/*
 * BlinkCursor
 *  A nice blinky caret routine for your progs
 *
 * v. 1.00 (23 July 1993)
 *
 * © 1993-1998 Straylight
 */

/*----- Licensing note ----------------------------------------------------*
 *
 * This file is part of Straylight's Steel library.
 *
 * Steel 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 2, or (at your option)
 * any later version.
 *
 * Steel 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 Steel.  If not, write to the Free Software Foundation,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "wimp.h"
#include "wimpt.h"
#include "os.h"
#include "blinkC.h"
#include "alarm.h"
#include "swiv.h"
#include <stdlib.h>

#include "dll.h"

#ifndef _dll_NODLL
  extern void _dllEntry(blink__exit)(void);
  extern void _dllEntry(blink__doBlink)(int at,void *handle);
#endif

/*
 * A handle thing for alarm.  It's not used by the routine, but it helps
 * identify the alarm routine to be removed.
 */
#define blink__MYHANDLE (void *)&blink__onAlready

/*
 * The SWI number for Wimp_SendMessage.
 */
#define Wimp_SendMessage 0x600E7

/*
 * Due to circular definitions, I am forced to add in a prototype for this
 * function.
 */
static void blink__setupAlarm(void);

/*
 * A flag to say whether we are on already or not.
 */
static BOOL blink__onAlready;

/*
 * A flag to say whether the caret is visible or not.
 */
static BOOL blink__caretVisible;

/*
 * void blink__onCaret(void)
 *
 * Use
 *  Makes the caret visible.
 */

static void blink__onCaret(void)
{
  wimp_caretstr c;
  wimpt_noerr(wimp_get_caret_pos(&c));
  c.height &= ~(1<<25);
  wimpt_noerr(wimp_set_caret_pos(&c));
  blink__caretVisible=TRUE;
}

/*
 * void blink__offCaret(void)
 *
 * Use
 *  Makes the caret invisible.
 */

static void blink__offCaret(void)
{
  wimp_caretstr c;
  wimpt_noerr(wimp_get_caret_pos(&c));
  c.height |= 1<<25;
  wimpt_noerr(wimp_set_caret_pos(&c));
  blink__caretVisible=FALSE;
}

/*
 * BOOL blink__ownCaret(void)
 *
 * Use
 *  Returns whether the task owns the caret or not!
 *
 * Returns
 *  TRUE if it does.
 */

static BOOL blink__ownCaret(void)
{
  wimp_caretstr c;
  wimp_msgstr m;
  int task;
  wimpt_noerr(wimp_get_caret_pos(&c));
  if (c.w<=0)
    return (FALSE);
  m.hdr.size=20;
  m.hdr.your_ref=0;
  _swix(Wimp_SendMessage, _inr(0,2)+_out(2), 19,&m,c.w, &task);
  return (task==wimpt_task());
}

_dll_static void blink__doBlink(int at,void *handle)
{
  handle=handle;
  at=at;
  if (blink__ownCaret())
  {
    switch (blink__caretVisible)
    {
      case TRUE:
        blink__offCaret();
        break;
      case FALSE:
        blink__onCaret();
        break;
    }
  }
  blink__setupAlarm();
}

/*
 * void blink__setupAlarm(void)
 *
 * Use
 *  Sets up next alarm ready.
 */

static void blink__setupAlarm(void)
{
  int nextTime=((alarm_timenow()/25)*25)+25;
  alarm_set(nextTime,_dllEntry(blink__doBlink),blink__MYHANDLE);
}

/*
 * void blinkCursor(BOOL onOrOff)
 *
 * Use
 *  Turns the blinkingness of the cursor on or off.  You must call
 *  alarm_init() before this function, or all hell breaks loose.
 *
 * Parameters
 *  BOOL onOrOff == whether you want to turn blinking cursor on or off
 */

void blinkCursor(BOOL onOrOff)
{
  if (onOrOff==blink__onAlready)
    return;
  switch (onOrOff)
  {
    case TRUE:
      blink__setupAlarm();
      blink__onAlready=TRUE;
      break;
    case FALSE:
      if (blink__ownCaret())
        blink__onCaret();
      alarm_removeall(blink__MYHANDLE);
      blink__onAlready=FALSE;
      break;
  }
}

/*
 * void blink__exit(void)
 *
 * Use
 *  Turns off the caret blinking.
 */

_dll_static void blink__exit(void)
{
  blinkCursor(FALSE);
}

/*
 * void blink_init(void)
 *
 * Use
 *  Sets everything up nicely.
 */

void blink_init(void)
{
  atexit(_dllEntry(blink__exit));
}