/* -*-C-*-

$Id: ntenv.c,v 1.19 2000/12/05 21:23:45 cph Exp $

Copyright (c) 1992-1999 Massachusetts Institute of Technology

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 2 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "scheme.h"
#include "nt.h"
#include "osenv.h"
#include "ntscreen.h"
#include <stdlib.h>
#include <string.h>

extern unsigned long file_time_to_unix_time (FILETIME *);
extern void unix_time_to_file_time (unsigned long, FILETIME *);

static unsigned long
system_time_to_unix_time (SYSTEMTIME * st)
{
  FILETIME ft;
  (void) SystemTimeToFileTime (st, (&ft));
  return (file_time_to_unix_time (&ft));
}

#if 0
static void
unix_time_to_system_time (unsigned long ut, SYSTEMTIME * st)
{
  FILETIME ft;
  unix_time_to_file_time (ut, (&ft));
  (void) FileTimeToSystemTime ((&ft), st);
}
#endif

time_t
DEFUN_VOID (OS_encoded_time)
{
  SYSTEMTIME t;
  GetSystemTime (&t);
  return (system_time_to_unix_time (&t));
}

void
OS_decode_time (time_t t, struct time_structure * buffer)
{
  struct tm * ts;
  STD_PTR_UNIX_CALL (ts, localtime, (&t));
  (buffer -> year) = ((ts -> tm_year) + 1900);
  (buffer -> month) = ((ts -> tm_mon) + 1);
  (buffer -> day) = (ts -> tm_mday);
  (buffer -> hour) = (ts -> tm_hour);
  (buffer -> minute) = (ts -> tm_min);
  (buffer -> second) = (ts -> tm_sec);
  (buffer -> daylight_savings_time) = (ts -> tm_isdst);
  /* I'm assuming that `timezone' is implemented by the C library;
     this might need conditionalization.  -- cph */
  (buffer -> time_zone) = timezone;
  {
    /* In localtime() encoding, 0 is Sunday; in ours, it's Monday. */
    int wday = (ts -> tm_wday);
    (buffer -> day_of_week) = ((wday == 0) ? 6 : (wday - 1));
  }
}

void
OS_decode_utc (time_t t, struct time_structure * buffer)
{
  struct tm * ts;
  STD_PTR_UNIX_CALL (ts, gmtime, (&t));
  (buffer -> year) = ((ts -> tm_year) + 1900);
  (buffer -> month) = ((ts -> tm_mon) + 1);
  (buffer -> day) = (ts -> tm_mday);
  (buffer -> hour) = (ts -> tm_hour);
  (buffer -> minute) = (ts -> tm_min);
  (buffer -> second) = (ts -> tm_sec);
  (buffer -> daylight_savings_time) = (ts -> tm_isdst);
  (buffer -> time_zone) = 0;
  {
    /* In gmtime() encoding, 0 is Sunday; in ours, it's Monday. */
    int wday = (ts -> tm_wday);
    (buffer -> day_of_week) = ((wday == 0) ? 6 : (wday - 1));
  }
}

#if 0
/* This nice implementation can't be used because it only works under
   Windows NT.  */
void
OS_decode_time (time_t t, struct time_structure * buffer)
{
  SYSTEMTIME st;
  SYSTEMTIME lst;
  TIME_ZONE_INFORMATION tzi;
  unix_time_to_system_time (t, (&st));
  switch (GetTimeZoneInformation (&tzi))
    {
    case TIME_ZONE_ID_STANDARD:
      (buffer -> daylight_savings_time) = 0;
      (buffer -> time_zone) = (tzi . Bias);
      break;
    case TIME_ZONE_ID_DAYLIGHT:
      (buffer -> daylight_savings_time) = 1;
      (buffer -> time_zone) = (tzi . Bias);
      break;
    default:
      (buffer -> daylight_savings_time) = -1;
      (buffer -> time_zone) = 0;
      break;
    }
  if (((buffer -> daylight_savings_time) == 0) && ((buffer -> time_zone) == 0))
    lst = st;
  else
    (void) SystemTimeToTzSpecificLocalTime ((&tzi), (&st), (&lst));
  (buffer -> year) = (lst . wYear);
  (buffer -> month) = (lst . wMonth);
  (buffer -> day) = (lst . wDay);
  (buffer -> hour) = (lst . wHour);
  (buffer -> minute) = (lst . wMinute);
  (buffer -> second) = (lst . wSecond);
  {
    /* In SYSTEMTIME encoding, 0 is Sunday; in ours, it's Monday. */
    int wday = (lst . wDayOfWeek);
    (buffer -> day_of_week) = ((wday == 0) ? 6 : (wday - 1));
  }
}
#endif

