/*	SCCS Id: @(#)winmesg.c	3.1	92/05/19		  */
/* Copyright (c) Dean Luick, 1992				  */
/* NetHack may be freely redistributed.  See license for details. */

/*
 * Message window routines.
 *
 * Global functions:
 *	set_message_height()
 *	create_message_window()
 *	destroy_message_window()
 *	display_message_window()
 *	append_message()
 */
#include <X11/Intrinsic.h>
#include <X11/StringDefs.h>
#include <X11/Shell.h>
#include <X11/Xaw/Cardinals.h>
#include <X11/Xaw/Viewport.h>
#include "Window.h"	/* Window widget declarations */

#include "hack.h"
#include "winX.h"

static const char message_translations[] =
    "#override\n\
    <Key>: no-op()";

static struct line_element *get_previous();
static void set_circle_buf();
static char *split();
static void add_line();
static void redraw_message_window();
static void mesg_check_size_change();
static void mesg_exposed();
static void get_gc();
static void mesg_resized();

/* Adjust the number of rows on the given message window. */
void
set_message_height(wp, rows)
    struct xwindow *wp;
    Dimension rows;
{
    Arg args[1];

    wp->pixel_height = wp->mesg_information->char_height * rows;

    XtSetArg(args[0], XtNheight, wp->pixel_height);
    XtSetValues(wp->w, args, ONE);
}

/* Move the message window's vertical scrollbar's slider to the bottom. */
void
set_message_slider(wp)
    struct xwindow *wp;
{
    Widget scrollbar;
    float top;

    scrollbar = XtNameToWidget(XtParent(wp->w), "vertical");

    if (scrollbar) {
	top = 1.0;
	XtCallCallbacks(scrollbar, XtNjumpProc, &top);
    }
}


void
create_message_window(wp, create_popup, parent)
    struct xwindow *wp;			/* window pointer */
    boolean create_popup;
    Widget parent;
{
    Arg args[8];
    Cardinal num_args;
    Widget viewport;
    struct mesg_info_t *mesg_info;

    wp->type = NHW_MESSAGE;

    wp->mesg_information = mesg_info =
		    (struct mesg_info_t *) alloc(sizeof(struct mesg_info_t));

    mesg_info->fs = 0;
    mesg_info->num_lines = 0;
    mesg_info->head = mesg_info->last_pause =
			mesg_info->last_pause_head = (struct line_element *) 0;
    mesg_info->dirty = False;
    mesg_info->viewport_width = mesg_info->viewport_height = 0;

    /*
     * We should have an .Xdefaults option that specifies the number of lines
     * to be displayed.  Until then, we'll use DEFAULT_LINES_DISPLAYED.
     * E.g.:
     *
     *	if (a lines value from .Xdefaults exists)
     *	    lines_displayed = lines value from .Xdefaults;
     *	else
     *	    lines_displayed = DEFAULT_LINES_DISPLAYED;
     */
    if (flags.msg_history < DEFAULT_LINES_DISPLAYED)
	flags.msg_history = DEFAULT_LINES_DISPLAYED;
    if (flags.msg_history > MAX_HISTORY)	/* a sanity check */
	flags.msg_history = MAX_HISTORY;

    set_circle_buf(mesg_info, (int) flags.msg_history);

    /* Create a popup that becomes the parent. */
    if (create_popup) {
	num_args = 0;
	XtSetArg(args[num_args], XtNallowShellResize, True); num_args++;

	wp->popup = parent = XtCreatePopupShell("message_popup",
					topLevelShellWidgetClass,
					toplevel, args, num_args);
    }

    /*
     * Create the viewport.  We only want the vertical scroll bar ever to be
     * visible.  If we allow the horizontal scrollbar to be visible it will
     * always be visible, due to the stupid way the Athena viewport operates.
     */
    num_args = 0;
    XtSetArg(args[num_args], XtNallowVert,  True);      num_args++;
    viewport = XtCreateManagedWidget(
                        "mesg_viewport",         /* name */
                        viewportWidgetClass,    /* widget class from Window.h */
                        parent,                 /* parent widget */
                        args,                   /* set some values */
                        num_args);              /* number of values to set */

    /*
     * Create a message window.  We will change the width and height once
     * we know what font we are using.
     */
    num_args = 0;
    XtSetArg(args[num_args], XtNtranslations,
	XtParseTranslationTable(message_translations));	num_args++;
    wp->w = XtCreateManagedWidget(
		"message",		/* name */
		windowWidgetClass,	/* widget class from Window.h */
		viewport,		/* parent widget */
		args,			/* set some values */
		num_args);		/* number of values to set */

