module Exercise08 where

import Data.Bits
import Data.List
import System.Random (Random, mkStdGen, randomIO, randoms)

-- Player is either 1 or -1
type Player = Int

-- A field is just an Int value where the absolute gives the number of pieces on the field
-- and the sign corresponds to the player
-- e.g. -3 would mean there are three blobs in this field of player -1
type Field = Int

type Row = [Field]

type Column = [Field]

-- boards are rectangles represented as a list of rows
type Board = [Row]

-- A position on the board is represented as (row, column)
-- (0,0) is the top left corner, coordinate values increase towards the bottom right
type Pos = (Int, Int)

-- A size represented as (height,width)
type Size = (Int, Int)

-- A strategy takes the player who's move it is, optionally takes a list of double values
-- to allow for probabilistic strategies, takes the current board and gives back the position
-- of the move the player should do
type Strategy = [Double] -> Player -> Board -> Pos

-- A stateful strategy can additionally pass some object between invocations
type StatefulStrategyFunc a = a -> [Double] -> Player -> Board -> (Pos, a)

-- first value is the state object to pass to the first invocation of each game
type StatefulStrategy a = (a, StatefulStrategyFunc a)

defaultSize :: (Int, Int)
defaultSize = (9, 6)

-- Some useful helper functions
row :: Board -> Int -> Row
row = (!!)

column :: Board -> Int -> Column
column = row . transpose

width :: Board -> Int
width (x : _) = length x
width _ = 0

height :: Board -> Int
height = length

size :: Board -> Size
size b = (height b, width b)

getCell :: Pos -> Board -> Field
getCell (y, x) b = b !! y !! x

-- pretty print a single cell
showCell :: Field -> String
showCell c = "- +" !! succ (signum c) : show (abs c)

-- pretty print the given board
showBoard :: Board -> String
showBoard = unlines . map (unwords . map showCell)

-- print a board to the console
printBoard :: Board -> IO ()
printBoard = putStr . showBoard

-- check if a position is one a board of the given size
isValidPos :: Size -> Pos -> Bool
isValidPos (r, c) (y, x) = y >= 0 && y < r && x >= 0 && x < c

{- x.1 -}

-- Check if the given player can put an orb on the given position
canPlaceOrb :: Player -> Pos -> Board -> Bool
canPlaceOrb p (y, x) b
  | p > 0 = row b y !! x >= 0
  | p < 0 = row b y !! x <= 0

-- Check if the given player has won the game,
-- you can assume that the opponent has made at least one move before
hasWon :: Player -> Board -> Bool
hasWon p b
  | p > 0 = all (all (>= 0)) b
  | p < 0 = all (all (<= 0)) b

-- the list of neighbors of a cell
neighbors :: Size -> Pos -> [Pos]
neighbors (r, c) (y, x) = pos
  where
    pos = if y /= r -1 then (y + 1, x) : pos2 else pos2
    pos2 = if y /= 0 then (y -1, x) : pos3 else pos3
    pos3 = if x /= c -1 then (y, x + 1) : pos4 else pos4
    pos4 = [(y, x - 1) | x /= 0]

-- update a single position on the board
-- f: function that modifies the number of orbs in the cell
-- p: player to whom the updated cell should belong
updatePos :: (Int -> Int) -> Player -> Pos -> Board -> Board
updatePos f p (y, x) b = newb
  where
    newb = take y b ++ [newrow] ++ drop (y + 1) b
    newrow = take x (row b y) ++ [neworb] ++ drop (x + 1) (row b y)
    neworb
      | p > 0 = if getCell (y, x) b > 0 then f (getCell (y, x) b) else f $abs (getCell (y, x) b)
      | p < 0 = if getCell (y, x) b > 0 then negate (f (getCell (y, x) b)) else negate (f $abs (getCell (y, x) b))

{- x.2 -}

-- place an orb for the given player in the given cell
putOrb :: Player -> Pos -> Board -> Board
putOrb p (y, x) b = checkoverflow
  where
    update = updatePos (1 +) p (y, x) b
    neigh = neighbors (size b) (y, x)
    deleted = take y update ++ [newrow] ++ drop (y + 1) update
    newrow = take x (row update y) ++ [0] ++ drop (x + 1) (row update y)
    loop bo [] = bo
    loop bo (x : xs) = if hasWon p bo then bo else loop (putOrb p x bo) xs
    checkoverflow = if abs (getCell (y, x) update) == length neigh && not (hasWon p update) then loop deleted neigh else update

{- x.3 -}


{-WETT-}
-- Your strategy
strategy :: Strategy
strategy rando p b = if not (null placed) then far else putcorner
  where
    far = if countMine p (putOrb p faraway b) all > myorbsum + 1 then faraway else putcorner
    putcorner = if not (null corners) then head corners else later
    later = if not (null attacklater) && not (null $head attacklater) then head $ head attacklater else sideTwo
    sideTwo = if not (null $sides b p) then head (sides b p) else head randomy

