/* GPM (General purpose mouse) functions
   Copyright (C) 1997 William M. Perry <wmperry@gnu.org>
   Copyright (C) 1999 Free Software Foundation, Inc.

This file is part of XEmacs.

XEmacs 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.

XEmacs 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 XEmacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* Synched up with: Not in FSF. */

/* Authors: William Perry */

#include <config.h>
#include "lisp.h"
#include "console.h"
#include "console-tty.h"
#include "device.h"
#include "events.h"
#include "events-mod.h"
#include "sysdep.h"
#include "commands.h"
#include "lstream.h"
#include "sysproc.h" /* for MAXDESC */
#include "process.h"

#ifdef HAVE_GPM
#include "gpmevent.h"
#include <gpm.h>

#if (!defined(__linux__))	/* possible under xterm */
#define KG_SHIFT	0
#define KG_CTRL		2
#define KG_ALT		3
#else
#include <linux/keyboard.h>
#endif

extern int gpm_tried;
extern void *gpm_stack;

static int (*orig_event_pending_p) (int);
static void (*orig_next_event_cb) (Lisp_Event *);

static Lisp_Object gpm_event_queue;
static Lisp_Object gpm_event_queue_tail;

struct __gpm_state {
	int gpm_tried;
	int gpm_flag;
	void *gpm_stack;
};

static struct __gpm_state gpm_state_information[MAXDESC];

static void
store_gpm_state (int fd)
{
	gpm_state_information[fd].gpm_tried = gpm_tried;
	gpm_state_information[fd].gpm_flag = gpm_flag;
	gpm_state_information[fd].gpm_stack = gpm_stack;
}

static void
restore_gpm_state (int fd)
{
	gpm_tried = gpm_state_information[fd].gpm_tried;
	gpm_flag = gpm_state_information[fd].gpm_flag;
	gpm_stack = gpm_state_information[fd].gpm_stack;
	gpm_consolefd = gpm_fd = fd;
}

static void
clear_gpm_state (int fd)
{
	if (fd >= 0)
	{
		memset(&gpm_state_information[fd], '\0', sizeof(struct __gpm_state));
	}
	gpm_tried = gpm_flag = 1;
	gpm_fd = gpm_consolefd = -1;
	gpm_stack = NULL;
}

static int
get_process_infd (Lisp_Process *p)
{
  Lisp_Object instr, outstr;
  get_process_streams (p, &instr, &outstr);
  assert (!NILP (instr));
  return filedesc_stream_fd (XLSTREAM (instr));
}

DEFUN ("receive-gpm-event", Freceive_gpm_event, 0, 2, 0, /*
Run GPM_GetEvent().
This function is the process handler for the GPM connection.
*/
       (process, string))
{
	Gpm_Event ev;
	int modifiers = 0;
	int button = 1;
	Lisp_Object fake_event;
	Lisp_Event *event = NULL;
	struct gcpro gcpro1;
	static int num_events;

	CHECK_PROCESS (process);

	restore_gpm_state (get_process_infd (XPROCESS (process)));

	if (!Gpm_GetEvent(&ev))
	{
		warn_when_safe (Qnil, Qcritical, "Gpm_GetEvent failed - %d", gpm_fd);
		return(Qzero);
	}

	GCPRO1(fake_event);

	num_events++;

	fake_event = Fmake_event (Qnil, Qnil);
	event = XEVENT(fake_event);

	event->timestamp = 0;
	event->channel   = Fselected_frame (Qnil); /* CONSOLE_SELECTED_FRAME (con); */

	/* Whow, wouldn't named defines be NICE!?!?! */
	modifiers = 0;

	if (ev.modifiers & 1)   modifiers |= MOD_SHIFT;
	if (ev.modifiers & 2)   modifiers |= MOD_META;
	if (ev.modifiers & 4)   modifiers |= MOD_CONTROL;
	if (ev.modifiers & 8)   modifiers |= MOD_META;

	if (ev.buttons & GPM_B_LEFT)
	{
		button = 1;
	}
	else if (ev.buttons & GPM_B_MIDDLE)
	{
		button = 2;
	}
	else if (ev.buttons & GPM_B_RIGHT)
	{
		button = 3;
	}

	switch (GPM_BARE_EVENTS(ev.type)) {
	case GPM_DOWN:
	case GPM_UP:
		event->event_type =
			(ev.type & GPM_DOWN) ? button_press_event : button_release_event;
		event->event.button.x         = ev.x;
		event->event.button.y         = ev.y;
		event->event.button.button    = button;
		event->event.button.modifiers = modifiers;
		break;
	case GPM_MOVE:
	case GPM_DRAG:
		event->event_type             = pointer_motion_event;
		event->event.motion.x         = ev.x;
		event->event.motion.y         = ev.y;
		event->event.motion.modifiers = modifiers;
	default:
		/* This will never happen */
		break;
	}