    XtAddCallback(wp->w, XtNexposeCallback, mesg_exposed, (XtPointer) 0);

    /*
     * Now adjust the height and width of the message window so that it
     * is DEFAULT_LINES_DISPLAYED high and DEFAULT_MESSAGE_WIDTH wide.
     */

    /* Get the font information. */
    num_args = 0;
    XtSetArg(args[num_args], XtNfont, &mesg_info->fs);	       num_args++;
    XtGetValues(wp->w, args, num_args);

    /* Save character information for fast use later. */
    mesg_info->char_width    = mesg_info->fs->max_bounds.width;
    mesg_info->char_height   = mesg_info->fs->max_bounds.ascent +
					    mesg_info->fs->max_bounds.descent;
    mesg_info->char_ascent   = mesg_info->fs->max_bounds.ascent;
    mesg_info->char_lbearing = -mesg_info->fs->min_bounds.lbearing;

    get_gc(wp->w, mesg_info);

    wp->pixel_height = DEFAULT_LINES_DISPLAYED * mesg_info->char_height;

    /* If a variable spaced font, only use 2/3 of the default size */
    if (mesg_info->fs->min_bounds.width != mesg_info->fs->max_bounds.width) {
	wp->pixel_width  = ((2*DEFAULT_MESSAGE_WIDTH)/3) *
					mesg_info->fs->max_bounds.width;
    } else
	wp->pixel_width  = (DEFAULT_MESSAGE_WIDTH *
					mesg_info->fs->max_bounds.width);

    /* Set the new width and height. */
    num_args = 0;
    XtSetArg(args[num_args], XtNwidth,        wp->pixel_width);  num_args++;
    XtSetArg(args[num_args], XtNheight,       wp->pixel_height); num_args++;
    XtSetValues(wp->w, args, num_args);

    XtAddEventHandler(wp->w, KeyPressMask, False,
		      (XtEventHandler) msgkey, (XtPointer) 0);
    XtAddCallback(wp->w, XtNresizeCallback, mesg_resized, (XtPointer) 0);

    /*
     * If we have created our own popup, then realize it so that the
     * viewport is also realized.  Then resize the mesg window.
     */
    if (create_popup) {
	XtRealizeWidget(wp->popup);
	set_message_height(wp, (int) flags.msg_history);
    }
}


void
destroy_message_window(wp)
    struct xwindow *wp;
{
    if (wp->popup) {
	nh_XtPopdown(wp->popup);
	XtDestroyWidget(wp->popup);
	set_circle_buf(wp->mesg_information, 0);	/* free buffer list */
	free((char *)wp->mesg_information);
    }
    wp->type = NHW_NONE;
}


/* Redraw message window if new lines have been added. */
void
display_message_window(wp)
    struct xwindow *wp;
{
    if (wp->mesg_information->dirty) redraw_message_window(wp);
}


/*
 * Append a line of text to the message window.  Split the line if the
 * rendering of the text is too long for the window.
 */
void
append_message(wp, str)
    struct xwindow *wp;
    const char *str;
{
    char *mark, *remainder, buf[BUFSZ];

    if (!str) return;

    Strcpy(buf, str);	/* we might mark it up */

    remainder = buf;
    do {
	mark = remainder;
	remainder = split(mark, wp->mesg_information->fs, wp->pixel_width);
	add_line(wp->mesg_information, mark);
    } while (remainder);
}

/* private functions ======================================================= */

/*
 * Return the element in the circular linked list just before the given
 * element.
 */
static struct line_element *
get_previous(mark)
    struct line_element *mark;
{
    struct line_element *curr;

    if (!mark) return (struct line_element *) 0;

    for (curr = mark; curr->next != mark; curr = curr->next)
	;
    return curr;
}


/*
 * Set the information buffer size to count lines.  We do this by creating
 * a circular linked list of elements, each of which represents a line of
 * text.  New buffers are created as needed, old ones are freed if they
 * are no longer used.
 */
static void
set_circle_buf(mesg_info, count)
    struct mesg_info_t *mesg_info;
    int count;
{
    int i;
    struct line_element *tail, *curr, *head;

    if (count < 0) panic("set_circle_buf: bad count [= %d]", count);
    if (count == mesg_info->num_lines) return;	/* no change in size */