time_t
OS_encode_time (struct time_structure * buffer)
{
  time_t t;
  struct tm ts_s, * ts;
  ts = &ts_s;
  (ts -> tm_year) = ((buffer -> year) - 1900);
  (ts -> tm_mon) = ((buffer -> month) - 1);
  (ts -> tm_mday) = (buffer -> day);
  (ts -> tm_hour) = (buffer -> hour);
  (ts -> tm_min) = (buffer -> minute);
  (ts -> tm_sec) = (buffer -> second);
  (ts -> tm_isdst) = (buffer -> daylight_savings_time);
  STD_UINT_UNIX_CALL (t, mktime, (ts));
  /* mktime assumes its argument is local time, and converts it to
     UTC; if the specified time zone is different, adjust the result.  */
  if (((buffer -> time_zone) != INT_MAX)
      && ((buffer -> time_zone) != timezone))
    t = ((t - timezone) + (buffer -> time_zone));
  return (t);
}

#define FILETIME_TO_MSECS(ft) \
  (((4294967296.0 * (double)  ft.dwHighDateTime) + ft.dwLowDateTime)*100e-6)

double
DEFUN_VOID (OS_process_clock)
{
  /* This must not signal an error in normal use. */
  /* Return answer in milliseconds, was in 1/100th seconds */

  FILETIME  creation_time, exit_time, kernel_time, user_time;
  if(GetProcessTimes(GetCurrentProcess(),
		     &creation_time, &exit_time, &kernel_time, &user_time)) {
    return  FILETIME_TO_MSECS(user_time) + FILETIME_TO_MSECS(kernel_time);
  } else {
    return ((((double) (clock ())) * 1000.0) / ((double) CLOCKS_PER_SEC));
  }
}

double
DEFUN_VOID (OS_real_time_clock)
{
  return ((((double) (clock ())) * 1000.0) / ((double) CLOCKS_PER_SEC));
}

/* The timers are all the same.
   This just provides three distinct timers.
 */

#define TIMER_ID_REAL		(TIMER_ID_BASE + 2)
#define TIMER_ID_PROFILE	(TIMER_ID_BASE + 1)
#define TIMER_ID_PROCESS	(TIMER_ID_BASE + 0)

#ifdef USE_WM_TIMER

#define TIMER_ID_BASE		0x100

enum timer_next
{
  timer_next_none,
  timer_next_normal,
  timer_next_disable,
  timer_next_set_period
};

struct timer_state_s
{
  int local_id;
  int global_id;
  clock_t period;
  enum timer_next next;
};

struct timer_state_s scheme_timers[3] =
{
  { TIMER_ID_PROCESS, 0, 0, timer_next_none, },
  { TIMER_ID_PROFILE, 0, 0, timer_next_none, },
  { TIMER_ID_REAL,    0, 0, timer_next_none, },
};

extern HANDLE master_tty_window;

static void
DEFUN (clear_timer, (timer_id), int timer_id)
{
  struct timer_state_s * timer = &scheme_timers[timer_id - TIMER_ID_BASE];
  if (timer->global_id != 0)
    KillTimer (master_tty_window, timer->global_id);
  timer->global_id = 0;
  timer->next = timer_next_none;
  return;
}

extern VOID /* CALLBACK */ EXFUN (TimerProc, (HWND, UINT, UINT, DWORD));

#define THE_TIMER_PROC ((TIMERPROC) NULL) /* TimerProc */

VOID /* CALLBACK */
DEFUN (TimerProc, (hwnd, umsg, timer_id, dwtime),
       HWND hwnd AND UINT umsg AND UINT timer_id AND DWORD dwtime)
{
  if (hwnd == master_tty_window)
  {
    struct timer_state_s * timer;

    REQUEST_INTERRUPT (INT_Timer);
    timer = &scheme_timers[timer_id - TIMER_ID_BASE];
    switch (timer->next)
    {
    case timer_next_set_period:
      // clear_timer (timer_id);
      timer->global_id = (SetTimer (master_tty_window,
				    timer->local_id,
				    timer->period,
				    THE_TIMER_PROC));
      timer->next = timer_next_normal;
      break;
      
    case timer_next_normal:
      break;

    case timer_next_none:
    case timer_next_disable:
    default:      
      clear_timer (timer_id);
      break;
    }
  }
  return;
}

static void
DEFUN (set_timer, (timer_id, first, interval),
       int timer_id AND clock_t first AND clock_t interval)
{
  struct timer_state_s * timer = &scheme_timers[timer_id - TIMER_ID_BASE];
  if (timer->global_id != 0)
  {
    KillTimer (master_tty_window, timer->global_id);
    timer->global_id = 0;
  }
  
