/* ----------------------- twindow.c --------------------- */

#include <stdio.h>
#include <ctype.h>
#include <stdarg.h>
#include <dos.h>
#include <alloc.h>
#include <stdlib.h>
#include <string.h>
#include "twindow.h"
#include "keys.h"

#define TABS 4
#define SCRNHT 25
#define SCRNWIDTH 80
#define ON  1
#define OFF 0
#define ERROR -1

/* -------- local prototypes ---------- */
static void redraw(WINDOW *wnd);
static void wframe(WINDOW *wnd);
static void dtitle(WINDOW *wnd);
static int *waddr(WINDOW *wnd, int x, int y);
static void vswap(WINDOW *wnd);
static void vsave(WINDOW *wnd);
static void vrstr(WINDOW *wnd);
static void add_list(WINDOW *wnd);
static void beg_list(WINDOW *wnd);
static void remove_list(WINDOW *wnd);
static void insert_list(WINDOW *w1, WINDOW *w2);
#ifndef FASTWINDOWS
static int verify_wnd(WINDOW **w1);
static int dget(WINDOW *wnd, int x, int y);
#endif
/*page*/
/* ---- array of border character sets ------ */
struct {
	int nw, ne, se, sw, side, line;
} wcs[] = {
	{218,191,217,192,179,196},	/* single line */
	{201,187,188,200,186,205},	/* double line */
	{214,183,189,211,186,196},	/* single top, double side */
	{213,184,190,212,179,205},	/* double top, single side */
	{194,194,217,192,179,196}	/* pop-down menu */
};

/* ---- window structure linked list head & tail ---- */
WINDOW *listhead = NULL;
WINDOW *listtail = NULL;
int VSG;	/* video segment address */

/* ----------- establish a new window -------------- */
WINDOW *establish_window(x, y, h, w)
{
	WINDOW *wnd;

	VSG = (vmode() == 7 ? 0xb000 : 0xb800);
	if ((wnd = (WINDOW *) malloc(sizeof (WINDOW))) == NULL)
		return NULL;
	/* ------- adjust for out-of bounds parameters ------- */
	WTITLE = "";
	HEIGHT = min(h, SCRNHT);
	WIDTH = min(w, SCRNWIDTH);
	COL = max(0, min(x, SCRNWIDTH-WIDTH));
	ROW = max(0, min(y, SCRNHT-HEIGHT));
	WCURS = 0;
	SCROLL = 0;
	SELECT = 1;
	BTYPE = 0;
	VISIBLE = HIDDEN = 0;
	PREV = NEXT = NULL;
	FHEAD = FTAIL = NULL;
	WBORDER=WNORMAL=PNORMAL=WTITLEC =
				clr(BLACK, WHITE, BRIGHT);
	WACCENT = clr(WHITE, BLACK, DIM);
	if ((SAV = malloc(WIDTH * HEIGHT * 2)) == (char *) 0)
		return NULL;
	add_list(wnd);
#ifndef FASTWINDOWS
	clear_window(wnd);
	wframe(wnd);
#endif
	return wnd;
}

/* ------ set the window's border --------- */
void set_border(WINDOW *wnd, int btype)
{
	if (verify_wnd(&wnd))	{
		BTYPE = btype;
		redraw(wnd);
	}
}

/* ------- set colors ----------- */
void set_colors(WINDOW *wnd,int area,int bg,int fg,int inten)
{
	if (vmode() == 7)	{
		if (bg != WHITE && bg != BLACK)
			return;
		if (fg != WHITE && fg != BLACK)
			return;
	}
	if (verify_wnd(&wnd))	{
		if (area == ALL)
			while (area)
				WCOLOR [--area] = clr(bg, fg, inten);
		else
			WCOLOR [area] = clr(bg, fg, inten);
		redraw(wnd);
	}
}
/*page*/
/* ----- set the intensity of a window ------ */
void set_intensity(WINDOW *wnd, int inten)
{
	int area = ALL;

	if (verify_wnd(&wnd))	{
		while (area)	{
			WCOLOR [--area] &= ~BRIGHT;
			WCOLOR [area] |= inten;
		}
		redraw(wnd);
	}
}

/* -------- set title ------------- */
void set_title(WINDOW *wnd, char *title)
{
	if (verify_wnd(&wnd))	{
		WTITLE = title;
		redraw(wnd);
	}
}

/* ------ redraw a window when an attribute changes ----- */
static void redraw(WINDOW *wnd)
{
#ifndef FASTWINDOWS
	int x, y, chat, atr;

	for (y = 1; y < HEIGHT-1; y++)
		for (x = 1; x < WIDTH-1; x++)	{
			chat = dget(wnd, x, y);
			atr = (((chat>>8)&255) ==
				PNORMAL ? WNORMAL : WACCENT);
			displ(wnd, x, y, chat&255, atr);
		}
	wframe(wnd);
#endif
	PNORMAL = WNORMAL;
}

