module Haddock.InterfaceFile (
  InterfaceFile(..),
  writeInterfaceFile,
  readInterfaceFile,
  hmod2interface
) where

import Haddock.Types
import Haddock.Exception

import Data.List
import Data.Word
import Data.Array
import Data.IORef
import qualified Data.Map as Map
import System.IO
import Control.Monad

import Binary
import Name
import UniqSupply
import UniqFM
import IfaceEnv
import Module
import Packages
import SrcLoc
import HscTypes
import FastMutInt
import InstEnv
import HsDoc

data InterfaceMod = InterfaceMod {
  imModule       :: Module,
  imFilename     :: FilePath,
  imExportItems  :: [ExportItem DocName]
}

data InterfaceFile = InterfaceFile {
  ifDocEnv  :: DocEnv
--  ifModules :: [InterfaceMod]  
} 

instance Binary InterfaceFile where
  put_ bh (InterfaceFile x) = put_ bh (Map.toList x)
  get  bh = do
    env <- get bh
    return (InterfaceFile (Map.fromList env))

hmod2interface hmod = InterfaceMod {
  imModule      = hmod_mod             hmod,
  imFilename    = hmod_orig_filename   hmod,
  imExportItems = hmod_rn_export_items hmod
}
  
binaryInterfaceMagic = 0xD0Cface :: Word32
binaryInterfaceVersion = 0 :: Word16

initBinMemSize = (1024*1024) :: Int

writeInterfaceFile :: FilePath -> InterfaceFile -> IO ()
writeInterfaceFile filename iface = do 
  bh <- openBinMem initBinMemSize
  put_ bh binaryInterfaceMagic
  put_ bh binaryInterfaceVersion

  -- remember where the dictionary pointer will go
  dict_p_p <- tellBin bh
  put_ bh dict_p_p	

  -- remember where the symbol table pointer will go
  symtab_p_p <- tellBin bh
  put_ bh symtab_p_p

  -- Make some intial state
  ud <- newWriteState

  -- put the main thing
  bh <- return $ setUserData bh ud
  put_ bh iface

  -- write the symtab pointer at the fornt of the file
  symtab_p <- tellBin bh
  putAt bh symtab_p_p symtab_p
  seekBin bh symtab_p		

  -- write the symbol table itself
  symtab_next <- readFastMutInt (ud_symtab_next ud)
  symtab_map  <- readIORef (ud_symtab_map ud)
  putSymbolTable bh symtab_next symtab_map

  -- write the dictionary pointer at the fornt of the file
  dict_p <- tellBin bh
  putAt bh dict_p_p dict_p
  seekBin bh dict_p

  -- write the dictionary itself
  dict_next <- readFastMutInt (ud_dict_next ud)
  dict_map  <- readIORef (ud_dict_map ud)
  putDictionary bh dict_next dict_map

	-- snd send the result to the file
  writeBinMem bh filename
  return ()
    
readInterfaceFile :: FilePath -> IO InterfaceFile
readInterfaceFile filename = do
  bh <- readBinMem filename

  magic <- get bh
  when (magic /= binaryInterfaceMagic) $ throwE $
    "Magic number mismatch: couldn't load interface file: " ++ filename

  version <- get bh
  when (version /= binaryInterfaceVersion) $ throwE $
    "Interface file is of wrong version: " ++ filename

  -- get the dictionary
  dict_p <- get bh
  data_p <- tellBin bh		
  seekBin bh dict_p
  dict <- getDictionary bh
  seekBin bh data_p		

  -- initialise the user-data field of bh
  ud <- newReadState dict
  bh <- return (setUserData bh ud)
	
  -- get the symbol table
  symtab_p <- get bh
  data_p   <- tellBin bh
  seekBin bh symtab_p
  -- (construct an empty name cache)
  u  <- mkSplitUniqSupply 'a' -- ??
  let nc = initNameCache u []
  (_, symtab) <- getSymbolTable bh nc
  seekBin bh data_p

  -- set the symbol table
  let ud = getUserData bh
  bh <- return $! setUserData bh ud{ud_symtab = symtab}

  -- load the actual data
  iface <- get bh
  return iface

-------------------------------------------------------------------------------
-- Symbol table
-------------------------------------------------------------------------------

putSymbolTable :: BinHandle -> Int -> UniqFM (Int,Name) -> IO ()
putSymbolTable bh next_off symtab = do
  put_ bh next_off
  let names = elems (array (0,next_off-1) (eltsUFM symtab))
  mapM_ (\n -> serialiseName bh n symtab) names

getSymbolTable :: BinHandle -> NameCache -> IO (NameCache, Array Int Name)
getSymbolTable bh namecache = do
  sz <- get bh
  od_names <- sequence (replicate sz (get bh))
  let 
        arr = listArray (0,sz-1) names
        (namecache', names) =    
                mapAccumR (fromOnDiskName arr) namecache od_names
  --
  return (namecache', arr)

type OnDiskName = (PackageId, ModuleName, OccName)

fromOnDiskName
   :: Array Int Name
   -> NameCache
   -> OnDiskName
   -> (NameCache, Name)
fromOnDiskName arr nc (pid, mod_name, occ) =
  let 
        mod   = mkModule pid mod_name
        cache = nsNames nc
  in
  case lookupOrigNameCache cache  mod occ of
     Just name -> (nc, name)
     Nothing   -> 
        let 
                us        = nsUniqs nc
                uniq      = uniqFromSupply us
                name      = mkExternalName uniq mod occ noSrcSpan
                new_cache = extendNameCache cache mod occ name
        in        
        case splitUniqSupply us of { (us',_) -> 
        ( nc{ nsUniqs = us', nsNames = new_cache }, name )
        }

serialiseName :: BinHandle -> Name -> UniqFM (Int,Name) -> IO ()
serialiseName bh name symtab = do
  let mod = nameModule name
  put_ bh (modulePackageId mod, moduleName mod, nameOccName name)