/* See LICENSE file for copyright and license details. */
#include <ctype.h>
#include <locale.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <pwd.h>
#include <time.h>
#include <unistd.h>

#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xutil.h>
#ifdef XINERAMA
#include <X11/extensions/Xinerama.h>
#endif
#include <X11/Xft/Xft.h>

#include "drw.h"
#include "util.h"

#include "pinentry/pinentry.h"
#include "pinentry/memory.h"

#define INTERSECT(x,y,w,h,r)  (MAX(0, MIN((x)+(w),(r).x_org+(r).width)  - MAX((x),(r).x_org)) \
                             * MAX(0, MIN((y)+(h),(r).y_org+(r).height) - MAX((y),(r).y_org)))
#define TEXTW(X) (drw_fontset_getwidth(drw, (X)) + lrpad)
#define MINDESCLEN 8

/* enums */
enum { SchemePrompt, SchemeNormal, SchemeSelect, SchemeDesc, SchemeLast }; /* color schemes */
enum { WinPin, WinConfirm };
enum { Nothing, Yes, No };

/* FIXME: this can't currently be set */
static char *embed;
static int bh, mw, mh;
static int sel;
static int promptw, pdescw;
static int lrpad; /* sum of left and right padding */
static size_t cursor;
static int mon = -1, screen;

static char *pin;
static int pin_len;
static char *pin_repeat;
static int pin_repeat_len;
static int repeat;

static Atom clip, utf8;
static Display *dpy;
static Window root, parentwin, win;
static XIC xic;

static Drw *drw;
static Clr *scheme[SchemeLast];

static int timed_out;
static int winmode;
pinentry_t pinentry_info;

#include "config.h"

static int
drawitem(const char* text, Bool sel, int x, int y, int w)
{
	unsigned int i = (sel) ? SchemeSelect : SchemeNormal;

	drw_setscheme(drw, scheme[i]);

	return drw_text(drw, x, y, w, bh, lrpad / 2, text, 0);
}

static void
grabfocus(void)
{
	struct timespec ts = { .tv_sec = 0, .tv_nsec = 10000000  };
	Window focuswin;
	int i, revertwin;

	for (i = 0; i < 100; ++i) {
		XGetInputFocus(dpy, &focuswin, &revertwin);
		if (focuswin == win)
			return;
		XSetInputFocus(dpy, win, RevertToParent, CurrentTime);
		nanosleep(&ts, NULL);
	}
	die("cannot grab focus");
}

static void
grabkeyboard(void)
{
	struct timespec ts = { .tv_sec = 0, .tv_nsec = 1000000  };
	int i;

	if (embed)
		return;
	/* try to grab keyboard, we may have to wait for another process to ungrab */
	for (i = 0; i < 1000; i++) {
		if (XGrabKeyboard(dpy, DefaultRootWindow(dpy), True, GrabModeAsync,
		                  GrabModeAsync, CurrentTime) == GrabSuccess)
			return;
		nanosleep(&ts, NULL);
	}
	die("cannot grab keyboard");
}

static size_t
nextrune(int inc)
{
	ssize_t n;

	/* return location of next utf8 rune in the given direction (+1 or -1) */
	for (n = cursor + inc; n + inc >= 0 && (pin[n] & 0xc0) == 0x80; n += inc)
		;
	return n;
}

static void
setup_pin(char *pin_ptr, int len, int reset)
{
	pin = pin_ptr;
	pin_len = len;

	if (reset) {
		promptw = (prompt) ? TEXTW(prompt) - lrpad / 4 : 0;
		cursor = 0;

		if (pin)
			pin[0] = '\0';
	}
}

static void
insert(const char *str, ssize_t n)
{
	size_t len = strlen(pin);

	// FIXME: Pinentry crashes when increasing the pin buffer the second time.
	//        Other pinentry programs has a limited passwort field length.
	if (len + n > pin_len - 1) {
		if (repeat) {
			pin_repeat_len = 2 * pin_repeat_len;
			pin_repeat = secmem_realloc(pin_repeat, pin_repeat_len);
			setup_pin(pin_repeat, pin_repeat_len, 0);
			if (!pin_repeat)
				pin_len = 0;
		} else {
			if (!pinentry_setbufferlen(pinentry_info, 2 * pinentry_info->pin_len))
				pin_len = 0;
			else
				setup_pin(pinentry_info->pin, pinentry_info->pin_len, 0);
		}
		if (pin_len == 0) {
			printf("Error: Couldn't allocate secure memory\n");
			return;
		}
	}

