with
     GNAT.OS_Lib,
     Ada.Strings.Fixed,
     Ada.Strings.Maps,
     Ada.Unchecked_Deallocation,
     Ada.Unchecked_Conversion;


package body Shell.Commands
is

   --- Strings
   --

   function To_String_Vector (Strings : String_Array) return String_Vector
   is
      use String_Vectors;
      Vector : String_Vector;
   begin
      for Each of Strings
      loop
         Vector.Append (Each);
      end loop;

      return Vector;
   end To_String_Vector;



   function To_String_Array (Strings : String_Vector) return String_Array
   is
      use String_Vectors;
      The_Array : String_Array (1 .. Natural (Strings.Length));
   begin
      for i in The_Array'Range
      loop
         The_Array (i) := Strings.Element (i);
      end loop;

      return The_Array;
   end To_String_Array;



   function To_Arguments (All_Arguments : in String) return String_Array
   is
      use GNAT.OS_Lib;
      Command_Name : constant String := "Command_Name";     -- 'Argument_String_To_List' expects the command name to be
                                                            -- the 1st piece of the string, so we provide a dummy name.
      Arguments    : Argument_List_Access := Argument_String_To_List (Command_Name & " " & All_Arguments);
      Result       : String_Array (1 .. Arguments'Length - 1);
   begin
      for i in Result'Range
      loop
         Result (i) := +Arguments (i + 1).all;
      end loop;

      Free (Arguments);
      return Result;
   end To_Arguments;



   --- Commands
   --

   function Image (The_Command : in Command) return String
   is
      use String_Vectors;
      Result : Unbounded_String;
   begin
      Append (Result, "(" & The_Command.Name & ", (");

      for Each of The_Command.Arguments
      loop
         Append (Result, Each);

         if Each = Last_Element (The_Command.Arguments)
         then
            Append (Result, ")");
         else
            Append (Result, ", ");
         end if;
      end loop;

      --  Append (Result, ", Input_Pipe => "  & Image (The_Command.Input_Pipe));
      --  Append (Result, ", Output_Pipe => " & Image (The_Command.Output_Pipe));
      --  Append (Result, ", Error_Pipe => "  & Image (The_Command.Error_Pipe));

      Append (Result, ")");
      return To_String (Result);
   end Image;



   function To_Command_Lines (Pipeline : in String) return String_Array
   is
      use Ada.Strings.Fixed;

      Cursor : Positive := Pipeline'First;
      First,
      Last   : Positive;
      Count  : Natural := 0;

      Max_Commands_In_Pipeline : constant := 50;     -- Arbitrary.

      Result : String_Array (1 .. Max_Commands_In_Pipeline);
   begin
      loop
         Find_Token (Source => Pipeline,
                     Set    => Ada.Strings.Maps.To_Set ('|'),
                     From   => Cursor,
                     Test   => Ada.Strings.Outside,
                     First  => First,
                     Last   => Last);
         declare
            Full_Command : constant String := Trim (Pipeline (First .. Last),
                                                    Ada.Strings.Both);
         begin
            Count          :=  Count + 1;
            Result (Count) := +Full_Command;
         end;

         exit when Last = Pipeline'Last;

         Cursor := Last + 1;
      end loop;

      return Result (1 .. Count);
   end To_Command_Lines;



   procedure Define (The_Command : out Command;   Command_Line : in String)
   is
      use Ada.Strings.Fixed;

      I : constant Natural := Index (Command_Line, " ");
   begin
      The_Command.Copy_Count := new Count' (1);

      if I = 0
      then
         The_Command.Name := +Command_Line;
         return;
      end if;

      declare
         Name      : constant String       :=               Command_Line (Command_Line'First .. I - 1);
         Arguments : constant String_Array := To_Arguments (Command_Line (I + 1              .. Command_Line'Last));
      begin
         The_Command.Name      := +(Name);
         The_Command.Arguments := To_String_Vector (Arguments);
      end;
   end Define;



