{- |
Module      : Dodge.Event
Description : Direct event handling

Deals with direct events.
This includes individual key or mouse presses, but /not/ continuous held down input.
We cannot handle multiple keys held down at once here,
(eg left mouse button + right mouse button)
because these are separate events.
Instead we store the events in a set, and deal with the combinations in
"Dodge.Update".
-}
module Dodge.Event 
    ( handleEvent
    ) where
import Dodge.Event.Keyboard
import Dodge.Event.Menu
import Dodge.Data
import Dodge.Base
import Dodge.CreatureAction
import Dodge.SoundLogic
import Dodge.Inventory
import Geometry
import Control.Lens
import Data.Maybe
import Data.Char
import Data.List
import Data.Function (on)
import qualified Data.Set as S
import qualified Data.IntMap.Strict as IM
import SDL

handleEvent :: World -> Event -> Maybe World
handleEvent = flip handleEvent'

handleEvent' :: Event -> World -> Maybe World
handleEvent' e = case eventPayload e of
    KeyboardEvent kev           -> handleKeyboardEvent kev
    MouseMotionEvent mmev       -> handleMouseMotionEvent mmev
    MouseButtonEvent mbev       -> handleMouseButtonEvent mbev
    MouseWheelEvent mwev        -> handleMouseWheelEvent mwev
    WindowSizeChangedEvent sev  -> handleResizeEvent sev
    _                           -> Just

handleMouseMotionEvent :: MouseMotionEventData -> World -> Maybe World
handleMouseMotionEvent mmev w
    = Just $ w & mousePos .~ (fromIntegral x - 0.5*_windowX w
                             ,0.5*_windowY w - fromIntegral y
                             )
    where P (V2 x y) = mouseMotionEventPos mmev

handleMouseButtonEvent :: MouseButtonEventData -> World -> Maybe World
handleMouseButtonEvent mbev w = case mouseButtonEventMotion mbev of
    Released -> Just    $ over mouseButtons (S.delete but) w
    Pressed  -> handlePressedMouseButton but 
                        $ over mouseButtons (S.insert but) w
    where but = mouseButtonEventButton mbev

handleMouseWheelEvent :: MouseWheelEventData -> World -> Maybe World
handleMouseWheelEvent mwev w = case _menuLayers w of
   [] -> case mouseWheelEventPos mwev of
        V2 x y | y > 0      -> Just (wheelUpEvent w)
               | y < 0      -> Just (wheelDownEvent w)
               | otherwise  -> Just w
   _ -> Just w

handleResizeEvent :: WindowSizeChangedEventData -> World -> Maybe World
handleResizeEvent sev = Just . set windowX (fromIntegral x)
                             . set windowY (fromIntegral y)
  where V2 x y = windowSizeChangedEventSize sev

handlePressedMouseButton :: MouseButton -> World -> Maybe World
handlePressedMouseButton but w 
    | but == ButtonMiddle || _carteDisplay w 
                = Just $ w & clickMousePos .~ _mousePos w
    | otherwise = Just w

wheelUpEvent :: World -> World
wheelUpEvent w = case _carteDisplay w of
    True    | rbDown    -> w & carteZoom .~ min 0.75 (z+(0.1*z))
            | otherwise -> w & selLocation %~ (`mod` numLocs) . (\i -> i - 1)
    _       | rbDown    -> fromMaybe (closeObjScrollUp w) 
                            $ (yourItem w ^? itScrollUp) 
                                <*> pure (_crInvSel (you w))
                                <*> pure w
            | lbDown    -> w & cameraZoom +~ 0.1
            | otherwise -> upInvPos w
  where 
    rbDown = ButtonRight `S.member` _mouseButtons w
    lbDown = ButtonLeft `S.member` _mouseButtons w
    z = _carteZoom w
    numLocs = (fst . IM.findMax $ _seenLocations w) + 1

wheelDownEvent :: World -> World
wheelDownEvent w = case _carteDisplay w of
    True    | rbDown    -> w & carteZoom .~ max 0.05 (z-(0.1*z))
            | otherwise -> w & selLocation %~ (`mod` numLocs) . (\i -> i + 1)
    False   | rbDown    -> fromMaybe (closeObjScrollDown w)
                                  $ (yourItem w ^? itScrollDown) 
                                      <*> pure (_crInvSel (you w))
                                      <*> pure w
            | lbDown     -> w {_cameraZoom = max (_cameraZoom w - 0.1) 0.01}
            | otherwise   -> downInvPos w
  where 
    rbDown = ButtonRight `S.member` _mouseButtons w
    lbDown = ButtonLeft `S.member` _mouseButtons w
    z = _carteZoom w
    numLocs = (fst . IM.findMax $ _seenLocations w) + 1

upInvPos :: World -> World
upInvPos w = stopSoundFrom (CrReloadSound 0) $ set (creatures . ix (_yourID w) . crInvSel) x w
    where is = IM.keys $ _crInv $ _creatures w IM.! _yourID w
          isis = is ++ is
          x = before (_crInvSel (you w)) isis
downInvPos :: World -> World
downInvPos w = stopSoundFrom (CrReloadSound 0) $ set (creatures . ix (_yourID w) . crInvSel) x w
    where is = IM.keys $ _crInv $ _creatures w IM.! _yourID w
          isis = is ++ is
          x = after (_crInvSel (you w)) isis

-- these are incomplete: should put in error case here!
before y (x:z:ys) | y == z    = x
                  | otherwise = before y (z:ys)
after y (x:z:ys)  | y == x    = z
                  | otherwise = after y (z:ys)