	/* move existing text out of the way, insert new text, and update cursor */
	memmove(&pin[cursor + n], &pin[cursor], pin_len - cursor - MAX(n, 0));

	if (n > 0)
		memcpy(&pin[cursor], str, n);

	cursor += n;
	pin[len + n] = '\0';
}

static void
drawmenu(void)
{
	unsigned int curpos;
	int x = 0, fh = drw->fonts->h, pb, pbw = 0, i;
	size_t asterlen = strlen(asterisk);
	size_t pdesclen;
	int leftinput;
	char *censort;

	char *pprompt = (repeat) ? pinentry_info->repeat_passphrase : pinentry_info->prompt;
	int ppromptw = (pprompt) ? TEXTW(pprompt) : 0;

	unsigned int censortl = minpwlen * TEXTW(asterisk) / strlen(asterisk);
	unsigned int confirml = TEXTW(" YesNo ") + 3 * lrpad;

	drw_setscheme(drw, scheme[SchemeNormal]);
	drw_rect(drw, 0, 0, mw, mh, 1, 1);

	if (prompt) {
		drw_setscheme(drw, scheme[SchemePrompt]);
		x = drw_text(drw, x, 0, promptw, bh, lrpad / 2, prompt, 0);
	}

	if (pprompt) {
		drw_setscheme(drw, scheme[SchemePrompt]);
		drw_text(drw, x, 0, ppromptw, bh, lrpad / 2, pprompt, 0);
		x += ppromptw;
	}

	if (pinentry_info->description) {
		pb = mw - x;
		pdesclen = strlen(pinentry_info->description);

		if (pb > 0) {
			pb -= (winmode == WinPin) ? censortl : confirml;
			pbw = MINDESCLEN * pdescw / pdesclen;
			pbw = MIN(pbw, pdescw);

			if (pb >= pbw) {
				pbw = MAX(pbw, pdescw);
				pbw = MIN(pbw, pb);
				pb = mw - pbw;

				for (i = 0; i < pdesclen; i++)
					if (pinentry_info->description[i] == '\n')
						pinentry_info->description[i] = ' ';

				drw_setscheme(drw, scheme[SchemeDesc]);
				drw_text(drw, pb, 0, pbw, bh, lrpad / 2, pinentry_info->description,
				         0);
			} else {
				pbw = 0;
			}
		}
	}

	/* Draw input field */
	drw_setscheme(drw, scheme[SchemeNormal]);

	if (winmode == WinPin) {
		censort = ecalloc(1, asterlen * pin_len);

		for (i = 0; i < asterlen * strlen(pin); i += asterlen)
			memcpy(&censort[i], asterisk, asterlen);

		censort[i+1] = '\n';
		leftinput = mw - x - pbw;
		drw_text(drw, x, 0, leftinput, bh, lrpad / 2, censort, 0);
		curpos = TEXTW(censort) - TEXTW(&censort[cursor]);

		if ((curpos += lrpad / 2 - 1) < leftinput) {
			drw_setscheme(drw, scheme[SchemeNormal]);
			drw_rect(drw, x + curpos, 2 + (bh - fh) / 2, 2, fh - 4, 1, 0);
		}

		free(censort);
	} else {
		x += TEXTW(" ");
		x = drawitem("No", (sel == No), x, 0, TEXTW("No"));
		x = drawitem("Yes", (sel == Yes), x, 0, TEXTW("Yes"));
	}
	drw_map(drw, win, 0, 0, mw, mh);
}

static void
setup(void)
{
	int x, y, i, j;
	unsigned int du;
	XSetWindowAttributes swa;
	XIM xim;
	Window w, dw, *dws;
	XWindowAttributes wa;
	XClassHint ch = {"pinentry-dmenu", "pinentry-dmenu"};
#ifdef XINERAMA
	XineramaScreenInfo *info;
	Window pw;
	int a, di, n, area = 0;
#endif
	/* init appearance */
	for (j = 0; j < SchemeLast; j++)
		scheme[j] = drw_scm_create(drw, colors[j], 2);

	clip = XInternAtom(dpy, "CLIPBOARD",   False);
	utf8 = XInternAtom(dpy, "UTF8_STRING", False);

