/************************************************************************
* "Epsilon", "EEL" and "Lugaru" are trademarks of Lugaru Software, Ltd. *
*									*
*  Copyright (C) 1985, 1990 Lugaru Software Ltd.  All rights reserved.	*
*									*
* Limited permission is hereby granted to reproduce and modify this	*
* copyrighted material provided that the resulting code is used only in	*
* conjunction with Lugaru products and that this notice is retained in	*
* any such reproduction or modification.				*
*************************************************************************
*  The previous copyright and trademark notice applies to some of the	*
*  code herein. All other changes, enhancements and extension routines	*
*									*
*  Copyright (C) 1989, 1990 by Jonas H. Hedberg. All rights reserved.   *
*									*
*  These changes may be redistributed free allowed for any purpose	*
*  providing both the Lugaru and my copyrights remain intact.		*
*  I assume no liability for the use or inability to use		*
*  this software. Neither do I take responsibility for any damage	*
*  cased by this software extension.					*
*  This extension may NOT be redistributed for profit.			*
*************************************************************************
* File.......: MOUSE.E                                                  *
* Ver........: 1.00                                                     *
* Date.......: 1990-08-16                                               *
* īpsilon ver: 5.0                                                      *
* By.........: Jonas Hedberg                                            *
*     Title..: Software Engineer                                        *
*     Company: TEAMSTER AB                                              *
*     Address: P.O. Box 8321                                            *
*              S-402 79  G™TEBORG                                       *
*     Country: SWEDEN                                                   *
*     Tel....: Int +46-31-22 22 65  (GMT + 1h)                          *
*     Fax....: Int +46-31-22 75 46                                      *
* Description: Mouse driver for Epsilon.                                *
*                                                                       *
*              Commands:                                                *
*              -------------------------------------------------        *
*              mouse            = Toggle mouse on/off                   *
*              set_double_click = Set the dobble click intervall        *
*                                 in n*0.055s parts.                    *
*                                                                       *
*              Buttons:                                                 *
*              -------------------------------------------------        *
*              Single left  = Move cursor to mouse cursor.              *
*                             If in echo area move to point in          *
*                             buffer.                                   *
*                             |        ECHO AREA             |          *
*                             0%           50%            100%          *
*                             If mouse cursor is in another window      *
*                             that isn't current the window is          *
*                             made the current one.                     *
*                             If the button is held down, a mark is     *
*                             set at the current mouse position.        *
*              Single right = Delete from mark to mouse cursor.         *
*              Doubble left = Runs the Epsilon command:                 *
*                             exchange-point-and-mark                   *
*              Doubble right= Yank at mouse cursor                      *
*                                                                       *
*              Other:                                                   *
*              -------------------------------------------------        *
*              If mouse cursor in top of screen and mouse still         *
*              beeing move upwords scroll down, it works the            *
*              same way the other way. It also can scroll left          *
*              and right witch works so that if the mouse cursor        *
*              is at the left edge of screen and columns of text        *
*              is "hidden" beound the window scrolls right. It's        *
*              the same way to the right exept that the text            *
*              cursor must be on a row that reatches so long            *
*              that you want to scroll.                                 *
* Algorithm..:                                                          *
* Comments...: Tested with Microsoft mouse driver version 7.04.         *
* Change log                                                            *
* Date      | Ver   | Change                                            *
* ----------+-------+-------------------------------------------------- *
*           |       |                                                   *
*           |       |                                                   *
*           |       |                                                   *
************************************************************************/

#include "eel.h"
#include "lowlevel.h"

char mouse_present = 0;			/* non-zero if a mouse is present */
int double_click_interval = 10;		/* int ticks, 18.2 ticks per second */

#define MOUSE_IO 0x33			/* Interrupt 33H for mouse services */
#define CHAR_SIZE 8			/* Pixels per character */
#define LEFT_BUTTON 0
#define RIGHT_BUTTON 1
#define BUTTON_MASK(button) (1 << button)	/* Button mask for button word */
#define SCROLL_VERT -1
#define SCROLL_HORZ -2