/* ------------ display an established window ------------ */
void display_window(WINDOW *wnd)
{
	if (verify_wnd(&wnd) && !VISIBLE)	{
		VISIBLE = 1;
#ifdef FASTWINDOWS
		if (HIDDEN)	{
			HIDDEN = 0;
			vrstr(wnd);
		}
		else	{
			vsave(wnd);
			clear_window(wnd);
			wframe(wnd);
		}
#else
		vswap(wnd);
#endif
	}
}

/* ---------- close all windows -------------- */
void close_all()
{
	WINDOW *sav, *wnd = listtail;

	while (wnd)	{
		sav = PREV;
		delete_window(wnd);
		wnd = sav;
	}
}
/*page*/
/* ------------ remove a window ------------------ */
void delete_window(WINDOW *wnd)
{
	if (verify_wnd(&wnd))		{
		hide_window(wnd);
		free(SAV);
		remove_list(wnd);	/* remove window from list */
		free(wnd);
	}
}

/* ----------- hide a window --------------- */
void hide_window(WINDOW *wnd)
{
	if (verify_wnd(&wnd) && VISIBLE)	{
#ifndef FASTWINDOWS
		vswap(wnd);
#else
		vrstr(wnd);
#endif
		HIDDEN = 1;
		VISIBLE = 0;
	}
}
/*page*/
#ifndef FASTWINDOWS
/* ------ reposition the window in its 3-axis plane ------ */
void repos_wnd(WINDOW *wnd, int x, int y, int z)
{
	WINDOW *twnd;
	int x1, y1, chat;
	if (!verify_wnd(&wnd))
		return;
	twnd = establish_window(x+COL, y+ROW, HEIGHT, WIDTH);
	twnd->_tl = WTITLE;
	twnd->btype = BTYPE;
	twnd->wcolor[BORDER] = WBORDER;
	twnd->wcolor[TITLE] = WTITLEC;
	twnd->wcolor[ACCENT] = WACCENT;
	twnd->wcolor[NORMAL] = WNORMAL;
	twnd->_wsp = SCROLL;
	twnd->_cr = WCURS;
	if (z != 1)	{
		remove_list(twnd);
		if (z == 0)
			insert_list(twnd, wnd);
		else
			beg_list(twnd);
	}
	for (y1 = 0; y1 < twnd->_wh; y1++)
		for (x1 = 0; x1 < twnd->_ww; x1++)	{
			chat = dget(wnd, x1, y1);
			displ(twnd, x1, y1, chat&255, (chat>>8)&255);
		}
	twnd->_wv = 1;
	vswap(twnd);
	hide_window(wnd);
	free(SAV);
	remove_list(wnd);
	*wnd = *twnd;
	insert_list(wnd, twnd);
	remove_list(twnd);
	free(twnd);
}
#endif

/* ----------- clear the window area -------------- */
void clear_window(WINDOW *wnd)
{
	register int x1, y1;

	if (verify_wnd(&wnd))
		for (y1 = 1; y1 < HEIGHT-1; y1++)
			for (x1 = 1; x1 < WIDTH-1; x1++)
				displ(wnd,x1, y1, ' ', WNORMAL);
}

/* ------------ draw the window frame --------------- */
static void wframe(WINDOW *wnd)
{
	register int x1, y1;

	if (!verify_wnd(&wnd))
		return;
	/* --------- window title -------------- */
	displ(wnd,0, 0, NW, WBORDER);
	dtitle(wnd);
	displ(wnd,WIDTH-1, 0, NE, WBORDER);
	/* ------------ window sides ----------------- */
	for (y1 = 1; y1 < HEIGHT-1; y1++)	{
		displ(wnd,0, y1, SIDE, WBORDER);
		displ(wnd,WIDTH-1, y1, SIDE, WBORDER);
	}
	/* --------------- bottom of frame ---------------- */
	displ(wnd,0, y1, SW, WBORDER);
	for (x1 = 1; x1 < WIDTH-1; x1++)
		displ(wnd,x1, y1, LINE, WBORDER);
	displ(wnd,x1, y1, SE, WBORDER);
}
/*page*/
/* ------------- displ the window title -------------------- */
static void dtitle(WINDOW *wnd)
{
	int x1 = 1, i, ln;
	char *s = WTITLE;

	if (!verify_wnd(&wnd))
		return;
	if (s)	{
		ln = strlen(s);
		if (ln > WIDTH-2)
			i = 0;
		else
			i = ((WIDTH-2-ln) / 2);
		if (i > 0)
			while (i--)
				displ(wnd, x1++, 0, LINE, WBORDER);
		while (*s && x1 < WIDTH-1)
			displ(wnd, x1++, 0, *s++, WTITLEC);
	}
	while (x1 < WIDTH-1)
		displ(wnd, x1++, 0, LINE, WBORDER);
}