	/* Handle the event */
	enqueue_event (fake_event, &gpm_event_queue, &gpm_event_queue_tail);

	UNGCPRO;

	return (Qzero);
}

static void turn_off_gpm (char *process_name)
{
	Lisp_Object process = Fget_process (build_string (process_name));
	int fd = -1;

	if (NILP (process))
	{
		/* Something happened to our GPM process - fail silently */
		return;
	}

	fd = get_process_infd (XPROCESS (process));

	restore_gpm_state (fd);

	Gpm_Close();

	clear_gpm_state (fd);

	Fdelete_process (build_string (process_name));
}

#ifdef TIOCLINUX
static Lisp_Object
tty_get_foreign_selection (Lisp_Object selection_symbol, Lisp_Object target_type)
{
	/* This function can GC */
	struct device *d = decode_device (Qnil);
	int fd = DEVICE_INFD (d);
	char c = 3;
	Lisp_Object output_stream;
	Lisp_Object terminal_stream;
	Lisp_Object output_string;
	struct gcpro gcpro1,gcpro2,gcpro3;

	GCPRO3(output_stream,terminal_stream,output_string);

	/* The ioctl() to paste actually puts things in the input queue of
	** the virtual console, so we need to trap that data, since we are
	** supposed to return the actual string selection from this
	** function.
	*/

	/* I really hate doing this, but it doesn't seem to cause any
	** problems, and it makes the Lstream_read stuff further down
	** error out correctly instead of trying to indefinitely read from
	** the console.
	**
	** There is no set_descriptor_blocking() function call, but in my
	** testing under linux, it has not proved fatal to leave the
	** descriptor in non-blocking mode.
	**
	** William Perry Nov 5, 1999
	*/
	set_descriptor_non_blocking (fd);

	/* We need two streams, one for reading from the selected device,
	** and one to write the data into.  There is no writable version
	** of the lisp-string lstream, so we make do with a resizing
	** buffer stream, and make a string out of it after we are
	** done.
	*/
	output_stream = make_resizing_buffer_output_stream ();
	terminal_stream = make_filedesc_input_stream (fd, 0, -1, LSTR_BLOCKED_OK);
	output_string = Qnil;

	/* #### We should arguably use a specbind() and an unwind routine here,
	** #### but I don't care that much right now.
	*/
	if (NILP (output_stream) || NILP (terminal_stream))
	{
		/* Should we signal an error here? */
		goto out;
	}

	if (ioctl (fd, TIOCLINUX, &c) < 0)
	{
		/* Could not get the selection - eek */
		UNGCPRO;
		return (Qnil);
	}

	while (1)
	{
		Bufbyte tempbuf[1024]; /* some random amount */
		ssize_t i;
		ssize_t size_in_bytes =
		  Lstream_read (XLSTREAM (terminal_stream),
				tempbuf, sizeof (tempbuf));

		if (size_in_bytes <= 0)
		{
			/* end of the stream */
			break;
		}

		/* convert CR->LF */
		for (i = 0; i < size_in_bytes; i++)
		{
			if (tempbuf[i] == '\r')
			{
				tempbuf[i] = '\n';
			}
		}

		Lstream_write (XLSTREAM (output_stream), tempbuf, size_in_bytes);
	}

	Lstream_flush (XLSTREAM (output_stream));

	output_string = make_string (resizing_buffer_stream_ptr (XLSTREAM (output_stream)),
								 Lstream_byte_count (XLSTREAM (output_stream)));

	Lstream_delete (XLSTREAM (output_stream));
	Lstream_delete (XLSTREAM (terminal_stream));

 out:
	UNGCPRO;
	return (output_string);
}

static Lisp_Object
tty_selection_exists_p (Lisp_Object selection)
{
	return (Qt);
}
#endif /* TIOCLINUX */

#if 0
static Lisp_Object
tty_own_selection (Lisp_Object selection_name, Lisp_Object selection_value)
{
	/* There is no way to do this cleanly - the GPM selection
	** 'protocol' (actually the TIOCLINUX ioctl) requires a start and
	** end position on the _screen_, not a string to stick in there.
	** Lame.
	**
	** William Perry Nov 4, 1999
	*/
}
#endif

