(* Copyright (c) 2008, Adam Chlipala
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - The names of contributors may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *)

structure Corify :> CORIFY = struct

structure EM = ErrorMsg
structure L = Expl
structure L' = Core

structure IM = IntBinaryMap
structure SM = BinaryMapFn(struct
                           type ord_key = string
                           val compare = String.compare
                           end)

local
    val count = ref 0
in

fun reset v = count := v

fun alloc () =
    let
        val r = !count
    in
        count := r + 1;
        r
end

end

structure St : sig
    type t

    val empty : t

    val enter : t -> t
    val leave : t -> {outer : t, inner : t}

    val bindCore : t -> string -> int -> t * int
    val lookupCoreById : t -> int -> int option
    val lookupCoreByName : t -> string -> int

    val bindStr : t -> string -> int -> t -> t
    val lookupStrById : t -> int -> t
    val lookupStrByName : string * t -> t
end = struct

datatype flattening = F of {
         core : int SM.map,
         strs : flattening SM.map
}
                           
type t = {
     core : int IM.map,
     strs : flattening IM.map,
     current : flattening,
     nested : flattening list
}

val empty = {
    core = IM.empty,
    strs = IM.empty,
    current = F { core = SM.empty, strs = SM.empty },
    nested = []
}

fun bindCore {core, strs, current, nested} s n =
    let
        val n' = alloc ()

        val current =
            let
                val F {core, strs} = current
            in
                F {core = SM.insert (core, s, n'),
                   strs = strs}
            end
    in
        ({core = IM.insert (core, n, n'),
          strs = strs,
          current = current,
          nested = nested},
         n')
    end

fun lookupCoreById ({core, ...} : t) n = IM.find (core, n)

fun lookupCoreByName ({current = F {core, ...}, ...} : t) x =
    case SM.find (core, x) of
        NONE => raise Fail "Corify.St.lookupCoreByName"
      | SOME n => n

fun enter {core, strs, current, nested} =
    {core = core,
     strs = strs,
     current = F {core = SM.empty,
                  strs = SM.empty},
     nested = current :: nested}

fun dummy f = {core = IM.empty,
               strs = IM.empty,
               current = f,
               nested = []}

fun leave {core, strs, current, nested = m1 :: rest} =
        {outer = {core = core,
                  strs = strs,
                  current = m1,
                  nested = rest},
         inner = dummy current}
  | leave _ = raise Fail "Corify.St.leave"

fun bindStr ({core, strs, current = F {core = mcore, strs = mstrs}, nested} : t) x n ({current = f, ...} : t) =
    {core = core,
     strs = IM.insert (strs, n, f),
     current = F {core = mcore,
                  strs = SM.insert (mstrs, x, f)},
     nested = nested}

fun lookupStrById ({strs, ...} : t) n =
    case IM.find (strs, n) of
        NONE => raise Fail "Corify.St.lookupStr"
      | SOME f => dummy f

fun lookupStrByName (m, {current = F {strs, ...}, ...} : t) =
    case SM.find (strs, m) of
        NONE => raise Fail "Corify.St.lookupStrByName"
      | SOME f => dummy f

end


fun corifyKind (k, loc) =
    case k of
        L.KType => (L'.KType, loc)
      | L.KArrow (k1, k2) => (L'.KArrow (corifyKind k1, corifyKind k2), loc)
      | L.KName => (L'.KName, loc)
      | L.KRecord k => (L'.KRecord (corifyKind k), loc)

fun corifyCon st (c, loc) =
    case c of
        L.TFun (t1, t2) => (L'.TFun (corifyCon st t1, corifyCon st t2), loc)
      | L.TCFun (x, k, t) => (L'.TCFun (x, corifyKind k, corifyCon st t), loc)
      | L.TRecord c => (L'.TRecord (corifyCon st c), loc)

      | L.CRel n => (L'.CRel n, loc)
      | L.CNamed n =>
        (case St.lookupCoreById st n of
             NONE => (L'.CNamed n, loc)
           | SOME n => (L'.CNamed n, loc))
      | L.CModProj (m, ms, x) =>
        let
            val st = St.lookupStrById st m
            val st = foldl St.lookupStrByName st ms
            val n = St.lookupCoreByName st x
        in
            (L'.CNamed n, loc)
        end

