{-# OPTIONS_HADDOCK ignore-exports #-}

module Diagram (t,
                dX,
                dY,
                alg,
                gd,
                defaultProp,
                diag,
                diagS,
                gifDiag,
                gifDiagS,
                whiteRect) where

import Algorithms.ConvexHull
import Codec.Picture.Gif
import Class.Defaults
import Diagrams.Backend.Cairo
import Diagrams.Prelude
import LinearAlgebra.Vector
import Parser.Meshparser


type MeshString = String


-- |Represents a Cairo Diagram. This allows us to create multiple
-- diagrams with different algorithms but based on the same
-- coordinates and common properties.
data Diag = Diag {
  mkDiag :: DiagProp
         -> [PT]
         -> Diagram Cairo R2
}


-- |Holds the properties for a Diagram, like thickness of 2d points etc.
-- This can also be seen as a context when merging multiple diagrams.
data DiagProp = MkProp {
  -- |The thickness of the dots.
  t :: Double,
  -- |The dimensions of the x-axis.
  dX :: Coord,
  -- |The dimensions of the y-axis.
  dY :: Coord,
  -- |Algorithm to use.
  alg :: Int,
  -- |If we want to show the grid.
  gd :: Bool,
  -- |Square size used to show the grid and x/y-axis.
  sqS :: Double
}


instance Def DiagProp where
  def = defaultProp


instance Monoid Diag where
  mempty = Diag (\_ _ -> mempty)
  mappend d1 d2 = Diag g
    where
      g p vt = mkDiag d1 p vt <> mkDiag d2 p vt
  mconcat = foldr mappend mempty


-- |The default properties of the Diagram.
defaultProp :: DiagProp
defaultProp = MkProp 2 (0,500) (0,500) 0 False 50


-- |Extract the lower bound of the x-axis dimension.
xlD :: DiagProp -> Double
xlD = fst . dX


-- |Extract the upper bound of the x-axis dimension.
xuD :: DiagProp -> Double
xuD = snd . dX


-- |Extract the lower bound of the y-axis dimension.
ylD :: DiagProp -> Double
ylD = fst . dY


-- |Extract the upper bound of the y-axis dimension.
yuD :: DiagProp -> Double
yuD = snd . dY


-- |Creates a Diagram that shows the coordinates from the points
-- as dots. The points and thickness of the dots can be controlled
-- via DiagProp.
coordPoints :: Diag
coordPoints = Diag f
  where
    f p vt =
      position (zip (filter (inRange (dX p) (dY p)) $ vt)
        (repeat dot))
      where
        dot = (circle $ t p :: Diagram Cairo R2) # fc black


-- |Create a diagram which shows the points of the convex hull.
convexHullPoints :: Diag
convexHullPoints = Diag f
  where
    f p vt =
      position (zip (filter (inRange (dX p) (dY p)) $ vtch)
        (repeat dot))
      where
        dot = (circle $ t p :: Diagram Cairo R2) # fc red # lc red
        vtch = grahamGetCH vt


-- |Create a diagram which shows the lines along the convex hull
-- points.
convexHullLines :: Diag
convexHullLines = Diag f
  where
    f _ [] = mempty
    f p vt =
      (strokeTrail                           .
          fromVertices                       .
          flip (++) [head $ grahamGetCH vtf] .
          grahamGetCH                        $
          vtf)                          #
        moveTo (head $ grahamGetCH vtf) #
        lc red
      where
        vtf = filter (inRange (dX p) (dY p)) vt


-- |Same as showConvexHullLines, except that it returns an array
-- of diagrams with each step of the algorithm.
-- Unfortunately this is very difficult to implement as a Diag (TODO).
convexHullLinesInterval :: DiagProp -> [PT] -> [Diagram Cairo R2]
convexHullLinesInterval p xs =
  fmap g (grahamGetCHSteps xs)
  where
    g vt =
      (strokeTrail         .
          fromVertices     $
          vtf)            #
        moveTo (head vtf) #
        lc red
      where
        vtf = filter (inRange (dX p) (dY p)) vt


-- |Creates a Diagram that shows an XAxis which is bound
-- by the dimensions given in xD from DiagProp.
xAxis :: Diag
xAxis =
  (Diag hRule)      `mappend`
    (Diag segments) `mappend`
    (Diag labels)
  where
    hRule p _ =
      arrowAt (p2 (xlD p,0)) (r2 (xuD p, 0)) # moveTo (p2 (xlD p,0))
    segments p _ =
      hcat' (with & sep .~ (sqS p))
            (take (floor . (/) (xuD p - xlD p) $ (sqS p)) .
              repeat $ (vrule 10)) #
      moveTo (p2 (xlD p,0))
    labels p _ =
      position $
        zip (mkPoint <$> xs)
            ((\x -> (flip (<>) (square 1 # lw none) .
              text . show $ x) # scale 10) <$> xs)
      where
        xs :: [Int]
        xs = take (floor . (/) (xuD p - xlD p) $ (sqS p))
                  (iterate (+(floor . sqS $ p)) 0)
        mkPoint x = p2 (fromIntegral x, -15)


