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

import Control.Lens
import Control.Monad
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 Dodge.WindowSize
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
    NoShadows -> do
        glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboLighting pdata)))
        let 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
        withArray [1,1,1,1] $ \ptr -> glClearNamedFramebufferfv
            (pdata ^. fboLighting . _1 . unFBO)
            GL_COLOR
            0
            ptr
        -- 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
        glStencilOpSeparate GL_FRONT GL_KEEP GL_KEEP GL_INCR_WRAP
        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
            with 0 $ \ptr -> glClearNamedFramebufferiv
                (pdata ^. fboLighting . _1 . unFBO)
                GL_STENCIL
                0 
                ptr
            glDisable GL_CULL_FACE
            glStencilFunc GL_ALWAYS 0 255
            --draw lightmap itself
            glDepthFunc GL_ALWAYS
            -- bind world position texture
            bindTO toPos
            glColorMask GL_TRUE GL_TRUE GL_TRUE GL_TRUE
            glStencilFunc GL_EQUAL 0 255
            glUseProgram (ltextShad ^. shadName)
            glUniform3f (_shadUnis ltextShad V.! 0) x y z
            glUniform4f (_shadUnis ltextShad V.! 1) r g b rad
            glBindVertexArray $ ltextShad ^. shadVAO . vaoName
            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
    NoLighting -> do
        glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboLighting pdata)))
        glBlendFunc GL_ZERO GL_ONE_MINUS_SRC_COLOR
        withArray [0,0,0,1] $ \ptr -> glClearNamedFramebufferfv
            (pdata ^. fboLighting . _1 . unFBO)
            GL_COLOR
            0
            ptr
        with 1 $ \ptr -> glClearNamedFramebufferfv
            (pdata ^. fboLighting . _1 . unFBO)
            GL_DEPTH
            0
            ptr
        glDisable GL_CULL_FACE
        glBindTextureUnit 0 (toPos ^. unTO)
        glDepthFunc GL_ALWAYS
        glDepthMask GL_FALSE
    _ -> do
        glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboLighting pdata)))
        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
        withArray [1,1,1,1] $ \ptr -> glClearNamedFramebufferfv
            (pdata ^. fboLighting . _1 . unFBO)
            GL_COLOR
            0
            ptr
        -- 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
        glStencilOpSeparate GL_FRONT GL_KEEP GL_KEEP GL_INCR_WRAP
        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
            with 0 $ \ptr -> glClearNamedFramebufferiv
                (pdata ^. fboLighting . _1 . unFBO)
                GL_STENCIL
                0 
                ptr
            glDisable GL_CULL_FACE
            glStencilFunc GL_ALWAYS 0 255
            --draw wall shadows
            glUseProgram (_shadName lwallShad)
            glUniform3f (_shadUnis lwallShad V.! 0) x y z
            glUniform1f (_shadUnis lwallShad V.! 1) rad
            glBindVertexArray $ lwallShad ^. shadVAO . vaoName -- Just (_vao $ _shadVAO lwallShad)
            glDrawArrays
                (marshalEPrimitiveMode $ _shadPrim' lwallShad)
                0
                (fromIntegral nWalls)
            case shadsdrawtype of
                GeoObjShads -> do
                    --draw silhouette shadows
                    glEnable GL_DEPTH_CLAMP
                    glUseProgram (_shadName 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
                    glCullFace GL_FRONT
                    glUseProgram (_shadName 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
                    glDisable GL_DEPTH_CLAMP
                CPUObjShads -> drawCPUShadows (V3 x y z) rad
                NoObjShads -> return ()
            --draw lightmap itself
            glDepthFunc GL_ALWAYS
            -- bind world position texture
            glDisable GL_CULL_FACE
            bindTO toPos
            glBindTextureUnit 1 (pdata ^. fboBase . _2 . _3 . unTO)
            glColorMask GL_TRUE GL_TRUE GL_TRUE GL_TRUE
            glStencilFunc GL_EQUAL 0 255
            glUseProgram (ltextShad ^. shadName) --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_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]


