Starting work on the Map handler...

1 files changed, 90 insertions, 0 deletions

diff --git a/src/map/struct/map_location.erl b/src/map/struct/map_location.erl
new file mode 100644
index 0000000..9670cb0
--- /dev/null
+++ b/src/map/struct/map_location.erl
@@ -0,0 +1,90 @@
+-module(btl_location).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% TYPES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-type type() :: ({non_neg_integer(), non_neg_integer()} | 'nowhere').
+
+-export_type([type/0]).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% EXPORTS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-export
+(
+   [
+      decode/1,
+      encode/1,
+      get_nowhere/0
+   ]
+).
+
+-export
+(
+   [
+      apply_direction/2,
+      dist/2
+   ]
+).
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% LOCAL FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-spec validate ({integer(), integer()}) -> type().
+validate ({X, Y}) ->
+   if
+      (X < 0) -> nowhere;
+      (Y < 0) -> nowhere;
+      true -> {X, Y}
+   end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% EXPORTED FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+-spec get_nowhere () -> type().
+get_nowhere () -> nowhere.
+
+-spec apply_direction (btl_direction:enum(), type()) -> type().
+apply_direction (left, {X, Y}) ->
+   validate({(X - 1), Y});
+apply_direction (right, {X, Y}) ->
+   validate({(X + 1), Y});
+apply_direction (up, {X, Y}) ->
+   validate({X, (Y - 1)});
+apply_direction (down, {X, Y}) ->
+   validate({X, (Y + 1)});
+apply_direction (_, nowhere) ->
+   error("Trying to move from 'nowhere'."),
+   nowhere.
+
+-spec dist(type(), type()) -> non_neg_integer().
+dist ({OX, OY}, {DX, DY}) ->
+   (abs(DY - OY) + abs(DX - OX));
+dist (_, _) ->
+   error("Trying to measure distance to 'nowhere'"),
+   999.
+
+-spec encode (type()) -> {list(any())}.
+encode ({X, Y}) ->
+   {
+      [
+         {<<"x">>, X},
+         {<<"y">>, Y}
+      ]
+   };
+encode (nowhere) ->
+   {
+      [
+         {<<"x">>, -1},
+         {<<"y">>, -1}
+      ]
+   }.
+
+-spec decode (map()) -> type().
+decode (Map) ->
+   X = maps:get(<<"x">>, Map),
+   Y = maps:get(<<"y">>, Map),
+
+   true = (is_integer(X) and is_integer(Y)),
+
+   validate({X, Y}).