(* check-mid-il.sml
 *
 * COPYRIGHT (c) 2010 The Diderot Project (http://diderot-language.cs.uchicago.edu)
 * All rights reserved.
 *)

structure CheckOps : OPERATOR_TY = struct

    structure Op = MidOps
    structure Ty = MidILTypes

    type rator = Op.rator
    type ty = Ty.ty

    val vec3Ty = Ty.vecTy 3

  (* utility function for synthesizing eigenvector/eigenvalue signature *)
    fun eigenSig dim = let
          val tplTy = Ty.TupleTy[
                  Ty.SeqTy(Ty.realTy, dim),
                  Ty.SeqTy(Ty.vecTy dim, dim)
                ]
          in
            (tplTy, [Ty.TensorTy[dim, dim]])
          end

  (* Return the signature of a MidIL operator. *)
    fun sigOf rator = (case rator
           of Op.Add ty => (ty, [ty, ty])
            | Op.Sub ty => (ty, [ty, ty])
            | Op.Mul ty => (ty, [ty, ty])
            | Op.Div ty => (ty, [ty, ty])
            | Op.Neg ty => (ty, [ty])
            | Op.Abs ty => (ty, [ty])
            | Op.LT ty => (Ty.BoolTy, [ty, ty])
            | Op.LTE ty => (Ty.BoolTy, [ty, ty])
            | Op.EQ ty => (Ty.BoolTy, [ty, ty])
            | Op.NEQ ty => (Ty.BoolTy, [ty, ty])
            | Op.GT ty => (Ty.BoolTy, [ty, ty])
            | Op.GTE ty => (Ty.BoolTy, [ty, ty])
            | Op.Not => (Ty.BoolTy, [Ty.BoolTy])
            | Op.Max => (Ty.realTy, [Ty.realTy, Ty.realTy])
            | Op.Min => (Ty.realTy, [Ty.realTy, Ty.realTy])
            | Op.Clamp ty => (ty, [ty, ty, ty])
            | Op.Lerp ty => (ty, [ty, ty, Ty.realTy])
            | Op.Dot d => (Ty.realTy, [Ty.vecTy d, Ty.vecTy d])
            | Op.MulVecMat(d1, d2) => (Ty.vecTy d2, [Ty.vecTy d1, Ty.TensorTy[d1, d2]])
            | Op.MulMatVec(d1, d2) => (Ty.vecTy d1, [Ty.TensorTy[d1, d2], Ty.vecTy d2])
            | Op.MulMatMat(d1, d2, d3) => (Ty.TensorTy[d1, d3], [Ty.TensorTy[d1, d2], Ty.TensorTy[d2, d3]])
            | Op.MulVecTen3(d1, d2, d3) => (Ty.TensorTy[d2, d3], [Ty.vecTy d1, Ty.TensorTy[d1, d2, d3]])
            | Op.MulTen3Vec(d1, d2, d3) => (Ty.TensorTy[d1, d2], [Ty.TensorTy[d1, d2, d3], Ty.vecTy d3])
            | Op.ColonMul(ty1 as Ty.TensorTy dd1, ty2 as Ty.TensorTy(d21::d22::dd2)) => let
                fun last2 ([d1, d2], prefix) = (prefix, d1, d2)
                  | last2 (d::dd, prefix) = last2(dd, d::prefix)
                  | last2 _ = raise Fail("sigOf: invalid operator " ^ Op.toString rator)
                val (prefix, d11, d12) = last2 (dd1, [])
                in
                  if (d11 <> d21) orelse (d12 <> d22)
                    then raise Fail("sigOf: invalid operator " ^ Op.toString rator)
                    else (Ty.TensorTy(List.revAppend(prefix, dd2)), [ty1, ty2])
                end
            | Op.Cross => (vec3Ty, [vec3Ty, vec3Ty])
            | Op.Norm(ty as Ty.TensorTy _) => (Ty.realTy, [ty])
            | Op.Normalize d => (Ty.vecTy d, [Ty.vecTy d])
            | Op.Scale(ty as Ty.TensorTy(_::_)) => (ty, [Ty.realTy, ty])
            | Op.PrincipleEvec _ => raise Fail "Op.PrincipleEvec unimplemented"
            | Op.EigenVecs2x2 => eigenSig 2
            | Op.EigenVecs3x3 => eigenSig 3
            | Op.EigenVals2x2 => (Ty.SeqTy(Ty.realTy, 2), [Ty.TensorTy[2,2]])
            | Op.EigenVals3x3 => (Ty.SeqTy(Ty.realTy, 3), [Ty.TensorTy[3,3]])