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 lcapShad = _shadowCapShader 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 $ pdata ^. fboShadow . _1 . unFBO
    glDepthMask GL_FALSE
    withArray [0,0,0,0] $ \ptr -> glClearNamedFramebufferfv
        (pdata ^. fboShadow . _1 . unFBO)
        GL_COLOR
        0
        ptr
    with 0 $ \ptr -> glClearNamedFramebufferiv
        (pdata ^. fboShadow . _1 . unFBO)
        GL_STENCIL
        0 
        ptr
    -- stencil out the shadows from each light's point of view
    -- setup stencil
    glEnable GL_STENCIL_TEST
    glStencilOpSeparate GL_FRONT GL_KEEP GL_KEEP GL_INCR_WRAP
    glStencilOpSeparate GL_BACK GL_KEEP GL_KEEP GL_DECR_WRAP
    glDepthFunc GL_LESS
    glColorMask GL_FALSE GL_FALSE GL_FALSE GL_FALSE
    glDisable GL_BLEND
    glDisable GL_CULL_FACE
    glStencilFunc GL_ALWAYS 0 255
    --draw wall shadows
    glUseProgram $ pdata ^. shadowWallShader . shadName
    glBindVertexArray $ pdata ^. shadowWallShader . shadVAO . vaoName
    glDrawArrays
        (marshalEPrimitiveMode $ pdata ^. shadowWallShader . shadPrim')
        0
        (fromIntegral nWalls)
    --draw silhouette shadows
    glUseProgram $ pdata ^. shadowEdgeShader . shadName
    glBindVertexArray $ pdata ^. shadowEdgeShader . shadVAO . vaoName
    glDrawElements
        (marshalEPrimitiveMode $ pdata ^. shadowEdgeShader . shadPrim')
        (fromIntegral nSils)
        GL_UNSIGNED_SHORT
        nullPtr
    --draw caps on the near plane as required
    glEnable GL_CULL_FACE
    glCullFace GL_BACK
    --glCullFace GL_FRONT
    glUseProgram (_shadName lcapShad)
    glBindVertexArray $ lcapShad ^. shadVAO . vaoName
    glDrawElements
        (marshalEPrimitiveMode $ _shadPrim' lcapShad)
        (fromIntegral nCaps)
        GL_UNSIGNED_SHORT
        nullPtr
    --draw lightmap itself
    glDepthFunc GL_ALWAYS
    glColorMask GL_TRUE GL_TRUE GL_TRUE GL_TRUE
    glStencilFunc GL_EQUAL 0 255
    glUseProgram (pdata ^. shadowLightShader . _1 . shadName)
    -- bind world position texture
    bindTO toPos
--    glBindVertexArray $ pdata ^. shadowLightShader . shadVAO' . vaoName
    glDrawArrays
        (marshalEPrimitiveMode $ pdata ^. shadowLightShader . _1 . shadPrim')
        0
        1
    glDisable GL_CULL_FACE
    glDisable GL_STENCIL_TEST
    --draw to the lighting framebuffer here
    glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboLighting pdata)))
    withArray [1,1,1,1] $ \ptr -> glClearNamedFramebufferfv
        (pdata ^. fboLighting . _1 . unFBO)
        GL_COLOR
        0
        ptr
    glBindTexture GL_TEXTURE_2D_ARRAY (pdata ^. fboShadow . _2 . _1 . unTO)
    glEnable GL_BLEND
    glBlendFunc GL_ZERO GL_ONE_MINUS_SRC_COLOR
    glUseProgram (pdata ^. shadowCombineShader . _1 . shadName)
    glDrawArrays
        (marshalEPrimitiveMode EPoints)
        0
        1
    withArray [GL_COLOR_ATTACHMENT0, GL_DEPTH_STENCIL_ATTACHMENT] $ \ptr ->
        glInvalidateNamedFramebufferData
            (pdata ^. fboShadow . _1 . unFBO)
            2
            ptr

-- 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,VBO) ->
    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,VBO) ->
    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)