1 files changed, 170 insertions, 0 deletions
diff --git a/elm/battlemap/src/Battlemap/Navigator/Path.elm b/elm/battlemap/src/Battlemap/Navigator/Path.elm
new file mode 100644
index 0000000..5ce2d4c
--- /dev/null
+++ b/elm/battlemap/src/Battlemap/Navigator/Path.elm
@@ -0,0 +1,170 @@
+module Battlemap.Navigator.Path exposing
+   (
+      Type,
+      new,
+      get_current_location,
+      get_remaining_points,
+      follow_directions
+   )
+
+import Set
+
+import Battlemap.Direction
+import Battlemap.Location
+import Battlemap.Tile
+
+--------------------------------------------------------------------------------
+-- TYPES -----------------------------------------------------------------------
+--------------------------------------------------------------------------------
+type alias Type =
+   {
+      current_location : Battlemap.Location.Type,
+      visited_locations : (Set.Set Battlemap.Location.Ref),
+      previous_directions : (List Battlemap.Direction.Type),
+      remaining_points : Int
+   }
+
+--------------------------------------------------------------------------------
+-- LOCAL -----------------------------------------------------------------------
+--------------------------------------------------------------------------------
+has_not_been_to : (
+      Type ->
+      Battlemap.Location.Type ->
+      Bool
+   )
+has_not_been_to path location =
+   (
+      (path.current_location /= location)
+      &&
+      (not
+         (Set.member
+            (Battlemap.Location.get_ref location)
+            path.visited_locations
+         )
+      )
+   )
+
+move_to : (
+      Type ->
+      Battlemap.Direction.Type ->
+      Battlemap.Location.Type ->
+      Int ->
+      Type
+   )
+move_to path dir next_loc cost =
+   {path |
+      current_location = next_loc,
+      visited_locations =
+         (Set.insert
+            (Battlemap.Location.get_ref path.current_location)
+            path.visited_locations
+         ),
+      previous_directions = (dir :: path.previous_directions),
+      remaining_points = (path.remaining_points - cost)
+   }
+
+battlemap_backtrack : (
+      Battlemap.Type ->
+      Battlemap.Location.Type ->
+      Battlemap.Type
+   )
+battlemap_backtrack battlemap current_loc =
+   (Battlemap.apply_to_tile_unsafe
+      battlemap
+      current_loc
+      (Battlemap.Tile.set_direction
+         Battlemap.Direction.None
+      )
+   )
+
+navigator_backtrack : (
+      Battlemap.Navigator.Type ->
+      Battlemap.Location.Type ->
+      (List Battlemap.Direction.Type) ->
+      Battlemap.Navigator.Type
+   )
+try_backtracking_to path location dir =
+               case (Util.List.pop nav.previous_directions) of
+                     (Just (head, tail)) ->
+                        if (head == (Battlemap.Direction.opposite_of dir))
+                        then
+                           (backtrack_to
+                              nav
+                              next_location
+                              tail
+                           )
+                           )
+                        else
+                           (battlemap, nav)
+                     Nothing -> (battlemap, nav)
+               move_to path next_location
+               if (can_move_to_new_tile path next_location)
+               then
+               else
+   {nav |
+      current_location = next_loc,
+      visited_locations =
+         (Set.remove
+            (Battlemap.Location.get_ref next_loc)
+            nav.visited_locations
+         ),
+      previous_directions = prev_dir_tail,
+      remaining_points = (nav.remaining_points + 1)
+   }
+
+
+to : (
+      Type ->
+      Battlemap.Direction.Type ->
+      (Battlemap.Type, Battlemap.Navigator.Type)
+   )
+to battlemap nav dir char_list =
+
+--------------------------------------------------------------------------------
+-- EXPORTED --------------------------------------------------------------------
+--------------------------------------------------------------------------------
+
+new : Battlemap.Location.Type -> Int -> Type
+new start points =
+   {
+      current_location = start,
+      visited_locations = Set.empty,
+      previous_directions = [],
+      remaining_points = points
+   }
+
+get_current_location : Type -> Battlemap.Location.Type
+get_current_location path = path.current_location
+
+get_remaining_points : Type -> Int
+get_remaining_points path = path.remaining_points
+
+follow_direction : (
+      (Battlemap.Location.Type -> Bool) ->
+      (Maybe Type) ->
+      Battlemap.Direction.Type ->
+      (Maybe Type)
+   )
+follow_direction can_cross cost_fun maybe_path dir =
+   case maybe_path of
+      (Just path) ->
+         let
+            next_location =
+               (Battlemap.Location.neighbor
+                  nav.current_location
+                  dir
+               )
+         in
+            if (can_cross path next_location)
+            then
+               if (has_not_been_to path next_location)
+               then
+                  (Just (move_to path next_location dir))
+               else
+                  (try_backtracking_to path next_location dir)
+            else
+               Nothing
+            else
+               (battlemap, nav)
+
+      Nothing -> Nothing