	/* Calculate menu geometry */
	bh = drw->fonts->h + 2;
	mh = bh;
#ifdef XINERAMA
	i = 0;
	if (parentwin == root && (info = XineramaQueryScreens(dpy, &n))) {
		XGetInputFocus(dpy, &w, &di);
		if (mon >= 0 && mon < n)
			i = mon;
		else if (w != root && w != PointerRoot && w != None) {
			/* find top-level window containing current input focus */
			do {
				if (XQueryTree(dpy, (pw = w), &dw, &w, &dws, &du) && dws)
					XFree(dws);
			} while (w != root && w != pw);
			/* find xinerama screen with which the window intersects most */
			if (XGetWindowAttributes(dpy, pw, &wa))
				for (j = 0; j < n; j++)
					if ((a = INTERSECT(wa.x, wa.y, wa.width, wa.height, info[j])) > area) {
						area = a;
						i = j;
					}
		}
		/* no focused window is on screen, so use pointer location instead */
		if (mon < 0 && !area && XQueryPointer(dpy, root, &dw, &dw, &x, &y, &di, &di, &du))
			for (i = 0; i < n; i++)
				if (INTERSECT(x, y, 1, 1, info[i]) != 0)
					break;

		x = info[i].x_org;
		y = info[i].y_org + (topbar ? 0 : info[i].height - mh);
		mw = info[i].width;
		XFree(info);
	} else
#endif
	{
		if (!XGetWindowAttributes(dpy, parentwin, &wa))
			die("could not get embedding window attributes: 0x%lx",
			    parentwin);
		x = 0;
		y = topbar ? 0 : wa.height - mh;
		mw = wa.width;
	}

	pdescw = (pinentry_info->description) ? TEXTW(pinentry_info->description) : 0;

	/* Create menu window */
	swa.override_redirect = True;
	swa.background_pixel = scheme[SchemePrompt][ColBg].pixel;
	swa.event_mask = ExposureMask | KeyPressMask | VisibilityChangeMask;
	win = XCreateWindow(dpy, parentwin, x, y, mw, mh, 0,
	                    CopyFromParent, CopyFromParent, CopyFromParent,
	                    CWOverrideRedirect | CWBackPixel | CWEventMask, &swa);
	XSetClassHint(dpy, win, &ch);

	/* input methods */
	if ((xim = XOpenIM(dpy, NULL, NULL, NULL)) == NULL)
		die("XOpenIM failed: could not open input device");

	xic = XCreateIC(xim, XNInputStyle, XIMPreeditNothing | XIMStatusNothing,
	                XNClientWindow, win, XNFocusWindow, win, NULL);
	XMapRaised(dpy, win);
	if (embed) {
		XSelectInput(dpy, parentwin, FocusChangeMask | SubstructureNotifyMask);

		if (XQueryTree(dpy, parentwin, &dw, &w, &dws, &du) && dws) {
			for (i = 0; i < du && dws[i] != win; ++i)
				XSelectInput(dpy, dws[i], FocusChangeMask);
			XFree(dws);
		}
		grabfocus();
	}
	drw_resize(drw, mw, mh);
}

static void
cleanup(void)
{
	size_t i;

