-- | Contains the central drawing functions for the dodge loop.
module Dodge.Render (
    doDrawing,
    getWindowSize,
) where

import Control.Lens
import Control.Monad
import qualified Control.Monad.Parallel as MP
--import Data.List (sortOn)
import qualified Data.Map.Strict as M
import Data.Preload.Render
import qualified Data.Vector as V
import qualified Data.Vector.Unboxed.Mutable as UMV
import Dodge.Data.Universe
import Dodge.Render.Lights
import Dodge.Render.ShapePicture
import Dodge.Render.Walls
import Dodge.Shadows
import Dodge.WindowSize
import Foreign
import GLHelp
import Geometry
import Graphics.GL.Core45
import MatrixHelper
import Render
import qualified SDL
import Shader
import Shader.Bind
import Shader.Data
import Shader.Poke
import Shader.Poke.Cloud

doDrawing :: SDL.Window -> Universe -> IO ()
doDrawing window u
    | SDL.ScancodeY `M.member` (u ^. uvWorld . input . pressedKeys) = doTestDrawing rdata u
    | otherwise = doDrawing' window rdata u
  where
    rdata = u ^. preloadData . renderData

doTestDrawing :: RenderData -> Universe -> IO ()
doTestDrawing _ _ = do
    return ()

doDrawing' :: SDL.Window -> RenderData -> Universe -> IO ()
doDrawing' win pdata u = do
    --sTicks <- SDL.ticks
    checkGLError "during drawing"
    let w = _uvWorld u
        cfig = _uvConfig u
        (windowPoints, wallSPics, wallsToPoke) = wallsToDraw w
        lightPoints = lightsToRender cfig (w ^. wCam) (w ^. cWorld . lWorld)
        shadV = _pictureShaders pdata
        nFls = w ^. cWorld . numberFloorVerxs
        nchs = w ^. cWorld . numberChasmVerxs
    -- bind as much data into vbos as feasible at this point
    -- count mutable vectors setup
    pokeCounts <- UMV.replicate (numLayers * numShads) 0
    -- attempt to poke in parallel
    let wswp = wallSPics <> worldSPic cfig u
        ws = wswp ^. _1
        wp = wswp ^. _2
    ((nWins, trueNWalls), (nShapeVs, nIndices, nSilIndices)) <-
        MP.liftM3
            (\_ a b -> (a, b))
            ( pokeLayVerxs
                shadV
                pokeCounts
                wp
            )
            ( pokeWallsWindows
                (pdata ^. winVBO . vboPtr)
                (pdata ^. wallVBO . vboPtr)
                windowPoints
                wallsToPoke
            )
            ( pokeShape
                (drawShadowsByImportance $ cfig ^. gr_shadow_size)
                (_vboPtr $ _vboShapes pdata)
                (_uiboPtr $ _shapeEBO pdata)
                (_uiboPtr $ _silhouetteEBO pdata)
                (0, 0, 0)
                ws
            )
    nCloudVs' <-
        V.foldM'
            (pokeCloud (pdata ^. cloudVBO . vboPtr))
            0
            (V.fromList $ w ^. cWorld . lWorld . clouds)
    nCloudVs <-
        V.foldM'
            (pokeDust (pdata ^. cloudVBO . vboPtr))
            nCloudVs'
            (V.fromList $ w ^. cWorld . lWorld . dusts)
    -- bind wall points, silhouette data, surface geometry
    bufferShaderLayers shadV pokeCounts
    bufferPokedVBO (_vboShapes pdata) nShapeVs
    bufferPokedVBO (pdata ^. winVBO) nWins
    bufferPokedVBO (pdata ^. wallVBO) trueNWalls
    bufferPokedVBO (pdata ^. cloudVBO) nCloudVs
    bufferEBO (_shapeEBO pdata) nIndices
    bufferEBO (pdata ^. silhouetteEBO) nSilIndices
    -- set the coordinate uniform ready for drawing elements using world coordinates
    bufferPerspectiveMatrixUBO cfig (w ^. wCam) (pdata ^. matUBO)
    setViewport _gr_world_res cfig
    glBindFramebuffer GL_FRAMEBUFFER (pdata ^. fboBase . _1 . unFBO)
    glDepthMask GL_TRUE
    glDisable GL_BLEND
    glDepthFunc GL_LESS
    -- clear depth and stencil buffers
    glStencilMask 255 -- to alter the entire stencil
    glClearNamedFramebufferfi
        (pdata ^. fboBase . _1 . unFBO)
        GL_DEPTH_STENCIL
        0
        1
        0
    -- draw wall occlusions from the camera's point of view
    glStencilFunc GL_NOTEQUAL 128 255
