{-# LANGUAGE ConstraintKinds           #-}
{-# LANGUAGE CPP                       #-}
{-# LANGUAGE DeriveDataTypeable        #-}
{-# LANGUAGE DeriveGeneric             #-}
{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE FlexibleContexts          #-}
{-# LANGUAGE FlexibleInstances         #-}
{-# LANGUAGE GADTs                     #-}
{-# LANGUAGE MultiParamTypeClasses     #-}
{-# LANGUAGE ScopedTypeVariables       #-}
{-# LANGUAGE TemplateHaskell           #-}
{-# LANGUAGE TupleSections             #-}
{-# LANGUAGE TypeFamilies              #-}
{-# LANGUAGE TypeSynonymInstances      #-}
{-# LANGUAGE ViewPatterns              #-}

-------------------------------------------------------------------------------
-- |
-- Module      :  Diagrams.Backend.Rasterific
-- Copyright   :  (c) 2014-2015 diagrams-rasterific team (see LICENSE)
-- License     :  BSD-style (see LICENSE)
-- Maintainer  :  diagrams-discuss@googlegroups.com
--
-- A full-featured rendering backend for diagrams using Rasterific,
-- implemented natively in Haskell (making it easy to use on any
-- platform). Can create png, tif, bmp, jpg, pdf, and animated GIFs.
--
-- To invoke the Rasterific backend, you have three options.
--
-- * You can use the "Diagrams.Backend.Rasterific.CmdLine" module to create
--   standalone executables which output images when invoked.
--
-- * You can use the 'renderRasterific' function provided by this module,
--   which gives you more flexible programmatic control over when and
--   how images are output (making it easy to, for example, write a
--   single program that outputs multiple images, or one that outputs
--   images dynamically based on user input, and so on).
--
-- * For the most flexibility (/e.g./ if you want access to the
--   resulting Rasterific value directly in memory without writing it to
--   disk), you can manually invoke the 'renderDia' method from the
--   'Diagrams.Core.Types.Backend' instance for @Rasterific@.  In particular,
--   'Diagrams.Core.Types.renderDia' has the generic type
--
-- > renderDia :: b -> Options b v n -> QDiagram b v n m -> Result b v n
--
-- (omitting a few type class constraints).  @b@ represents the
-- backend type, @v@ the vector space, @n@ the numeric field, and @m@ the type
-- of monoidal query annotations on the diagram.  'Options' and 'Result' are
-- associated data and type families, respectively, which yield the
-- type of option records and rendering results specific to any
-- particular backend.  For @b ~ Rasterific@, @v ~ V2@, and @n ~ n@, we have
--
-- > data Options Rasterific V2 n = RasterificOptions
-- >        { _size      :: SizeSpec2D n -- ^ The requested size of the output
-- >        }
--
-- @
-- type family Result Rasterific V2 n = 'Image PixelRGBA8'
-- @
--
-- So the type of 'renderDia' resolves to
--
-- @
-- renderDia :: Rasterific -> Options Rasterific V2 n -> QDiagram Rasterific V2 n m -> 'Image PixelRGBA8'
-- @
--
-- which you could call like @renderDia Rasterific (RasterificOptions (mkWidth 250))
-- myDiagram@.
--
-------------------------------------------------------------------------------
module Diagrams.Backend.Rasterific
  ( -- * Rasterific backend
    Rasterific(..)
  , B -- rendering token
  , Options(..)