/* Initiate the mouse and check for a mouse */
init_mouse()
{
	if (!mouse_present) {
		m_regs.w.ax = 0;		/* Mouse installed */
		do_interrupt(MOUSE_IO, &m_regs);
	}
	
	if (m_regs.w.ax) {
		mouse_present = m_regs.w.ax;
		
		m_regs.w.ax = 0x1130;		/* Get screen size from video card */
		m_regs.b.bh = 0;
		m_regs.b.bl = 24;
		do_interrupt(VIDEO_IO, &m_regs);
		
		m_regs.w.ax = 8;		/* Set min and max vertikal position */
		m_regs.w.cx = 0;		/* for mouse */
		m_regs.w.dx = (m_regs.b.dl + 1)*CHAR_SIZE - 1;
		do_interrupt(MOUSE_IO, &m_regs);
	}
}

/* Show mouse cursor on screen */
show_mouse_cursor()
{
	m_regs.w.ax = 1;			/* Show cursor */
	do_interrupt(MOUSE_IO, &m_regs);
	m_regs.w.ax = 11;			/* Read mouse motion counters */
	do_interrupt(MOUSE_IO, &m_regs);
}

/* Turn of mouse cursor */
hide_mouse_cursor()
{
	m_regs.w.ax = 2;			/* Hide cursor */
	do_interrupt(MOUSE_IO, &m_regs);
}

/* Redraw screen, but hide mouse first, then show it again */
refresh_for_mouse()
{
	hide_mouse_cursor();
	refresh();
	show_mouse_cursor();
}

/* Wrap the mouse cursor to the hardware cursor */
mouse_to_cursor()
{
	m_regs.b.ah = 3;			/* Get position an buttom status */
	m_regs.b.bh = 0;
	do_interrupt(VIDEO_IO, &m_regs);
	set_mouse_cursor(m_regs.b.dh * CHAR_SIZE, m_regs.b.dl * CHAR_SIZE);
}

/* Set the mouse cursor to given row and column */
set_mouse_cursor(row, col)
{
	m_regs.w.ax = 4;			/* Set mouse cursor position */
	m_regs.w.cx = col;
	m_regs.w.dx = row;
	do_interrupt(MOUSE_IO, &m_regs);
}
	
/* Return the nuber of BIOS ticks */
bios_ticks()
{
	int ticks;
	
	m_regs.b.ah = 0;
	do_interrupt(0x1A, &m_regs);
	
	if (m_regs.b.al == 0) {
		/* Calculate ticks */
		ticks = (m_regs.w.cx << 16) + m_regs.w.dx;
	} else {
		/* We have passed midnight since last call, make sure pasue() exits */
		ticks = 0x7FFFFFFFL;
	}
	
	return ticks;
}

/* Waits for the specified number of BIOS ticks */
pause(ticks)
{
	int alarm;
	
	alarm = bios_ticks() + ticks;
	while (alarm > bios_ticks()) {
	}
}

/* Reset mouse buttons */
flash_mouse_buttons()
{
	short button;
	
	for (button = LEFT_BUTTON; button <= RIGHT_BUTTON; ++button) {
		m_regs.w.ax = 5;		/* Get button press information */
		m_regs.w.bx = button;
		do_interrupt(MOUSE_IO, &m_regs);
	}
}

/* screen_set_point takes mouse row and column coordinates and sets point there */
/* If the coordinates lie in another window, it's made current */
/* Non-zero is returned if the specified row is an editable line */
/* Otherwise (modeline or echo line) zero is returned */
screen_set_point(row, col)
{
	int r, current_window = window_number, window_size = window_height;
	
	row /= CHAR_SIZE;
	col /= CHAR_SIZE;
		
	/* Find which window the coordinates lie in */
	if (number_of_windows() == 1) 
		window_number = 0;
	else 
		for (window_number = number_of_windows() - 1;
			!((row >= window_edge(VERTICAL, TOPLEFT)) &&
			(row <= window_edge(VERTICAL, BOTTOMRIGHT)) &&
			(col >= window_edge(HORIZONTAL, TOPLEFT)) &&
			(col <= window_edge(HORIZONTAL, BOTTOMRIGHT))) && 
			(window_number >= 0);
			--window_number)
		r = window_number;
		if ((screen_lines - 1) > row) {  
			/* If row = mode line, don't change point */
			if (row < window_edge(VERTICAL, BOTTOMRIGHT)) {
				col = col - window_edge(HORIZONTAL, TOPLEFT) + display_column;
				row = row - window_edge(VERTICAL, TOPLEFT);
				point = window_start;
				point = next_screen_line(row);
				r = current_column();
				move_to_column(r + col);
				r = current_column() - (r + col);
				if (r > 0)
					point -= r;
				return 1;
			} else {
				current_window = window_number;
				return 0;
			}
		} else  {
			r += window_size + 1;
			/* Row in echo area, don't do anything */
			window_number = current_window;
			return 0;		
		}
}