    glStencilOp GL_KEEP GL_KEEP GL_REPLACE
    glEnable GL_CULL_FACE
    unless (debugOn Remove_LOS cfig) $ do
        glUseProgram (pdata ^. ceilingStencilShader)
        glBindVertexArray $ pdata ^. dummyVAO
        glEnable GL_DEPTH_CLAMP
        glDrawArrays GL_TRIANGLES 0 (fromIntegral (trueNWalls * 6))
        glDisable GL_DEPTH_CLAMP
    glStencilMask 127 -- to alter last seven bits
    glStencilOp GL_KEEP GL_KEEP GL_KEEP
    -- clear color and normals
    withArray [0, 0, 0, 1] $
        glClearNamedFramebufferfv (pdata ^. fboBase . _1 . unFBO) GL_COLOR 0
    withArray [0, 0, 0, 0] $
        glClearNamedFramebufferfv (pdata ^. fboBase . _1 . unFBO) GL_COLOR 2
    withArray [GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2] $
        glNamedFramebufferDrawBuffers (pdata ^. fboBase . _1 . unFBO) 3
    --draw walls onto base buffer
    glEnable GL_CULL_FACE
    glUseProgram (pdata ^. pullWallShader)
    glDrawArrays GL_TRIANGLES 0 (fromIntegral trueNWalls * 6)
    --draw object shapes onto base buffer
    let fs = _shapeShader pdata
    glUseProgram fs
    glDrawArrays GL_TRIANGLES 0 (fromIntegral nIndices)
    -- draw chasm shader blocking floor
    glUseProgram (pdata ^. chasmShader)
    glDepthMask GL_FALSE
    glDrawBuffer GL_NONE
    glStencilOp GL_KEEP GL_KEEP GL_INCR
    with 0 $ glClearNamedFramebufferiv (pdata ^. fboBase . _1 . unFBO) GL_STENCIL 0
    glDrawArrays GL_TRIANGLES 0 (fromIntegral nchs)
    withArray [GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2] $
        glNamedFramebufferDrawBuffers (pdata ^. fboBase . _1 . unFBO) 3
    glDepthMask GL_TRUE
    glDisable GL_CULL_FACE
    --draw floor onto base buffer
    glUseProgram (pdata ^. floorShader)
    glStencilFunc GL_EQUAL 0 255
    glDrawArrays GL_TRIANGLES 0 (fromIntegral nFls)
    --glDisable GL_STENCIL_TEST
    glEnable GL_BLEND
    --draw lightmap into its own buffer
    createLightMap
        (w ^. wCam)
        cfig
        (cfig ^. gr_shadow_rendering)
        (fromIntegral trueNWalls)
        nSilIndices
        nIndices
        (pdata ^. fboBase . _2 . _2)
        (pdata ^. fboBase . _2 . _3)
        lightPoints
        pdata
    glColorMask GL_TRUE GL_TRUE GL_TRUE GL_TRUE
    --apply lightmap to base buffer
    glDisable GL_CULL_FACE
    glDepthFunc GL_ALWAYS
    glDepthMask GL_FALSE
    glBindFramebuffer GL_FRAMEBUFFER (pdata ^. fboBase . _1 . unFBO)
    glBindTextureUnit 0 (pdata ^. fboLighting . _2 . unTO)
    glEnable GL_BLEND
    glBlendFunc GL_ZERO GL_ONE_MINUS_SRC_COLOR
    glUseProgram (pdata ^. fullscreenShader)
    glDrawArrays GL_TRIANGLES 0 6
    with GL_COLOR_ATTACHMENT0 $
        glInvalidateNamedFramebufferData (pdata ^. fboLighting . _1 . unFBO) 1
    --draw bloom onto bloom buffer
    glBindFramebuffer GL_FRAMEBUFFER (pdata ^. fboBloom . _1 . unFBO)
    withArray [0, 0, 0, 0] $
        glClearNamedFramebufferfv (pdata ^. fboBloom . _1 . unFBO) GL_COLOR 0
    glDepthFunc GL_LEQUAL
    --glBlendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA
    --glBlendFunc GL_ONE GL_ONE_MINUS_SRC_ALPHA
    glBlendFunc GL_ONE GL_ONE
    glDepthMask GL_FALSE
    renderLayer BloomNoZWrite shadV pokeCounts
    glDepthMask GL_TRUE
    renderLayer BloomLayer shadV pokeCounts
    -- draw clouds to block bloom particles, transparency blocks some alpha
    glDepthMask GL_FALSE
    --glBlendColor 0 0 0 0.1 -- using this and GL_CONSTANT_ALPHA below
    glBlendColor 0 0 0 0.05 -- using this and GL_CONSTANT_ALPHA below
    -- can allow for extra bloom to bleed through underneath the clouds
    -- note that BloomNoZWrite will always be under the clouds, this should be
    -- rethought, either do another pass and write just the depth or even remove
    -- the layer entirely
    glBlendFuncSeparate GL_ZERO GL_ONE GL_CONSTANT_ALPHA GL_ONE_MINUS_SRC_ALPHA
    glUseProgram (pdata ^. cloudShader)
    glDrawArrays GL_TRIANGLES 0 (fromIntegral nCloudVs * 6)

