{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE GADTs           #-}
{-# LANGUAGE TemplateHaskell #-}
--------------------------------------------------------------------------------
module Xanthous.Generators
  ( generate
  , SGenerator(..)
  , GeneratorInput
  , generateFromInput
  , parseGeneratorInput
  , showCells
  , Level(..)
  , levelWalls
  , levelItems
  , levelCreatures
  , levelCharacterPosition
  , levelTutorialMessage
  , generateLevel
  ) where
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import           Xanthous.Prelude hiding (Level)
import           Data.Array.Unboxed
import           System.Random (RandomGen)
import qualified Options.Applicative as Opt
import           Control.Monad.Random
--------------------------------------------------------------------------------
import qualified Xanthous.Generators.CaveAutomata as CaveAutomata
import qualified Xanthous.Generators.Dungeon as Dungeon
import           Xanthous.Generators.Util
import           Xanthous.Generators.LevelContents
import           Xanthous.Data (Dimensions, Position'(Position), Position)
import           Xanthous.Data.EntityMap (EntityMap)
import qualified Xanthous.Data.EntityMap as EntityMap
import           Xanthous.Entities.Environment
import           Xanthous.Entities.Item (Item)
import           Xanthous.Entities.Creature (Creature)
--------------------------------------------------------------------------------

data Generator
  = CaveAutomata
  | Dungeon
  deriving stock (Show, Eq)

data SGenerator (gen :: Generator) where
  SCaveAutomata :: SGenerator 'CaveAutomata
  SDungeon :: SGenerator 'Dungeon

type family Params (gen :: Generator) :: Type where
  Params 'CaveAutomata = CaveAutomata.Params
  Params 'Dungeon = Dungeon.Params

generate
  :: RandomGen g
  => SGenerator gen
  -> Params gen
  -> Dimensions
  -> g
  -> Cells
generate SCaveAutomata = CaveAutomata.generate
generate SDungeon = Dungeon.generate

data GeneratorInput where
  GeneratorInput :: forall gen. SGenerator gen -> Params gen -> GeneratorInput

generateFromInput :: RandomGen g => GeneratorInput -> Dimensions -> g -> Cells
generateFromInput (GeneratorInput sg ps) = generate sg ps

parseGeneratorInput :: Opt.Parser GeneratorInput
parseGeneratorInput = Opt.subparser
  $ generatorCommand SCaveAutomata
      "cave"
      "Cellular-automata based cave generator"
      CaveAutomata.parseParams
  <> generatorCommand SDungeon
      "dungeon"
      "Classic dungeon map generator"
      Dungeon.parseParams
  where
    generatorCommand sgen name desc parseParams =
      Opt.command name
        (Opt.info
          (GeneratorInput <$> pure sgen <*> parseParams)
          (Opt.progDesc desc)
        )


showCells :: Cells -> Text
showCells arr =
  let ((minX, minY), (maxX, maxY)) = bounds arr
      showCellVal True = "x"
      showCellVal False = " "
      showCell = showCellVal . (arr !)
      row r = foldMap (showCell . (, r)) [minX..maxX]
      rows = row <$> [minY..maxY]
  in intercalate "\n" rows

cellsToWalls :: Cells -> EntityMap Wall
cellsToWalls cells = foldl' maybeInsertWall mempty . assocs $ cells
  where
    maybeInsertWall em (pos@(x, y), True)
      | not (surroundedOnAllSides pos) =
        let x' = fromIntegral x
            y' = fromIntegral y
        in EntityMap.insertAt (Position x' y') Wall em
    maybeInsertWall em _ = em
    surroundedOnAllSides pos = numAliveNeighbors cells pos == 8

--------------------------------------------------------------------------------

data Level = Level
  { _levelWalls             :: !(EntityMap Wall)
  , _levelItems             :: !(EntityMap Item)
  , _levelCreatures         :: !(EntityMap Creature)
  , _levelTutorialMessage   :: !(EntityMap GroundMessage)
  , _levelCharacterPosition :: !Position
  }
makeLenses ''Level

generateLevel :: MonadRandom m => SGenerator gen -> Params gen -> Dimensions -> m Level
generateLevel gen ps dims = do
  rand <- mkStdGen <$> getRandom
  let cells = generate gen ps dims rand
      _levelWalls = cellsToWalls cells
  _levelItems <- randomItems cells
  _levelCreatures <- randomCreatures cells
  _levelCharacterPosition <- chooseCharacterPosition cells
  _levelTutorialMessage <- tutorialMessage cells _levelCharacterPosition
  pure Level {..}