{-# LANGUAGE ForeignFunctionInterface, TypeSynonymInstances #-}

{- TODO

Rip the array trnaslation stuff out to a utility function. same with hashes.

install as package. This is a bit iffy for GHC/JHC compatibility - if we commit to
Cabal, that leaves JHC out in the cold.

perhaps need cabal file for ghc and equivalent for jhc.

also: do we want to support different versions of ruby? for the moment, you just get
whichever ruby.h is first in the search place.

-}


module Language.Ruby.Hubris.Binding where
#include "rshim.h"
#include <ruby.h>

import Control.Applicative
-- import Control.Monad
import Data.Word
-- import Foreign.Ptr
import Foreign.C.Types	
import Foreign.C.String
-- import Foreign.Storable
import System.IO.Unsafe (unsafePerformIO)

-- import Foreign.Marshal.Array

{# context lib="rshim" #}

{# enum RubyType {} deriving (Eq, Show) #} -- maybe Ord?
rubyType :: Value -> RubyType
rubyType = toEnum . rtype

constToRuby :: RubyConst -> Value
constToRuby = fromIntegral . fromEnum 

#if RUBY_VERSION_CODE <= 187
data RubyConst  = RUBY_Qfalse 
                | RUBY_Qtrue  
                | RUBY_Qnil   
                | RUBY_Qundef 

instance Enum RubyConst where
  fromEnum RUBY_Qfalse = 0
  fromEnum RUBY_Qtrue = 2
  fromEnum RUBY_Qnil = 4
  fromEnum RUBY_Qundef = 6

  toEnum 0 = RUBY_Qfalse
  toEnum 2 = RUBY_Qtrue
  toEnum 4 = RUBY_Qnil
  toEnum 6 = RUBY_Qundef
#else
{# enum ruby_special_consts as RubyConst {} deriving (Eq,Show) #}
#endif

str2cstr str = rb_str2cstr str 0
type Value = CULong -- FIXME, we'd prefer to import the type VALUE directly
foreign import ccall safe "ruby.h rb_str2cstr"    rb_str2cstr    :: Value -> CInt -> IO CString
foreign import ccall safe "ruby.h rb_str_new2"    rb_str_new2    :: CString -> IO Value
foreign import ccall safe "ruby.h rb_str_new2"    rb_str_new_    :: CString -> Int -> IO Value 
foreign import ccall safe "ruby.h rb_ary_new2"    rb_ary_new2    :: CLong -> IO Value
foreign import ccall safe "ruby.h rb_ary_push"    rb_ary_push    :: Value -> Value -> IO ()
foreign import ccall safe "ruby.h rb_float_new"   rb_float_new   :: Double -> Value
foreign import ccall safe "ruby.h rb_big2str"     rb_big2str     :: Value -> Int -> IO Value
foreign import ccall safe "ruby.h rb_str_to_inum" rb_str_to_inum :: Value -> Int -> Int -> Value
-- foreign import ccall safe "ruby.h ruby_init" ruby_init :: IO ()

rb_str_new = uncurry rb_str_new_

-- we're being a bit filthy here - the interface is all macros, so we're digging in to find what it actually is
foreign import ccall safe "rshim.h rb_ary_len" rb_ary_len :: Value -> CUInt
foreign import ccall safe "rshim.h rtype"      rtype      :: Value -> Int

foreign import ccall safe "rshim.h int2fix"    int2fix    :: Int -> Value
foreign import ccall safe "rshim.h fix2int"    fix2int    :: Value -> Int
foreign import ccall safe "rshim.h num2dbl"    num2dbl    :: Value -> Double  -- technically CDoubles, but jhc promises they're the same
foreign import ccall safe "rshim.h keys"       rb_keys    :: Value -> IO Value
foreign import ccall safe "rshim.h buildException" buildException :: CString -> IO Value
-- foreign import ccall safe "ruby.h rb_funcall" rb_funcall :: Value -> ID ->