/* Return 1 if any mouse nutton is pressed */
/* At the same time check for vertical or horizontal scrolling */
/* an preform the scrolling */
mouse_button_pressed()
{
	short status, row, col, i;

	for(;;) {
		m_regs.w.ax = 3;		/* Get position and button status */
		do_interrupt(MOUSE_IO, &m_regs);
		status = m_regs.w.bx & (BUTTON_MASK(LEFT_BUTTON) + BUTTON_MASK(RIGHT_BUTTON));
		row = m_regs.w.dx / CHAR_SIZE;
		col = m_regs.w.cx / CHAR_SIZE;
		
		m_regs.w.ax = 11;		/* Read mouse motion counters */
		do_interrupt(MOUSE_IO, &m_regs);

		/* Check if not much horizontal motion */
		if (!(m_regs.w.cx / 8) && (((row == 0) && (m_regs.w.dx < 0)) || (row == (screen_lines - 1) && (m_regs.w.dx > 0)))) {
			if (prev_cmd == SCROLL_VERT) {
				window_scroll(m_regs.w.dx / 4);
				refresh_for_mouse();
			} else {
				pause(3);
				prev_cmd = SCROLL_VERT; 
				m_regs.w.ax = 11;	/* Read mouse motion counters */
				do_interrupt(MOUSE_IO, &m_regs);
			}
		} else {
			if ((prev_cmd == SCROLL_VERT) && (row > 0) && (row < (screen_lines - 1)))
				prev_cmd = 0;		
			if (!(m_regs.w.dx / 8) && (((col == 0) && (m_regs.w.cx < 0)) || (col == (screen_cols - 1) && (m_regs.w.cx > 0))) && (row < screen_lines - 2)) {
				if (prev_cmd == SCROLL_HORZ) {
					if ((col == 0) && (display_column > (0 + -m_regs.w.cx / 4) - 1)) {
						int old_iter = iter, old_arg = has_arg;
						int old_prev = prev_cmd, old_this = this_cmd;
						
						iter = -m_regs.w.cx / 4;
						has_arg = 0;
						prev_cmd = 0;
						scroll_right();
						refresh_for_mouse();
						iter = old_iter, has_arg = old_arg;
						prev_cmd = old_prev, this_cmd = old_this;
						break;
					} 
					if (col == screen_cols -1) {
						int old_iter = iter, old_arg = has_arg;
						int old_prev = prev_cmd, old_this = this_cmd;
						
						iter = m_regs.w.cx / 4;
						has_arg = 0;
						prev_cmd = 0;
						scroll_left();
						refresh_for_mouse();
						iter = old_iter, has_arg = old_arg;
						prev_cmd = old_prev, this_cmd = old_this;
						break;
					}
				} else {
					pause(3);
					prev_cmd = SCROLL_HORZ;
					m_regs.w.ax = 11;	/* Read mouse motion counters */
					do_interrupt(MOUSE_IO, &m_regs);
				}
			} else {
				break;
			}
		}
	} 
	return status;
}

/* If any mouse button were pressed do the proper thing for each button */
do_mouse_command()
{
	short status;
	
	pause(double_click_interval);		/* Give user time to doble click */
	m_regs.w.ax = 5;			/* Get button press information */
	m_regs.w.bx = LEFT_BUTTON;
	do_interrupt(MOUSE_IO, &m_regs);
	status = m_regs.w.ax;
	switch(m_regs.w.bx) {
		case 1:	
			/* Check if user clicked i echo area */
			if ((m_regs.w.dx / CHAR_SIZE) == (screen_lines -1)) {
				point = size() * m_regs.w.cx / (screen_cols - 1) / CHAR_SIZE;
				build_first = 1;
				break;
			}