    -- * Rendering
  , renderRasterific
  , renderPdf
  , renderPdfBS
  , renderPdfBSWithDPI
  , size

  , writeJpeg
  , GifDelay
  , GifLooping (..)
  , animatedGif

    -- * Text with envelopes
  , texterific
  , texterific'

    -- * Internals
    -- | These are low level functions whose implimentaion may change in
    --   the future. They're exported because they can sometimes be
    --   useful.
  , PaletteOptions (..)
  , defaultPaletteOptions
  , rasterGif
  , rasterRgb8

  ) where

import           Diagrams.Core.Compile
import           Diagrams.Core.Transform             (matrixHomRep)
import           Diagrams.Core.Types

import           Diagrams.Prelude                    hiding (height, local,
                                                      opacity, output, width)
import           Diagrams.TwoD.Adjust                (adjustDia2D)
import           Diagrams.TwoD.Text                  hiding (Font)

import           Codec.Picture
import           Codec.Picture.ColorQuant            (defaultPaletteOptions)
import           Codec.Picture.Types                 (convertImage,
                                                      convertPixel,
                                                      dropTransparency,
                                                      promoteImage)


import qualified Graphics.Rasterific                 as R
import           Graphics.Rasterific.Texture         (Gradient,
                                                      linearGradientTexture, radialGradientWithFocusTexture,
                                                      transformTexture,
                                                      uniformTexture,
                                                      withSampler)

import qualified Graphics.Rasterific.Transformations as R
import           Graphics.Text.TrueType              (Dpi)

import           Control.Monad.Reader
import           Diagrams.Backend.Rasterific.Text

import           Data.ByteString.Lazy                (ByteString)
import qualified Data.ByteString.Lazy                as L (writeFile)
import qualified Data.Foldable                       as F
import           Data.Hashable                       (Hashable (..))
import           Data.Maybe                          (fromMaybe)
import           Data.Tree
import           Data.Typeable
import           Data.Word                           (Word8)

import           System.FilePath                     (takeExtension)

--------------------------------------------------------------------------------
-- | This data declaration is simply used as a token to distinguish
--   the Rasterific backend: (1) when calling functions where the type
--   inference engine would otherwise have no way to know which
--   backend you wanted to use, and (2) as an argument to the
--   'Backend' and 'Renderable' type classes.
data Rasterific = Rasterific
  deriving (Eq,Ord,Read,Show,Typeable)

type B = Rasterific

type instance V Rasterific = V2
type instance N Rasterific = Double

-- | The custom monad in which intermediate drawing options take
--   place; 'Graphics.Rasterific.Drawing' is Rasterific's own rendering
--   monad.
type RenderM n = ReaderT (Style V2 n) RenderR

type RenderR = R.Drawing PixelRGBA8

liftR :: RenderR a -> RenderM n a
liftR = lift

runRenderM :: TypeableFloat n => RenderM n a -> RenderR a
runRenderM = flip runReaderT (mempty # recommendFillColor transparent)

-- From Diagrams.Core.Types.
instance TypeableFloat n => Backend Rasterific V2 n where
  newtype Render  Rasterific V2 n = R (RenderM n ())
  type Result  Rasterific V2 n = Image PixelRGBA8
  data Options Rasterific V2 n = RasterificOptions
          { _sizeSpec  :: SizeSpec V2 n -- ^ The requested size of the output
          }
    deriving (Show, Eq)

  renderRTree _ opts t =
    R.renderDrawing (round w) (round h) bgColor r
    where
      r       = runRenderM . runR . fromRTree $ t
      V2 w h  = specToSize 100 (opts^.sizeSpec)
      bgColor = PixelRGBA8 0 0 0 0

  adjustDia c opts d = adjustDia2D sizeSpec c opts (d # reflectY)

fromRTree :: TypeableFloat n => RTree Rasterific V2 n Annotation -> Render Rasterific V2 n
fromRTree (Node n rs) = case n of
  RPrim p                 -> render Rasterific p
  RStyle sty              -> R $ clip sty (local (<> sty) r)
  RAnnot (OpacityGroup x) -> R $ mapReaderT (R.withGroupOpacity (round $ 255 * x)) r
  _                       -> R r
  where R r = F.foldMap fromRTree rs