/* This function appears to work once in a blue moon.  I'm not sure
** exactly why either.  *sigh*
**
** William Perry Nov 4, 1999
**
** Apparently, this is the way (mouse-position) is supposed to work,
** and I was just expecting something else.  (mouse-pixel-position)
** works just fine.
**
** William Perry Nov 7, 1999
*/
static int
tty_get_mouse_position (struct device *d, Lisp_Object *frame, int *x, int *y)
{
	Gpm_Event ev;
	int num_buttons;

	memset(&ev,'\0',sizeof(ev));

	num_buttons = Gpm_GetSnapshot(&ev);

	if (!num_buttons)
	{
		/* This means there are events pending... */

		/* #### In theory, we should drain the events pending, stick
		** #### them in the queue, and return the mouse position
		** #### anyway.
		*/
		return(-1);
	}
	*x = ev.x;
	*y = ev.y;
	*frame = DEVICE_SELECTED_FRAME (d);
	return (1);
}

static void
tty_set_mouse_position (struct window *w, int x, int y)
{
	/*
	   #### I couldn't find any GPM functions that set the mouse position.
	   #### Mr. Perry had left this function empty; that must be why.
	   #### karlheg
	*/
}

static int gpm_event_pending_p (int user_p)
{
	Lisp_Object event;

	EVENT_CHAIN_LOOP (event, gpm_event_queue)
	{
		if (!user_p || command_event_p (event))
		{
			return (1);
		}
	}
	return (orig_event_pending_p (user_p));
}

static void gpm_next_event_cb (Lisp_Event *event)
{
	/* #### It would be nice to preserve some sort of ordering of the
	** #### different types of events, but that would be quite a bit
	** #### of work, and would more than likely break the abstraction
	** #### between the other event loops and this one.
	*/

	if (!NILP (gpm_event_queue))
	{
		Lisp_Object queued_event = dequeue_event (&gpm_event_queue, &gpm_event_queue_tail);
		*event = *(XEVENT (queued_event));

		if (event->event_type == pointer_motion_event)
		{
			struct device *d = decode_device (event->channel);
			int fd = DEVICE_INFD (d);

			/* Ok, now this is just freaky.  Bear with me though.
			**
			** If you run gnuclient and attach to a XEmacs running in
			** X or on another TTY, the mouse cursor does not get
			** drawn correctly.  This is because the ioctl() fails
			** with EPERM because the TTY specified is not our
			** controlling terminal.  If you are the superuser, it
			** will work just spiffy.  The appropriate source file (at
			** least in linux 2.2.x) is
			** .../linux/drivers/char/console.c in the function
			** tioclinux().  The following bit of code is brutal to
			** us:
			**
			** if (current->tty != tty && !suser())
			**    return -EPERM;
			**
			** I even tried setting us as a process leader, removing
			** our controlling terminal, and then using the TIOCSCTTY
			** to set up a new controlling terminal, all with no luck.
			**
			** What is even weirder is if you run XEmacs in a VC, and
			** attach to it from another VC with gnuclient, go back to
			** the original VC and hit a key, the mouse pointer
			** displays (in BOTH VCs), until you hit a key in the
			** second VC, after which it does not display in EITHER
			** VC.  Bizarre, no?
			**
			** All I can say is thank god Linux comes with source code
			** or I would have been completely confused.  Well, ok,
			** I'm still completely confused.  I don't see why they
			** don't just check the permissions on the device
			** (actually, if you have enough access to it to get the
			** console's file descriptor, you should be able to do
			** with it as you wish, but maybe that is just me).
			**
			** William M. Perry - Nov 9, 1999
			*/

			Gpm_DrawPointer (event->event.motion.x,event->event.motion.y, fd);
		}

		return;
	}

	orig_next_event_cb (event);
}

static void hook_event_callbacks_once (void)
{
	static int hooker;

	if (!hooker)
	{
		orig_event_pending_p = event_stream->event_pending_p;
		orig_next_event_cb = event_stream->next_event_cb;
		event_stream->event_pending_p = gpm_event_pending_p;
		event_stream->next_event_cb = gpm_next_event_cb;
		hooker = 1;
	}
}

static void hook_console_methods_once (void)
{
	static int hooker;

	if (!hooker)
	{
		/* Install the mouse position methods for the TTY console type */
		CONSOLE_HAS_METHOD (tty, get_mouse_position);
		CONSOLE_HAS_METHOD (tty, set_mouse_position);
		CONSOLE_HAS_METHOD (tty, get_foreign_selection);
		CONSOLE_HAS_METHOD (tty, selection_exists_p);
#if 0
		CONSOLE_HAS_METHOD (tty, own_selection);
#endif
	}
}