/* ------------- window-oriented printf ---------------- */
void wprintf(WINDOW *wnd, char *ln, ...)
{
	char dlin [100], *dl = dlin;

	if (verify_wnd(&wnd))		{
		va_list ap;
		va_start(ap, ln);
		vsprintf(dlin, ln, ap);
		va_end(ap);
		while (*dl)
			wputchar(wnd, *dl++);
	}
}
/*page*/
/* ------------ write a character to the window ---------- */
void wputchar(WINDOW *wnd, int c)
{
	if (!verify_wnd(&wnd))
		return;
	switch (c)	{
		case '\n':
			if (SCROLL == HEIGHT-3)
				scroll(wnd, UP);
			else
				SCROLL++;
			WCURS = 0;
			break;
		case '\t':
			do displ(wnd,(WCURS++)+3,SCROLL+1,' ',WNORMAL);
				while ((WCURS%TABS) && (WCURS+1) < WIDTH-1);
			break;
		default:
			if ((WCURS+1) < WIDTH-1)	{
				displ(wnd, WCURS+1, SCROLL+1, c, WNORMAL);
				WCURS++;
			}
			break;
	}
}

/* ------- set window cursor --------- */
void wcursor(WINDOW *wnd, int x, int y)
{
	if (verify_wnd(&wnd) && x < WIDTH-1 && y < HEIGHT-1)	{
		WCURS = x;
		SCROLL = y;
		cursor(COL+x+1, ROW+y+1);
	}
}
/*page*/
/* ------ allow the user to make a window selection ------ */
int get_selection(WINDOW *wnd, int s, char *keys)
{
	int c = 0, ky;
	if (!verify_wnd(&wnd))
		return 0;
	SELECT = s;
	while (c != ESC && c != '\r' && c != BS && c != FWD)	{
		accent(wnd);
		c = get_char();
		deaccent(wnd);
		switch (c)		{
			case UP:	if (SELECT >  1)
							SELECT--;
						else
							SELECT = SCROLL+1;
						break;
			case DN:	if (SELECT < SCROLL+1)
							SELECT++;
						else 
							SELECT = 1;
						break;
			case '\r':
			case ESC:
			case FWD:
			case BS:	break;
			default:	if (keys)	{
							ky = 0;
							while (*(keys + ky))	{
								if (*(keys+ky)==toupper(c) ||
									*(keys+ky)==tolower(c))
									return ky + 1;
								ky++;
							}
						}
						break;
		}
	}
	return 	c == '\r' ? SELECT : c == ESC ? 0 : c;
}

union REGS rg;

/* ------- scroll a window's contents up or down --------- */
void scroll(WINDOW *wnd, int dir)
{
	int row = HEIGHT-1, col, chat;

	if (!verify_wnd(&wnd))
		return;
	if (NEXT == NULL && HEIGHT > 3 && VISIBLE)	{
		rg.h.ah = dir == UP ? 6 : 7;
		rg.h.al = 1;
		rg.h.bh = WNORMAL;
		rg.h.cl = COL + 1;
		rg.h.ch = ROW + 1;
		rg.h.dl = COL + WIDTH - 2;
		rg.h.dh = ROW + HEIGHT - 2;
		int86(16, &rg, &rg);
		return;
	}
	if (dir == UP)	{
		for (row = 2; row < HEIGHT-1; row++)
			for (col = 1; col < WIDTH-1; col++)	{
				chat = dget(wnd, col, row);
				displ(wnd,col,row-1,chat&255,(chat>>8)&255);
			}
		for (col = 1; col < WIDTH-1; col++)
			displ(wnd, col, row-1, ' ', WNORMAL);
	}
	else	{
		for (row = HEIGHT-2; row > 1; --row)
			for (col = 1; col < WIDTH-1; col++)	{
				chat = dget(wnd, col, row-1);
				displ(wnd,col,row,chat&255,(chat>>8)&255);
			}
		for (col = 1; col < WIDTH-1; col++)
			displ(wnd, col, row, ' ', WNORMAL);
	}
}
/*page*/
#ifndef FASTWINDOWS
/* --- compute address of a window's display character --- */
static int *waddr(WINDOW *wnd, int x, int y)
{
	WINDOW *nxt = NEXT;
	int *vp;

	if (!VISIBLE)
		return (int *) (SAV+y*(WIDTH*2)+x*2);
	x += COL;
	y += ROW;
	while (nxt)	{
		if (nxt->_wv)
			if (x >= nxt->_wx && x <= nxt->_wx + nxt->_ww-1)
				if (y >= nxt->_wy &&
						y <= nxt->_wy + nxt->_wh-1)	{
					x -= nxt->_wx;
					y -= nxt->_wy;
					vp = (int *)
						((nxt->_ws) +y*(nxt->_ww*2)+x*2);
					return vp;
				}
		nxt = nxt->_nx;
	}
	return NULL;
}