-- | Clip a render using the Clip from the style.
clip :: TypeableFloat n => Style V2 n -> RenderM n () -> RenderM n ()
clip sty r = go (sty ^. _clip)
  where
    go []     = r
    go (p:ps) = mapReaderT (R.withClipping $ R.fill (renderPath p)) (go ps)

runR :: Render Rasterific V2 n -> RenderM n ()
runR (R r) = r

instance Semigroup (Render Rasterific V2 n) where
  R rd1 <> R rd2 = R (rd1 >> rd2)

instance Monoid (Render Rasterific V2 n) where
  mempty = R $ return ()
#if !MIN_VERSION_base(4,11,0)
  mappend = (<>)
#endif

instance Hashable n => Hashable (Options Rasterific V2 n) where
  hashWithSalt s (RasterificOptions sz) = s `hashWithSalt` sz

sizeSpec :: Lens' (Options Rasterific V2 n) (SizeSpec V2 n)
sizeSpec = lens _sizeSpec (\o s -> o {_sizeSpec = s})

rasterificStrokeStyle :: TypeableFloat n => Style v n
                     -> (n, R.Join, (R.Cap, R.Cap), Maybe (R.DashPattern, n))
rasterificStrokeStyle s = (strokeWidth, strokeJoin, (strokeCap, strokeCap), strokeDash)
  where
    strokeWidth = views _lineWidthU (fromMaybe 1) s
    strokeJoin  = views _lineJoin   fromLineJoin s
    strokeCap   = views _lineCap    fromLineCap s
    strokeDash  = views _dashingU   (fmap fromDashing) s

fromLineCap :: LineCap -> R.Cap
fromLineCap LineCapButt   = R.CapStraight 0
fromLineCap LineCapRound  = R.CapRound
fromLineCap LineCapSquare = R.CapStraight 1

fromLineJoin :: LineJoin -> R.Join
fromLineJoin LineJoinMiter = R.JoinMiter 0
fromLineJoin LineJoinRound = R.JoinRound
fromLineJoin LineJoinBevel = R.JoinMiter 1

fromDashing :: Real n => Dashing n -> (R.DashPattern, n)
fromDashing (Dashing ds d) = (map realToFrac ds, d)

fromFillRule :: FillRule -> R.FillMethod
fromFillRule EvenOdd = R.FillEvenOdd
fromFillRule _       = R.FillWinding

rasterificColor :: SomeColor -> Double -> PixelRGBA8
rasterificColor c o = PixelRGBA8 r g b a
  where
    (r, g, b, a) = (int r', int g', int b', int (o * a'))
    (r', g', b', a') = colorToSRGBA (toAlphaColour c)
    int x = round (255 * x)

rasterificSpreadMethod :: SpreadMethod -> R.SamplerRepeat
rasterificSpreadMethod GradPad     = R.SamplerPad
rasterificSpreadMethod GradReflect = R.SamplerReflect
rasterificSpreadMethod GradRepeat  = R.SamplerRepeat

rasterificStops :: TypeableFloat n => [GradientStop n] -> Gradient PixelRGBA8
rasterificStops = map fromStop
  where
    fromStop (GradientStop c v) = (realToFrac v, rasterificColor c 1)

rasterificLinearGradient :: TypeableFloat n => LGradient n -> R.Texture PixelRGBA8
rasterificLinearGradient g = transformTexture tr tx
  where
    tr = rasterificMatTransf (inv $ g^.lGradTrans)
    tx = withSampler spreadMethod (linearGradientTexture gradDef p0 p1)
    spreadMethod = rasterificSpreadMethod (g^.lGradSpreadMethod)
    gradDef = rasterificStops (g^.lGradStops)
    p0 = p2v2 (g^.lGradStart)
    p1 = p2v2 (g^.lGradEnd)

rasterificRadialGradient :: TypeableFloat n => RGradient n -> R.Texture PixelRGBA8
rasterificRadialGradient g = transformTexture tr tx
  where
    tr = rasterificMatTransf (inv $ g^.rGradTrans)
    tx = withSampler spreadMethod (radialGradientWithFocusTexture gradDef c (realToFrac r1) f)
    spreadMethod = rasterificSpreadMethod (g^.rGradSpreadMethod)
    c = p2v2 (g^.rGradCenter1)
    f = p2v2 (g^.rGradCenter0)
    gradDef = rasterificStops ss

