#include <u.h>
#include <libc.h>
#include <stdio.h>
#include <draw.h>
#include <event.h>
#include <cursor.h>

typedef struct Slide {
	char *cmd;
	char *arg;
	int linum;
	int nlines;
	char *lines[];
} Slide;

typedef struct GalleryCell {
	Image *img;
	Rectangle location;
} GalleryCell;

enum {
	MenuNext = 0,
	MenuPrev,
	MenuGoto,
	MenuExit,
	MenuN
};

char *menuitems[] = {
	[MenuNext] = "Next Slide",
	[MenuPrev] = "Prev Slide",
	[MenuGoto] = "Goto Slide",
	[MenuExit] = "Exit",
	nil
};
Menu menu = {
	.item = menuitems
};

char *mimetab[] = {
	"image/png",	"png",
	"image/jpeg",	"jpg",
	"image/ppm",	"ppm",
	"image/tiff",	"tif",
	"image/bmp",	"bmp",

	"audio/mpeg",	"",	/* bug in file(1) */
	"image/p9bit",	"",
	nil
};

int checkonly, lightmode, nslides, cslide, xm, ym;
char *file, *contents, *offset, *tfname, *hfname;
Image *bg,*fg,*tmp;
Font *tfont, *hfont, *nfont;
Slide **slides;
GalleryCell *cells;

Point
SPt(int x, int y)
{
	return addpt(Pt(x, y), screen->r.min);
}

Rectangle
SRect(int x0, int y0, int x1, int y1)
{
	return rectaddpt(Rect(x0, y0, x1, y1), screen->r.min);
}

Point
imagecenter(Image* img)
{
	return divpt(addpt(img->r.min, img->r.max), 2);
}

Point
rectdims(Rectangle r)
{
	return subpt(r.max, r.min);
}

char *
nextline(char **p, int *linum)
{
	char *line;
	for(;;){
		(*linum)++;
		line = *p;
		while(**p != '\n' && **p != '\0') (*p)++;
		if(**p == '\0')
			return nil;

		**p = '\0';
		(*p)++;
		return line;
	}
}

Slide *
nextslide(char **p, int *linum)
{
	char *cmd, *arg, *line1, *line, *lineN;
	int nlines, blines, i, slinum;
	Slide *s;

	for(;;){
		if((cmd = nextline(p, linum)) == nil)
			return nil;
		if(cmd[0] != '%')
			continue;
		break;
	}
	slinum = *linum;

	cmd++;
	arg = cmd;

	while(*arg != ' ' && *arg != '\t' && *arg != '\0') arg++;
	if(*arg == '\0')
		arg = nil;
	else{
		*(arg++) = '\0';
		while(*arg == ' ' && *arg == '\t' && *arg != '\0') arg++;
		if(*arg == '\0')
			arg = nil;
	}

	line1 = nextline(p, linum);
	if(line1 != nil && *line1 == '%'){
		*p = line1;
		line1[strlen(line1)] = '\n';
		line1 = nil;
	}
	if(line1 == nil){
		s = malloc(sizeof(Slide));
		s->cmd = cmd;
		s->arg = arg;
		s->linum = slinum;
		s->nlines = 0;
		return s;
	}
	lineN = line1;
	nlines = 1;
	blines = 0;

	while((line = nextline(p, linum)) != nil){
		if(*line == '\0'){
			blines++;
			continue;
		}
		if(*line == '%'){
			*p = line;
			line[strlen(line)] = '\n';
			break;
		}

		nlines += blines;
		blines = 0;
		nlines++;
		lineN = line;
	}

	s = malloc(sizeof(Slide) + sizeof(char*) * nlines);

	s->cmd = cmd;
	s->arg = arg;
	s->linum = slinum;
	s->nlines = nlines;

	line = line1;
	for(i = 0; line != lineN; i++){
		s->lines[i] = line;
		line += strlen(line) + 1;
	}
	s->lines[i] = lineN;

	return s;
}

#pragma varargck argpos checkerr 2
void
checkerr(Slide *s, char *msg, ...)
{
	va_list args;

	va_start(args, msg);

	fprint(2,"%s:%d: %%%s: ", file, s->linum, s->cmd);
	vfprint(2,msg, args);
	fprint(2,"\n");
}
void
checkfile(void)
{
	int waserr, linum;
	char *c2, *p;
	Slide *s;

	waserr = 0;
	linum = 0;

	c2 = strdup(contents);
	p = c2;

