/* debug.h - Debugging implementation.
   Copyright (C) 2007 Free Software Foundation, Inc.
   Written by Neal H. Walfield <neal@gnu.org>.

   This file is part of the GNU Hurd.

   The GNU Hurd 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.

   The GNU Hurd 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 "debug.h"
#include "shutdown.h"
#include "scheduler.h"
#include "thread.h"
#include "object.h"
#include "activity.h"
#include <s-printf.h>

int output_debug;

static struct debug_command reboot_command =
  {
    "reboot",
    '6',
    "Reboot the machine.",
    (void (*) (int, const char *[])) reset,
    NULL
  };

static struct debug_command halt_command = 
  {
    "halt",
    '^',
    "Halt the machine.",
    (void (*) (int, const char *[])) halt,
    &reboot_command
  };

static int continue_execution;

static void
do_continue_execution (int argc, char *argv[])
{
  continue_execution = 1;
}

static struct debug_command continue_command = 
  {
    "continue",
    'c',
    "Continue execution.",
    (void (*) (int, const char *[])) do_continue_execution,
    &halt_command
  };

static void help (int argc, char *argv[]);

static struct debug_command help_command =
  {
    "help",
    '?',
    NULL,
    (void (*) (int, const char *[])) help,
    &continue_command
  };


static struct debug_command *commands = &help_command;

static void
help (int argc, char *argv[])
{
  struct debug_command *cmd;

  int maxlen = 0;
  for (cmd = commands; cmd; cmd = cmd->next)
    if (cmd->help && maxlen < strlen (cmd->name))
      maxlen = strlen (cmd->name);

  for (cmd = commands; cmd; cmd = cmd->next)
    if (cmd->help)
      {
	printf ("%s", cmd->name);

	int i;
	for (i = strlen (cmd->name); i < maxlen; i ++)
	  putchar (' ');

	printf (" %c %s\n",
		cmd->short_name ?: ' ', cmd->help);
      }
}

void
debug_register (struct debug_command *command)
{
  command->next = commands;
  commands = command;
}

void
debugger (void)
{
  continue_execution = 0;

  while (! continue_execution)
    {
#define BUFFER_SIZE (sizeof (buffer))
      char buffer[128];
      int len = 0;

      printf ("\ndebugger> ");

      /* Read a line of input.  */
      while (len == 0 || buffer[len - 1] != 0)
	{
	  int c = getchar ();
	  switch (c)
	    {
	    case 27:
	      /* Escape.  */
	      return;

	    case 127:
	      /* Delete.  */
	      c = 8;
	      /* Fall through.  */
	    case 8:
	      /* Backspace.  */
	      if (len > 0)
		{
		  len --;
		  printf ("%c ", 8);
		}
	      else
		continue;
	      break;

	    case '\n':
	    case '\r':
	      buffer[len ++] = 0;
	      printf ("\n");
	      break;

	    default:
	      buffer[len ++] = c;
	      break;
	    }
	  printf ("%c", c);
	}
      buffer[len - 1] = '\0';

#define ARGS 10
      char *argv[ARGS];
      int argc = 0;

      char *p = buffer;

      while (*p == ' ')
	p ++;
      argv[argc ++] = p;

      for (; *p && argc < ARGS - 1; p ++)
	if (*p == ' ')
	  {
	    *p = 0;
	    p ++;
	    while (*p == ' ')
	      p ++;
	    argv[argc ++] = p;
	  }
      /* The last arg could be an empty string.  */
      if (*argv[argc - 1] == 0)
	argc --;

      argv[argc] = NULL;

      if (! argv[0])
	continue;

      struct debug_command *cmd;
      struct debug_command *match = NULL;
      for (cmd = commands; cmd; cmd = cmd->next)
	if (strlen (argv[0]) == 1)
	  /* A short name.  */
	  {
	    if (argv[0][0] == cmd->short_name)
	      {
		match = cmd;
		break;
	      }
	  }
	else if (strncmp (argv[0], cmd->name, strlen (argv[0])) == 0)
	  {
	    if (match)
	      {
		printf ("%s is ambiguous.  Could be %s or %s",
			argv[0], match->name, cmd->name);
		continue;
	      }
	    match = cmd;
	  }

      if (! match)
	printf ("Unknown command: %s", argv[0]);
      else
	match->function (argc, argv);
    }

  return;
}