    -- Adjust the stops so that the gradient begins at the perimeter of
    -- the inner circle (center0, radius0) and ends at the outer circle.
    r0 = g^.rGradRadius0
    r1 = g^.rGradRadius1
    stopFracs = r0 / r1 : map (\s -> (r0 + (s^.stopFraction) * (r1 - r0)) / r1)
                (g^.rGradStops)
    gradStops = case g^.rGradStops of
      []       -> []
      xs@(x:_) -> x : xs
    ss = zipWith (\gs sf -> gs & stopFraction .~ sf ) gradStops stopFracs

-- Convert a diagrams @Texture@ and opacity to a rasterific texture.
rasterificTexture :: TypeableFloat n => Texture n -> Double -> R.Texture PixelRGBA8
rasterificTexture (SC c) o = uniformTexture $ rasterificColor c o
rasterificTexture (LG g) _ = rasterificLinearGradient g
rasterificTexture (RG g) _ = rasterificRadialGradient g

p2v2 :: Real n => P2 n -> R.Point
p2v2 (P v) = r2v2 v
{-# INLINE p2v2 #-}

r2v2 :: Real n => V2 n -> R.Point
r2v2 (V2 x y) = R.V2 (realToFrac x) (realToFrac y)
{-# INLINE r2v2 #-}

rv2 :: (Real n, Fractional n) => Iso' R.Point (P2 n)
rv2 = iso (\(R.V2 x y) -> V2 (realToFrac x) (realToFrac y)) r2v2 . from _Point
{-# INLINE rv2 #-}

rasterificPtTransf :: TypeableFloat n => T2 n -> R.Point -> R.Point
rasterificPtTransf t = over rv2 (papply t)

rasterificMatTransf :: TypeableFloat n => T2 n -> R.Transformation
rasterificMatTransf tr = R.Transformation a c e b d f
  where
    [[a, b], [c, d], [e, f]] = map realToFrac <$> matrixHomRep tr

-- Note: Using view patterns confuses ghc to think there are missing patterns,
-- so we avoid them here.
renderSeg :: TypeableFloat n => Located (Segment Closed V2 n) -> R.Primitive
renderSeg l =
  case viewLoc l of
    (p, Linear (OffsetClosed v)) ->
      R.LinePrim $ R.Line p' (p' + r2v2 v)
      where
        p' = p2v2 p
    (p, Cubic u1 u2 (OffsetClosed u3)) ->
      R.CubicBezierPrim $ R.CubicBezier q0 q1 q2 q3
      where
        (q0, q1, q2, q3) = (p2v2 p, q0 + r2v2 u1, q0 + r2v2 u2, q0 + r2v2 u3)

renderPath :: TypeableFloat n => Path V2 n -> [[R.Primitive]]
renderPath p = (map . map) renderSeg (pathLocSegments p)

-- Stroke both dashed and solid lines.
mkStroke :: TypeableFloat n => n ->  R.Join -> (R.Cap, R.Cap) -> Maybe (R.DashPattern, n)
      -> [[R.Primitive]] -> RenderR ()
mkStroke (realToFrac -> l) j c d primList =
  maybe (R.stroke l j c $ concat primList)
        (\(dsh, off) -> R.dashedStrokeWithOffset (realToFrac off) dsh l j c $ concat primList)
        d

instance TypeableFloat n => Renderable (Path V2 n) Rasterific where
  render _ p = R $ do
    sty <- ask
    let f = sty ^. _fillTexture
        s = sty ^. _lineTexture
        o = sty ^. _opacity
        r = sty ^. _fillRule

        (l, j, c, d) = rasterificStrokeStyle sty
        canFill      = anyOf (_head . located) isLoop p && (f ^? _AC) /= Just transparent
        rule         = fromFillRule r

