module Render (
    createLightMap,
    renderFoldable,
    renderLayer,
    pingPongBetween,
    bindTO,
    bindFBO,
) where

import Control.Monad
import Dodge.WindowSize
import Control.Lens
import Control.Monad.Primitive
import Data.Preload.Render
import qualified Data.Vector as V
--import Control.Monad
import qualified Data.Vector.Fusion.Stream.Monadic as VFSM
import qualified Data.Vector.Mutable as MV
import qualified Data.Vector.Unboxed.Mutable as UMV
import Dodge.Data.Config
import Foreign hiding (rotate)
import Geometry.Data
import Graphics.GL.Core45
import Picture.Data
import Shader
import Shader.Data
import Shader.ExtraPrimitive

-- | Determine where light is shining in the world.
-- think of the produced texture as showing what RGB values should be "taken
-- away" from the shape colors.
createLightMap ::
    Configuration ->
    RenderData ->
    [(Point3, Float, Point3)] -> -- Lights
    -- | number of walls
    Int ->
    -- | number of silhoutte lines to draw
    Int ->
    -- | number of "caps" to attempt to draw
    Int ->
    -- | whether to draw object shadows or not
    ObjectShadows ->
    -- | the texture object giving positions
    TO ->
    (Point3 -> Float -> IO ()) -> -- attempt at drawing shadow not using geo shader
    IO ()
createLightMap cfig pdata lightPoints nWalls nSils nCaps shadsdrawtype toPos drawCPUShadows = case shadsdrawtype of
  InstancingShads -> instanceLightMap cfig pdata lightPoints nWalls nSils nCaps toPos
  _ -> do
    let llinesShad = _lightingLineShadowShader pdata
        lcapShad = _lightingCapShader pdata
        lwallShad = _lightingWallShadShader pdata
        ltextShad = _lightingTextureShader pdata
    -- we assume that the renderbuffer's depth has been correctly set elsewhere
    -- we will not be changing that here
    glDepthMask GL_FALSE
    -- clearColor is specified differently in preloadRender
    -- the colors are inverted
    glClearColor 1 1 1 1
    glClear GL_COLOR_BUFFER_BIT
    -- for each of the lights:
    -- 1. stencil out the shadows from this light's point of view
    -- 2. calculate lighting based on each fragment's position
    -- to consider: adding normals/a "material" for each fragment
    glBlendFunc GL_ZERO GL_ONE_MINUS_SRC_COLOR
    glEnable GL_STENCIL_TEST
    --stencilTest $= Enabled
    glStencilOpSeparate GL_FRONT GL_KEEP GL_KEEP GL_INCR_WRAP
    --stencilOpSeparate Front $= (OpKeep, OpKeep, OpIncrWrap)
    --stencilOpSeparate Back $= (OpKeep, OpKeep, OpDecrWrap)
    glStencilOpSeparate GL_BACK GL_KEEP GL_KEEP GL_DECR_WRAP
    flip VFSM.mapM_ (VFSM.fromList lightPoints) $ \(V3 x y z, rad, V3 r g b) -> do
        glDepthFunc GL_LESS
        -- setup stencil
        glColorMask GL_FALSE GL_FALSE GL_FALSE GL_FALSE 
        glClear GL_STENCIL_BUFFER_BIT
        glDisable GL_CULL_FACE
        --cullFace $= Nothing
        glStencilFunc GL_ALWAYS 0 255
        --draw wall shadows
        --currentProgram $= Just (_shadProg lwallShad)
        glUseProgram (_shadProg' lwallShad)
        --uniform (_shadUnis lwallShad V.! 0)
        --    $= Vector3 x y z
        glUniform3f (_shadUnis' lwallShad V.! 0) x y z
        --bindVertexArrayObject $= lwallShad ^? shadVAO' . vaoName -- Just (_vao $ _shadVAO lwallShad)
        glBindVertexArray $ lwallShad ^. shadVAO' . vaoName -- Just (_vao $ _shadVAO lwallShad)
        glDrawArrays
            (marshalEPrimitiveMode $ _shadPrim' lwallShad)
            0
            (fromIntegral nWalls)
        case shadsdrawtype of
            GeoObjShads -> do
                --draw silhouette shadows
                glUseProgram (_shadProg' llinesShad)
                glUniform3f (_shadUnis' llinesShad V.! 0) x y z
                glUniform1f (_shadUnis' llinesShad V.! 1) rad
                glBindVertexArray (_vaoName $ _shadVAO' llinesShad)
                glDrawElements
                    (marshalEPrimitiveMode $ _shadPrim' llinesShad)
                    (fromIntegral nSils)
                    GL_UNSIGNED_SHORT
                    nullPtr
                --draw caps on the near plane as required
                glEnable GL_CULL_FACE
                glCullFace GL_BACK
                glUseProgram (_shadProg' lcapShad)
                glUniform3f (_shadUnis' lcapShad V.! 0) x y z
                glBindVertexArray $ lcapShad ^. shadVAO' . vaoName --Just (_vao $ _shadVAO lcapShad)
                glDrawElements
                    (marshalEPrimitiveMode $ _shadPrim' lcapShad)
                    (fromIntegral nCaps)
                    GL_UNSIGNED_SHORT
                    nullPtr
            CPUObjShads -> drawCPUShadows (V3 x y z) rad
            NoObjShads -> return ()
        --draw lightmap itself
        glEnable GL_DEPTH_TEST
        glDepthFunc GL_ALWAYS
        --depthFunc $= Just Always
        -- bind world position texture
        bindTO toPos
        glColorMask GL_TRUE GL_TRUE GL_TRUE GL_TRUE
        --stencilOp $= (OpKeep, OpKeep, OpKeep)
        glStencilFunc GL_EQUAL 0 255
        --currentProgram $= ltextShad ^? shadProg --Just (_shadProg ltextShad)
        --uniform (_shadUnis ltextShad V.! 0) $= Vector3 x y z
        --uniform (_shadUnis ltextShad V.! 1) $= Vector4 r g b rad
        glUseProgram (ltextShad ^. shadProg') --Just (_shadProg ltextShad)
        glUniform3f (_shadUnis' ltextShad V.! 0) x y z
        glUniform4f (_shadUnis' ltextShad V.! 1) r g b rad
        --bindVertexArrayObject $= ltextShad ^? shadVAO' . vaoName -- Just (_vao $ _shadVAO ltextShad)
        glBindVertexArray $ ltextShad ^. shadVAO' . vaoName -- Just (_vao $ _shadVAO ltextShad)
        glDrawArrays
            (marshalEPrimitiveMode (_shadPrim' ltextShad))
            0
            (fromIntegral (4 :: Int))
    --cleanup: may not be necessary, depending on what comes after...
    glDisable GL_CULL_FACE
    glDisable GL_STENCIL_TEST