   --  package body Forge
   --  is
   --
   --     function To_Command (Command_Line : in String) return Command
   --     is
   --     begin
   --        return Result : Command
   --        do
   --           Define (Result, Command_Line);
   --        end return;
   --     end to_Command;
   --
   --
   --
   --     function To_Commands (Pipeline : in String) return Command_Array
   --     is
   --        All_Commands : constant String_Array := To_Command_Lines (Pipeline);
   --     begin
   --        return Result : Command_Array (1 .. All_Commands'Length)
   --        do
   --           for i in 1 .. All_Commands'Length
   --           loop
   --              Define ( Result (i),
   --                      +All_Commands (i));
   --           end loop;
   --        end return;
   --     end To_Commands;
   --
   --  end Forge;



   --  procedure Connect (From, To : in out Command)
   --  is
   --     Pipe : constant Shell.Pipe := To_Pipe;
   --  begin
   --     From.Output_Pipe := Pipe;
   --     To.   Input_Pipe := Pipe;
   --
   --     From.Owns_Input_Pipe  := True;
   --     To.  Owns_Output_Pipe := True;
   --  end Connect;



   --  procedure Connect (Commands : in out Command_Array)
   --  is
   --  begin
   --     for i in Commands'First .. Commands'Last - 1
   --     loop
   --        Connect (From => Commands (i),
   --                 To   => Commands (i + 1));
   --     end loop;
   --  end Connect;



   --  procedure Close_Pipe_Write_Ends (The_Command : in out Command)
   --  is
   --  begin
   --     if The_Command.Output_Pipe /= Standard_Output
   --     then
   --        Close_Write_End (The_Command.Output_Pipe);
   --     end if;
   --
   --     if The_Command.Error_Pipe /= Standard_Error
   --     then
   --        Close_Write_End (The_Command.Error_Pipe);
   --     end if;
   --  end Close_Pipe_Write_Ends;



   --  function Input_Pipe (The_Command : in Command) return Pipe
   --  is
   --  begin
   --     return The_Command.Input_Pipe;
   --  end Input_Pipe;



   --  function Output_Pipe (The_Command : in Command) return Pipe
   --  is
   --  begin
   --     return The_Command.Output_Pipe;
   --  end Output_Pipe;



   --  function Error_Pipe (The_Command : in Command) return Pipe
   --  is
   --  begin
   --     return The_Command.Error_Pipe;
   --  end Error_Pipe;



   function Name (The_Command : in Command) return String
   is
   begin
      return +The_Command.Name;
   end Name;



   function Arguments (The_Command : in Command) return String
   is
      All_Arguments : Unbounded_String;
      Last          : constant Natural := Natural (The_Command.Arguments.Length);
   begin
      for i in 1 .. Last
      loop
         Append (All_Arguments, The_Command.Arguments.Element (i));

         if i /= Last
         then
            Append (All_Arguments, " ");
         end if;
      end loop;

      return To_String (All_Arguments);
   end Arguments;



   --  function Process (The_Command : in out Command) return access Shell.Process
   --  is
   --  begin
   --     return The_Command.Process'Unchecked_Access;
   --  end Process;



   --- Start
   --

   --  procedure Start (The_Command : in out Command;
   --                   Input       : in     Data    := No_Data;
   --                   Pipeline    : in     Boolean := False)
   --  is
   --  begin
   --     if Input /= No_Data
   --     then
   --        The_Command.Input_Pipe := To_Pipe;
   --        Write_To (The_Command.Input_Pipe, Input);
   --     end if;
   --
   --     if The_Command.Output_Pipe = Null_Pipe
   --     then
   --        The_Command.Owns_Output_Pipe := True;
   --        The_Command.Output_Pipe      := To_Pipe (Blocking => False);
   --     end if;
   --
   --     if The_Command.Error_Pipe = Null_Pipe
   --     then
   --        The_Command. Error_Pipe := To_Pipe (Blocking => False);
   --     end if;
   --
   --     The_Command.Process := Start (Program   => +The_Command.Name,
   --                                   Arguments =>  To_String_Array (The_Command.Arguments),
   --                                   Input     =>  The_Command.Input_Pipe,
   --                                   Output    =>  The_Command.Output_Pipe,
   --                                   Errors    =>  The_Command.Error_Pipe,
   --                                   Pipeline  =>  Pipeline);
   --  end Start;