	XUngrabKey(dpy, AnyKey, AnyModifier, root);
	for (i = 0; i < SchemeLast; i++)
		free(scheme[i]);
	drw_free(drw);
	XSync(dpy, False);
	XCloseDisplay(dpy);
}

static int
keypress_confirm(XKeyEvent *ev, KeySym ksym)
{
	if (ev->state & ControlMask) {
		switch(ksym) {
		case XK_c:
			pinentry_info->canceled = 1;
			sel = No;
			return 1;
		default:
			return 1;
		}
	}

	switch(ksym) {
	case XK_KP_Enter:
	case XK_Return:
		if (sel != Nothing)
			return 1;
		break;
	case XK_y:
	case XK_Y:
		sel = Yes;
		return 1;
	case XK_n:
	case XK_N:
		sel = No;
		return 1;
	case XK_g:
	case XK_G:
	case XK_Escape:
		pinentry_info->canceled = 1;
		sel = No;
		return 1;
	case XK_h:
	case XK_j:
	case XK_Home:
	case XK_KP_Home:
	case XK_Left:
	case XK_KP_Left:
	case XK_Prior:
	case XK_KP_Prior:
	case XK_Up:
	case XK_KP_Up:
		sel = No;
		break;
	case XK_k:
	case XK_l:
	case XK_Down:
	case XK_KP_Down:
	case XK_End:
	case XK_Next:
	case XK_Right:
	case XK_KP_Right:
		sel = Yes;
		break;
	}

	return 0;
}

static int
keypress_pin(XKeyEvent *ev, KeySym ksym, char* buf, int len)
{
	int old;

	if (ev->state & ControlMask) {
		switch(ksym) {
		case XK_a: ksym = XK_Home;      break;
		case XK_b: ksym = XK_Left;      break;
		case XK_c: ksym = XK_Escape;    break;
		case XK_d: ksym = XK_Delete;    break;
		case XK_e: ksym = XK_End;       break;
		case XK_f: ksym = XK_Right;     break;
		case XK_g: ksym = XK_Escape;    break;
		case XK_h: ksym = XK_BackSpace; break;
		case XK_k:
			old = cursor;
			cursor = strlen(pin);
			insert(NULL, old - cursor);
			break;
		case XK_u:
			insert(NULL, -cursor);
			break;
		case XK_v:
			XConvertSelection(dpy, (ev->state & ShiftMask) ? clip : XA_PRIMARY,
			                  utf8, utf8, win, CurrentTime);
			return 0;
		case XK_Return:
		case XK_KP_Enter:
			break;
		case XK_bracketleft:
			pinentry_info->canceled = 1;
			return 1;
		default:
			return 1;
		}
	}

	switch(ksym) {
	case XK_Delete:
	case XK_KP_Delete:
		if (pin[cursor] == '\0')
			return 0;
		cursor = nextrune(+1);
		/* Fallthrough */
	case XK_BackSpace:
		if (cursor == 0)
			return 0;
		insert(NULL, nextrune(-1) - cursor);
		break;
	case XK_Escape:
		pinentry_info->canceled = 1;
		return 1;
	case XK_Left:
	case XK_KP_Left:
		if (cursor > 0)
			cursor = nextrune(-1);
		break;
	case XK_Right:
	case XK_KP_Right:
		if (pin[cursor] != '\0')
			cursor = nextrune(+1);
		break;
	case XK_Home:
	case XK_KP_Home:
		cursor = 0;
		break;
	case XK_End:
	case XK_KP_End:
		cursor = strlen(pin);
		break;
	case XK_Return:
	case XK_KP_Enter:
		return 1;
		break;
	default:
		if (!iscntrl((unsigned char)*buf))
			insert(buf, len);
	}

	return 0;
}

static int
keypress(XKeyEvent *ev)
{
	char buf[32];
	int len;
	int ret = 1;

	KeySym ksym = NoSymbol;
	Status status;
	len = XmbLookupString(xic, ev, buf, sizeof(buf), &ksym, &status);

	if (status != XBufferOverflow) {
		if (winmode == WinConfirm)
			ret = keypress_confirm(ev, ksym);
		else
			ret = keypress_pin(ev, ksym, buf, len);

		if (ret == 0)
			drawmenu();
	}

	return ret;
}

static void
paste(void)
{
	char *p, *q;
	int di;
	unsigned long dl;
	Atom da;

