Internal/Karel.hs

@@ -2,6 +2,8 @@
 
 module Internal.Karel where
 
+import Text.Printf
+
 import Internal.Types
 import Internal.World
 
@@ -11,7 +13,97 @@ data Karel = Karel
     karelBeepers :: Int,
     karelWorld :: World
   }
-  deriving (Show, Eq)
+  deriving (Eq)
+
+xor :: Bool -> Bool -> Bool
+xor True a = not a
+xor False a = a
+
+getHeader :: Karel -> String
+getHeader karel = unlines [
+    printf " %8s   %s  %s  %s" "POSITION" "FACING" "BEEP-BAG" "BEEP-POS",
+    printf "(%3d, %3d)  %6s  %8d  %8d" x y dir bag pos,
+    " Y +" <> replicate (4 * width - 1) '-' <> "+"
+  ]
+  where
+    (x, y) = karelPosition karel
+    dir = show $ karelDirection karel
+    bag = karelBeepers karel
+    pos = getBeepersAt (x, y) $ karelWorld karel
+    (width, _) = worldDimensions $ karelWorld karel
+
+getFooter :: Karel -> String
+getFooter karel = unlines [
+    "   +" <> replicate (4 * width - 1) '-' <> "+",
+    "    " <> foldl1 (<>) [ printf " %-2d " column | column <- [1..width] ] <> " X"
+  ]
+  where
+    (width, _) = worldDimensions $ karelWorld karel
+
+mapDirection :: Karel -> String
+mapDirection karel = case karelDirection karel of
+  North -> " ^ "
+  East -> " > "
+  South -> " v "
+  West -> " < "
+
+mapCell :: Karel -> Int -> Int -> String
+mapCell karel x y
+  | karelPosition karel == (x, y) = mapDirection karel
+  | beepersAt > 0 = printf " %-2d" beepersAt
+  | otherwise = " . "
+  where beepersAt = getBeepersAt (x, y) $ karelWorld karel
+
+
+mapWall :: Karel -> Int -> Int -> String
+mapWall karel x y = leftPart <> rightPart
+  where
+    world = karelWorld karel
+    (northWall:eastWall:westWall:_) = map (\d -> hasWallAt (x, y) d world) [North, East, West]
+    (northWallOnLeft:northWallOnRight:_) = map (\d -> hasWallAt (x + d, y) North world) [-1, 1]
+    (eastWallAbove:westWallAbove:_) = map (\d -> hasWallAt (x, y + 1) d world) [East, West]
+    verticalWall = eastWall && eastWallAbove
+    wallEnds = northWall && not northWallOnRight
+    wallStarts = northWall && x > 1 && not northWallOnLeft
+    leftPart
+      | wallStarts && not (westWall || westWallAbove) = "+-"
+      | northWall = "--"
+      | otherwise = "  "
+    rightPart
+      | northWall && wallEnds && verticalWall = "-|"
+      | wallEnds || (northWall && eastWallAbove) = "-+"
+      | northWall = "--"
+      | (verticalWall && northWallOnRight) || (eastWall `xor` eastWallAbove) = " +"
+      | verticalWall = " |"
+      | otherwise = "  "
+
+getRow :: Karel -> Int -> String
+getRow karel row
+  | row == height = line
+  | otherwise = horizontalWalls <> "\n" <> line
+  where
+    world = karelWorld karel
+    (width, height) = worldDimensions world
+    horizontalWalls = "   |" <> foldl1 (<>) [
+      mapWall karel column row
+      | column <- [1..width]
+      ]
+    line = printf "%2d |" row <> foldl1 (<>) [
+      position <> wall
+      | column <- [1..width],
+      let wall = if hasWallAt (column, row) East world then "|" else " ",
+      let position = mapCell karel column row
+      ]
+
+getMap :: Karel -> String
+getMap karel = unlines [
+  getRow karel row
+  | row <- reverse [1..height]
+  ]
+  where (_, height) = worldDimensions $ karelWorld karel
+
+instance Show Karel where
+  show karel = getHeader karel <> getMap karel <> getFooter karel
 
 stepVector :: Direction -> Vector
 stepVector = \case