            | Op.Identity d => (Ty.TensorTy[d,d], [])
            | Op.Zero ty => (ty, [])
            | Op.Trace d => (Ty.realTy, [Ty.TensorTy[d, d]])
            | Op.Transpose(d1, d2) => (Ty.TensorTy[d2, d1], [Ty.TensorTy[d1, d2]])
            | Op.Select(ty as Ty.TupleTy tys, i) => (List.nth(tys, i-1), [ty])
            | Op.Index(ty as Ty.TensorTy[d], _) => (Ty.realTy, [ty])
            | Op.Index(ty as Ty.SeqTy(elemTy, _), _) => (elemTy, [ty])
            | Op.Subscript(ty as Ty.TensorTy dd) => (Ty.realTy, ty :: List.map (fn _ => Ty.intTy) dd)
            | Op.Subscript(ty as Ty.SeqTy(elemTy, d)) => (elemTy, [ty, Ty.intTy])
            | Op.Subscript(ty as Ty.DynSeqTy(elemTy)) => (elemTy, [ty, Ty.intTy])
            | Op.MkDynamic(ty, n) => (Ty.DynSeqTy ty, [Ty.SeqTy(ty, n)])
            | Op.Prepend ty => (Ty.DynSeqTy ty, [ty, Ty.DynSeqTy ty])
            | Op.Append ty => (Ty.DynSeqTy ty, [Ty.DynSeqTy ty, ty])
            | Op.Concat ty => (Ty.DynSeqTy ty, [Ty.DynSeqTy ty, Ty.DynSeqTy ty])
            | Op.Length ty => (Ty.intTy, [Ty.DynSeqTy ty])
            | Op.Ceiling d => (Ty.vecTy d, [Ty.vecTy d])
            | Op.Floor d => (Ty.vecTy d, [Ty.vecTy d])
            | Op.Round d => (Ty.vecTy d, [Ty.vecTy d])
            | Op.Trunc d => (Ty.vecTy d, [Ty.vecTy d])
            | Op.IntToReal => (Ty.realTy, [Ty.intTy])
            | Op.RealToInt 1 => (Ty.IntTy, [Ty.realTy])
            | Op.RealToInt d => (Ty.SeqTy(Ty.IntTy, d), [Ty.TensorTy[d]])
(* FIXME: the type of RealToInt should be
            | Op.RealToInt d => (Ty.SeqTy(Ty.IntTy, d), [Ty.SeqTy(Ty.realTy, d)])
*)
            | Op.VoxelAddress(info, offset) => let
                val dim = ImageInfo.dim info
                in
                  (Ty.AddrTy info, Ty.ImageTy info :: List.tabulate(dim, fn _ => Ty.intTy))
                end
            | Op.LoadVoxels(info, n) => (Ty.vecTy n, [Ty.AddrTy info])
            | Op.PosToImgSpace info => let
                val dim = ImageInfo.dim info
                in
                  (Ty.vecTy dim, [Ty.ImageTy info, Ty.vecTy dim])
                end
            | Op.TensorToWorldSpace(info, ty) => (ty, [Ty.ImageTy info, ty])
            | Op.EvalKernel(d, _, _) => (Ty.vecTy d, [Ty.vecTy d])
            | Op.Inside(info, _) => (Ty.BoolTy, [Ty.vecTy(ImageInfo.dim info), Ty.ImageTy info])
            | Op.LoadSeq(ty, _) => (ty, [])
            | Op.LoadImage(ty, _, _) => (ty, [])
            | Op.Input(Inputs.INP{ty, ...}) => (ty, [])
            | Op.Print tys => (Ty.TupleTy[], tys)
            | _ => raise Fail("sigOf: invalid operator " ^ Op.toString rator)
          (* end case *))

    fun typeOfCons (_, []) = false
      | typeOfCons (Ty.SeqTy(ty, n), tys) =
          List.all (fn ty' => Ty.same(ty, ty')) tys andalso (List.length tys = n)
      | typeOfCons (expectedTy, tys as ty1::_) =
          if List.all (fn ty => Ty.same(ty1, ty)) tys
            then (case (expectedTy, ty1)
               of (Ty.SeqTy(_, n), Ty.IntTy) => (n = List.length tys)
                | (Ty.TensorTy dd, Ty.TensorTy dd') => (dd = List.length tys :: dd')
                | _ => false
              (* end case *))
            else false

  end

structure CheckMidIL = CheckILFn (
    structure IL = MidIL
    structure OpTy = CheckOps)

structure MidPP = SSAPPFn (MidIL)