	/* we have been given the current selection, now insert it into input */
	if (XGetWindowProperty(dpy, win, utf8, 0, (pin_len/ 4) + 1, False,
	                   utf8, &da, &di, &dl, &dl, (unsigned char **)&p)
	    == Success && p) {
		insert(p, (q = strchr(p, '\n')) ? q - p : (ssize_t)strlen(p));
		XFree(p);
	}
	drawmenu();
}

void
run(void)
{
	XEvent ev;

	drawmenu();

	while (!XNextEvent(dpy, &ev)) {
		if (XFilterEvent(&ev, win))
			continue;
		switch(ev.type) {
		case DestroyNotify:
			if (ev.xdestroywindow.window != win)
				break;
			cleanup();
			exit(1);
		case Expose:
			if (ev.xexpose.count == 0)
				drw_map(drw, win, 0, 0, mw, mh);
			break;
		case KeyPress:
			if (keypress(&ev.xkey))
				return;
			break;
		case SelectionNotify:
			if (ev.xselection.property == utf8)
				paste();
			break;
		case VisibilityNotify:
			if (ev.xvisibility.state != VisibilityUnobscured)
				XRaiseWindow(dpy, win);
			break;
		}
	}
}

/* FIXME: this does nothing */
static void
catchsig(int sig)
{
	if (sig == SIGALRM)
		timed_out = 1;
}

static void
password(void)
{
	winmode = WinPin;
	repeat = 0;
	setup_pin(pinentry_info->pin, pinentry_info->pin_len, 1);
	run();

	if (!pinentry_info->canceled && pinentry_info->repeat_passphrase) {
		repeat = 1;
		pin_repeat_len = pinentry_info->pin_len;
		pin_repeat = secmem_malloc(pinentry_info->pin_len);
		setup_pin(pin_repeat, pin_repeat_len, 1);
		run();

		pinentry_info->repeat_okay = (strcmp(pinentry_info->pin, pin_repeat) == 0)? 1 : 0;
		secmem_free(pin_repeat);

		if (!pinentry_info->repeat_okay) {
			pinentry_info->result = -1;
			return;
		}
	}

	if (pinentry_info->canceled) {
		pinentry_info->result = -1;
		return;
	}

	pinentry_info->result = strlen(pinentry_info->pin);
}

static void
confirm(void)
{
	winmode = WinConfirm;
	sel = Nothing;
	run();
	pinentry_info->result = sel != No;
}

static int
cmdhandler(pinentry_t received_pinentry)
{
	struct sigaction sa;
	XWindowAttributes wa;

	pinentry_info = received_pinentry;

	if (!setlocale(LC_CTYPE, "") || !XSupportsLocale())
		fputs("warning: no locale support\n", stderr);
	if (!(dpy = XOpenDisplay(pinentry_info->display)))
		die("cannot open display");
	screen = DefaultScreen(dpy);
	root = RootWindow(dpy, screen);
	embed = (pinentry_info->parent_wid) ? embed : 0;
	parentwin = (embed) ? pinentry_info->parent_wid : root;
	if (!XGetWindowAttributes(dpy, parentwin, &wa))
		die("could not get embedding window attributes: 0x%lx", parentwin);
	drw = drw_create(dpy, screen, root, wa.width, wa.height);
	if (!drw_fontset_create(drw, fonts, LENGTH(fonts)))
		die("no fonts could be loaded.");
	lrpad = drw->fonts->h;

#ifdef __OpenBSD__
	if (pledge("stdio rpath", NULL) == -1)
		die("pledge");
#endif

	drw_setscheme(drw, scheme[SchemePrompt]);

	if (pinentry_info->timeout) {
		memset(&sa, 0, sizeof(sa));
		sa.sa_handler = catchsig;
		sigaction(SIGALRM, &sa, NULL);
		alarm(pinentry_info->timeout);
	}

	grabkeyboard();
	setup();

	if (pinentry_info->pin)
		do {
			password();
		} while (!pinentry_info->canceled && pinentry_info->repeat_passphrase
		         && !pinentry_info->repeat_okay);
	else
		confirm();

	cleanup();

	return pinentry_info->result;
}

pinentry_cmd_handler_t pinentry_cmd_handler = cmdhandler;

int
main(int argc, char *argv[])
{
	pinentry_init("pinentry-dmenu");
	pinentry_parse_opts(argc, argv);

	if (pinentry_loop())
		return 1;

	return 0;
}