lightsToArray :: [(Point3,Float,Point3)] -> [Float]
lightsToArray xs = concat (take 20 $ map t xs ++ repeat [0,0,0,0])
    ++ concat (take 20 $ map s xs ++ repeat [0,0,0,0])
  where
    t (V3 a b c,_,_) = [a,b,c,1]
    s (_,d,V3 e f g) = [e,f,g,d]
    --t (V3 a b c,d,V3 e f g) = [a,b,c,1]

instanceLightMap ::
    Configuration ->
    RenderData ->
    [(Point3, Float, Point3)] -> -- Lights
    -- | number of walls
    Int ->
    -- | number of silhoutte lines to draw
    Int ->
    -- | number of "caps" to attempt to draw
    Int ->
    -- | the texture object giving positions
    TO ->
    IO ()
instanceLightMap cfig pdata lightPoints nWalls nSils nCaps toPos = do
    let llinesShad = _shadowEdgeShader pdata
        lcapShad = _shadowCapShader pdata
        lwallShad = _shadowWallShader pdata
        (xsize,ysize) = getWindowSize cfig
    withArray (lightsToArray lightPoints) $ \ptr ->
        glNamedBufferSubData (pdata ^. lightsUBO) 0 620 ptr

    forM_ [0..19] $ \i -> glCopyImageSubData 
        (pdata ^. rboBaseBloom) 
        GL_RENDERBUFFER 
        0 
        0 0 0
        (pdata ^. fboShadow . _2 . _2 . unTO) 
        GL_TEXTURE_2D_ARRAY 0 0 0 i (fromIntegral xsize) (fromIntegral ysize) 
        1
    glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboShadow pdata)))
    glDepthMask GL_FALSE
    -- clearColor is specified differently in preloadRender
    -- the colors are inverted
    glClearColor 0 0 0 0
    glClear $ GL_COLOR_BUFFER_BIT + GL_STENCIL_BUFFER_BIT
    -- for each of the lights:
    -- 1. stencil out the shadows from this light's point of view
    -- 2. calculate lighting based on each fragment's position
    -- to consider: adding normals/a "material" for each fragment
    glEnable GL_STENCIL_TEST
    glStencilOpSeparate GL_FRONT GL_KEEP GL_KEEP GL_INCR_WRAP
    glStencilOpSeparate GL_BACK GL_KEEP GL_KEEP GL_DECR_WRAP
    -- this was a loop
    glDepthFunc GL_LESS
    -- setup stencil
    glColorMask GL_FALSE GL_FALSE GL_FALSE GL_FALSE 
    glDisable GL_CULL_FACE
    glStencilFunc GL_ALWAYS 0 255
    --draw wall shadows
    glUseProgram (_shadProg' lwallShad)
    glBindVertexArray $ lwallShad ^. shadVAO' . vaoName -- Just (_vao $ _shadVAO lwallShad)
    glDrawArrays
        (marshalEPrimitiveMode $ _shadPrim' lwallShad)
        0
        (fromIntegral nWalls)
    --draw silhouette shadows
    glUseProgram (_shadProg' llinesShad)
    glBindVertexArray (_vaoName $ _shadVAO' llinesShad)
    glDrawElements
        (marshalEPrimitiveMode $ _shadPrim' llinesShad)
        (fromIntegral nSils)
        GL_UNSIGNED_SHORT
        nullPtr
    --draw caps on the near plane as required
    glEnable GL_CULL_FACE
    glCullFace GL_BACK
    glUseProgram (_shadProg' lcapShad)
