#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curses.h>
#include "mfjterm.h"
#include "misc.h"


char *sb_buf;
char *sb_bufstr[809];
int strno = 0, strptr = 0, sb_up = 0, sb_dn = 0, firstup = 0, lncntr = 0, lines_in_buffer = 0;
WINDOW *sbwin;


void init_scrollback(void)
{
	int i;

	sb_buf = malloc(65536);
	for (i = 0; i < 809; i++)
		sb_bufstr[i] = sb_buf+(81*i);
}


void exit_scrollback(void)
{
	free(sb_buf);
}


static void chk_firstup(void)
{
	int i;

	if (firstup) {
		firstup = FALSE;
		for (i = tnc_y; i > 0 ; i--) {
			if (++lncntr > lines_in_buffer) break;
			if (--sb_up < 0) sb_up = 808;
		}
	}
}


static void plot_uppage(int refresh)
{
	char buf[1440], *p;
	int i, j;

	j = sb_up;		

	memset(buf, 0x20, 1440);
	
	p = buf;
	
	for (i = 1; i <= tnc_y; i++) {
		if (++j > 808) j = 0;
		memcpy(p, sb_bufstr[j], strlen(sb_bufstr[j]));
		p += 80;
	}

	wmove(sbwin, 0, 0);
	waddnstr(sbwin, buf, 1440);
	if (refresh)
		wrefresh(sbwin);
}


static void plot_dnpage(int refresh)
{
	char buf[1440], *p;
	int i, j;

	j = sb_dn;

	memset(buf, 0x20, 1440);

	p = buf + 1360;
	
	for (i = tnc_y; i > 0; i--) {
		if ((--j) < 0) j = 808;
		memcpy(p, sb_bufstr[j], strlen(sb_bufstr[j]));
		p -= 80;
	}

	wmove(sbwin, 0, 0);
	waddnstr(sbwin, buf, 1440);
	if (refresh)
		wrefresh(sbwin);
}


static void home(void)
{
	chk_firstup();
	if (lncntr <= lines_in_buffer) {
		while (lncntr <= lines_in_buffer) {
			if (--sb_up < 0) sb_up = 808;
			if (--sb_dn < 0) sb_dn = 808;
			lncntr++;
		}
		plot_uppage(1);
	}
}


static void end(void)
{
	if (lncntr > 18){
		while (lncntr > 18) {
			if (++sb_up > 808) sb_up = 0;
			if (++sb_dn > 808) sb_dn = 0;
			lncntr--;
		}
		plot_dnpage(1);
	}
}


static void pgup(int refresh)
{
	int i;

	chk_firstup();
	if (lncntr <= lines_in_buffer) {
		for (i = 1; i < 19; i++) {
			if (--sb_up < 0) sb_up = 808;
			if (--sb_dn < 0) sb_dn = 808;
			if (++lncntr > lines_in_buffer) break;

		}
		plot_uppage(refresh);
	}
}


static void pgdn(int refresh)
{
	int i;

	if (lncntr > 18) {
		for (i = 1; i < 19; i++){
			if (++sb_up > 808) sb_up = 0;
			if (++sb_dn > 808) sb_dn = 0;
			if (--lncntr == 18) break;
		}
		plot_dnpage(refresh);
	}
}


static void lnup(void)
{
	char *s;
	
	chk_firstup();
	if (lncntr <= lines_in_buffer) {
		wmove(sbwin, 0, 0);
		wscrl(sbwin, -1); 
		s = sb_bufstr[sb_up];
		waddstr(sbwin, s);
		wrefresh(sbwin);
		if (--sb_up < 0) sb_up = 808;
		if (--sb_dn < 0) sb_dn = 808;
		lncntr++;
	}
}


static void lndn(void)
{
	char *s;
	
	if (lncntr > 18) {
		wmove(sbwin, 17, 0);
		wscrl(sbwin, 1); 
		s = sb_bufstr[sb_dn];
		waddstr(sbwin, s);
		wrefresh(sbwin);
		if (++sb_up > 808) sb_up = 0;
		if (++sb_dn > 808) sb_dn = 0;
		lncntr--;
	}
}



void scrollback(void)
{
	int k;
	
	sbwin = newwin(18, 80, 1, 0);
	if (sbwin == NULL)
		return;
	scrollok(sbwin, TRUE);
	curs_set(0);
	
	attrset(A_REVERSE);
	move(19, 1);
	addstr("Scroll-back Mode");
	attrset(A_NORMAL);

	firstup = TRUE;
	sb_dn = (strno)+1;
	sb_up = strno;
	lncntr = 0;

	pgup(0);
	pgdn(0);
	wrefresh(sbwin);

	while (1) {
		k = getch();
		
		switch(k){
			case KEY_HOME : 
				home();
				break;
			case KEY_END : 
				end() ;
				break;
			case KEY_PPAGE : 
				pgup(1);
				break;
			case KEY_NPAGE : 
				pgdn(1);
				break;
			case KEY_UP : 
				lnup();
				break;
			case KEY_DOWN : 
				lndn();
				break;
			case 'q':
			case 'Q': 
				goto rdy;
		}
	}
rdy:
	delwin(sbwin);
	redrawwin(stdscr);
	attrset(A_REVERSE);
	move(19, 1);
	addstr("                ");
	attrset(A_NORMAL);
	curs_set(1);
	move(tnc_y, tnc_x);
	refresh();
}
.