			/* Single click left -> set point at mouse cursor */
			screen_set_point(m_regs.w.dx, m_regs.w.cx);
			refresh_for_mouse();

			/* Check if the button is still being held down -> set mark at point */
			/* Then set point at new mouse cursor when button is released */
			if (status & BUTTON_MASK(LEFT_BUTTON)) {
				set_mark();
				while (mouse_button_pressed() & BUTTON_MASK(LEFT_BUTTON));
				m_regs.w.ax = 6;	/* Get button release information */
				m_regs.w.bx = LEFT_BUTTON;
				do_interrupt(MOUSE_IO, &m_regs);
				screen_set_point(m_regs.w.dx, m_regs.w.cx);
				refresh_for_mouse();
			}
			break;

		case 2:	
			/* Double click left -> xhange mark and cursor */
			/* Then set point and mouse cursor to previous mark */
/*			screen_set_point(m_regs.w.dx, m_regs.w.cx); */
			exchange_point_and_mark();
			refresh_for_mouse();
			return;
			
		case 0:
			/* No left clicks, check the right button */
			m_regs.w.ax = 5;	/* Get button press information */
			m_regs.w.bx = RIGHT_BUTTON;
			do_interrupt(MOUSE_IO, &m_regs);
			
			switch(m_regs.w.bx) {
				int *point_save, pos;
				
				case 0:
					return;
					
				case 1:
					/* Check if user clicked in echo area */
					if ((m_regs.w.dx / CHAR_SIZE) == (screen_lines - 1)) {
						break;
					}
					
				case 2:
					/* Click right -> delete from mark to mouse cursor */
					/* Double click right -> yank at mouse cursor */
					point_save = alloc_spot();
					if (screen_set_point(m_regs.w.dx, m_regs.w.cx)) {
						if (m_regs.w.bx == 1)
							kill_region();
						else
							yank();
						refresh_for_mouse();
						point = *point_save;
					} else
						maybe_ding();
					free_spot(point_save);
					break;
					
				default:
					goto too_many_clicks;
				
			}
			break;
			
		default:
		too_many_clicks:
			maybe_ding();
			return;
	}
	hide_mouse_cursor();
	maybe_refresh();
	show_mouse_cursor();
}

/* Turn mouse functions on and off */
command mouse()
{
	if ((iter == 0) || (!has_arg && mouse_present)) {
		mouse_present = 0;
		say("Mouse off.");
	} else {
		init_mouse();
		if (mouse_present) 
			say("Mouse on.");
		else
			error("No mouse were found!");
	}
	iter = 1;
}

/* Allow you to set the double click wait interval */
command set_double_click()
{
	char prompt[80];
	
	sprintf(prompt, "Current double click interval is %d. New value: ", double_click_interval);
	double_click_interval = get_number(prompt);
}

new_mouse_getkey()
{
	if (!cmd_len && !char_avail() && mouse_present && !another) {
		flash_mouse_buttons();
		show_mouse_cursor();
		while (!char_avail()) {
			if (mouse_button_pressed()) {
				prev_cmd = 0;
				do_mouse_command();
				flash_mouse_buttons();
			}
		}
		hide_mouse_cursor();
	}
	return mouse_getkey();
}

new_next_video()
{
	mouse_next_video();
	if (mouse_present)
		init_mouse();
	
}

new_set_video()
{
	mouse_set_video();
	if (mouse_present)
		init_mouse();
	
}

when_loading()
{
	sayput("MOUSE-module  Ver 1.00  (C) 1990 by Jonas Hedberg. Loading...");

	/* Change Epsilon's getkey() */
	if (!find_index("mouse_getkey"))
		replace_name("getkey", "mouse_getkey");
	else
		drop_name("getkey");
	replace_name("new_mouse_getkey", "getkey");

	/* Change Epsilon's next_video() */
	if (!find_index("mouse_next_video"))
		replace_name("next_video", "mouse_next_video");
	else
		drop_name("next_video");
	replace_name("new_next_video", "next_video");

	/* Change Epsilon's set_video() */
	if (!find_index("mouse_set_video"))
		replace_name("set_video", "mouse_set_video");
	else
		drop_name("set_video");
	replace_name("new_set_video", "set_video");

	delay(300, COND_KEY);
}