      | L.CApp (c1, c2) => (L'.CApp (corifyCon st c1, corifyCon st c2), loc)
      | L.CAbs (x, k, c) => (L'.CAbs (x, corifyKind k, corifyCon st c), loc)

      | L.CName s => (L'.CName s, loc)

      | L.CRecord (k, xcs) =>
        (L'.CRecord (corifyKind k, map (fn (c1, c2) => (corifyCon st c1, corifyCon st c2)) xcs), loc)
      | L.CConcat (c1, c2) => (L'.CConcat (corifyCon st c1, corifyCon st c2), loc)

fun corifyExp st (e, loc) =
    case e of
        L.EPrim p => (L'.EPrim p, loc)
      | L.ERel n => (L'.ERel n, loc)
      | L.ENamed n =>
        (case St.lookupCoreById st n of
             NONE => (L'.ENamed n, loc)
           | SOME n => (L'.ENamed n, loc))
      | L.EModProj (m, ms, x) =>
        let
            val st = St.lookupStrById st m
            val st = foldl St.lookupStrByName st ms
            val n = St.lookupCoreByName st x
        in
            (L'.ENamed n, loc)
        end
      | L.EApp (e1, e2) => (L'.EApp (corifyExp st e1, corifyExp st e2), loc)
      | L.EAbs (x, dom, ran, e1) => (L'.EAbs (x, corifyCon st dom, corifyCon st ran, corifyExp st e1), loc)
      | L.ECApp (e1, c) => (L'.ECApp (corifyExp st e1, corifyCon st c), loc)
      | L.ECAbs (x, k, e1) => (L'.ECAbs (x, corifyKind k, corifyExp st e1), loc)

      | L.ERecord xes => (L'.ERecord (map (fn (c, e, t) => (corifyCon st c, corifyExp st e, corifyCon st t)) xes), loc)
      | L.EField (e1, c, {field, rest}) => (L'.EField (corifyExp st e1, corifyCon st c,
                                                       {field = corifyCon st field, rest = corifyCon st rest}), loc)

fun corifyDecl ((d, loc : EM.span), st) =
    case d of
        L.DCon (x, n, k, c) =>
        let
            val (st, n) = St.bindCore st x n
        in
            ([(L'.DCon (x, n, corifyKind k, corifyCon st c), loc)], st)
        end
      | L.DVal (x, n, t, e) =>
        let
            val (st, n) = St.bindCore st x n
        in
            ([(L'.DVal (x, n, corifyCon st t, corifyExp st e), loc)], st)
        end
                                                                        
      | L.DSgn _ => ([], st)

      | L.DStr (x, n, _, str) =>
        let
            val (ds, {inner, outer}) = corifyStr (str, st)
            val st = St.bindStr outer x n inner
        in
            (ds, st)
        end

and corifyStr ((str, _), st) =
    case str of
        L.StrConst ds =>
        let
            val st = St.enter st
            val (ds, st) = ListUtil.foldlMapConcat corifyDecl st ds
        in
            (ds, St.leave st)
        end
      | L.StrVar n => ([], {inner = St.lookupStrById st n, outer = st})
      | L.StrProj (str, x) =>
        let
            val (ds, {inner, outer}) = corifyStr (str, st)
        in
            (ds, {inner = St.lookupStrByName (x, inner), outer = outer})
        end

fun maxName ds = foldl (fn ((d, _), n) =>
                           case d of
                               L.DCon (_, n', _, _) => Int.max (n, n')
                             | L.DVal (_, n', _ , _) => Int.max (n, n')
                             | L.DSgn (_, n', _) => Int.max (n, n')
                             | L.DStr (_, n', _, str) => Int.max (n, Int.max (n', maxNameStr str)))
                 0 ds

and maxNameStr (str, _) =
    case str of
        L.StrConst ds => maxName ds
      | L.StrVar n => n
      | L.StrProj (str, _) => maxNameStr str

fun corify ds =
    let
        val () = reset (maxName ds + 1)
        val (ds, _) = ListUtil.foldlMapConcat corifyDecl St.empty ds
    in
        ds
    end

end