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|
module Battlemap.Navigator exposing
(
Navigator,
new_navigator,
reset_navigation,
go
)
import Set exposing (Set, member, empty, insert, remove)
import List as Lt exposing (head, tail)
import Battlemap exposing (Battlemap, has_location, apply_to_tile)
import Battlemap.Direction exposing (Direction(..), opposite_of)
import Battlemap.Tile exposing (Tile, set_direction)
import Battlemap.Location exposing
(
Location,
LocationRef,
neighbor,
to_comparable
)
type alias Navigator =
{
current_location : Location,
visited_locations : (Set LocationRef),
previous_directions : (List Direction)
}
new_navigator : Location -> Navigator
new_navigator start =
{
current_location = start,
visited_locations = empty,
previous_directions = []
}
reset_navigation : Tile -> Tile
reset_navigation t =
{t |
nav_level = None
}
go : Battlemap -> Navigator -> Direction -> (Battlemap, Navigator)
go battlemap nav dir =
let
next_location = (neighbor nav.current_location dir)
in
if
(
(has_location battlemap next_location)
&& (nav.current_location /= next_location)
&& (not (member (to_comparable next_location) nav.visited_locations))
)
then
(
(case
(apply_to_tile
battlemap
nav.current_location
(set_direction dir)
)
of
Nothing -> battlemap
(Just bmap0) ->
(case
(apply_to_tile
bmap0
next_location
(set_direction dir)
)
of
Nothing -> battlemap
(Just bmap1) -> bmap1
)
),
{nav |
current_location = next_location,
visited_locations =
(insert
(to_comparable nav.current_location)
nav.visited_locations
),
previous_directions = (dir :: nav.previous_directions)
}
)
else
case
(
(Lt.head nav.previous_directions),
(Lt.tail nav.previous_directions)
)
of
(Nothing, _) -> (battlemap, nav)
(_ , Nothing) -> (battlemap, nav)
((Just prev_dir), (Just prev_dir_list)) ->
if (dir == (opposite_of prev_dir))
then
(
(case
(apply_to_tile
battlemap
nav.current_location
(set_direction None)
)
of
Nothing -> battlemap
(Just bmap) -> bmap
),
{nav |
current_location = next_location,
visited_locations =
(remove
(to_comparable next_location)
nav.visited_locations
),
previous_directions = prev_dir_list
}
)
else
(battlemap, nav)
|