   --  procedure Start (Commands : in out Command_Array;
   --                   Input    : in     Data    := No_Data;
   --                   Pipeline : in     Boolean := True)
   --  is
   --  begin
   --     if not Pipeline
   --     then
   --        for Each of Commands
   --        loop
   --           Start (Each, Input);
   --        end loop;
   --
   --        return;
   --     end if;
   --
   --     Connect (Commands);
   --
   --     for i in Commands'Range
   --     loop
   --        if i = Commands'First
   --        then
   --           Start (Commands (i),
   --                  Input,
   --                  Pipeline => True);
   --        else
   --           Start (Commands (i),
   --                  Pipeline => True);
   --        end if;
   --
   --        -- Since we are making a pipeline, we need to close the write ends of
   --        -- the Output & Errors pipes ourselves.
   --        --
   --        if i /= Commands'First
   --        then
   --           Close_Pipe_Write_Ends (Commands (i - 1));    -- Close ends for the prior command.
   --        end if;
   --
   --     end loop;
   --
   --     Close_Pipe_Write_Ends (Commands (Commands'Last));  -- Close ends for the final command.
   --  end Start;



   --  procedure Send (To    : in Command;
   --                  Input : in Data)
   --  is
   --  begin
   --     Write_To (To.Input_Pipe, Input);
   --  end Send;



   --- Run
   --

   --  procedure Gather_Results (The_Command : in out Command)
   --  is
   --  begin
   --     declare
   --        The_Output : constant Data := Output_Of (The_Command.Output_Pipe);
   --     begin
   --        if The_Output'Length /= 0
   --        then
   --           The_Command.Output.Append (The_Output);
   --        end if;
   --     end;
   --
   --     declare
   --        The_Errors : constant Data := Output_Of (The_Command.Error_Pipe);
   --     begin
   --        if The_Errors'Length /= 0
   --        then
   --           The_Command.Errors.Append (The_Errors);
   --        end if;
   --     end;
   --  end Gather_Results;



   --  procedure Run (The_Command : in out Command;
   --                 Input       : in     Data    := No_Data;
   --                 Raise_Error : in     Boolean := False)
   --  is
   --  begin
   --     Start (The_Command, Input);
   --
   --     loop
   --        Gather_Results (The_Command);   -- Gather on-going results.
   --        exit when Has_Terminated (The_Command.Process);
   --     end loop;
   --
   --     Gather_Results (The_Command);      -- Gather any final results.
   --
   --     if not Normal_Exit (The_Command.Process)
   --        and Raise_Error
   --     then
   --        declare
   --           Error : constant String := +Output_Of (The_Command.Error_Pipe);
   --        begin
   --           raise Command_Error with Error;
   --        end;
   --     end if;
   --  end Run;



   function Run (The_Command : in out Command'Class;
                 Input       : in     Data    := No_Data;
                 Raise_Error : in     Boolean := False) return Command_Results
   is
   begin
      Run (The_Command, Input, Raise_Error);

      return Results_Of (The_Command);
   end Run;



   --  procedure Run (The_Pipeline : in out Command_Array;
   --                 Input        : in     Data    := No_Data;
   --                 Raise_Error  : in     Boolean := False)
   --  is
   --     Last_Command : Command renames The_Pipeline (The_Pipeline'Last);
   --     i            : Positive     := 1;
   --  begin
   --     Last_Command.Output_Pipe := To_Pipe;
   --
   --     Start (The_Pipeline, Input);
   --
   --     loop
   --        Gather_Results (Last_Command);            -- Gather on-going results.
   --
   --        if Has_Terminated (The_Pipeline (i).Process)
   --        then
   --           if Normal_Exit (The_Pipeline (i).Process)
   --           then
   --              i := i + 1;
   --
   --              if i > The_Pipeline'Last
   --              then
   --                 Gather_Results (Last_Command);   -- Gather any final results.
   --                 exit;
   --              end if;
   --
   --           else
   --              declare
   --                 Error : constant String :=   "Pipeline command" & Integer'Image (i)
   --                                            & " '" & (+The_Pipeline (i).Name) & "' failed.";
   --              begin
   --                 -- Stop the pipeline.
   --                 --
   --                 while i <= The_Pipeline'Last
   --                 loop
   --                    Stop (The_Pipeline (i));
   --                    i := i + 1;
   --                 end loop;
   --
   --                 if Raise_Error
   --                 then
   --                    raise Command_Error with Error;
   --                 else
   --                    exit;
   --                 end if;
   --              end;
   --           end if;
   --        end if;
   --     end loop;
   --  end Run;