    if (count < mesg_info->num_lines) {
	/*
	 * Toss num_lines - count line entries from our circular list.
	 *  
	 * We lose lines from the front (top) of the list.  We _know_
	 * the list is non_empty.
	 */
	tail = get_previous(mesg_info->head);
	for (i = mesg_info->num_lines - count;	i--; ) {
	    curr = mesg_info->head;
	    mesg_info->head = curr->next;
	    if (curr->line) free(curr->line);
	    free((genericptr_t)curr);
	}
	if (count == 0) {
	    /* make sure we don't have a dangling pointer */
	    mesg_info->head = (struct line_element *) 0;
	} else {
	    tail->next = mesg_info->head;	/* link the tail to the head */
	}
    } else {
	/*
	 * Add count - num_lines blank lines to the head of the list.
	 *
	 * Create a separate list, keeping track of the tail.
	 */
	for (head = tail = 0, i = 0; i < count - mesg_info->num_lines; i++) {
	    curr = (struct line_element *) alloc(sizeof(struct line_element));
	    curr->line = 0;
	    curr->buf_length = 0;
	    curr->str_length = 0;
	    if (tail) {
		tail->next = curr;
		tail = curr;
	    } else {
		head = tail = curr;
	    }
	}
	/*
	 * Complete the circle by making the new tail point to the old head
	 * and the old tail point to the new head.  If our line count was
	 * zero, then make the new list circular.
	 */
	if (mesg_info->num_lines) {
	    curr = get_previous(mesg_info->head);/* get end of old list */

	    tail->next = mesg_info->head;	/* new tail -> old head */
	    curr->next = head;			/* old tail -> new head */
	} else {
	    tail->next = head;
	}
	mesg_info->head = head;
    }

    mesg_info->num_lines = count;
    /* Erase the line on a resize. */
    mesg_info->last_pause = (struct line_element *) 0;
}


/*
 * Make sure the given string is shorter than the given pixel width.  If
 * not, back up from the end by words until we find a place to split.
 */
static char *
split(s, fs, pixel_width)
    char *s;
    XFontStruct *fs;		/* Font for the window. */
    Dimension pixel_width;
{
    char save, *end, *remainder;

    save = '\0';
    remainder = 0;
    end = eos(s);	/* point to null at end of string */

    /* assume that if end == s, XXXXXX returns 0) */
    while ((Dimension) XTextWidth(fs, s, (int) strlen(s)) > pixel_width) {
	*end-- = save;
	while (*end != ' ') {
	    if (end == s) panic("split: eos!");
	    --end;
	}
	save = *end;
	*end = '\0';
	remainder = end + 1;
    }
    return remainder;
}

/*
 * Add a line of text to the window.  The first line in the curcular list
 * becomes the last.  So all we have to do is copy the new line over the
 * old one.  If the line buffer is too small, then allocate a new, larger
 * one.
 */
static void
add_line(mesg_info, s)
    struct mesg_info_t *mesg_info;
    const char *s;
{
    register struct line_element *curr = mesg_info->head;
    register int new_line_length = strlen(s);

    if (new_line_length + 1 > curr->buf_length) {
	if (curr->line) free(curr->line);	/* free old line */

	curr->buf_length = new_line_length + 1;
	curr->line = (char *) alloc(curr->buf_length);
    }

    Strcpy(curr->line, s);			/* copy info */
    curr->str_length = new_line_length;		/* save string length */

    mesg_info->head = mesg_info->head->next;	/* move head to next line */
    mesg_info->dirty = True;			/* we have undrawn lines */
}


/*
 * Save a position in the text buffer so we can draw a line to seperate
 * text from the last time this function was called.
 *
 * Save the head position, since it is the line "after" the last displayed
 * line in the message window.  The window redraw routine will draw a
 * line above this saved pointer.
 */
void
set_last_pause(wp)
    struct xwindow *wp;
{
    register struct mesg_info_t *mesg_info = wp->mesg_information;

#ifdef ERASE_LINE
    /*
     * If we've erased the pause line and haven't added any new lines,
     * don't try to erase the line again.
     */
    if (!mesg_info->last_pause
			    && mesg_info->last_pause_head == mesg_info->head)
	return;

    if (mesg_info->last_pause == mesg_info->head) {
	/* No new messages in last turn.  Redraw window to erase line. */
	mesg_info->last_pause = (struct line_element *) 0;
	mesg_info->last_pause_head = mesg_info->head;
	redraw_message_window(wp);
    } else {
#endif
	mesg_info->last_pause = mesg_info->head;
#ifdef ERASE_LINE
    }
#endif
}


static void
redraw_message_window(wp)
    struct xwindow *wp;
{
    struct mesg_info_t *mesg_info = wp->mesg_information;
    register struct line_element *curr;
    register int row;

