{-|
Module      : Input
Description : Handles input events such as keystrokes
Copyright   : (c) Christopher Howard, 2016
License     : GPL-3
Maintainer  : ch.howard@zoho.com
-}

module Input where

import Prelude (Bool(..), Maybe(..), return, IO, map)
import Graphics.Gloss.Interface.IO.Game ( Event(EventKey), SpecialKey(KeyEnter, KeyLeft, KeyRight, KeySpace, KeyTab, KeyUp), Modifiers(Modifiers, alt, ctrl, shift), KeyState(Down, Up), Key(Char, SpecialKey) )

import Universe
import Lance

handleInput :: Event -> Universe -> IO Universe

handleInput (EventKey (Char '<') Down Modifiers { shift = Down
                                                , ctrl = Down
                                                , alt = Down
                                                } _) u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { inventory =
                                 map (\_ -> True) (inventory l) 
                             , swClock = 0.0
                             }
                           }
                         }

handleInput (EventKey (Char ':') Down Modifiers { shift = Down
                                                , ctrl = Down
                                                , alt = Down
                                                } _) u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { godMode = True } } }

handleInput (EventKey (Char '"') Down Modifiers { shift = Down
                                                , ctrl = Down
                                                , alt = Down
                                                } _) u
  = return u { skipLevel = True }

--- two-hand keys ---

handleInput (EventKey (SpecialKey KeyLeft) Down _ _) u
  = ccwThrusters u

handleInput (EventKey (SpecialKey KeyLeft) Up _ _) u
  = stabilizeThrusters u

handleInput (EventKey (SpecialKey KeyRight) Down _ _) u
  = cwThrusters u

handleInput (EventKey (SpecialKey KeyRight) Up _ _) u
  = stabilizeThrusters u

handleInput (EventKey (SpecialKey KeyUp) Down _ _) u
  = activateForwardThrusters u

handleInput (EventKey (SpecialKey KeyUp) Up _ _) u
  = deactivateForwardThrusters u

handleInput (EventKey (SpecialKey KeySpace) Down _ _) u
  = activateDeflector u

handleInput (EventKey (SpecialKey KeySpace) Up _ _) u
  = deactivateDeflector u

handleInput (EventKey (Char 'a') Down _ _) u
  = setFireTrigger u
 
handleInput (EventKey (Char 'a') Up _ _) u
  = releaseFireTrigger u

handleInput (EventKey (SpecialKey KeyTab) Down _ _) u
  = switchWeapon u

--------------------- keypad keys

handleInput (EventKey (Char '4') Down _ _) u
  = ccwThrusters u

handleInput (EventKey (Char '4') Up _ _) u
  = stabilizeThrusters u

handleInput (EventKey (Char '6') Down _ _) u
  = cwThrusters u

handleInput (EventKey (Char '6') Up _ _) u
  = stabilizeThrusters u

handleInput (EventKey (Char '8') Down _ _) u
  = activateForwardThrusters u

handleInput (EventKey (Char '8') Up _ _) u
  = deactivateForwardThrusters u

handleInput (EventKey (Char '0') Down _ _) u
  = setFireTrigger u

handleInput (EventKey (Char '0') Up _ _) u
  = releaseFireTrigger u

handleInput (EventKey (SpecialKey KeyEnter) Down _ _) u
  = activateDeflector u

handleInput (EventKey (SpecialKey KeyEnter) Up _ _) u
  = deactivateDeflector u

handleInput (EventKey (Char '5') Down _ _) u
  = switchWeapon u

handleInput _ u = return u

setFireTrigger u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { fireTrigger = True } } }

releaseFireTrigger u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { fireTrigger = False } } }

activateDeflector u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { deflector = True } } }

deactivateDeflector u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { deflector = False } } }

ccwThrusters u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { rotationalThrusters = CCW } } }

stabilizeThrusters u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { rotationalThrusters = Stable } } }

cwThrusters u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { rotationalThrusters = CW } } }

activateForwardThrusters u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { linearThrusters = True } } }

deactivateForwardThrusters u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just l
                             { linearThrusters = False } } }

switchWeapon u
  = let a = arena u in
    let mL = lance a in
    case mL of
      Nothing -> return u
      Just l -> return u { arena = a
                           { lance = Just (changeCurrentWeapon l) }
                         }