{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FunctionalDependencies #-}
{- |
 - Module      : GLSL.Internal.Compile
 - Description : prints
 - Copyright   : 2025 Andromeda
 - License     : BSD 3-Clause
 - Maintainer  : @Andromeda:tchncs.de
 - Stability   : Experimental
 -}
module GLSL.Internal.Compile where

import GLSL.Internal

-- | prints version as version header
showVersion :: Version -> String
showVersion Version'330_core = "#version 330 core"

-- | prints variable with uniform qualifier
showUniform :: Var -> String
showUniform var = "uniform " ++ showVar var

-- | prints variable with in qualifier
showIn :: Var -> String
showIn var = "in " ++ showVar var

-- | prints variable with layout (location = <>) in qualifier
showLayoutIn :: (Int, Var) -> String
showLayoutIn (i, var) = "layout (location = " ++ show i ++ ") in " ++ showVar var

-- | prints variable with out qualifier
showOut :: Var -> String
showOut var = "out " ++ showVar var

-- | prints variable declaration <typ> <name>
showVar :: Var -> String
showVar (Var name typ) = showType typ ++ " " ++ showId name

-- | prints a dynamic expression
showDExp :: DExp -> String
showDExp (Lit'float f) = show f
showDExp (E'var (Var name _)) = showId name
showDExp (E'let (Var name _) exp0) = showId name ++ " = " ++ showDExp exp0
showDExp (E'if cond exp0 exp1) = "if " ++ showDExp cond ++ "\nthen\n" ++ showDExp exp0 ++ "\nelse\n" ++ showDExp exp1
showDExp (E'add exp0 exp1) = showDExp exp0 ++ " + " ++ showDExp exp1
showDExp (E'mul exp0 exp1) = showDExp exp0 ++ " * " ++ showDExp exp1
showDExp (E'normalize exp0) = "normalize(" ++ showDExp exp0 ++ ")"
showDExp (Lit'bool cond) = if cond then "true" else "false"
showDExp (Lit'vec2 exp0) = showDExp exp0
showDExp (Lit'vec3 exp0) = showDExp exp0
showDExp (Lit'vec4 exp0) = showDExp exp0
showDExp (E'vec2_2 f0 f1) = "vec2(" ++ showDExp f0 ++ ", " ++ showDExp f1 ++ ")"
showDExp (E'vec3_2 f0 f1) = "vec3(" ++ showDExp f0 ++ ", " ++ showDExp f1 ++ ")"
showDExp (E'vec4_2 f0 f1) = "vec4(" ++ showDExp f0 ++ ", " ++ showDExp f1 ++ ")"
showDExp (E'vec3_3 f0 f1 f2) = "vec3(" ++ showDExp f0 ++ ", " ++ showDExp f1 ++ ", " ++ showDExp f2 ++ ")"
showDExp (E'vec4_3 f0 f1 f2) = "vec4(" ++ showDExp f0 ++ ", " ++ showDExp f1 ++ ", " ++ showDExp f2 ++ ")"
showDExp (E'vec4_4 f0 f1 f2 f3) = "vec4(" ++ showDExp f0 ++ ", " ++ showDExp f1 ++ ", " ++ showDExp f2 ++ ", " ++ showDExp f3 ++ ")"

-- | toString for Type
showType :: Type -> String
showType T'bool = "bool"
showType T'float = "float"
showType T'vec2 = "vec2"
showType T'vec3 = "vec3"
showType T'vec4 = "vec4"
showType T'mat4 = "mat4"

-- | prints verbatim identifier
showId :: Id -> String
showId (Id s) = s