/* TUI Interpreter definitions for GDB, the GNU debugger.

   Copyright (C) 2003, 2007, 2008, 2009, 2010, 2011
   Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "interps.h"
#include "top.h"
#include "event-top.h"
#include "event-loop.h"
#include "ui-out.h"
#include "cli-out.h"
#include "tui/tui-data.h"
#include "readline/readline.h"
#include "tui/tui-win.h"
#include "tui/tui.h"
#include "tui/tui-io.h"
#include "exceptions.h"

/* Set to 1 when the TUI mode must be activated when we first start
   gdb.  */
static int tui_start_enabled = 0;

/* Cleanup the tui before exiting.  */

static void
tui_exit (void)
{
  /* Disable the tui.  Curses mode is left leaving the screen in a
     clean state (see endwin()).  */
  tui_disable ();
}

/* True if TUI is the top-level interpreter.  */
static int tui_is_toplevel = 0;

/* These implement the TUI interpreter.  */

static void *
tui_init (int top_level)
{
  tui_is_toplevel = top_level;

  /* Install exit handler to leave the screen in a good shape.  */
  atexit (tui_exit);

  tui_initialize_static_data ();

  tui_initialize_io ();
  tui_initialize_win ();
  if (ui_file_isatty (gdb_stdout))
    tui_initialize_readline ();

  return NULL;
}

/* True if enabling the TUI is allowed.  Example, if the top level
   interpreter is MI, enabling curses will certainly lose.  */

int
tui_allowed_p (void)
{
  /* Only if TUI is the top level interpreter.  Also don't try to
     setup curses (and print funny control characters) if we're not
     outputting to a terminal.  */
  return tui_is_toplevel && ui_file_isatty (gdb_stdout);
}

static int
tui_resume (void *data)
{
  struct ui_file *stream;

  /* gdb_setup_readline will change gdb_stdout.  If the TUI was
     previously writing to gdb_stdout, then set it to the new
     gdb_stdout afterwards.  */

  stream = cli_out_set_stream (tui_old_uiout, gdb_stdout);
  if (stream != gdb_stdout)
    {
      cli_out_set_stream (tui_old_uiout, stream);
      stream = NULL;
    }

  gdb_setup_readline ();

  if (stream != NULL)
    cli_out_set_stream (tui_old_uiout, gdb_stdout);

  if (tui_start_enabled)
    tui_enable ();
  return 1;
}

static int
tui_suspend (void *data)
{
  tui_start_enabled = tui_active;
  tui_disable ();
  return 1;
}

/* Display the prompt if we are silent.  */

static int
tui_display_prompt_p (void *data)
{
  if (interp_quiet_p (NULL))
    return 0;
  else
    return 1;
}

static struct gdb_exception
tui_exec (void *data, const char *command_str)
{
  internal_error (__FILE__, __LINE__, _("tui_exec called"));
}


/* Initialize all the necessary variables, start the event loop,
   register readline, and stdin, start the loop.  */

static void
tui_command_loop (void *data)
{
  /* If we are using readline, set things up and display the first
     prompt, otherwise just print the prompt.  */
  if (async_command_editing_p)
    {
      int length;
      char *a_prompt;
      char *gdb_prompt = get_prompt ();

      /* Tell readline what the prompt to display is and what function
         it will need to call after a whole line is read. This also
         displays the first prompt.  */
      length = strlen (PREFIX (0)) 
	+ strlen (gdb_prompt) + strlen (SUFFIX (0)) + 1;
      a_prompt = (char *) alloca (length);
      strcpy (a_prompt, PREFIX (0));
      strcat (a_prompt, gdb_prompt);
      strcat (a_prompt, SUFFIX (0));
      rl_callback_handler_install (a_prompt, input_handler);
    }
  else
    display_gdb_prompt (0);

  /* Loop until there is nothing to do. This is the entry point to the
     event loop engine. gdb_do_one_event, called via catch_errors()
     will process one event for each invocation.  It blocks waits for
     an event and then processes it.  >0 when an event is processed, 0
     when catch_errors() caught an error and <0 when there are no
     longer any event sources registered.  */
  while (1)
    {
      int result = catch_errors (gdb_do_one_event, 0, "", RETURN_MASK_ALL);

      if (result < 0)
	break;

      /* Update gdb output according to TUI mode.  Since catch_errors
         preserves the uiout from changing, this must be done at top
         level of event loop.  */
      if (tui_active)
        uiout = tui_out;
      else
        uiout = tui_old_uiout;
      
      if (result == 0)
	{
	  /* If any exception escaped to here, we better enable
	     stdin.  Otherwise, any command that calls async_disable_stdin,
	     and then throws, will leave stdin inoperable.  */
	  async_enable_stdin ();
	  /* FIXME: this should really be a call to a hook that is
	     interface specific, because interfaces can display the
	     prompt in their own way.  */
	  display_gdb_prompt (0);
	  /* This call looks bizarre, but it is required.  If the user
	     entered a command that caused an error,
	     after_char_processing_hook won't be called from
	     rl_callback_read_char_wrapper.  Using a cleanup there
	     won't work, since we want this function to be called
	     after a new prompt is printed.  */
	  if (after_char_processing_hook)
	    (*after_char_processing_hook) ();
	  /* Maybe better to set a flag to be checked somewhere as to
	     whether display the prompt or not.  */
	}
    }

  /* We are done with the event loop. There are no more event sources
     to listen to.  So we exit GDB.  */
  return;
}

/* Provide a prototype to silence -Wmissing-prototypes.  */
extern initialize_file_ftype _initialize_tui_interp;

void
_initialize_tui_interp (void)
{
  static const struct interp_procs procs = {
    tui_init,
    tui_resume,
    tui_suspend,
    tui_exec,
    tui_display_prompt_p,
    tui_command_loop,
  };

  /* Create a default uiout builder for the TUI.  */
  tui_out = tui_out_new (gdb_stdout);
  interp_add (interp_new (INTERP_TUI, NULL, tui_out, &procs));
  if (interpreter_p && strcmp (interpreter_p, INTERP_TUI) == 0)
    tui_start_enabled = 1;

  if (interpreter_p && strcmp (interpreter_p, INTERP_CONSOLE) == 0)
    {
      xfree (interpreter_p);
      interpreter_p = xstrdup (INTERP_TUI);
    }
}