-- |Creates a Diagram that shows an YAxis which is bound
-- by the dimensions given in yD from DiagProp.
yAxis :: Diag
yAxis =
  (Diag vRule)      `mappend`
    (Diag segments) `mappend`
    (Diag labels)
  where
    vRule p _ =
      arrowAt (p2 (0, ylD p)) (r2 (0, yuD p)) # moveTo (p2 (0, ylD p))
    segments p _ =
      vcat' (with & sep .~ (sqS p))
            (take (floor . (/) (yuD p - ylD p) $ (sqS p)) .
              repeat $ (hrule 10)) #
      alignB                       #
      moveTo (p2 (0, (ylD p)))
    labels p _ =
      position $
        zip (mkPoint <$> ys)
            ((\x -> (flip (<>) (square 1 # lw none) .
              text . show $ x) # scale 10) <$> ys)
        where
          ys :: [Int]
          ys = take (floor . (/) (yuD p - ylD p) $ (sqS p))
                    (iterate (+(floor . sqS $ p)) 0)
          mkPoint y = p2 (-15, fromIntegral y)


-- |Creates a Diagram that shows a white rectangle which is a little
-- bit bigger as both X and Y axis dimensions from DiagProp.
whiteRectB :: Diag
whiteRectB = Diag f
  where
    f p _ = whiteRect (w' + 50) (h' + 50) # moveTo (p2 (w' / 2, h' / 2))
      where
        w' = xuD p - xlD p
        h' = yuD p - ylD p


-- |Create the Diagram from the points.
diag :: DiagProp -> [PT] -> Diagram Cairo R2
diag p = case alg p of
  0 ->
    mkDiag
      (mconcat [coordPoints, xAxis, yAxis,
        (if gd p then grid else mempty), whiteRectB])
      p
  1 ->
    mkDiag
      (mconcat
        [convexHullPoints, convexHullLines, coordPoints,
        xAxis, yAxis, (if gd p then grid else mempty), whiteRectB])
      p
  _ -> mempty


-- |Create the Diagram from a String which is supposed to be the contents
-- of an obj file.
diagS :: DiagProp -> MeshString -> Diagram Cairo R2
diagS p mesh =
  (diag p       .
      meshToArr $
      mesh) #
    bg white


-- |Return a list of tuples used by 'gifMain' to generate an animated gif.
gifDiag :: DiagProp -> [PT] -> [(Diagram Cairo R2, GifDelay)]
gifDiag p xs =
  fmap (\x -> (x, 100))                      .
    fmap (\x -> x <> g)                      .
    flip (++)
      [mkDiag (convexHullLines `mappend`
      convexHullPoints) p xs]                $
    (convexHullLinesInterval p xs)
  where
    g =
      mconcat                      .
        fmap (\x -> mkDiag x p xs) $
        [coordPoints,
        xAxis,
        yAxis,
        whiteRectB]


-- |Same as gifDiag, except that it takes a string containing the
-- mesh file content instead of the the points.
gifDiagS :: DiagProp -> MeshString -> [(Diagram Cairo R2, GifDelay)]
gifDiagS p = gifDiag p . meshToArr


-- |Create a white rectangle with the given width and height.
whiteRect :: Double -> Double -> Diagram Cairo R2
whiteRect x y = rect x y # lwG 0.00 # bg white


-- |Create a grid across the whole diagram with 50*50 squares.
grid :: Diag
grid = Diag f `mappend` Diag g
  where
    f p _ =
      hcat' (with & sep .~ (sqS p))
            (take (floor . (/) (xuD p - xlD p) $ (sqS p)) .
              repeat $ (vrule $ xuD p - xlD p))   #
      moveTo (p2 (xlD p, (yuD p - ylD p) / 2))    #
      lw ultraThin
    g p _ =
      vcat' (with & sep .~ (sqS p))
            (take (floor . (/) (yuD p - ylD p) $ (sqS p)) .
              repeat $ (hrule $ yuD p - ylD p))  #
      alignB                                     #
      moveTo (p2 ((xuD p - xlD p) / 2, ylD p))   #
      lw ultraThin