   --  function Run (The_Pipeline : in out Command_Array;
   --                Input        : in     Data    := No_Data;
   --                Raise_Error  : in     Boolean := False) return Command_Results
   --  is
   --     Last_Command : Command renames The_Pipeline (The_Pipeline'Last);
   --  begin
   --     Run (The_Pipeline, Input, Raise_Error);
   --
   --     return Results_Of (Last_Command);
   --  end Run;



   --  procedure Stop (The_Command : in out Command)
   --  is
   --     use Ada.Characters.Handling,
   --         Ada.Exceptions;
   --  begin
   --     The_Command.Gather_Results;
   --
   --     Close (The_Command. Input_Pipe);
   --     Close (The_Command.Output_Pipe);
   --     Close (The_Command. Error_Pipe);
   --
   --     begin
   --        Kill (The_Command);
   --     exception
   --        when E : POSIX.POSIX_Error =>
   --           if To_Upper (Exception_Message (E)) /= "NO_SUCH_PROCESS"
   --           then
   --              Log ("Unable to kill process" & Image (The_Command.Process));
   --              raise;
   --           end if;
   --     end;
   --
   --     begin
   --        Wait_On (The_Command.Process);   -- Reap zombies.
   --     exception
   --        when E : POSIX.POSIX_Error =>
   --           if To_Upper (Exception_Message (E)) /= "NO_CHILD_PROCESS"
   --           then
   --              Log ("Unable to wait on process" & Image (The_Command.Process));
   --              raise;
   --           end if;
   --     end;
   --  end Stop;



   function Failed (The_Command : in Command'Class) return Boolean
   is
   begin
      return not Normal_Exit (The_Command);
   end Failed;



   --  function Failed (The_Pipeline : in Command_Array) return Boolean
   --  is
   --  begin
   --     for Each of The_Pipeline
   --     loop
   --        if Failed (Each)
   --        then
   --           return True;
   --        end if;
   --     end loop;
   --
   --     return False;
   --  end Failed;



   --  function Which_Failed (The_Pipeline : in Command_Array) return Natural
   --  is
   --  begin
   --     for i in The_Pipeline'Range
   --     loop
   --        if not Normal_Exit (The_Pipeline (i).Process)
   --        then
   --           return i;
   --        end if;
   --     end loop;
   --
   --     return 0;
   --  end Which_Failed;



   -- Command Results
   --

   function Results_Of (The_Command : in out Command'Class) return Command_Results
   is
      use Data_Vectors;

      Output_Size : Data_Offset := 0;
      Errors_Size : Data_Offset := 0;
   begin
      Gather_Results (The_Command);

      for Each of The_Command.Output
      loop
         Output_Size := Output_Size + Each'Length;
      end loop;

      for Each of The_Command.Errors
      loop
         Errors_Size := Errors_Size + Each'Length;
      end loop;

      declare
         Output : Data (1 .. Output_Size);
         Errors : Data (1 .. Errors_Size);

         procedure Set_Data (From : in out Data_Vector;
                             To   :    out Data)
         is
            First : Data_Index := 1;
            Last  : Data_Index;
         begin
            for Each of From
            loop
               Last               := First + Each'Length - 1;
               To (First .. Last) := Each;
               First              := Last + 1;
            end loop;

            From.Clear;
         end Set_Data;

      begin
         Set_Data (The_Command.Output, Output);
         Set_Data (The_Command.Errors, Errors);

         return (Output_Size => Output_Size,
                 Error_Size  => Errors_Size,
                 Output      => Output,
                 Errors      => Errors);
      end;

   exception
      when Storage_Error =>
         raise Command_Error with "Command output exceeds stack capacity. "
                                & "Increase the stack limit via 'ulimit -s'.";
   end Results_Of;



   function Output_Of (The_Results : in Command_Results) return Data
   is
   begin
      return The_Results.Output;
   end Output_Of;



   function Errors_Of (The_Results : in Command_Results) return Data
   is
   begin
      return The_Results.Errors;
   end Errors_Of;



