3 files changed, 95 insertions, 7 deletions
diff --git a/src/roster-editor/src/ElmModule/Update.elm b/src/roster-editor/src/ElmModule/Update.elm
index 88d059d..923b552 100644
--- a/src/roster-editor/src/ElmModule/Update.elm
+++ b/src/roster-editor/src/ElmModule/Update.elm
@@ -13,12 +13,13 @@ import Update.SelectCharacter
 import Update.SelectTab
 import Update.SendRoster
 import Update.SetArmor
-import Update.SetName
 import Update.SetGlyph
 import Update.SetGlyphBoard
+import Update.SetName
 import Update.SetPortrait
 import Update.SetRequestedHelp
 import Update.SetWeapon
+import Update.ToggleBattleIndex
 
 --------------------------------------------------------------------------------
 -- LOCAL -----------------------------------------------------------------------
@@ -53,11 +54,10 @@ update event model =
          )
 
       (Struct.Event.ToggleCharacterBattleIndex char_id) ->
-         (new_model, Cmd.none)
-         -- (Update.ToggleCharacterBattleIndex.apply_to
-         --    (Struct.Model.save_character new_model)
-         --    char_id
-         -- )
+         (Update.ToggleBattleIndex.apply_to
+            (Struct.Model.save_character new_model)
+            char_id
+         )
 
       (Struct.Event.TabSelected tab) ->
          (Update.SelectTab.apply_to
diff --git a/src/roster-editor/src/Update/ToggleBattleIndex.elm b/src/roster-editor/src/Update/ToggleBattleIndex.elm
new file mode 100644
index 0000000..42d8374
--- /dev/null
+++ b/src/roster-editor/src/Update/ToggleBattleIndex.elm
@@ -0,0 +1,82 @@
+module Update.ToggleBattleIndex exposing (apply_to)
+
+-- Elm -------------------------------------------------------------------------
+import Array
+
+-- Roster Editor ---------------------------------------------------------------
+import Util.Array
+
+import Struct.Character
+import Struct.Event
+import Struct.Model
+
+--------------------------------------------------------------------------------
+-- LOCAL -----------------------------------------------------------------------
+--------------------------------------------------------------------------------
+remove_battle_index : (
+      Struct.Model.Type ->
+      Struct.Character.Type->
+      Int ->
+      Struct.Model.Type
+   )
+remove_battle_index model char index =
+   {model |
+      edited_char = Nothing,
+      used_indices =
+         (Array.set
+            (Struct.Character.get_battle_index char)
+            False
+            model.used_indices
+         ),
+      characters =
+         (Array.set
+            index
+            (Struct.Character.set_battle_index -1 char)
+            model.characters
+         )
+   }
+
+give_battle_index : (
+      Struct.Model.Type ->
+      Struct.Character.Type->
+      Int ->
+      Struct.Model.Type
+   )
+give_battle_index model char index =
+   case (Util.Array.indexed_search (\e -> (not e)) model.used_indices) of
+      Nothing -> model
+      (Just (battle_index, _)) ->
+         {model |
+            edited_char = Nothing,
+            used_indices = (Array.set battle_index True model.used_indices),
+            characters =
+               (Array.set
+                  index
+                  (Struct.Character.set_battle_index battle_index char)
+                  model.characters
+               )
+         }
+
+--------------------------------------------------------------------------------
+-- EXPORTED --------------------------------------------------------------------
+--------------------------------------------------------------------------------
+apply_to : (
+      Struct.Model.Type ->
+      Int ->
+      (Struct.Model.Type, (Cmd Struct.Event.Type))
+   )
+apply_to model index =
+   case (Array.get index model.characters) of
+      Nothing ->
+         -- TODO: error
+         (model, Cmd.none)
+
+      (Just char) ->
+         (
+            (
+               if ((Struct.Character.get_battle_index char) == -1)
+               then (give_battle_index model char index)
+               else (remove_battle_index model char index)
+            ),
+            Cmd.none
+         )
diff --git a/src/shared/elm/Util/Array.elm b/src/shared/elm/Util/Array.elm
index 9e57c18..362c924 100644
--- a/src/shared/elm/Util/Array.elm
+++ b/src/shared/elm/Util/Array.elm
@@ -2,7 +2,8 @@ module Util.Array exposing
    (
       update,
       update_unsafe,
-      filter_first
+      filter_first,
+      indexed_search
    )
 
 import Array
@@ -32,3 +33,8 @@ update_unsafe index fun array =
 filter_first : (t -> Bool) -> (Array.Array t) -> (Maybe t)
 filter_first fun array =
    (Array.get 0 (Array.filter fun array))
+
+indexed_search : (t -> Bool) -> (Array.Array t) -> (Maybe (Int, t))
+indexed_search fun array =
+   -- TODO
+   Nothing