/* ---------- display a character to a window --------- */
void displ(WINDOW *wnd, int x, int y, int ch, int at)
{
	int *vp;
	int vch = (ch&255)|(at<<8);

	if ((vp = waddr(wnd, x, y)) != NULL)
		*vp = vch;
	else
		vpoke(VSG,vad(x+COL,y+ROW),vch);
}
/*page*/
/* ----- get a displayed character from a window ----- */
static int dget(WINDOW *wnd, int x, int y)
{
	int *vp;

	if ((vp = waddr(wnd, x, y)) != NULL)
		return *vp;
	return vpeek(VSG,vad(x+COL,y+ROW));
}

/* ------------- low-level video functions --------------- */

/* ------- swap the video image with the save buffer ----- */
static void vswap(WINDOW *wnd)
{
	int x, y, chat;
	int *bf = (int *) SAV;

	for (y = 0; y < HEIGHT; y++)
		for (x = 0; x < WIDTH; x++)	{
			chat = *bf;
			*bf++ = dget(wnd, x, y);
			displ(wnd, x, y, chat&255, (chat>>8)&255);
		}
}

#else

/* -------- save video memory into the save buffer ---- */
static void vsave(WINDOW *wnd)
{
	int x, y;
	int *bf = (int *) SAV;

	for (y = 0; y < HEIGHT; y++)
		for (x = 0; x < WIDTH; x++)
			*bf++ = vpeek(VSG, vad(x+COL, y+ROW));
}
/*page*/
/* ----- restore video memory from the save buffer ----- */
static void vrstr(WINDOW *wnd)
{
	int x, y;
	int *bf = (int *) SAV;

	for (y = 0; y < HEIGHT; y++)
		for (x = 0; x < WIDTH; x++)
			vpoke(VSG,vad(x+COL,y+ROW), *bf++);
}
#endif

/* ----- (de)accent the line where SELECT points ------- */
void acline(WINDOW *wnd, int set)
{
	int x, ch;

	if (!verify_wnd(&wnd))
		return;
	for (x = 1; x < WIDTH - 1; x++)	{
		ch = dget(wnd, x, SELECT) & 255;
		displ(wnd, x, SELECT, ch, set);
	}
}

/* ---------- linked list functions --------- */

/* ----- add a window to the end of the list ------ */
static void add_list(WINDOW *wnd)
{
	if (listtail)	{
		PREV = listtail;
		listtail->_nx = wnd;
	}
	listtail = wnd;
	if (!listhead)
		listhead = wnd;
}
/*page*/
/* ----- add a window to the beginning of the list ------ */
static void beg_list(WINDOW *wnd)
{
	if (listhead)	{
		NEXT = listhead;
		listhead->_pv = wnd;
	}
	listhead = wnd;
	if (!listtail)
		listtail = wnd;
}

/* --------- remove a window from the list -------- */
static void remove_list(WINDOW *wnd)
{
	if (NEXT)
		NEXT->_pv = PREV;
	if (PREV)
		PREV->_nx = NEXT;
	if (listhead == wnd)
		listhead = NEXT;
	if (listtail == wnd)
		listtail = PREV;
	NEXT = PREV = NULL;
}

/* ----- insert w1 after w2 ------ */
static void insert_list(WINDOW *w1, WINDOW *w2)
{
	w1->_pv = w2;
	w1->_nx = w2->_nx;
	w2->_nx = w1;
	if (w1->_nx == NULL)
		listtail = w1;
	else
		w1->_nx->_pv = w1;
}
/*page*/
#ifndef FASTWINDOWS
/* ---- verify the presence of a window in the list ----- */
static int verify_wnd(WINDOW **w1)
{
	WINDOW *wnd;

	wnd = listhead;
	if (*w1 == NULL)
		*w1 = listtail;
	else	{
		while (wnd != NULL)	{
			if (*w1 == wnd)
				break;
			wnd = NEXT;
		}
	}
	return wnd != NULL;
}
#endif

WINDOW *ewnd = NULL;

/* ------- error messages ------- */
void error_message(char *s)
{
	ewnd = establish_window(50, 22, 3, max(10, strlen(s)+2));
	set_colors(ewnd, ALL, RED, YELLOW, BRIGHT);
	set_title(ewnd, " ERROR! ");
	display_window(ewnd);
	wprintf(ewnd, s);
	putchar(BELL);
}

void clear_message()
{
	if (ewnd)
		delete_window(ewnd);
	ewnd = NULL;
}