-- this line crashes jhc
foreign import ccall safe "intern.h rb_ary_entry" rb_ary_entry :: Value -> CLong -> IO Value

foreign import ccall safe "ruby.h rb_raise" rb_raise :: Value -> CString -> IO ()
foreign import ccall safe "ruby.h rb_eval_string" rb_eval_string :: CString -> IO Value

foreign import ccall safe "intern.h rb_hash_aset" rb_hash_aset :: Value -> Value -> Value -> IO ()
foreign import ccall safe "intern.h rb_hash_new" rb_hash_new :: IO Value
foreign import ccall safe "intern.h rb_hash_aref" rb_hash_aref :: Value -> Value -> IO Value


createException :: String -> IO Value
createException s = newCAString s >>= buildException --  ("puts HaskellError.methods(); HaskellError.new") >>= rb_eval_string



-- data RValue = T_NIL  
--             | T_FLOAT Double
--             | T_STRING Value

--             -- List is non-ideal. Switch to uvector? Array? There's always going
--             -- to be an extraction step to pull the RValues out.
--             | T_ARRAY [RValue]
--             | T_FIXNUM Int 
--             | T_HASH  Value --  Int -- definitely FIXME - native ruby hashes, or going to transliterate into Data.Map?
--             | T_BIGNUM Integer    

--             -- technically, these are mapping over the types True and False,
--             -- I'm going to treat them as values, though.
--             | T_TRUE  
--             | T_FALSE      
--             | T_OBJECT Value
--             | T_CLASS  Value
-- --            | T_EXCEPTION String
--             | T_SYMBOL Word -- interned string
--               deriving (Eq, Show)
-- These are the other basic Ruby structures that we're not handling yet.
--          | T_REGEXP     
--          | T_FILE
--          | T_STRUCT     
--          | T_DATA       


--          | T_MODULE     
-- -- leaky as hell
-- fromRVal :: RValue -> Value
-- fromRVal r = case r of
--            T_FLOAT d -> rb_float_new d
--            -- need to take the address of the cstr, just cast it to a value
--            -- sadly no bytestrings yet - unpack it to a list. yeah it's ugly.
--            T_STRING str -> str --  unsafePerformIO $ newCAString str >>= rb_str_new2
--            T_FIXNUM i -> int2fix i

--            -- so this is just bizarre - there's no boolean type. True and False have their own types
--            -- as well as their own values.
--            T_TRUE     -> constToRuby RUBY_Qtrue
--            T_FALSE    -> constToRuby RUBY_Qfalse
--            T_NIL      -> constToRuby RUBY_Qnil
--            T_HASH h   -> h
--            T_ARRAY l  -> unsafePerformIO $ do
--                            ary <- rb_ary_new2 $ fromIntegral $ length l
--                            mapM_ (rb_ary_push ary . fromRVal) l
--                            return ary
--            T_OBJECT v -> v
--  --          T_CLASS v -> v
--            T_BIGNUM b -> rb_str_to_inum (unsafePerformIO $ (newCAString $ show b) >>= rb_str_new2) 10 1
--            _          -> error "sorry, haven't implemented that yet."



-- fromVal :: Value -> RValue
-- fromVal v = case target of
--                RT_NIL -> T_NIL
--                RT_FIXNUM -> T_FIXNUM $ fix2int v
--                RT_STRING -> T_STRING v -- $ unsafePerformIO $ str2cstr >>= peekCString 
--                RT_FLOAT ->  T_FLOAT $ num2dbl v
--                RT_BIGNUM -> T_BIGNUM $ read  $ unsafePerformIO (rb_big2str v 10 >>= str2cstr >>= peekCString)
--                RT_TRUE -> T_TRUE
--                RT_FALSE -> T_FALSE
--                RT_HASH  -> T_HASH v
--                RT_ARRAY -> T_ARRAY $ map fromVal $ unsafePerformIO  $ mapM (rb_ary_entry v . fromIntegral) [0..(rb_ary_len v) - 1]
--                RT_OBJECT -> T_OBJECT v
-- --               RT_CLASS -> T_CLASS v
--                _ -> error ("didn't work: " ++ show target)
--       where target :: RubyType
--             target = toEnum $ rtype v