    all = [(x, y) | x <- [0 .. height b -1], y <- [0 .. width b -1]]
    placed = filter (isMine p b) all
    oppo = filter (isMine (negate p) b) all
    myorbsum = sum $ map (\x -> abs (getCell x b)) placed
    faraway = foldl1 (\x y -> if countMine p (putOrb p x b) all > countMine p (putOrb p y b) all then x else y) placed
    corners = filter (\x -> getCell x b == 0 && oppoCanAttack x b p) ((height b -1, width b -1) : (0, 0) : (height b -1, 0) : [(0, width b -1)])
    attacklater = map (\x -> placeBeside x b p) oppo 
    randomy = filter (\x -> canPlaceOrb p x b) all

countMine :: Int -> Board -> [Pos] -> Int
countMine p b all = sum $ map (\x -> abs (getCell x b)) (filter (isMine p b) all)

oppoCanAttack :: Pos -> Board -> Int -> Bool
oppoCanAttack pos b p = null $filter (\a -> not (canPlaceOrb p a b) && length (neighbors (size b) a) -1 == abs (getCell a b)) (neighbors (size b) pos)

sides :: Board -> Int -> [Pos]
sides b p = filter (\x -> canPlaceOrb p x b && oppoCanAttack x b p && abs (getCell x b) < length (neighbors (size b) x) -1) blanks
  where
    blanks = concat [(x, y) : [(w, z)] | x <- [0, 2 .. height b -1], w <- [1, 3 .. height b -1], z <- [1, 3 .. width b -1], y <- [0, 2 .. width b -1]]

placeBeside :: Pos -> Board -> Int -> [Pos]
placeBeside pos b p = filter (\a -> length (neighbors (size b) a) - abs (getCell a b) <= length (neighbors (size b) pos) - abs (getCell pos b) && oppoattack (neighbors (size b) a)) neigh
  where
    neigh = filter (\x -> canPlaceOrb p x b) (neighbors (size b) pos)
    oppoattack n = null $filter (\a -> not (canPlaceOrb p a b) && length (neighbors (size b) a) - abs (getCell a b) < length (neighbors (size b) pos) - abs (getCell pos b)) n

neighborOppo :: Pos -> Board -> Int -> Bool
neighborOppo pos b p
  | p > 0 = any (\a -> getCell a b < 0) (neighbors (size b) pos)
  | p < 0 = any (\a -> getCell a b > 0) (neighbors (size b) pos)

isMine :: Int -> Board -> Pos -> Bool
isMine p b pos
  | p > 0 && getCell pos b > 0 = True
  | p < 0 && getCell pos b < 0 = True
  | otherwise = False

-- adds state to a strategy that doesn't use it
wrapStrategy :: Strategy -> StatefulStrategy Int
wrapStrategy strat = (0, \s r p b -> (strat r p b, succ s))

-- the actual strategy submissions
-- if you want to use state modify this instead of strategy
-- additionally you may change the Int in this type declaration to any type that is usefully for your strategy
strategyState :: StatefulStrategy Int
strategyState = wrapStrategy strategy

{-TTEW-}

-- Simulate a game between two strategies on a board of the given size and
-- returns the state of the board before each move together with the player that won the game
play :: [Int] -> Size -> StatefulStrategy a -> StatefulStrategy b -> [(Board, Pos)]
play rss (r, c) (isa, sa) (isb, sb) = go rss isa sa isb sb 1 0 (replicate r (replicate c 0))
  where
    -- type signature is necessary, inferred type is wrong!
    go :: [Int] -> a -> StatefulStrategyFunc a -> b -> StatefulStrategyFunc b -> Player -> Int -> Board -> [(Board, Pos)]
    go (rs : rss) stc sc stn sn p n b
      | won = []
      | valid = (b, m) : go rss stn sn st' sc (- p) (succ n) (putOrb p m b)
      | otherwise = []
      where
        won = n > 1 && hasWon (- p) b
        (m, st') = sc stc (mkRandoms rs) p b
        valid = isValidPos (size b) m && canPlaceOrb p m b

-- Play a game and print it to the console
playAndPrint :: Size -> StatefulStrategy a -> StatefulStrategy b -> IO ()
playAndPrint size sa sb = do
  seed <- randomIO
  -- let seed = 42
  let moves = play (mkRandoms seed) size sa sb
  putStr $
    unlines (zipWith showState moves $ cycle ['+', '-']) ++ "\n"
      ++ (case length moves `mod` 2 of 1 -> "Winner: +"; 0 -> "Winner: -")
      ++ "\n"
      ++ "View at https://vmnipkow16.in.tum.de/christmas2020/embed.html#i"
      ++ base64 (1 : t size ++ concatMap (t . snd) moves)
      ++ "\n"
  where
    showState (b, pos) p = showBoard b ++ p : " places at " ++ show pos ++ "\n"
    t (a, b) = [a, b]

mkRandoms :: Random a => Int -> [a]
mkRandoms = randoms . mkStdGen

base64 :: [Int] -> String
base64 xs = case xs of
  [] -> ""
  [a] -> f1 a : f2 a 0 : "=="
  [a, b] -> f1 a : f2 a b : f3 b 0 : "="
  a : b : c : d -> f1 a : f2 a b : f3 b c : f4 c : base64 d
  where
    alphabet = (!!) "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
    f1 a = alphabet $ shiftR a 2
    f2 a b = alphabet $ shiftL (a .&. 3) 4 .|. shiftR b 4
    f3 b c = alphabet $ shiftL (b .&. 15) 2 .|. shiftR c 6
    f4 c = alphabet $ c .&. 63