(* 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.
 *)

(* Pretty-printing C jr. *)

structure CjrPrint :> CJR_PRINT = struct

open Print.PD
open Print

open Cjr

structure E = CjrEnv
structure EM = ErrorMsg

val debug = ref false

val dummyTyp = (TNamed 0, ErrorMsg.dummySpan)

fun p_typ' par env (t, loc) =
    case t of
        TTop => string "void*"
      | TFun =>
        (EM.errorAt loc "Undetermined function type";
         string "?->")
      | TCode (t1, t2) => parenIf par (box [p_typ' true env t2,
                                            space,
                                            string "(*)",
                                            space,
                                            string "(",
                                            p_typ env t1,
                                            string ")"])
      | TRecord i => box [string "struct",
                          space,
                          string "__lws_",
                          string (Int.toString i)]
      | TNamed n =>
        (string ("__lwt_" ^ #1 (E.lookupTNamed env n) ^ "_" ^ Int.toString n)
         handle CjrEnv.UnboundNamed _ => string ("__lwt_UNBOUND__" ^ Int.toString n))
      | TFfi (m, x) => box [string "lw_", string m, string "_", string x]

and p_typ env = p_typ' false env

fun p_rel env n = string ("__lwr_" ^ #1 (E.lookupERel env n) ^ "_" ^ Int.toString (E.countERels env - n - 1))
    handle CjrEnv.UnboundRel _ => string ("__lwr_UNBOUND_" ^ Int.toString (E.countERels env - n - 1))

fun p_exp' par env (e, _) =
    case e of
        EPrim p => Prim.p_t p
      | ERel n => p_rel env n
      | ENamed n =>
        (string ("__lwn_" ^ #1 (E.lookupENamed env n) ^ "_" ^ Int.toString n)
         handle CjrEnv.UnboundNamed _ => string ("__lwn_UNBOUND_" ^ Int.toString n))
      | EFfi (m, x) => box [string "lw_", string m, string "_", string x]
      | EFfiApp (m, x, es) => box [string "lw_",
                                   string m,
                                   string "_",
                                   string x,
                                   string "(",
                                   p_list (p_exp env) es,
                                   string ")"]
      | ECode n => string ("__lwc_" ^ Int.toString n)
      | EApp (e1, e2) => parenIf par (box [p_exp' true env e1,
                                           string "(",
                                           p_exp env e2,
                                           string ")"])

      | ERecord (i, xes) => box [string "({",
                                 space,
                                 string "struct",
                                 space,
                                 string ("__lws_" ^ Int.toString i),
                                 space,
                                 string "__lw_tmp",
                                 space,
                                 string "=",
                                 space,
                                 string "{",
                                 p_list (fn (_, e) =>
                                            p_exp env e) xes,
                                 string "};",
                                 space,
                                 string "__lw_tmp;",
                                 space,
                                 string "})" ]
      | EField (e, x) =>
        box [p_exp' true env e,
             string ".",
             string x]

      | ELet (xes, e) =>
        let
            val (env, pps) = foldl (fn ((x, t, e), (env, pps)) =>
                                       let
                                           val env' = E.pushERel env x t
                                       in
                                           (env',
                                            List.revAppend ([p_typ env t,
                                                             space,
                                                             p_rel env' 0,
                                                             space,
                                                             string "=",
                                                             space,
                                                             p_exp env e,
                                                             string ";",
                                                             newline],
                                                            pps))
                                       end)
                                   (env, []) xes
        in
            box [string "({",
                 newline,
                 box (rev pps),
                 p_exp env e,
                 space,
                 string ";",
                 newline,
                 string "})"]
        end

and p_exp env = p_exp' false env

fun p_decl env ((d, _) : decl) =
    case d of
        DStruct (n, xts) =>
        box [string "struct",
             space,
             string ("__lws_" ^ Int.toString n),
             space,
             string "{",
             newline,
             p_list_sep (box []) (fn (x, t) => box [p_typ env t,
                                                    space,
                                                    string x,
                                                    string ";",
                                                    newline]) xts,
             string "};"]

      | DVal (x, n, t, e) =>
        box [p_typ env t,
             space,
             string ("__lwn_" ^ x ^ "_" ^ Int.toString n),
             space,
             string "=",
             space,
             p_exp env e,
             string ";"]
      | DFun (n, x, dom, ran, e) =>
        let
            val env' = E.pushERel env x dom
        in
            box [p_typ env ran,
                 space,
                 string ("__lwc_" ^ Int.toString n),
                 string "(",
                 p_typ env dom,
                 space,
                 p_rel env' 0,
                 string ")",
                 space,
                 string "{",
                 newline,
                 box[string "return(",
                     p_exp env' e,
                     string ");"],
                 newline,
                 string "}"]
        end

fun p_page env (xts, (e, loc)) =
    case e of
        ERecord (_, xes) =>
        let
            fun read x = ListUtil.search (fn (x', e) => if x' = x then SOME e else NONE) xes
        in
            case (read "code", read "env") of
                (SOME code, SOME envx) =>
                (case #1 code of
                     ECode i =>
                     let
                         val (_, (dom, _), _) = E.lookupF env i
                     in
                         case dom of
                             TRecord ri =>
                             let
                                 val axts = E.lookupStruct env ri
                                 fun read x = ListUtil.search (fn (x', t) => if x' = x then SOME t else NONE) axts
                             in
                                 case read "arg" of
                                     NONE => string "Page handler is too complicated! [5]"
                                   | SOME (at, _) =>
                                     case at of
                                         TRecord ari =>
                                         let
                                             val r = (ERecord (ri, [("env", envx),
                                                                    ("arg", (ERecord (ari, []), loc))]), loc)
                                         in
                                             box [string "return",
                                                  space,
                                                  p_exp env (EApp (code, r), loc),
                                                  string ";"]
                                         end
                                       | _ => string "Page handler is too complicated! [6]"
                             end
                           | _ => string "Page handler is too complicated! [4]"
                     end
                   | _ => string "Page handler is too complicated! [3]")

              | _ => string "Page handler is too complicated! [1]"
        end
      | _ => string "Page handler is too complicated! [2]"

fun p_file env (ds, ps) =
    let
        val (pds, env) = ListUtil.foldlMap (fn (d, env) =>
                                             (p_decl env d,
                                              E.declBinds env d))
                             env ds
        val pds' = map (p_page env) ps
    in
        box [string "#include \"lacweb.h\"",
             newline,
             newline,
             p_list_sep newline (fn x => x) pds,
             newline,
             string "char *lw_handle(void) {",
             newline,
             p_list_sep newline (fn x => x) pds',
             newline,
             string "}",
             newline]
    end

end