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|
module Battlemap.Navigator.Path exposing
(
Type,
new,
get_current_location,
get_remaining_points,
try_following_direction
)
import Set
import Util.List
import Battlemap.Direction
import Battlemap.Location
--------------------------------------------------------------------------------
-- TYPES -----------------------------------------------------------------------
--------------------------------------------------------------------------------
type alias Type =
{
current_location : Battlemap.Location.Type,
visited_locations : (Set.Set Battlemap.Location.Ref),
previous_directions : (List Battlemap.Direction.Type),
previous_points : (List Int),
remaining_points : Int
}
--------------------------------------------------------------------------------
-- LOCAL -----------------------------------------------------------------------
--------------------------------------------------------------------------------
has_been_to : (
Type ->
Battlemap.Location.Type ->
Bool
)
has_been_to path location =
(
(path.current_location == location)
||
(Set.member
(Battlemap.Location.get_ref location)
path.visited_locations
)
)
try_moving_to : (
Type ->
Battlemap.Direction.Type ->
Battlemap.Location.Type ->
Int ->
(Maybe Type)
)
try_moving_to path dir next_loc cost =
let
remaining_points = (path.remaining_points - cost)
in
if (remaining_points >= 0)
then
(Just
{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),
previous_points =
(path.remaining_points :: path.previous_points),
remaining_points = remaining_points
}
)
else
Nothing
try_backtracking_to : (
Type ->
Battlemap.Direction.Type ->
Battlemap.Location.Type ->
(Maybe Type)
)
try_backtracking_to path dir location =
case
(
(Util.List.pop path.previous_directions),
(Util.List.pop path.previous_points)
)
of
(
(Just (prev_dir_head, prev_dir_tail)),
(Just (prev_pts_head, prev_pts_tail))
) ->
if (prev_dir_head == (Battlemap.Direction.opposite_of dir))
then
(Just
{path |
current_location = location,
visited_locations =
(Set.remove
(Battlemap.Location.get_ref location)
path.visited_locations
),
previous_directions = prev_dir_tail,
previous_points = prev_pts_tail,
remaining_points = prev_pts_head
}
)
else
Nothing
(_, _) ->
Nothing
--------------------------------------------------------------------------------
-- EXPORTED --------------------------------------------------------------------
--------------------------------------------------------------------------------
new : Battlemap.Location.Type -> Int -> Type
new start points =
{
current_location = start,
visited_locations = Set.empty,
previous_directions = [],
previous_points = [],
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
try_following_direction : (
(Battlemap.Location.Type -> Bool) ->
(Battlemap.Location.Type -> Int) ->
(Maybe Type) ->
Battlemap.Direction.Type ->
(Maybe Type)
)
try_following_direction can_cross cost_fun maybe_path dir =
case maybe_path of
(Just path) ->
let
next_location =
(Battlemap.Location.neighbor
path.current_location
dir
)
in
if (can_cross next_location)
then
if (has_been_to path next_location)
then
(try_backtracking_to path dir next_location)
else
(try_moving_to
path
dir
next_location
(cost_fun next_location)
)
else
Nothing
Nothing -> Nothing
|
