their_content; order }