module Dodge.Item.HeldOffset where
import Dodge.Data
import Dodge.Creature.HandPos
import Geometry
import LensHelp

import Data.Maybe

heldItemOffset :: Item -> Creature -> Point3 -> Point3
heldItemOffset itm cr
    | isSelected && _posture (_crStance cr) == Aiming =
         (+.+.+ V3 (aimingWeaponZeroPos cr itm) 0 shoulderD)
    | isSelected && isTwoHandFlat
        = (+.+.+ V3 (_crRad cr) 0 handD)
        . rotate3 (twoFlatHRot cr)
        . transToHandle
    | isSelected && isOneHand
        = (+.+.+ V3 0 0 handD)
        . (+.+.+ V3 (_crRad cr * 0.7 + handPos) (_crRad cr * negate 0.7) 0)
        . (+.+.+ V3 (-2) 0 0)
        . transToHandle
    | isSelected 
        = (+.+.+ V3 0 0 handD)
        . (+.+.+ V3 (_crRad cr) 0 0)
        . rotate3 (strideRot cr + 1.2)
        . (+.+.+ V3 (-5) 0 0)
--        . (+.+.+ V3 (-5) 0 0)
        . transToHandle
    | otherwise = id
  where 
    transToHandle = fromMaybe id $ do
        x <- itm ^? itUse . useAim . aimHandlePos
        return (-.-.- V3 x 0 0)
    shoulderD = 18
    handD = 15
    isSelected = _itIsHeld itm
    handPos = case cr^? crStance . carriage of
        Just (Walking x LeftForward) -> f x * 50
        _ -> 0
    theIt = itm
    isOneHand       = theIt ^? itUseAimStance == Just OneHand
                        || isNothing (theIt ^? itUseAimStance)
    isTwoHandFlat   = theIt ^? itUseAimStance == Just TwoHandFlat
    itUseAimStance = itUse . useAim . aimStance   
    f i = 0.1 * fromIntegral (sLen - i) / fromIntegral sLen
    sLen = _strideLength $ _crStance cr

strideRot :: Creature -> Float
strideRot cr = case cr ^? crStance . carriage of
    Just (Walking x LeftForward)  -> f x
    Just (Walking x RightForward) -> - f x
    _ -> 0
  where
    f i = 0.1 * fromIntegral (sLen - i) / fromIntegral sLen
    sLen = _strideLength $ _crStance cr

twoFlatHRot :: Creature -> Float
twoFlatHRot cr = 2*strideRot cr