    /*
     * Do this the cheap and easy way.  Clear the window and just redraw
     * the whole thing.
     *
     * This could be done more effecently with one call to XDrawText() instead
     * of many calls to XDrawString().  Maybe later.
     */
    XClearWindow(XtDisplay(wp->w), XtWindow(wp->w));

    /* For now, just update the whole shootn' match. */
    for (row = 0, curr = mesg_info->head;
			row < mesg_info->num_lines; row++, curr = curr->next) {

	register int y_base = row * mesg_info->char_height;

	XDrawString(XtDisplay(wp->w), XtWindow(wp->w),
                mesg_info->gc,
		mesg_info->char_lbearing,
                mesg_info->char_ascent + y_base,
		curr->line,
		curr->str_length);

	/*
	 * This draws a line at the _top_ of the line of text pointed to by
	 * mesg_info->last_pause.
	 */
	if (appResources.message_line && curr == mesg_info->last_pause) {
	    XDrawLine(XtDisplay(wp->w), XtWindow(wp->w),
                mesg_info->gc,
		0, y_base, wp->pixel_width, y_base);
	}
    }

    mesg_info->dirty = False;
}


/*
 * Check the size of the viewport.  If it has shrunk, then we want to
 * move the vertical slider to the bottom.
 */
static void
mesg_check_size_change(wp)
    struct xwindow *wp;
{
    struct mesg_info_t *mesg_info = wp->mesg_information;
    Arg arg[2];
    Dimension new_width, new_height;
    Widget viewport;

    viewport = XtParent(wp->w);

    XtSetArg(arg[0], XtNwidth,  &new_width);
    XtSetArg(arg[1], XtNheight, &new_height);
    XtGetValues(viewport, arg, TWO);

    /* Only move slider to bottom if new size is smaller. */
    if (new_width < mesg_info->viewport_width
		    || new_height < mesg_info->viewport_height) {
	set_message_slider(wp);
    }

    mesg_info->viewport_width = new_width;
    mesg_info->viewport_height = new_height;
}


/* Event handler for message window expose events. */
/*ARGSUSED*/
static void
mesg_exposed(w, event)
    Widget w;
    XExposeEvent *event;	/* unused */
{
    struct xwindow *wp;

    if (!XtIsRealized(w)) return;
    wp = find_widget(w);
    mesg_check_size_change(wp);
    redraw_message_window(wp);
}


static void
get_gc(w, mesg_info)
    Widget w;
    struct mesg_info_t *mesg_info;
{
    XGCValues values;
    XtGCMask mask = GCFunction | GCForeground | GCBackground | GCFont;
    Pixel fgpixel, bgpixel;
    Arg arg[2];

    XtSetArg(arg[0], XtNforeground, &fgpixel);
    XtSetArg(arg[1], XtNbackground, &bgpixel);
    XtGetValues(w, arg, TWO);

    values.foreground = fgpixel;
    values.background = bgpixel;
    values.function   = GXcopy;
    values.font       = WindowFont(w);
    mesg_info->gc = XtGetGC(w, mask, &values);
}

/*
 * Handle resizes on a message window.  Correct saved pixel height and width.
 * Adjust circle buffer to accomidate the new size.
 * 
 * Problem:  If the resize decreases the width of the window such that
 * some lines are now longer than the window, they will be cut off by
 * X itself.  All new lines will be split to the new size, but the ends
 * of the old ones will not be seen again unless the window is lengthened.
 * I don't deal with this problem because it isn't worth the trouble.
 */
/* ARGSUSED */
static void
mesg_resized(w, client_data, call_data)
    Widget w;
    XtPointer call_data, client_data;
{
    Arg args[4];
    Cardinal num_args;
    Dimension pixel_width, pixel_height;
    struct xwindow *wp;
#ifdef VERBOSE
    int old_lines;

    old_lines = wp->mesg_information->num_lines;;
#endif

    num_args = 0;
    XtSetArg(args[num_args], XtNwidth,  &pixel_width);   num_args++;
    XtSetArg(args[num_args], XtNheight, &pixel_height);  num_args++;
    XtGetValues(w, args, num_args);

    wp = find_widget(w);
    wp->pixel_width  = pixel_width;
    wp->pixel_height = pixel_height;

    set_circle_buf(wp->mesg_information,
			(int) pixel_height / wp->mesg_information->char_height);

#ifdef VERBOSE
    printf("Message resize.  Pixel: width = %d, height = %d;  Lines: old = %d, new = %d\n", 
	pixel_width,
	pixel_height,
	old_lines,
	wp->mesg_information->num_lines);
#endif
}