DEFUN ("gpm-enabled-p", Fgpm_enabled_p, 0, 1, 0, /*
Return non-nil if GPM mouse support is currently enabled on DEVICE.
*/
	   (device))
{
	char *console_name = ttyname (DEVICE_INFD (decode_device (device)));
	char process_name[1024];
	Lisp_Object proc;

	if (!console_name)
	{
		return (Qnil);
	}

	memset (process_name, '\0', sizeof(process_name));
	snprintf (process_name, sizeof(process_name) - 1, "gpm for %s", console_name);

	proc = Fget_process (build_string (process_name));

	if (NILP (proc))
	{
		return (Qnil);
	}

	if (1) /* (PROCESS_LIVE_P (proc)) */
	{
		return (Qt);
	}
	return (Qnil);
}

DEFUN ("gpm-enable", Fgpm_enable, 0, 2, 0, /*
Toggle accepting of GPM mouse events.
*/
	   (device, arg))
{
	Gpm_Connect conn;
	int rval;
	Lisp_Object gpm_process;
	Lisp_Object gpm_filter;
	struct device *d = decode_device (device);
	int fd = DEVICE_INFD (d);
	char *console_name = ttyname (fd);
	char process_name[1024];

	hook_event_callbacks_once ();
	hook_console_methods_once ();

	if (noninteractive)
	{
		error ("Can't connect to GPM in batch mode.");
	}

	if (!console_name)
	{
		/* Something seriously wrong here... */
		return (Qnil);
	}

	memset (process_name, '\0', sizeof(process_name));
	snprintf (process_name, sizeof(process_name) - 1, "gpm for %s", console_name);

	if (NILP (arg))
	{
		turn_off_gpm (process_name);
		return (Qnil);
	}

	/* DANGER DANGER.
	** Though shalt not call (gpm-enable t) after we have already
	** started, or stuff blows up.
	*/
	if (!NILP (Fgpm_enabled_p (device)))
	{
		error ("GPM already enabled for this console.");
	}

	conn.eventMask = GPM_DOWN|GPM_UP|GPM_MOVE|GPM_DRAG;
	conn.defaultMask = GPM_MOVE;
	conn.minMod = 0;
	conn.maxMod = ((1<<KG_SHIFT)|(1<<KG_ALT)|(1<<KG_CTRL));

	/* Reset some silly static variables so that multiple Gpm_Open()
	** calls have even a sligh chance of working
	*/
	gpm_tried = 0;
	gpm_flag = 0;
	gpm_stack = NULL;

	/* Make sure Gpm_Open() does ioctl() on the correct
	** descriptor, or it can get the wrong terminal sizes, etc.
	*/
	gpm_consolefd = fd;

	/* We have to pass the virtual console manually, otherwise if you
	** use 'gnuclient -nw' to connect to an XEmacs that is running in
	** X, Gpm_Open() tries to use ttyname(0 | 1 | 2) to find out which
	** console you are using, which is of course not correct for the
	** new tty device.
	*/
	if (strncmp (console_name, "/dev/tty",8) || !isdigit (console_name[8]))
	{
		/* Urk, something really wrong */
		return (Qnil);
	}

	rval = Gpm_Open (&conn, atoi(console_name + 8));

	switch (rval) {
	case -1: /* General failure */
		break;
	case -2: /* We are running under an XTerm */
		Gpm_Close();
		break;
	default:
		/* Is this really necessary? */
		set_descriptor_non_blocking (gpm_fd);
		store_gpm_state (gpm_fd);
		gpm_process = connect_to_file_descriptor (build_string (process_name), Qnil,
												  make_int (gpm_fd),
												  make_int (gpm_fd));

		if (!NILP (gpm_process))
		{
			rval = 0;
			Fprocess_kill_without_query (gpm_process, Qnil);
			XSETSUBR (gpm_filter, &SFreceive_gpm_event);
			set_process_filter (gpm_process, gpm_filter, 1);

			/* Keep track of the device for later */
			/* Fput (gpm_process, intern ("gpm-device"), device); */
		}
		else
		{
			Gpm_Close();
			rval = -1;
		}
	}

	return(rval ? Qnil : Qt);
}

void vars_of_gpmevent (void)
{
	gpm_event_queue = Qnil;
	gpm_event_queue_tail = Qnil;
	staticpro (&gpm_event_queue);
	staticpro (&gpm_event_queue_tail);
	pdump_wire (&gpm_event_queue);
	pdump_wire (&gpm_event_queue_tail);
}

void syms_of_gpmevent (void)
{
	DEFSUBR (Freceive_gpm_event);
	DEFSUBR (Fgpm_enable);
	DEFSUBR (Fgpm_enabled_p);
}

#endif /* HAVE_GPM */