{--------------------------------------------------------------
-
- The main program of the XQuery interpreter
- Programmer: Leonidas Fegaras (fegaras@cse.uta.edu)
- Date: 05/02/2008
-
---------------------------------------------------------------}

{-# OPTIONS_GHC -fth #-}

module Main where

import System.Environment
import qualified Control.Exception
import XQueryCompiler(functions)
import XQueryInterpreter(evalInput,xqueryE)
import XQuery

version = "0.7.4"


parseEnv :: [String] -> [(String,String)]
parseEnv [] = [("o","Temp.hs")]
parseEnv ("-help":xs) = ("help",""):(parseEnv xs)
parseEnv ("-c":file:xs) = ("c",file):(parseEnv xs)
parseEnv ("-o":file:xs) = ("o",file):(parseEnv xs)
parseEnv ("-p":query:file:xs) = ("p","doc('"++file++"')"++query):(parseEnv xs)
parseEnv (('-':x):_) = error ("Unrecognized option -"++x++". Use -help.")
parseEnv (file:xs) = ("r",file):(parseEnv xs)


main = do putStrLn ("HXQ: XQuery Interpreter version "++version++". Use -help for help.")
          senv <- getArgs
          let env = parseEnv senv
              Just system_path = lookup "ghc" env
              Just hxq_path = lookup "hxq" env
          case lookup "help" env of
            Just _ -> do putStrLn "Command line options and files:"
                         putStrLn "   xquery-file               interpret the XQuery in xquery-file"
                         putStrLn "   -c xquery-file            compile the XQuery in xquery-file into Haskell code"
                         putStrLn "   -o haskell-file           set the Haskell file for -c (default is Temp.hs)"
                         putStrLn "   -p XPath-query xml-file   interpret the XPath query against the xml-file"
                         putStrLn "Without options, it reads and interprets the input:"
                         putStrLn "   The input may be an XQuery or a declare variable or function"
                         putStrLn "   To write an XQuery in multiple lines, wrap it in {}"
                         putStrLn ("Functions:  "++(foldr (\(f,_,_) r -> f++" "++r) "" functions))
            _ -> case lookup "c" env of
                   Just file -> do query <- readFile file
                                   let qf = map (\c -> if c=='\"' then '\'' else c)
                                                (foldr1 (\a r -> a++" "++r) (lines query))
                                       pr = "{-# OPTIONS_GHC -fth #-}\nmodule Main where\nimport XQuery\n\nmain = do res <- $(xq \""
                                            ++ qf ++ "\")\n          putXSeq res\n"
                                       Just ofile = lookup "o" env
                                   writeFile ofile pr
                   _ -> case lookup "r" env of
                          Just file -> do result <- xfile file
                                          putXSeq result
                          _ -> case lookup "p" env of
                                 Just query -> do result <- xquery query
                                                  putXSeq result
                                 _ -> evalInput (\s vs fs-> Control.Exception.catch (do (result,nvs,nfs) <- xqueryE s vs fs
                                                                                        putXSeq result
                                                                                        return (nvs,nfs))
                                                                              (\e -> do putStrLn (show e); return (vs,fs))) [] []