#!/usr/bin/env runhaskell

import Data.Char.CEDICT.GenerateCode

import System.IO.UTF8
import System.IO hiding
  ( appendFile
  , getContents
  , getLine
  , print
  , putStr
  , putStrLn
  , readFile
  , readLn
  , writeFile
  , hGetContents
  , hGetLine
  , hPutStr
  , hPutStrLn
  )
import Prelude hiding
  ( appendFile
  , getContents
  , getLine
  , print
  , putStr
  , putStrLn
  , readFile
  , readLn
  , writeFile
  ) 

import Distribution.Simple
import Distribution.PackageDescription
import Control.Monad
import System.FilePath
import System.Directory
import System.Time
import System.Locale

hooks                        =  defaultUserHooks { preBuild = optionalGenC }


main                         =  defaultMainWithHooks hooks


optionalGenC _ _             =  do
  n                         <-  needed
  when n genC 
  return emptyHookedBuildInfo
 where
  headerPath                 =  combine "c" "data.h"
  dictPath                   =  combine "d" "utf8-cedict"
  needed                     =  do
    f'                      <-  doesFileExist headerPath
    f''                     <-  if f' then tCompare else return True
    when (not f'') $ putStrLn $ "Found existing header file at " ++ headerPath
    return f''
  genC                       =  do
    hPutStrLn stderr "Generating CEDICT header file -- may take a few minutes."
    t                       <-  bench $ readAndWrite dictPath headerPath 
    hPutStrLn stderr $ "  " ++ show t ++ " seconds"
  tCompare                   =  do
    headerTime              <-  getModificationTime headerPath
    dictTime                <-  getModificationTime dictPath
    return $ headerTime < dictTime 
    

bench op                     =  do
  ts                        <-  getClockTime
  op 
  tf                        <-  getClockTime
  return $ tdSec $ diffClockTimes tf ts