forgivingStrategy :: [Char] -> [Char] -> Int -> [Char]
forgivingStrategy opponentMoves generatedMoves n
  | n > 100 || length opponentMoves == 1 = generatedMoves
  | n == 0                               
    = forgivingStrategy opponentMoves (generatedMoves ++ ['С']) (n + 1)
  | head opponentMoves == 'С'            
    = forgivingStrategy (tail opponentMoves) (generatedMoves ++ ['С']) (n + 1)
  | otherwise                            
    = forgivingStrategy (tail opponentMoves) (generatedMoves ++ ['П']) (n + 1)

indexOf :: (Eq t) => [t] -> t -> Int
indexOf [] _ = -1
indexOf (x : xs) target
  | x == target = 0
  | otherwise = 1 + indexOf xs target

nashEquilibriumStrategy :: [Char] -> [Char] -> Int -> [Char]
nashEquilibriumStrategy opponentMoves generatedMoves n =
  if n <= 100 && length opponentMoves > 0
    then
      nashEquilibriumStrategy (tail opponentMoves) (generatedMoves ++ [nextStep]) (n + 1)
    else generatedMoves
  where
    cases = [['С', 'С'], ['С', 'П'], ['П', 'С'], ['П', 'П']]
    results = [[1, 1], [10, 0], [0, 10], [5, 5]]
    p_years = min (results !! 1 !! 1) (results !! 3 !! 1)
    s_years = min (results !! 0 !! 1) (results !! 2 !! 1)
    nextStep | p_years <= s_years = 'П'
             | otherwise = 'С'

getScore :: [Char] -> [Char] -> Int -> Int -> (Int, Int)
getScore moves1 moves2 score1 score2 =
    if length moves1 == 0 then (score1, score2)
    else getScore (tail moves1) (tail moves2) newScore1 newScore2
    where 
        cases = [['С', 'С'], ['С', 'П'], ['П', 'С'], ['П', 'П']]
        results = [[1, 1], [10, 0], [0, 10], [5, 5]]
        newScore1 = score1 + results !! indexOf cases [head moves1, head moves2] !! 0
        newScore2 = score2 + results !! indexOf cases [head moves1, head moves2] !! 1


game :: [Char] -> ([Char] -> [Char] -> Int -> [Char]) -> [Char]
game playerMoves gameStrategy
  | null playerMoves = []
  | otherwise = gameStrategy playerMoves [] 0


playerMoves = ['С', 'П', 'С', 'С', 'П', 'П', 'С', 'С', 'П', 'П']
-- gameStrategy = forgivingStrategy
gameStrategy = nashEquilibriumStrategy
computerMoves = game playerMoves gameStrategy
(score1, score2) = getScore playerMoves computerMoves 0 0

main :: IO ()
main = do
  putStrLn $ "Ходы компьютера: " ++ computerMoves
  putStrLn $ "Годы заключения: " 
    ++ show score1 ++ " (игрок) - " ++ show score2 ++ " (компьютер)"