    glBindVertexArray $ lcapShad ^. shadVAO' . vaoName --Just (_vao $ _shadVAO lcapShad)
    glDrawElements
        (marshalEPrimitiveMode $ _shadPrim' lcapShad)
        (fromIntegral nCaps)
        GL_UNSIGNED_SHORT
        nullPtr
     --draw lightmap itself
    glEnable GL_DEPTH_TEST
    glDepthFunc GL_ALWAYS
    glColorMask GL_TRUE GL_TRUE GL_TRUE GL_TRUE
    glStencilFunc GL_EQUAL 0 255
    glUseProgram (pdata ^. shadowLightShader . shadProg')
    -- bind world position texture
    bindTO toPos
    glDisable GL_BLEND
    glBindVertexArray $ pdata ^. shadowLightShader . shadVAO' . vaoName
    glDrawArrays
        (marshalEPrimitiveMode $ pdata ^. shadowLightShader . shadPrim')
        0
        1

    -- this was the end of the loop
    glDisable GL_CULL_FACE
    glDisable GL_STENCIL_TEST

    --draw to the lighting framebuffer here
    glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboLighting pdata)))
    glClearColor 1 1 1 1
    glClear GL_COLOR_BUFFER_BIT
    glBindTexture GL_TEXTURE_2D_ARRAY (pdata ^. fboShadow . _2 . _1 . unTO)
    glEnable GL_BLEND
    glBlendFunc GL_ZERO GL_ONE_MINUS_SRC_COLOR
    glUseProgram (pdata ^. shadowCombineShader . shadProg') --Just (_shadProg ltextShad)
    glDrawArrays
        (marshalEPrimitiveMode EPoints)
        0
        1

-- assumes that vertices have already been sent to the shader
pingPongBetween ::
    (FBO, TO) ->
    (FBO, TO) ->
    FullShader ->
    IO ()
pingPongBetween (fb1, to1) (fb2, to2) fs = do
    --bindFramebuffer Framebuffer $= fb2
    glBindFramebuffer GL_FRAMEBUFFER (_unFBO fb2)
    --textureBinding Texture2D $= Just to1
    glBindTexture GL_TEXTURE_2D (_unTO to1)
    drawShader fs 4
    --bindFramebuffer Framebuffer $= fb1
    glBindFramebuffer GL_FRAMEBUFFER (_unFBO fb1)
    --textureBinding Texture2D $= Just to2
    glBindTexture GL_TEXTURE_2D (_unTO to2)
    drawShader fs 4

renderFoldable ::
    MV.MVector (PrimState IO) FullShader ->
    Picture ->
    IO ()
renderFoldable shadV struct = do
    counts <- UMV.replicate 6 0
    pokeBindFoldable shadV counts struct
    MV.imapM_ (drawShaderLay 0 counts) shadV

------------------------------end renderFoldable
renderLayer ::
    Layer ->
    MV.MVector (PrimState IO) FullShader ->
    UMV.MVector (PrimState IO) Int ->
    IO ()
renderLayer layer shads counts = do
    let layerCounts = UMV.slice (ln * numLayers) 6 counts
    MV.imapM_ (drawShaderLay ln layerCounts) shads
  where
    ln = layerNum layer

bindTO :: TO -> IO ()
bindTO t = glBindTexture GL_TEXTURE_2D (_unTO t)
    --textureBinding Texture2D $= Just t

bindFBO :: FBO -> IO ()
bindFBO fb = --bindFramebuffer Framebuffer $= fb
    glBindFramebuffer GL_FRAMEBUFFER (_unFBO fb)