{-# LANGUAGE TypeFamilies               #-}
{-# OPTIONS -Wall #-}

--------------------------------------------------------------------------------
-- |
-- Module      :  Wumpus.Drawing.Shapes.Diamond
-- Copyright   :  (c) Stephen Tetley 2010-2011
-- License     :  BSD3
--
-- Maintainer  :  Stephen Tetley <stephen.tetley@gmail.com>
-- Stability   :  highly unstable
-- Portability :  GHC
--
-- Diamond (rhombus).
-- 
--------------------------------------------------------------------------------

module Wumpus.Drawing.Shapes.Diamond
  ( 

    Diamond
  , DDiamond
  , diamond


  ) where

import Wumpus.Drawing.Paths
import Wumpus.Drawing.Shapes.Base

import Wumpus.Basic.Geometry.Base               -- package: wumpus-basic
import Wumpus.Basic.Geometry.Quadrant
import Wumpus.Basic.Kernel      

import Wumpus.Core                              -- package: wumpus-core


import Control.Applicative




--------------------------------------------------------------------------------
-- Diamond


data Diamond u = Diamond 
      { dia_ctm   :: ShapeCTM u
      , dia_hw    :: !u
      , dia_hh    :: !u
      }

type instance DUnit (Diamond u) = u

type DDiamond = Diamond Double


instance Functor Diamond where
  fmap f (Diamond ctm hw hh) = Diamond (fmap f ctm) (f hw) (f hh)

--------------------------------------------------------------------------------
-- Affine trans

mapCTM :: (ShapeCTM u -> ShapeCTM u) -> Diamond u -> Diamond u
mapCTM f = (\s i -> s { dia_ctm = f i }) <*> dia_ctm



instance (Real u, Floating u) => Rotate (Diamond u) where
  rotate ang            = mapCTM (rotate ang)
              
instance (Real u, Floating u) => RotateAbout (Diamond u) where
  rotateAbout ang pt    = mapCTM (rotateAbout ang pt)

instance Fractional u => Scale (Diamond u) where
  scale sx sy           = mapCTM (scale sx sy)

instance Num u => Translate (Diamond u) where
  translate dx dy       = mapCTM (translate dx dy)


--------------------------------------------------------------------------------
-- Anchors

-- | 'runDisplaceCenter' : @ ( half_width 
--                           * half_height -> Vec ) * diamond -> Point @
--
runDisplaceCenter :: (Real u, Floating u)
                  => (u -> u -> Vec2 u) -> Diamond u -> Anchor u
runDisplaceCenter fn (Diamond { dia_ctm = ctm
                              , dia_hw = hw
                              , dia_hh = hh }) = 
   projectFromCtr (fn hw hh) ctm


instance (Real u, Floating u) => CenterAnchor (Diamond u) where
  center = runDisplaceCenter $ \_ _ -> V2 0 0

instance (Real u, Floating u) => ApexAnchor (Diamond u) where
  apex = runDisplaceCenter $ \_  hh -> V2 0 hh

instance (Real u, Floating u) => 
    SideMidpointAnchor (Diamond u) where
  sideMidpoint n a = step (n `mod` 4) 
    where
      step 1 = midpoint (north a) (west a)
      step 2 = midpoint (west a)  (south a)
      step 3 = midpoint (south a) (east a)
      step _ = midpoint (east a)  (north a)


instance (Real u, Floating u) => CardinalAnchor (Diamond u) where
  north = apex
  south = runDisplaceCenter $ \_  hh -> V2 0 (-hh)
  east  = runDisplaceCenter $ \hw _  -> V2 hw 0
  west  = runDisplaceCenter $ \hw _  -> V2 (-hw) 0

instance (Real u, Floating u) => CardinalAnchor2 (Diamond u) where
  northeast x = midpoint (north x) (east x)
  southeast x = midpoint (south x) (east x)
  southwest x = midpoint (south x) (west x)
  northwest x = midpoint (north x) (west x)



instance (Real u, Floating u) => 
      RadialAnchor (Diamond u) where
  radialAnchor ang = runDisplaceCenter $ \hw hh -> 
                     diamondRadialVector hw hh ang




--------------------------------------------------------------------------------
-- Construction

-- | 'diamond'  : @ half_width * half_height -> shape @
--
-- Note - args might change to tull_width and full_height...
--
diamond :: (Real u, Floating u, InterpretUnit u, Tolerance u)
        => u -> u -> Shape Diamond u
diamond hw hh = makeShape (mkDiamond hw hh) (mkDiamondPath 0 hw hh)


mkDiamond :: InterpretUnit u => u -> u -> LocThetaQuery u (Diamond u)
mkDiamond hw hh = qpromoteLocTheta $ \ctr theta -> 
    pure $ Diamond { dia_ctm = makeShapeCTM ctr theta
                   , dia_hw  = hw
                   , dia_hh  = hh 
                   }


mkDiamondPath :: (Real u, Floating u, InterpretUnit u, Tolerance u)
              => u -> u -> u -> LocThetaQuery u (AbsPath u)
mkDiamondPath rnd hw hh = qpromoteLocTheta $ \ctr theta -> 
    qapplyLoc (placedTrailPoints $ diamondTrail hw hh) ctr >>= \ps ->
    roundCornerShapePath rnd $ map (rotateAbout theta ctr) ps