        -- For stroking we need to keep all of the contours separate.
        primList = renderPath p

        -- For filling we need to concatenate them into a flat list.
        prms = concat primList

    when canFill $
      liftR (R.withTexture (rasterificTexture f o) $ R.fillWithMethod rule prms)

    liftR (R.withTexture (rasterificTexture s o) $ mkStroke l j c d primList)

instance TypeableFloat n => Renderable (Text n) Rasterific where
  render _ (Text tr al str) = R $ do
    fs    <- views _fontSizeU (fromMaybe 12)
    slant <- view _fontSlant
    fw    <- view _fontWeight
    f     <- view _fillTexture
    o     <- view _opacity
    let fColor = rasterificTexture f o
        fs'    = R.PointSize (realToFrac fs)
        fnt    = fromFontStyle slant fw
        bb     = textBoundingBox fnt fs' str
        p      = case al of
          BaselineText         -> R.V2 0 0
          BoxAlignedText xt yt -> case getCorners bb of
            Just (P (V2 xl yl), P (V2 xu yu)) -> R.V2 (-lerp' xt xu xl) (lerp' yt yu yl)
            Nothing                           -> R.V2 0 0
    liftR (R.withTransformation (rasterificMatTransf (tr <> reflectionY))
          (R.withTexture fColor $ R.printTextAt fnt fs' p str))
    where
      lerp' t u v = realToFrac $ t * u + (1 - t) * v

toImageRGBA8 :: DynamicImage -> Image PixelRGBA8
toImageRGBA8 (ImageRGBA8 i)  = i
toImageRGBA8 (ImageRGB8 i)   = promoteImage i
toImageRGBA8 (ImageYCbCr8 i) = promoteImage (convertImage i :: Image PixelRGB8)
toImageRGBA8 (ImageY8 i)     = promoteImage i
toImageRGBA8 (ImageYA8 i)    = promoteImage i
toImageRGBA8 (ImageCMYK8 i)  = promoteImage (convertImage i :: Image PixelRGB8)
toImageRGBA8 _               = error "Unsupported Pixel type"

instance TypeableFloat n => Renderable (DImage n Embedded) Rasterific where
  render _ (DImage iD w h tr) = R $ liftR
                               (R.withTransformation
                               (rasterificMatTransf (tr <> reflectionY))
                               (R.drawImage img 0 p))
    where
      ImageRaster dImg = iD
      img = toImageRGBA8 dImg
      trl = moveOriginBy (r2 (fromIntegral w / 2, fromIntegral h / 2 :: n)) mempty
      p   = rasterificPtTransf trl (R.V2 0 0)

-- Saving files --------------------------------------------------------

-- | Render a 'Rasterific' diagram to a jpeg file with given quality
--   (between 0 and 100).
writeJpeg :: Word8 -> FilePath -> Result Rasterific V2 n -> IO ()
writeJpeg quality outFile img = L.writeFile outFile bs
  where
    bs = encodeJpegAtQuality quality (pixelMap (convertPixel . dropTransparency) img)


-- | Render a 'Rasterific' diagram to a pdf bytestring with given width,
-- height, & DPI.
renderPdfBSWithDPI
    :: TypeableFloat n
    => Int
    -> Int
    -> Dpi
    -> SizeSpec V2 n
    -> QDiagram Rasterific V2 n Any
    -> ByteString
renderPdfBSWithDPI w h dpi spec d = bs
  where
    bs    = R.renderDrawingAtDpiToPDF w h dpi (runRenderM . runR $ fromRTree rtree)
    rtree = rTree spec d

-- | Render a 'Rasterific' diagram to a pdf bytestring with given width and height
renderPdfBS :: TypeableFloat n => Int -> Int -> SizeSpec V2 n
                             -> QDiagram Rasterific V2 n Any -> ByteString
renderPdfBS w h =
    renderPdfBSWithDPI w h 96