   --  procedure Wait_On (The_Command : in out Command)
   --  is
   --  begin
   --     Wait_On (The_Command.Process);
   --  end Wait_On;



   --  function Has_Terminated (The_Command : in out Command) return Boolean
   --  is
   --  begin
   --     return Has_Terminated (The_Command.Process);
   --  end Has_Terminated;



   --  function Normal_Exit (The_Command : in Command) return Boolean
   --  is
   --  begin
   --     return Normal_Exit (The_Command.Process);
   --  end Normal_Exit;



   --  procedure Kill (The_Command : in Command)
   --  is
   --  begin
   --     Kill (The_Command.Process);
   --  end Kill;



   --  procedure Interrupt (The_Command : in Command)
   --  is
   --  begin
   --     Interrupt (The_Command.Process);
   --  end Interrupt;



   --  procedure Pause (The_Command : in out Command)
   --  is
   --  begin
   --     Pause (The_Command.Process);
   --     The_Command.Paused := True;
   --  end Pause;



   --  procedure Resume (The_Command : in out Command)
   --  is
   --  begin
   --     Resume (The_Command.Process);
   --     The_Command.Paused := False;
   --  end Resume;



   procedure Start (The_Command   : in out Command;
                    Input         : in     Data    := No_Data;
                    Accepts_Input : in     Boolean := False;
                    Pipeline      : in     Boolean := False)
   is
   begin
      if The_Command.Status /= Not_Started
      then
         raise Command_Error with "Cannot start '" & (+The_Command.Name) & "' as it is already started.";
      end if;

      The_Command.Status := Running;
   end Start;



   procedure Pause (The_Command : in out Command)
   is
   begin
      if The_Command.Status /= Running
      then
         raise Command_Error with "Cannot pause '" & (+The_Command.Name) & "' as it is not running.";
      end if;

      The_Command.Status := Paused;
   end Pause;



   procedure Resume (The_Command : in out Command)
   is
   begin
      if The_Command.Status /= Paused
      then
         raise Command_Error with "Cannot resume '" & (+The_Command.Name) & "' as it is not paused.";
      end if;

      The_Command.Status := Running;
   end Resume;



   procedure Kill (The_Command : in out Command)
   is
   begin
      case The_Command.Status
      is
         when Not_Started =>
            raise Command_Error with "Cannot kill '" & (+The_Command.Name) & "' as it is not started.";

         when Running
            | Paused =>
            The_Command.Status := Killed;

         when Normal_Exit
            | Failed_Exit =>
            raise Command_Error with "Cannot kill '" & (+The_Command.Name) & "' as it has exited.";

         when Killed =>
            raise Command_Error with "Cannot kill '" & (+The_Command.Name) & "' as it is already killed.";
      end case;
   end Kill;



   function Status (The_Command : in out Command) return State
   is
   begin
      return The_Command.Status;
   end Status;




   --- Controlled
   --

   overriding
   procedure Adjust (The_Command : in out Command)
   is
   begin
      The_Command.Copy_Count.all := The_Command.Copy_Count.all + 1;
   end Adjust;



   overriding
   procedure Finalize (The_Command : in out Command)
   is
      procedure Deallocate is new Ada.Unchecked_Deallocation (Count, Count_Access);
   begin
      The_Command.Copy_Count.all := The_Command.Copy_Count.all - 1;

      if The_Command.Copy_Count.all = 0
      then
         --  if The_Command.Owns_Input_Pipe
         --  then
         --     Close (The_Command.Input_Pipe);
         --  end if;
         --
         --  if The_Command.Owns_Output_Pipe
         --  then
         --     Close (The_Command.Output_Pipe);
         --  end if;
         --
         --  Close      (The_Command.Error_Pipe);
         Deallocate (The_Command.Copy_Count);
      end if;

   end Finalize;



   function Hash (Id : in Command_Id) return Ada.Containers.Hash_Type
   is
   begin
      return Ada.Containers.Hash_Type (Id);
   end Hash;


end Shell.Commands;