module Render (clearCanvas, CairoPosition(..), CairoSize(..), toDouble,
               renderWave, renderTurtle, renderPngFit, renderPngInline,
               renderText, yposSequence, renderSlide) where
import Data.Char
import Data.Bits
import System.FilePath ((</>),(<.>))
import Paths_carettah (getDataFileName)
import Control.Monad.Reader
import qualified Graphics.Rendering.Cairo as C
import Config(Config(..), gCfg, elapsedSecFromStart)

data CairoPosition = CairoPosition Double | CairoCenter
                   deriving Show
data CairoSize = CairoSize Double | CairoFit
                   deriving Show

-- copy from System.Glib.UTFString (gtk2hs/glib/System/Glib/UTFString.hs)
-- 本来はCStringを使うとこに埋め込んどくべき。gtk2hsを参考に
toUTF :: String -> String
toUTF [] = []
toUTF (x:xs) | ord x<=0x007F = x:toUTF xs
	     | ord x<=0x07FF = chr (0xC0 .|. ((ord x `shift` (-6)) .&. 0x1F)):
			       chr (0x80 .|. (ord x .&. 0x3F)):
			       toUTF xs
	     | otherwise     = chr (0xE0 .|. ((ord x `shift` (-12)) .&. 0x0F)):
			       chr (0x80 .|. ((ord x `shift` (-6)) .&. 0x3F)):
			       chr (0x80 .|. (ord x .&. 0x3F)):
			       toUTF xs

toDouble :: Integral a => a -> Double
toDouble = fromIntegral

mySetFontSize :: Double -> C.Render ()
mySetFontSize fsize = do
  C.selectFontFace (toUTF "Takao P明朝") C.FontSlantNormal C.FontWeightNormal
  C.setFontSize fsize

renderText :: CairoPosition -> CairoPosition -> Double -> String -> C.Render Double
renderText x y fsize text = do
  C.save
  mySetFontSize fsize
  (C.TextExtents _ yb w h _ _) <- C.textExtents (toUTF text)
  C.restore
  let truePosition (CairoPosition x') (CairoPosition y') = return (x', y')
      truePosition CairoCenter (CairoPosition y') =
          return (toDouble (canvasW gCfg) / 2 - w / 2, y')
      truePosition x' y' =
        error $ "called with x=" ++ show x' ++ " y=" ++ show y'
  (xt, yt) <- truePosition x y
  let nypos = yt + h - yb
  C.save
  mySetFontSize fsize
  C.moveTo xt nypos
  C.textPath $ toUTF text
  C.fill >> C.stroke >> C.restore
  return nypos

renderSurface :: Double -> Double -> Double -> C.Surface -> C.Render ()
renderSurface x y alpha surface = do
  C.save
  C.setSourceSurface surface x y
  C.paintWithAlpha alpha
  C.restore

pngSurfaceSize :: FilePath -> C.Render (C.Surface, Int, Int)
pngSurfaceSize file = do
  surface <- liftIO $ C.imageSurfaceCreateFromPNG file
  w <- C.imageSurfaceGetWidth surface
  h <- C.imageSurfaceGetHeight surface
  return (surface, w, h)

renderPngSize :: Double -> Double -> Double -> Double -> Double -> FilePath -> C.Render Double
renderPngSize x y w h alpha file = do
  C.save
  (surface, iw, ih) <- pngSurfaceSize file
  let xscale = w / toDouble iw
  let yscale = h / toDouble ih
  C.scale xscale yscale
  renderSurface (x / xscale) (y / yscale) alpha surface
  C.restore
  return $ y + h

renderPngInline :: CairoPosition -> CairoPosition -> CairoSize -> CairoSize -> Double -> FilePath -> C.Render Double
renderPngInline CairoCenter (CairoPosition y) CairoFit CairoFit alpha file = do
  C.save
  (surface, iw, ih) <- pngSurfaceSize file
  let diw = toDouble iw
      dih = toDouble ih
      cw = toDouble (canvasW gCfg)
      ch = toDouble (canvasH gCfg)
      iratio = diw / dih
      sratio = cw / ch
      scale = if iratio > sratio then dih / ch * 0.9 else diw / cw * 0.9
      tiw = diw * scale
      tih = tih * scale
  C.scale scale scale
  renderSurface ((cw / 2 - tiw / 2) / scale) (y / scale) alpha surface
  C.restore
  return $ y + tih
renderPngInline _ _ _ _ _ _ = return 0 -- xxx renerPngFit統合して一関数にすべき

renderPngFit :: Double -> FilePath -> C.Render ()
renderPngFit alpha file = do
  C.save
  (surface, iw, ih) <- pngSurfaceSize file
  let cw = toDouble $ canvasW gCfg
      ch = toDouble $ canvasH gCfg
  C.scale (cw / toDouble iw) (ch / toDouble ih)
  renderSurface 0 0 alpha surface
  C.restore

clearCanvas :: Int -> Int -> C.Render ()
clearCanvas w h = do
  C.save
  C.setSourceRGB 1 1 1
  C.rectangle 0 0 (toDouble w) (toDouble h)
  C.fill >> C.stroke >> C.restore

-- xxx プレゼン時間に応じて波表示
renderWave :: C.Render ()
renderWave = do
  sec <- liftIO elapsedSecFromStart
  let ws = waveSize gCfg
      ch = toDouble $ canvasH gCfg
      speechSec = 60 * speechMinutes gCfg
      charMax = waveCharMax gCfg
      numChar = round $ charMax * sec / speechSec
  _ <- renderText (CairoPosition 0) (CairoPosition $ ch - ws) ws $ replicate numChar '>'
  return ()

renderTurtle :: Double -> C.Render ()
renderTurtle progress = do
  fn <- liftIO . getDataFileName $ "data" </> "turtle" <.> "png"
  renderPngSize (ts / 2 + (cw - ts * 2) * progress) (ch - ts) ts ts 1 fn >> return ()
    where ts = turtleSize gCfg
          cw = toDouble $ canvasW gCfg
          ch = toDouble $ canvasH gCfg

yposSequence :: Double -> [Double -> C.Render Double] -> C.Render Double
yposSequence ypos (x:xs) = x ypos >>= (`yposSequence` xs)
yposSequence ypos [] = return ypos

renderSlideFilter :: Int -> Int -> [Double -> C.Render Double] -> C.Render ()
renderSlideFilter w h s = do
  clearCanvas w h
  let cw = toDouble $ canvasW gCfg
      ch = toDouble $ canvasH gCfg
      tcy = textContextY gCfg
  C.scale (toDouble w / cw) (toDouble h / ch)
  _ <- yposSequence tcy s
  renderWave

renderSlide :: [[Double -> C.Render Double]] -> Int -> Int -> Int -> C.Render ()
renderSlide s p w h = do
  renderSlideFilter w h (s !! p)
  renderTurtle $ toDouble p / toDouble (length s - 1)