	while((s = nextslide(&p, &linum)) != nil){
		nslides++;
		if(strcmp(s->cmd, "") == 0){
			nslides--;
			continue;
		}else if(strcmp(s->cmd, "bullet") == 0)
			continue;
		else if(strcmp(s->cmd, "blank") == 0)
			continue;
		else if(strcmp(s->cmd, "text") == 0)
			continue;
		else if(strcmp(s->cmd, "gallery") == 0)
			continue;
		else if(strcmp(s->cmd, "title") == 0){
			if(s->arg == nil){
				waserr = 1;
				checkerr(s, "missing arg");
			}
		}else{
			waserr = 1;
			checkerr(s, "unknown cmd");
		}
	}

	if(waserr)
		exits("checkfile");
}

Image *
openimage(char *name)
{
	int i, n, p[2], fd;
	char buf[64], *conv;
	Waitmsg *wm;
	Image *ret;

	pipe(p);

	if(fork() == 0){
		close(1);
		dup(p[0], 1);
		execl("/bin/file", "file", "-m", name, nil);
	}
	wm = wait();
	if(wm->msg != nil && *wm->msg != '\0')
		sysfatal("%s", wm->msg);
	free(wm);

	n = read(p[1], buf, sizeof(buf));
	buf[n - 1] = '\0'; /* replace the newline */

	conv = nil;
	for(i = 0; mimetab[i] != nil; i+=2){
		if(strcmp(buf, mimetab[i]) == 0){
			conv = mimetab[i+1];
			break;
		}
	}
	if(conv == nil)
		sysfatal("unknown image format '%s'", buf);

	if(*conv == '\0'){
		fd = open(name, OREAD);
		if(fd < 0)
			sysfatal("%r");
		ret = readimage(display, fd, 0);
		close(fd);
	}else{
		if(fork() == 0){
			close(1);
			dup(p[0], 1);
			sprint(buf, "/bin/%s", conv);
			execl(buf, conv, "-9c", name, nil);
		}
		ret = readimage(display, p[1], 0);
	}

	close(p[0]);
	close(p[1]);

	return ret;
}

Image *
resizeimage(Image *img, Point sdims)
{
	int p[2], fd;
	char namebuf[64], dimsbuf[64];
	Point idims;
	Image *ret;

	pipe(p);

	idims = subpt(img->r.max, img->r.min);
 
	sprint(namebuf, "/tmp/%s.%d.img", argv0, getpid());
	fd = create(namebuf, OWRITE, 0600);
	if(fd < 0)
		sysfatal("couldn't open tmp file: %r");
	writeimage(fd, img, 0);
	close(fd);

	if(fork() == 0){
		close(1);
		dup(p[0], 1);

		if(idims.x < idims.y || (idims.x == idims.y && sdims.x > sdims.y)){
			sprint(dimsbuf, "%d", sdims.x);
			execl("/bin/resize", "resize", "-x", dimsbuf, namebuf, nil);
		}else{
			sprint(dimsbuf, "%d", sdims.y);
			execl("/bin/resize", "resize", "-y", dimsbuf, namebuf, nil);
		}
	}

	ret = readimage(display, p[1], 0);
	close(p[0]);
	close(p[1]);

	return ret;
}

// FIXME: some of this could be done in-process but i am lazy
// TODO: should check image formats in checkimage() instead
void
loadimages(void){
	const Slide *s;
	GalleryCell *nextcell;
	Image *cimg;
	Point sdims;
	int i, j, cols, coln, rows, rowstart;

	if(cells != nil)
		return;

	s = slides[cslide];

	cells = calloc(s->nlines, sizeof(GalleryCell));
	nextcell = cells;

	cols = 0;
	i = 0;
	while(i < s->nlines && *(s->lines[i]) == '\0') i++;
	while(i < s->nlines){
		cols++;
		while(i < s->nlines && *(s->lines[i]) != '\0') i++; 
		while(i < s->nlines && *(s->lines[i]) == '\0') i++; 
	}

	coln = -1;
	rows = 0;
	rowstart = 0;

	for(i = 0; i < s->nlines; i++){
		if(*(s->lines[i]) == '\0'){
			rows = 0;
			continue;
		}
		if(rows == 0){
			coln++;
			j = i;
			rowstart = i;
			while(j < s->nlines && *(s->lines[j]) != '\0'){
				j++;
				rows++;
			}
		}

		sdims = subpt(screen->r.max, screen->r.min);
		sdims.x /= cols;
		sdims.y /= rows;