-- | Render a 'Rasterific' diagram to a pdf file with given width and height
renderPdf :: TypeableFloat n => Int -> Int -> FilePath -> SizeSpec V2 n
                             -> QDiagram Rasterific V2 n Any -> IO ()
renderPdf w h outFile spec d = L.writeFile outFile bs
  where
    bs = renderPdfBS w h spec d

rTree :: TypeableFloat n => SizeSpec V2 n -> QDiagram Rasterific V2 n Any
                         -> RTree Rasterific V2 n Annotation
rTree spec d = toRTree g2o d'
  where
  (_, g2o, d') = adjustDia Rasterific (RasterificOptions spec) d

-- | Render a 'Rasterific' diagram to a file with the given size. The
--   format is determined by the extension (@.png@, @.tif@, @.bmp@, @.jpg@ and
--   @.pdf@ supported. (jpeg quality is 80, use 'writeJpeg' to choose
--   quality).
renderRasterific :: TypeableFloat n => FilePath -> SizeSpec V2 n
                 -> QDiagram Rasterific V2 n Any -> IO ()
renderRasterific outFile spec d =
  case takeExtension outFile of
    ".png" -> writePng outFile img
    ".tif" -> writeTiff outFile img
    ".bmp" -> writeBitmap outFile img
    ".jpg" -> writeJpeg 80 outFile img
    -- pdfs need to be handle separately since rasterific makes them
    -- directely from drawings. i.e. they don't need to be converted to images.
    ".pdf" -> renderPdf (round w) (round h) outFile spec d
    _      -> writePng outFile img
  where
    img = renderDia Rasterific (RasterificOptions spec) d
    (w, h) = specToDims (aspectRatio d) spec

aspectRatio :: (V a ~ V2, Enveloped a) => a -> N a
aspectRatio d = h / w
  where
    V2 w h = boxExtents (boundingBox d)

specToDims :: (Fractional a, Ord a) => a -> SizeSpec V2 a -> (a, a)
specToDims ar s =
  case getSpec s of
    V2 (Just w) (Just h) -> (w, h)
    V2 (Just w) Nothing  -> (w, ar * w)
    V2 Nothing (Just h)  -> (h / ar, h)
    V2 Nothing Nothing   -> (100, 100)


-- | Render a 'Rasterific' diagram to an animated gif with the given
--   size and uniform delay. Diagrams should be the same size.
animatedGif
  :: TypeableFloat n
  => FilePath
  -> SizeSpec V2 n
  -> GifLooping
  -> GifDelay -- ^ Delay in 100th of seconds ('Int')
  -> [QDiagram Rasterific V2 n Any] -> IO ()
animatedGif outFile sz gOpts i ds =
  case rasterGif sz gOpts defaultPaletteOptions (map (,i) ds) of
    Right bs -> L.writeFile outFile bs
    Left e   -> putStrLn e

-- Gifs ----------------------------------------------------------------

-- | Turn a list of diagrams into a gif.
rasterGif
  :: TypeableFloat n
  => SizeSpec V2 n            -- ^ Size of output (in pixels)
  -> GifLooping               -- ^ looping options
  -> PaletteOptions           -- ^ palette options
  -> [(QDiagram Rasterific V2 n Any, Int)]  -- ^ Diagram zipped with its delay (100th of seconds)
  -> Either String ByteString
rasterGif sz gOpts pOpts ds = encodeGifImages gOpts (map pal imgs)
  where
    imgs = over (each . _1) (rasterRgb8 sz) ds
    pal (palettize pOpts -> (img,p), d) = (p, d, img)

-- | Render a 'Rasterific' diagram without an alpha channel.
rasterRgb8 :: TypeableFloat n
           => SizeSpec V2 n
           -> QDiagram Rasterific V2 n Any
           -> Image PixelRGB8
rasterRgb8 sz
  = pixelMap dropTransparency
  . renderDia Rasterific (RasterificOptions sz)