#include <xcb/xcb.h>
#include <xcb/xcb_aux.h>
#include <xcb/randr.h>
#include "dat.h"
#include "fn.h"

static xcb_connection_t *conn;
static xcb_screen_t *scr;
static xcb_window_t win;
static xcb_gcontext_t gc;
static xcb_pixmap_t pix;
static u32int *img;
static xcb_atom_t currentdesktop;
static xcb_atom_t workarea;
static int hasrandr, imgh, imgw;
static int shown, ptrx, ptry;	/* the popup, and where the pointer was as it came up */

static xcb_visualtype_t*
getvisual(xcb_screen_t *s)
{
	xcb_depth_iterator_t di;
	xcb_visualtype_iterator_t vi;

	for(di = xcb_screen_allowed_depths_iterator(s); di.rem;
	    xcb_depth_next(&di)){
		if(di.data->depth != s->root_depth)
			continue;
		for(vi = xcb_depth_visuals_iterator(di.data); vi.rem;
		    xcb_visualtype_next(&vi))
			if(vi.data->visual_id == s->root_visual)
				return vi.data;
	}
	return nil;
}

/* putimage writes native-endian x8r8g8b8; the root must take that. */
static int
validformat(xcb_connection_t *c, xcb_screen_t *s)
{
	const xcb_setup_t *setup;
	xcb_format_iterator_t fi;
	xcb_visualtype_t *v;
	u32int one;
	int lsb;

	setup = xcb_get_setup(c);
	v = getvisual(s);
	if(v == nil || s->root_depth != 24 ||
	   v->_class != XCB_VISUAL_CLASS_TRUE_COLOR ||
	   v->red_mask != 0xff0000 || v->green_mask != 0x00ff00 ||
	   v->blue_mask != 0x0000ff)
		return 0;
	one = 1;
	lsb = *(uchar*)&one != 0;
	if((lsb && setup->image_byte_order != XCB_IMAGE_ORDER_LSB_FIRST) ||
	   (!lsb && setup->image_byte_order != XCB_IMAGE_ORDER_MSB_FIRST))
		return 0;
	for(fi = xcb_setup_pixmap_formats_iterator(setup); fi.rem;
	    xcb_format_next(&fi))
		if(fi.data->depth == 24 && fi.data->bits_per_pixel == 32 &&
		   fi.data->scanline_pad == 32)
			return 1;
	return 0;
}

static xcb_atom_t
getatom(char *name)
{
	xcb_intern_atom_cookie_t cookie;
	xcb_intern_atom_reply_t *reply;
	xcb_atom_t atom;

	cookie = xcb_intern_atom(conn, 0, strlen(name), name);
	reply = xcb_intern_atom_reply(conn, cookie, nil);
	atom = reply == nil ? XCB_ATOM_NONE : reply->atom;
	free(reply);
	return atom;
}

static int
getcardinals(xcb_atom_t atom, u32int off, int n, u32int *v)
{
	xcb_get_property_cookie_t cookie;
	xcb_get_property_reply_t *reply;
	int ok;

	if(atom == XCB_ATOM_NONE)
		return 0;
	cookie = xcb_get_property(conn, 0, scr->root, atom,
		XCB_ATOM_CARDINAL, off, n);
	reply = xcb_get_property_reply(conn, cookie, nil);
	ok = reply != nil && reply->type == XCB_ATOM_CARDINAL &&
		reply->format == 32 &&
		xcb_get_property_value_length(reply) == n*(int)sizeof v[0];
	if(ok)
		memmove(v, xcb_get_property_value(reply), n*sizeof v[0]);
	free(reply);
	return ok;
}

static int
getworkarea(Area *a)
{
	u32int desktop, v[4];

	if(!getcardinals(currentdesktop, 0, 1, &desktop) ||
	   desktop > 0x3fffffff ||
	   !getcardinals(workarea, desktop*4, 4, v) ||
	   v[0] > 0x7fffffff || v[1] > 0x7fffffff ||
	   v[2] == 0 || v[2] > 0x7fffffff ||
	   v[3] == 0 || v[3] > 0x7fffffff)
		return 0;
	a->x = v[0];
	a->y = v[1];
	a->w = v[2];
	a->h = v[3];
	return 1;
}

static void
getrootarea(Area *a)
{
	xcb_get_geometry_cookie_t cookie;
	xcb_get_geometry_reply_t *reply;

	a->x = 0;
	a->y = 0;
	a->w = scr->width_in_pixels;
	a->h = scr->height_in_pixels;
	cookie = xcb_get_geometry(conn, scr->root);
	reply = xcb_get_geometry_reply(conn, cookie, nil);
	if(reply != nil && reply->width > 0 && reply->height > 0){
		a->w = reply->width;
		a->h = reply->height;
	}
	free(reply);
}

