------------------------------------------------------------------------------
--                             G N A T C O L L                              --
--                                                                          --
--                     Copyright (C) 2003-2017, AdaCore                     --
--                                                                          --
-- This library is free software;  you can redistribute it and/or modify it --
-- under terms of the  GNU General Public License  as published by the Free --
-- Software  Foundation;  either version 3,  or (at your  option) any later --
-- version. This library is distributed in the hope that it will be useful, --
-- but WITHOUT ANY WARRANTY;  without even the implied warranty of MERCHAN- --
-- TABILITY or FITNESS FOR A PARTICULAR PURPOSE.                            --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
------------------------------------------------------------------------------

with Ada.Strings.Fixed; use Ada.Strings.Fixed;
with Ada.Unchecked_Deallocation;
with GNAT.Strings;      use GNAT.Strings;

package body GNATCOLL.Scripts.Utils is

   ------------------------------------
   -- Argument_List_To_Quoted_String --
   ------------------------------------

   function Argument_List_To_Quoted_String
     (Args            : GNAT.Strings.String_List;
      Quote           : Character := '"';
      Quote_Backslash : Boolean := True) return String
   is
      Len : Natural := 1;
   begin
      --  Compute the maximum length of the output

      for J in Args'Range loop
         --  For each argument we append at most 3 characters, two quotes
         --  plus an ending space.

         if Args (J) /= null then
            Len := Len + Args (J)'Length + 3;

            for T in Args (J)'Range loop
               if Args (J)(T) = Quote or else Args (J)(T) = '\' then
                  Len := Len + 1;
               end if;
            end loop;
         end if;
      end loop;

      declare
         Result : String (1 .. Len + 1);
         Ind    : Natural := Result'First;

         procedure Append (Str : String);
         --  Append the contents of Str to Result, protecting quote characters

         ------------
         -- Append --
         ------------

         procedure Append (Str : String) is
         begin
            for J in Str'Range loop
               if Str (J) = Quote
                 or else (Quote_Backslash and then Str (J) = '\')
               then
                  Result (Ind)     := '\';
                  Result (Ind + 1) := Str (J);
                  Ind := Ind + 2;
               else
                  Result (Ind) := Str (J);
                  Ind := Ind + 1;
               end if;
            end loop;
         end Append;

      begin
         for J in Args'Range loop
            if Args (J) /= null then
               if Index (Args (J).all, " ") > 0 then
                  Result (Ind) := Quote;
                  Ind := Ind + 1;
                  Append (Args (J).all);
                  Result (Ind) := Quote;
                  Result (Ind + 1) := ' ';
                  Ind := Ind + 2;

               else
                  Append (Args (J).all);
                  Result (Ind) := ' ';
                  Ind := Ind + 1;
               end if;
            end if;
         end loop;

         return Result (1 .. Ind - 1);
      end;
   end Argument_List_To_Quoted_String;

   -------------------------------
   -- Argument_To_Quoted_String --
   -------------------------------

   function Argument_To_Quoted_String
     (Arg             : String;
      Quote           : Character := '"';
      Quote_Backslash : Boolean := True) return String
   is
      A : aliased String := Arg;
      L : constant String_List (1 .. 1) := (1 => A'Unchecked_Access);
   begin
      return Argument_List_To_Quoted_String (L, Quote, Quote_Backslash);
   end Argument_To_Quoted_String;

   ------------------------------------------------
   -- Argument_String_To_List_With_Triple_Quotes --
   ------------------------------------------------

   function Argument_String_To_List_With_Triple_Quotes
     (Arg_String : String) return String_List_Access
   is
      Max_Args : Integer := 128;
      New_Argv : String_List_Access := new String_List (1 .. Max_Args);
      New_Argc : Natural := 0;
      Idx      : Integer;

      procedure Unchecked_Free is new Ada.Unchecked_Deallocation
        (String_List, String_List_Access);

      Backslashed       : Boolean;
      Quoted            : Boolean;
      Triple_Quoted     : Boolean;
      Has_Triple        : Boolean;
      Start_Idx         : Integer;
      Start_With_Triple : Boolean;
      End_With_Triple   : Boolean;

   begin
      Idx := Arg_String'First;

      loop
         exit when Idx > Arg_String'Last;

         Backslashed   := False;
         Quoted        := False;
         Triple_Quoted := False;
         Start_Idx     := Idx;
         Start_With_Triple := False;
         End_With_Triple   := False;

         while Idx <= Arg_String'Last
           and then (Backslashed
                     or else Quoted
                     or else Triple_Quoted
                     or else Arg_String (Idx) /= ' ')
         loop
            End_With_Triple := False;

            if Backslashed then
               Backslashed := False;
            else

               case Arg_String (Idx) is
                  when '\' =>
                     Backslashed := True;

                  when '"' =>
                     if Quoted then
                        Quoted := False;
                     else
                        Has_Triple := Idx + 2 <= Arg_String'Last
                          and then Arg_String (Idx) = '"'
                          and then Arg_String (Idx + 1) = '"'
                          and then Arg_String (Idx + 2) = '"';
                        if Has_Triple then
                           Triple_Quoted := not Triple_Quoted;
                           if Idx = Start_Idx then
                              Start_With_Triple := Triple_Quoted;
                           end if;
                           End_With_Triple := True;
                           Idx := Idx + 2;
                        else
                           Quoted := True;
                        end if;
                     end if;

                  when others =>
                     null;
               end case;
            end if;

            Idx := Idx + 1;
         end loop;

         New_Argc := New_Argc + 1;

         --  Resize the table if needed
         if New_Argc > Max_Args then
            declare
               New_New_Argv : String_List (1 .. Max_Args * 2);
            begin
               New_New_Argv (1 .. Max_Args) := New_Argv.all;
               Unchecked_Free (New_Argv);
               New_Argv := new String_List'(New_New_Argv);
            end;

            Max_Args := Max_Args * 2;
         end if;

         if Start_With_Triple and End_With_Triple then
            New_Argv (New_Argc) :=
              new String'(Arg_String (Start_Idx + 3 .. Idx - 4));
         else
            New_Argv (New_Argc) :=
              new String'(Arg_String (Start_Idx .. Idx - 1));
         end if;

         --  Skip extraneous spaces

         while Idx <= Arg_String'Last and then Arg_String (Idx) = ' ' loop
            Idx := Idx + 1;
         end loop;
      end loop;

      declare
         Result : constant String_List := New_Argv (1 .. New_Argc);
      begin
         Unchecked_Free (New_Argv);
         return new String_List'(Result);
      end;
   end Argument_String_To_List_With_Triple_Quotes;

   ---------------
   -- Unprotect --
   ---------------

   function Unprotect (Str : String) return String is
      Result : String (Str'Range);
      Index  : Natural := Result'First;
      N      : Natural := Str'First;
   begin
      while N <= Str'Last loop
         if Str (N) = '\' then
            if N < Str'Last then
               Result (Index) := Str (N + 1);
            end if;

            N := N + 2;
         else
            Result (Index) := Str (N);
            N := N + 1;
         end if;

         Index := Index + 1;
      end loop;

      if Result'Length > 1
        and then Result (Result'First) = '"'
        and then Result (Index - 1) = '"'
      then
         return Result (Result'First + 1 .. Index - 2);
      else
         return Result (Result'First .. Index - 1);
      end if;
   end Unprotect;

end GNATCOLL.Scripts.Utils;