  timer->period = interval;
  if ((first == 0) || (interval == first))
    timer->next = timer_next_normal;
  else if (interval == 0)
    timer->next = timer_next_disable;
  else
    timer->next = timer_next_set_period;
  timer->global_id = (SetTimer (master_tty_window,
				timer->local_id,
				((first == 0) ? interval : first),
				THE_TIMER_PROC));
  if (timer->global_id == 0)
  {
    timer->next = timer_next_none;
    NT_error_api_call ((GetLastError ()), apicall_SetTimer);
  }
  return;
}

#else /* not USE_WM_TIMER */

#define TIMER_ID_BASE		0

struct timer_state_s
{
  int counter;
  int reload;
};

struct timer_state_s scheme_timers[3] = { { 0, 0, }, { 0, 0, }, { 0, 0, } };

extern void EXFUN (low_level_timer_tick, (void));

void
DEFUN_VOID (low_level_timer_tick)
{
  int i;
  int number_signalled = 0;

  for (i = 0; i < 3; i++)
    if (scheme_timers[i].counter != 0)
    {
      scheme_timers[i].counter -= 1;
      if (scheme_timers[i].counter == 0)
      {
	scheme_timers[i].counter = scheme_timers[i].reload;
	number_signalled += 1;
      }
    }

  if (number_signalled != 0)
    REQUEST_INTERRUPT (INT_Timer);
  return;
}

static void
DEFUN (set_timer, (timer_id, first, interval),
       int timer_id AND clock_t first AND clock_t interval)
{
  struct timer_state_s * timer = &scheme_timers[timer_id];

  /* Round up. */ 
  timer->counter = ((first + 49) / 50);
  timer->reload = ((interval + 49) / 50);
  return;
}

static void
DEFUN (clear_timer, (timer_id), int timer_id)
{
  struct timer_state_s * timer = &scheme_timers[timer_id];

  timer->counter = 0;
  timer->reload = 0;
  return;
}

#endif /* USE_WM_TIMER */

void
DEFUN (OS_process_timer_set, (first, interval),
       clock_t first AND clock_t interval)
{
  set_timer (TIMER_ID_PROCESS, first, interval);
  return;
}

void
DEFUN_VOID (OS_process_timer_clear)
{
  clear_timer (TIMER_ID_PROCESS);
  return;
}

void
DEFUN (OS_profile_timer_set, (first, interval),
       clock_t first AND clock_t interval)
{
  set_timer (TIMER_ID_PROFILE, first, interval);
  return;
}

void
DEFUN_VOID (OS_profile_timer_clear)
{
  clear_timer (TIMER_ID_PROFILE);
  return;
}

void
DEFUN (OS_real_timer_set, (first, interval),
       clock_t first AND clock_t interval)
{
  set_timer (TIMER_ID_REAL, first, interval);
  return;
}

void
DEFUN_VOID (OS_real_timer_clear)
{
  clear_timer (TIMER_ID_REAL);
  return;
}

static size_t current_dir_path_size = 0;
static char * current_dir_path = 0;

CONST char *
DEFUN_VOID (OS_working_dir_pathname)
{
  if (current_dir_path) {
    return (current_dir_path);
  }
  if (current_dir_path_size == 0)
    {
      current_dir_path = (OS_malloc (1024));
      current_dir_path_size = 1024;
    }
  while (1)
    {
      if ((getcwd (current_dir_path, current_dir_path_size)) != 0)
      {
	strlwr (current_dir_path);
	return (current_dir_path);
      }
#ifdef ERANGE
      if (errno != ERANGE)
	NT_error_unix_call (errno, syscall_getcwd);
#endif
      current_dir_path_size *= 2;
      {
	char * new_current_dir_path
	  = (OS_realloc (current_dir_path, current_dir_path_size));
	current_dir_path = new_current_dir_path;
      }
    }
}

void
DEFUN (OS_set_working_dir_pathname, (name), CONST char * name)
{
  size_t name_size = (strlen (name));
  CONST char * filename = name;

  STD_BOOL_API_CALL (SetCurrentDirectory, (filename));

  while (1)
  {
    if (name_size < current_dir_path_size)
    {
      strcpy(current_dir_path, name);
      return;
    }
    current_dir_path_size *= 2;
    {
      char * new_current_dir_path
	= (OS_realloc (current_dir_path, current_dir_path_size));
      current_dir_path = new_current_dir_path;
    }
  }
}