/* The area the popup may use: the RandR monitor under (x, y), or the
 * root, cut down to the EWMH work area. */
static void
popupwork(int x, int y, Area *out)
{
	xcb_randr_get_monitors_cookie_t cookie;
	xcb_randr_get_monitors_reply_t *reply;
	xcb_randr_monitor_info_iterator_t it;
	Area root, net, *mon;
	int n;

	mon = nil;
	n = 0;
	reply = nil;
	if(hasrandr){
		cookie = xcb_randr_get_monitors(conn, scr->root, 1);
		reply = xcb_randr_get_monitors_reply(conn, cookie, nil);
	}
	if(reply != nil && xcb_randr_get_monitors_monitors_length(reply) > 0){
		mon = emalloc(xcb_randr_get_monitors_monitors_length(reply) *
			sizeof mon[0]);
		it = xcb_randr_get_monitors_monitors_iterator(reply);
		for(; it.rem; xcb_randr_monitor_info_next(&it)){
			if(it.data->width == 0 || it.data->height == 0)
				continue;
			mon[n].x = it.data->x;
			mon[n].y = it.data->y;
			mon[n].w = it.data->width;
			mon[n].h = it.data->height;
			n++;
		}
	}
	if(n == 0){
		free(mon);
		getrootarea(&root);
		mon = &root;
		n = 1;
	}
	popuparea(mon, n, getworkarea(&net) ? &net : nil, x, y, out);
	if(mon != &root)
		free(mon);
	free(reply);
}

static void
wincleanup(void)
{
	textclose();
	free(img);
	xcb_disconnect(conn);
}

static int
wininit(void)
{
	int n;
	u32int mask, vals[5];
	xcb_atom_t type, tooltip;
	xcb_randr_query_version_cookie_t rc;
	xcb_randr_query_version_reply_t *rr;
	const xcb_query_extension_reply_t *rext;
	char *scale;

	scale = getenv("GDK_SCALE");
	if(scale != nil && atoi(scale) > 1)
		popupscale = min(atoi(scale), 4);
	conn = xcb_connect(nil, &n);
	if(xcb_connection_has_error(conn)){
		fprint(2, "strans: popup disabled: cannot connect to X display\n");
		wincleanup();
		return 0;
	}
	scr = xcb_aux_get_screen(conn, n);
	if(scr == nil || !validformat(conn, scr)){
		fprint(2, "strans: popup disabled: unsupported X root format\n");
		wincleanup();
		return 0;
	}
	rext = xcb_get_extension_data(conn, &xcb_randr_id);
	if(rext != nil && rext->present){
		rc = xcb_randr_query_version(conn, 1, 5);
		rr = xcb_randr_query_version_reply(conn, rc, nil);
		hasrandr = rr != nil && (rr->major_version > 1 ||
			(rr->major_version == 1 && rr->minor_version >= 5));
		free(rr);
	}
	currentdesktop = getatom("_NET_CURRENT_DESKTOP");
	workarea = getatom("_NET_WORKAREA");
	win = xcb_generate_id(conn);
	/* Clicks on the popup go nowhere, not to the root window under it. */
	mask = XCB_CW_BACK_PIXEL | XCB_CW_BORDER_PIXEL |
	       XCB_CW_OVERRIDE_REDIRECT | XCB_CW_SAVE_UNDER |
	       XCB_CW_DONT_PROPAGATE;
	vals[0] = Colbg;
	vals[1] = Colsep;
	vals[2] = 1;
	vals[3] = 1;
	vals[4] = XCB_EVENT_MASK_BUTTON_PRESS | XCB_EVENT_MASK_BUTTON_RELEASE;
	xcb_create_window(conn, XCB_COPY_FROM_PARENT, win, scr->root,
		0, 0, 1, 1, PopupBorder, XCB_WINDOW_CLASS_INPUT_OUTPUT,
		scr->root_visual, mask, vals);
	type = getatom("_NET_WM_WINDOW_TYPE");
	tooltip = getatom("_NET_WM_WINDOW_TYPE_TOOLTIP");
	if(type != XCB_ATOM_NONE && tooltip != XCB_ATOM_NONE)
		xcb_change_property(conn, XCB_PROP_MODE_REPLACE,
			win, type, XCB_ATOM_ATOM, 32, 1, &tooltip);
	gc = xcb_generate_id(conn);
	xcb_create_gc(conn, gc, win, 0, nil);
	textinit();
	return 1;
}