		cimg = openimage(s->lines[i]);
		if(cimg == nil)
			sysfatal("couldn't convert '%s': %r", s->lines[i]);
		waitpid();

		nextcell->img = resizeimage(cimg, sdims);
		if(nextcell->img == nil)
			sysfatal("couldn't scale '%s': %r", s->lines[i]);
		freeimage(cimg);
 
		nextcell->location = Rpt(Pt(0,0), sdims);
		nextcell->location = rectaddpt(nextcell->location, Pt(sdims.x * coln, sdims.y * (i - rowstart)));
		nextcell->location = rectaddpt(nextcell->location, screen->r.min);

		nextcell++;
	}
}
void
freeimages(void){
	const Slide *s;
	GalleryCell *p;
	int i;

	if(cells == nil)
		return;

	s = slides[cslide];
	p = cells;

	for(i = 0; i < s->nlines; i++){
		if(*(s->lines[i]) == '\0')
			continue;

		freeimage(p->img);
		p++;
	}

	free(cells);
	cells = nil;
}
void
rmtmp(void)
{
	char buf[64];

	sprint(buf, "/tmp/%s.%d.img", argv0, getpid());
	remove(buf);
}

void
render(void)
{
	int i, voff, height, width;
	char buf[32];
	Point p, center, prog0, prog1, smin, smax, imin, imax;
	const Slide *s;
	GalleryCell *cell;

	if(cslide < 0)
		cslide = 0;
	else if(cslide >= nslides)
		cslide = nslides -1;

	s = slides[cslide];

	center = imagecenter(screen);
	smin = screen->r.min;
	smax = screen->r.max;

	if(strcmp(s->cmd, "blank") == 0)
		draw(screen, screen->r, bg, nil, SPt(0, 0));
	else if(strcmp(s->cmd, "text") == 0){
		draw(screen, screen->r, bg, nil, SPt(0, 0));

		voff = ym;
		if(s->arg != nil){
			string(screen, SPt(xm, ym), fg, Pt(0, 0), hfont, s->arg);
			voff += hfont->height;
		}else
			voff = xm;
		for(i = 0; i < s->nlines; i++){
			string(screen, SPt(xm + 10, voff), fg, Pt(0, 0), tfont, s->lines[i]);
			voff += tfont->height;
		}
	}else if(strcmp(s->cmd, "title") == 0){
		draw(screen, screen->r, bg, nil, SPt(0, 0));

		height = hfont->height + tfont->height * s->nlines;
		voff = center.y - (height / 2);

		p = string(screen, smax, fg, Pt(0,0), hfont, s->arg);
		width = p.x - smax.x;
		string(screen, Pt(center.x - (width / 2), voff), fg, Pt(0,0), hfont, s->arg);

		voff += hfont->height;

		for(i = 0; i < s->nlines; i++){
			p = string(screen, smax, fg, Pt(0,0), tfont, s->lines[i]);
			width = p.x - smax.x;
			string(screen, Pt(center.x - (width / 2), voff), fg, Pt(0,0), tfont, s->lines[i]);
			voff += tfont->height;
		}
	
	}else if(strcmp(s->cmd, "gallery") == 0){
		loadimages();
		draw(screen, screen->r, bg, nil, SPt(0, 0));

		cell = cells;

		for(i = 0; i < s->nlines; i++){
			if(*(s->lines[i]) == '\0')
				continue;

			imin = cell->img->r.min;
			imax = cell->img->r.max;

			p = divpt(subpt(rectdims(cell->img->r), rectdims(cell->location)), 2);

			draw(screen, cell->location, cell->img, nil, p);

			cell++;
		}
	}

	if(cslide != 0){
		prog0 = Pt(smin.x, smax.y);
		prog1 = Pt(smin.x + cslide + (smax.x - smin.x) / (nslides - 1) * cslide, smax.y);

		line(screen, Pt(smin.x, smax.y), smax, Endsquare, Endsquare, 5, bg, Pt(0,0));
		line(screen, prog0, prog1, Endsquare, Enddisc, 5, fg, Pt(0,0));

		sprint(buf, "Slide %d", cslide);
		stringbg(screen, Pt(5, smax.y - 5 - nfont->height), fg, Pt(0,0), nfont, buf, bg, Pt(0,0));
	}
}

void
eresized(int new)
{
	if(new && getwindow(display, Refnone) < 0)
		fprint(2,"can't reattach to window\n");
	freeimages();
	render();
}

void
usage(void)
{
	fprint(2,"usage: %s [ -cl ] [ -x xmargin ] [ -y ymargin ] [ -f textfont ] [ -h headerfont ] filename\n", argv0);
	exits("usage");
}

void
main(int argc, char *argv[])
{
	int etype, fd, i, linum;
	char slabel[32], ask[32];
	Event e;
	Mouse m, lastm;
	Dir *d;

	xm = 50;
	ym = 10;

	tfname = "/n/ttf/lucida.ttf.32/font";
	hfname = "/n/ttf/lucida.ttf.80/font";

