module RPGEngine.Data.Game
( isLegalMove
, isPlayerAtExit
, isPlayerDead
) where

import RPGEngine.Data
    ( Player(Player, position),
      Direction,
      Physical(Exit, Walkable, Entrance),
      State(..),
      Game(..) )
import RPGEngine.Data.Level (findAt, directionOffsets)

------------------------------ Exported ------------------------------

-- Check if a move is legal by checking what is located at the new position.
isLegalMove :: Direction -> Game -> Bool
isLegalMove dir g@Game{ state = Playing{ level = lvl, player = p@Player{ position = (x, y) }}} = legality
    where legality = physical `elem` [Walkable, Entrance, Exit]
          physical = findAt newPos lvl
          newPos   = (x + xD, y + yD)
          (xD, yD) = directionOffsets dir
isLegalMove _   _ = False

-- Check if a player is standing on an exit
isPlayerAtExit :: Game -> Bool
isPlayerAtExit g@Game{ state = Playing{ player = player, level = level }} = atExit
    where playerPos = position player
          atPos     = findAt playerPos level
          atExit    = atPos == Exit
isPlayerAtExit _ = False

-- Check if the players health is <= 0, which means the player is dead.
isPlayerDead :: Game -> Bool
isPlayerDead _ = False