/* The image and its retained pixmap only ever grow. */
static int
resizebacking(int w, int h)
{
	xcb_generic_error_t *err;
	xcb_pixmap_t old, new;
	xcb_void_cookie_t cookie;
	int nh, nw;

	if(w <= imgw && h <= imgh)
		return 1;
	nw = max(w, imgw);
	nh = max(h, imgh);
	img = erealloc(img, (ulong)nw * nh * sizeof img[0]);
	new = xcb_generate_id(conn);
	cookie = xcb_create_pixmap_checked(conn, scr->root_depth, new, win,
		nw, nh);
	err = xcb_request_check(conn, cookie);
	if(err != nil){
		free(err);
		return 0;
	}
	cookie = xcb_change_window_attributes_checked(conn, win,
		XCB_CW_BACK_PIXMAP, &new);
	err = xcb_request_check(conn, cookie);
	if(err != nil){
		free(err);
		xcb_free_pixmap(conn, new);
		return 0;
	}
	old = pix;
	pix = new;
	imgw = nw;
	imgh = nh;
	if(old != 0)
		xcb_free_pixmap(conn, old);
	return 1;
}

static void
putimage(int w, int h)
{
	xcb_put_image(conn, XCB_IMAGE_FORMAT_Z_PIXMAP, pix, gc,
		w, h, 0, 0, 0, scr->root_depth, w * h * 4, (u8int*)img);
	/* The retained background pixmap lets the server repaint exposures. */
	xcb_clear_area(conn, 0, win, 0, 0, w, h);
}

static void
winhide(void)
{
	xcb_unmap_window(conn, win);
	xcb_flush(conn);
	shown = 0;
}

/*
 * Draws dc at the caret, or by the pointer when the caret is unknown:
 * where the pointer was as the popup came up, so that it does not
 * follow the mouse from key to key.
 */
static void
winshow(Drawcmd *dc)
{
	Area area;
	Popup p;
	int ax, ay, x, y;
	u32int vals[5];
	xcb_query_pointer_reply_t *ptr;
	xcb_query_pointer_cookie_t cookie;

	if(dc->nkouho == 0 && dc->pre.n == 0){
		winhide();
		return;
	}
	if(!dc->caret.valid && !shown){
		cookie = xcb_query_pointer(conn, scr->root);
		ptr = xcb_query_pointer_reply(conn, cookie, nil);
		if(ptr == nil)
			return;
		ptrx = ptr->root_x;
		ptry = ptr->root_y;
		free(ptr);
	}
	ax = dc->caret.valid ? dc->caret.x : ptrx;
	ay = dc->caret.valid ? dc->caret.y : ptry;
	popupwork(ax, ay, &area);
	popuplayout(dc, area.w, area.h, &p);
	if(p.w <= 0 || p.h <= 0){
		winhide();
		return;
	}
	if(!resizebacking(p.w, p.h))
		return;
	popupposition(&dc->caret, ptrx, ptry, &area, p.w + 2*PopupBorder,
		p.h + 2*PopupBorder, &x, &y);
	/* Mapping does not restack: raise above windows opened since. */
	vals[0] = x;
	vals[1] = y;
	vals[2] = p.w;
	vals[3] = p.h;
	vals[4] = XCB_STACK_MODE_ABOVE;
	xcb_configure_window(conn, win,
		XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y |
		XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT |
		XCB_CONFIG_WINDOW_STACK_MODE, vals);
	popupdraw(img, dc, &p);
	putimage(p.w, p.h);
	xcb_map_window(conn, win);
	xcb_flush(conn);
	shown = 1;
}

void
drawthread(void*)
{
	Drawcmd dc;

	threadsetname("draw");
	if(!wininit())
		return;
	while(chanrecv(drawc, &dc) > 0 && !xcb_connection_has_error(conn))
		winshow(&dc);
	wincleanup();
}