    --setup downscale viewport for blurring bloom
    --setViewportSize (round winx `div` (2 * resFact)) (round winy `div` (2 * resFact))
    setViewport _gr_downsize_res cfig
    glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboHalf1 pdata)))
    glDepthFunc GL_ALWAYS
    glBindTextureUnit 0 (pdata ^. fboBloom . _2 . unTO)
    glDisable GL_BLEND
    -- this all needs more tuning + more thought
    -- a fade effect would be cool, so not to fully reset last frames bloom
    -- buffers...
    --    withArray [0, 0, 0, 0] $
    --        glClearNamedFramebufferfv (pdata ^. fboHalf1 . _1 . unFBO) GL_COLOR 0
    --    withArray [0, 0, 0, 0] $
    --        glClearNamedFramebufferfv (pdata ^. fboHalf2 . _1 . unFBO) GL_COLOR 0
    --    glBlendFunc GL_ONE GL_ONE_MINUS_SRC_ALPHA
    glUseProgram (_bloomBlurShader pdata)
    glDrawArrays GL_TRIANGLES 0 6
    when (cfig ^. gr_bloom) $ do
        replicateM_ 1 $
            pingPongBetween
                (_fboHalf1 pdata)
                (_fboHalf2 pdata)
                (_bloomBlurShader pdata)
        glEnable GL_BLEND
    setViewport _gr_world_res cfig
    --draw clouds onto cloud buffer
    glBindFramebuffer GL_FRAMEBUFFER (pdata ^. fboCloud . _1 . unFBO)
    glDepthFunc GL_LEQUAL
    glDepthMask GL_FALSE
    glBlendFuncSeparatei 0 GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA GL_ONE_MINUS_DST_ALPHA GL_ONE
    --glBlendFunci 0 GL_ONE GL_ONE_MINUS_SRC_ALPHA
    --withArray [GL_COLOR_ATTACHMENT0, GL_NONE] $
    --withArray [GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1] $
    withArray [GL_COLOR_ATTACHMENT0] $
        glNamedFramebufferDrawBuffers (pdata ^. fboCloud . _1 . unFBO) 1
    withArray [0.5, 0.5, 0.5, 0] $
        glClearNamedFramebufferfv
            (pdata ^. fboCloud . _1 . unFBO)
            GL_COLOR
            0
    glUseProgram (pdata ^. cloudShader)
    glDrawArrays GL_TRIANGLES 0 (fromIntegral nCloudVs * 6)
    when (_gr_cloud_shadows cfig) $ do
        ----render transparency depths
        --        glDepthMask GL_TRUE
        glDepthFunc GL_ALWAYS
        withArray [GL_NONE, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2] $
            glNamedFramebufferDrawBuffers (pdata ^. fboCloud . _1 . unFBO) 3
        withArray [0, 0, 0, 0] $
            glClearNamedFramebufferfv (pdata ^. fboCloud . _1 . unFBO) GL_COLOR 1
        withArray [0, 0, 0, 0] $
            glClearNamedFramebufferfv (pdata ^. fboCloud . _1 . unFBO) GL_COLOR 2
        glEnable GL_BLEND
        -- we sum the positions weighted by alpha, and sum the alpha
        glBlendFuncSeparatei 1 GL_SRC_ALPHA GL_ONE GL_ONE GL_ONE
        -- we divide by the alpha later