	ARGBEGIN{
	case 'c':
		checkonly = 1;
		break;
	case 'l':
		lightmode = 1;
		break;
	case 'f':
		tfname = EARGF(usage());
		break;
	case 'h':
		hfname = EARGF(usage());
		break;
	case 'x':
		xm = atoi(EARGF(usage()));
		break;
	case 'y':
		ym = atoi(EARGF(usage()));
		break;
	default:
		usage();
	}ARGEND

	if(argc != 1)
		usage();

	fmtinstall('P', Pfmt);
	fmtinstall('R', Rfmt);

	file = argv[0];

	if((fd = open(file, OREAD)) < 0)
		sysfatal("%r");
	if((d = dirfstat(fd)) == nil)
		sysfatal("%r");

	contents = malloc(d->length + 2);
	if(readn(fd, contents, d->length) < 0)
		sysfatal("%r");
	// cursed but makes the handling nicer above
	contents[d->length] = '\n';
	contents[d->length + 1] = '\0';
	offset = contents;

	snprintf(slabel, sizeof(slabel), "%s %s", argv0, d->name);

	free(d);
	close(fd);

	checkfile();

	if(checkonly)
		exits(nil);

	atexit(rmtmp);
	atexit(freeimages);

	slides = malloc(nslides*sizeof(Slide*));
	for(i = 0; i < nslides; i++){
		slides[i] = nextslide(&offset, &linum);
		if(*slides[i]->cmd == '\0')
			i--;
	}

	if(initdraw(nil, nil, slabel) < 0)
		sysfatal("initdraw: %r");

	bg = allocimage(display, Rect(0,0, 1,1), RGB16, 1, DBlack);
	if(bg == nil)
		sysfatal("couldn't allocimage!");

	fg = allocimage(display, Rect(0,0, 1,1), RGB16, 1, DWhite);
	if(fg == nil)
		sysfatal("couldn't allocimage!");
	if(lightmode){
		tmp = fg;
		fg = bg;
		bg = tmp;
	}

	if(strncmp(tfname, "/n/ttf", 6) == 0 || strncmp(tfname, "/n/ttf", 6) == 0){
		if(fork() == 0)
			execl("/bin/truetypefs", "truetypefs", nil);
		else
			sleep(200);
	}

	tfont = openfont(display, tfname);
	if(tfont == nil)
		sysfatal("couldn't open font '%s'", tfname);
	hfont = openfont(display, hfname);
	if(hfont == nil)
		sysfatal("couldn't open font '%s'", hfname);
	nfont = openfont(display, "/lib/font/bit/vga/unicode.font");
	if(nfont == nil)
		sysfatal("couldn't open font '/lib/bit/vga/unicode.font'");
	
	einit(Emouse|Ekeyboard);

	for(;;){
		render();
		etype = event(&e);

		if(etype == Emouse){
			m = e.mouse;
			if(m.buttons & 1 && !(lastm.buttons & 1)){
				freeimages();
				cslide--;
			}
			if(m.buttons & 4 && !(lastm.buttons & 4)){
				freeimages();
				cslide++;
			}

			if(m.buttons & 2){
				emenuhit(2, &m, &menu);

				switch(menu.lasthit){
				case MenuNext:
					freeimages();
					cslide++;
					break;
				case MenuPrev:
					freeimages();
					cslide--;
					break;
				case MenuGoto:
					sprintf(ask, "%d", cslide);
					if(eenter("Go to", ask, sizeof(ask), &m) <= 0)
						break;
					freeimages();
					if(strncmp(ask, "end", 3) == 0)
						cslide = nslides;
					else
						cslide = atoi(ask);
					break;
				case MenuExit:
					exits(nil);
					break;
				}
			}

			lastm = m;
		}else if(etype == Ekeyboard){
			switch(e.kbdc){
			case 0xf012:
			case ' ':
				freeimages();
				cslide++;
				break;
			case 0xf011:
				freeimages();
				cslide--;
				break;
			case 0x7f:
			case 'q':
				exits(nil);
				break;
			}
		}
	}
}