module GF.Canon.CanonToJS (prCanon2js) where

import GF.Canon.GFC
import GF.Canon.CanonToGFCC
import GF.Canon.Look
import GF.Data.ErrM
import GF.Infra.Option
import qualified GF.Canon.GFCC.AbsGFCC as C
import qualified GF.JavaScript.AbsJS as JS
import qualified GF.JavaScript.PrintJS as JS


import Control.Monad (mplus)
import Data.Maybe (fromMaybe)

prCanon2js :: Options -> CanonGrammar -> String
prCanon2js opts gr = gfcc2js start $ mkCanon2gfcc gr
  where 
    start = fromMaybe "S" (getOptVal opts gStartCat 
                           `mplus` getOptVal grOpts gStartCat)
    grOpts = errVal noOptions $ lookupOptionsCan gr

gfcc2js :: String -> C.Grammar -> String
gfcc2js start (C.Grm (C.Hdr n _) as cs) = 
  JS.printTree $ JS.Program $ abstract2js start n as ++ concatMap (concrete2js n) cs

abstract2js :: String -> C.CId -> C.Abstract -> [JS.Element]
abstract2js start (C.CId n) (C.Abs ds) = 
    [JS.ElStmt $ JS.SDeclOrExpr $ JS.Decl [JS.DInit a (new "Abstract" [JS.EStr start])]] 
    ++ concatMap (absdef2js a) ds
  where a = JS.Ident n

absdef2js :: JS.Ident -> C.AbsDef -> [JS.Element]
absdef2js a (C.Fun (C.CId f) (C.Typ args (C.CId cat)) _) = 
    [JS.ElStmt $ JS.SDeclOrExpr $ JS.DExpr $ JS.ECall (JS.EMember (JS.EVar a) (JS.Ident "addType")) 
           [JS.EStr f, JS.EArray [JS.EStr x | C.CId x <- args], JS.EStr cat]]

concrete2js :: C.CId -> C.Concrete -> [JS.Element]
concrete2js (C.CId a) (C.Cnc (C.CId c) ds) = 
    [JS.ElStmt $ JS.SDeclOrExpr $ JS.Decl [JS.DInit l (new "Concrete" [JS.EVar (JS.Ident a)])]] 
    ++ concatMap (cncdef2js l) ds
  where l = JS.Ident c

cncdef2js :: JS.Ident -> C.CncDef -> [JS.Element]
cncdef2js l (C.Lin (C.CId f) t) = 
    [JS.ElStmt $ JS.SDeclOrExpr $ JS.DExpr $ JS.ECall (JS.EMember (JS.EVar l) (JS.Ident "addRule")) [JS.EStr f, JS.EFun [children] [JS.SReturn (term2js l t)]]]

term2js :: JS.Ident -> C.Term -> JS.Expr
term2js l t = f t
  where 
  f t = 
    case t of
      C.R xs           -> new "Arr" (map f xs)
      C.P x y          -> JS.ECall (JS.EMember (f x) (JS.Ident "sel")) [f y]
      C.S xs           -> new "Seq" (map f xs)
      C.K t            -> tokn2js t
      C.V i            -> JS.EIndex (JS.EVar children) (JS.EInt i)
      C.C i            -> new "Int" [JS.EInt i]
      C.F (C.CId f)    -> JS.ECall (JS.EMember (JS.EVar l) (JS.Ident "rule")) [JS.EStr f, JS.EVar children]
      C.FV xs          -> new "Variants" (map f xs)
      C.W str x        -> new "Suffix" [JS.EStr str, f x]
      C.RP x y         -> new "Rp" [f x, f y]
      C.TM             -> new "Meta" []

tokn2js :: C.Tokn -> JS.Expr
tokn2js (C.KS s) = new "Str" [JS.EStr s]
tokn2js (C.KP ss vs) = new "Seq" (map JS.EStr ss) -- FIXME

argIdent :: Integer -> JS.Ident
argIdent n = JS.Ident ("x" ++ show n)

children :: JS.Ident
children = JS.Ident "cs"

new :: String -> [JS.Expr] -> JS.Expr
new f xs = JS.ENew (JS.Ident f) xs