        -- and sum the normals weighted by alpha
        glBlendFunci 2 GL_SRC_ALPHA GL_ONE
        glUseProgram (pdata ^. cloudShader)
        glDrawArrays GL_TRIANGLES 0 (fromIntegral nCloudVs * 6)
        glBindFramebuffer GL_FRAMEBUFFER (pdata ^. fboPos . _1 . unFBO)
        withArray [0, 0, 0, 0] $ \ptr ->
            glClearNamedFramebufferfv
                (pdata ^. fboPos . _1 . unFBO)
                GL_COLOR
                0
                ptr
        glBindTextureUnit 0 (pdata ^. fboCloud . _2 . _2 . unTO)
        glDepthMask GL_FALSE
        glUseProgram (pdata ^. alphaDivideShader)
        glDrawArrays GL_TRIANGLES 0 6
        ----draw lightmap for cloud buffer
        glDepthMask GL_TRUE
        glDepthFunc GL_LESS
        glEnable GL_BLEND
        glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboLighting pdata)))
        createLightMap
            (w ^. wCam)
            cfig
            (cfig ^. gr_shadows_on_clouds)
            (fromIntegral trueNWalls)
            nSilIndices
            nIndices
            (pdata ^. fboPos . _2)
            (pdata ^. fboCloud . _2 . _3)
            lightPoints
            pdata
    --draw windows onto window buffer
    glBindFramebuffer GL_FRAMEBUFFER (pdata ^. fboWindow . _1 . unFBO)
    glBindTextureUnit 3 (pdata ^. fboPos . _2 . unTO)
    withArray [GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1] $
        glNamedFramebufferDrawBuffers (pdata ^. fboWindow . _1 . unFBO) 2
    withArray [0, 0, 0, 0] $
        glClearNamedFramebufferfv (pdata ^. fboWindow . _1 . unFBO) GL_COLOR 0
    withArray [0, 0, 0, 0] $
        glClearNamedFramebufferfv (pdata ^. fboWindow . _1 . unFBO) GL_COLOR 1
    glEnable GL_CULL_FACE
    glEnable GL_DEPTH_CLAMP
    glDepthFunc GL_LEQUAL
    glDepthMask GL_FALSE
    glEnable GL_BLEND
    glBlendFunc GL_SRC_ALPHA GL_ONE
    glUseProgram $ pdata ^. windowPullShader
    glBindVertexArray $ pdata ^. dummyVAO
    glDrawArrays GL_TRIANGLES 0 (fromIntegral nWins * 6)
    glDisable GL_DEPTH_CLAMP
    glDisable GL_CULL_FACE
    glInvalidateBufferData (pdata ^. vboShapes . vboName)
    --apply lightmap to cloud buffer
    glBindFramebuffer GL_FRAMEBUFFER (_unFBO (fst (_fboCloud pdata)))
    glDepthMask GL_FALSE
    withArray [GL_COLOR_ATTACHMENT0, GL_NONE] $
        glNamedFramebufferDrawBuffers (pdata ^. fboCloud . _1 . unFBO) 2
    glDepthFunc GL_ALWAYS
    glBindTextureUnit 0 (_unTO . snd $ _fboLighting pdata)
    glEnable GL_BLEND
    glBlendFuncSeparate GL_ZERO GL_ONE_MINUS_SRC_COLOR GL_ZERO GL_ONE
    glUseProgram (pdata ^. fullscreenShader)
    glDrawArrays GL_TRIANGLES 0 6
    glBlendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA

    -- bind base buffer for drawing clouds and bloom
    glBindFramebuffer GL_FRAMEBUFFER (pdata ^. fboBase . _1 . unFBO)

    glBlendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA
    --    --draw windows onto base buffer
    glBlendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA
    glBindTextureUnit 0 (pdata ^. fboWindow . _2 . _1 . unTO)
    glBindTextureUnit 1 (pdata ^. fboWindow . _2 . _2 . unTO)
    glBindTextureUnit 2 (pdata ^. fboCloud . _2 . _1 . unTO)
    glBindTextureUnit 3 (pdata ^. fboPos . _2 . unTO)
    
    --drawShader (_transparencyCompShader pdata) 4
    glUseProgram (pdata ^. transparencyCompShader)
    glDrawArrays GL_TRIANGLES 0 6

    --Draw blurred bloom onto base buffer
    glEnable GL_BLEND
    glBlendFunc GL_SRC_ALPHA GL_ONE
    --glBlendFunc GL_ONE GL_ONE
    glBindTextureUnit 0 (_unTO . snd $ _fboHalf1 pdata)
    glUseProgram (pdata ^. fullscreenShader)
    glDrawArrays GL_TRIANGLES 0 6
    --    glBlendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA

    --set viewport for radial distortion
    --setViewportSize (round winx) (round winy)
    setViewport (const FullRes) cfig
    glDepthFunc GL_ALWAYS
    glBlendFunc GL_ONE GL_ZERO
    -- perform any radial distortion
    -- this is hideous
    case (getDistortions cfig w, cfig ^. gr_distortions) of
        (rds, x) | null rds || not x -> do
            glBindTextureUnit 0 $ pdata ^. fboBase . _2 . _1 . unTO
            glBindFramebuffer GL_FRAMEBUFFER 0
            glUseProgram (pdata ^. fullscreenShader)
            glDrawArrays GL_TRIANGLES 0 6
        (rds, _) -> do
            let bindDrawDist :: Distortion -> IO ()
                bindDrawDist (RadialDistortion (V2 a b) (V2 c d) (V2 e f) g) = do
                    pokeArray (shadVBOptr $ _barrelShader pdata) [a, b, c, d, e, f, g]
                    bufferPokedVBO (snd $ _barrelShader pdata) 1
                    drawShader (fst $ _barrelShader pdata) 1
                fboList =
                    take (length rds - 1) (concat (repeat [fst $ _fbo2 pdata, fst $ _fbo3 pdata]))
                        ++ [FBO 0]
                toList = (pdata ^. fboBase . _2 . _1) : concat (repeat [snd $ _fbo2 pdata, snd $ _fbo3 pdata])
                bindings = zipWith (>>) (map bindFBO fboList) (map (glBindTextureUnit 1 . _unTO) toList)
            zipWithM_ (>>) bindings $ map bindDrawDist rds
    glBlendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA
    -- draw the overlay
    --glBindFramebuffer GL_FRAMEBUFFER (pdata ^. fboOverlay ._1 . unFBO)
    glDepthFunc GL_ALWAYS
    glDepthMask GL_FALSE
    glEnable GL_BLEND
    --glBlendFunc GL_SRC_ALPHA GL_ONE_MINUS_SRC_ALPHA
    glBlendFunc GL_ONE GL_ONE_MINUS_SRC_ALPHA -- assume premultiplied alpha
    renderLayer DebugLayer shadV pokeCounts
    glBindBufferBase GL_UNIFORM_BUFFER 0 (pdata ^. matUBO)
    withArray (scaleMatrix (2 / windowXFloat cfig) (2 / windowYFloat cfig)) $
        glNamedBufferSubData (pdata ^. matUBO) 0 64
    glDepthFunc GL_GEQUAL
    glDepthMask GL_TRUE
    with (-1) $ glClearNamedFramebufferfv 0 GL_DEPTH 0
    renderLayer FixedCoordLayer shadV pokeCounts
    SDL.glSwapWindow win

bufferPerspectiveMatrixUBO :: Config -> Camera -> GLuint -> IO ()
bufferPerspectiveMatrixUBO cfig cam uboid =
    withArray
        ( perspectiveMatrixb
            (cam ^. camRot)
            (cam ^. camZoom)
            (cam ^. camCenter)
            (V2 (windowXFloat cfig) (windowYFloat cfig))
            (cam ^. camViewFrom)
        )
        $ glNamedBufferSubData uboid 0 64

getDistortions :: Config -> World -> [Distortion]
getDistortions cfig w
    | cfig ^. gr_distortions = w ^. cWorld . lWorld . distortions
    | otherwise = []

setViewport :: (Config -> ResFactor) -> Config -> IO ()
setViewport f = uncurryV (glViewport 0 0) . getWindowSize f