/*
 * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Handles the data in ~/.telescope
 *
 * TODO: add some form of locking on the files
 */

#include "telescope.h"

#include <sys/stat.h>

#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static void		 die(void) __attribute__((__noreturn__));
static void		 serve_bookmarks(uint32_t);
static void		 handle_get(struct imsg*, size_t);
static void		 handle_quit(struct imsg*, size_t);
static void		 handle_bookmark_page(struct imsg*, size_t);
static void		 handle_save_cert(struct imsg*, size_t);
static void		 handle_session_start(struct imsg*, size_t);
static void		 handle_session_tab(struct imsg*, size_t);
static void		 handle_session_end(struct imsg*, size_t);
static void		 handle_dispatch_imsg(int, short, void*);

static struct event		 imsgev;
static struct imsgbuf		*ibuf;

static FILE			*session;

static char	bookmark_file[PATH_MAX];
static char	known_hosts_file[PATH_MAX];
static char	session_file[PATH_MAX];

static imsg_handlerfn *handlers[] = {
	[IMSG_GET] = handle_get,
	[IMSG_QUIT] = handle_quit,
	[IMSG_BOOKMARK_PAGE] = handle_bookmark_page,
	[IMSG_SAVE_CERT] = handle_save_cert,
	[IMSG_SESSION_START] = handle_session_start,
	[IMSG_SESSION_TAB] = handle_session_tab,
	[IMSG_SESSION_END] = handle_session_end,
};

static void __attribute__((__noreturn__))
die(void)
{
	abort(); 		/* TODO */
}

static void
serve_bookmarks(uint32_t peerid)
{
	const char	*t;
	char		 buf[BUFSIZ];
	size_t		 r;
	FILE		*f;

	if ((f = fopen(bookmark_file, "r")) == NULL) {
		t = "# Bookmarks\n\n"
		    "No bookmarks yet!\n"
		    "Create ~/.telescope/bookmarks.gmi or use `bookmark-page'.\n";
		imsg_compose(ibuf, IMSG_BUF, peerid, 0, -1, t, strlen(t));
		imsg_compose(ibuf, IMSG_EOF, peerid, 0, -1, NULL, 0);
		imsg_flush(ibuf);
		return;
	}

	for (;;) {
		r = fread(buf, 1, sizeof(buf), f);
		imsg_compose(ibuf, IMSG_BUF, peerid, 0, -1, buf, r);
		imsg_flush(ibuf);
		if (r != sizeof(buf))
			break;
	}

	imsg_compose(ibuf, IMSG_EOF, peerid, 0, -1, NULL, 0);
	imsg_flush(ibuf);

	fclose(f);
}

static void
handle_get(struct imsg *imsg, size_t datalen)
{
	char		*data;
	const char	*p;

	data = imsg->data;

	if (data[datalen-1] != '\0')
		die();

	if (!strcmp(data, "about:new")) {
		imsg_compose(ibuf, IMSG_BUF, imsg->hdr.peerid, 0, -1,
		    about_new, strlen(about_new));
		imsg_compose(ibuf, IMSG_EOF, imsg->hdr.peerid, 0, -1, NULL, 0);
		imsg_flush(ibuf);
	} else if (!strcmp(data, "about:bookmarks")) {
		serve_bookmarks(imsg->hdr.peerid);
	} else {
		p = "# not found!\n";
		imsg_compose(ibuf, IMSG_BUF, imsg->hdr.peerid, 0, -1, p, strlen(p));
		imsg_compose(ibuf, IMSG_EOF, imsg->hdr.peerid, 0, -1, NULL, 0);
		imsg_flush(ibuf);
	}
}

static void
handle_quit(struct imsg *imsg, size_t datalen)
{
	event_loopbreak();
}

static void
handle_bookmark_page(struct imsg *imsg, size_t datalen)
{
	char	*data;
	int	 res;
	FILE	*f;

	data = imsg->data;
	if (data[datalen-1] != '\0')
		die();

	if ((f = fopen(bookmark_file, "a")) == NULL) {
		res = errno;
		goto end;
	}
	fprintf(f, "=> %s\n", data);
	fclose(f);

	res = 0;
end:
	imsg_compose(ibuf, IMSG_BOOKMARK_OK, 0, 0, -1, &res, sizeof(res));
	imsg_flush(ibuf);
}

static void
handle_save_cert(struct imsg *imsg, size_t datalen)
{
	struct tofu_entry	 e;
	FILE			*f;
	int			 res;

	/* TODO: traverse the file to avoid duplications? */

	if (datalen != sizeof(e))
		die();
	memcpy(&e, imsg->data, datalen);

	if ((f = fopen(known_hosts_file, "a")) == NULL) {
		res = errno;
		goto end;
	}
	fprintf(f, "%s %s %d\n", e.domain, e.hash, e.verified);
	fclose(f);

	res = 0;
end:
	imsg_compose(ibuf, IMSG_SAVE_CERT_OK, imsg->hdr.peerid, 0, -1,
	    &res, sizeof(res));
	imsg_flush(ibuf);
}

static void
handle_session_start(struct imsg *imsg, size_t datalen)
{
	if (datalen != 0)
		die();

	if ((session = fopen(session_file, "w")) == NULL)
		die();
}

static void
handle_session_tab(struct imsg *imsg, size_t datalen)
{
	if (session == NULL)
		die();

	if (datalen == 0)
		die();

	/* skip the NUL-terminator */
        fwrite(imsg->data, 1, datalen-1, session);

	fprintf(session, "\n");
}

static void
handle_session_end(struct imsg *imsg, size_t datalen)
{
	if (session == NULL)
		die();
	fclose(session);
	session = NULL;
}

static void
handle_dispatch_imsg(int fd, short ev, void *d)
{
	struct imsgbuf	*ibuf = d;
	dispatch_imsg(ibuf, handlers, sizeof(handlers));
}

int
fs_init(void)
{
	char	dir[PATH_MAX];

	strlcpy(dir, getenv("HOME"), sizeof(dir));
	strlcat(dir, "/.telescope", sizeof(dir));
	mkdir(dir, 0700);

	strlcpy(bookmark_file, getenv("HOME"), sizeof(bookmark_file));
	strlcat(bookmark_file, "/.telescope/bookmarks.gmi", sizeof(bookmark_file));

	strlcpy(known_hosts_file, getenv("HOME"), sizeof(known_hosts_file));
	strlcat(known_hosts_file, "/.telescope/known_hosts", sizeof(known_hosts_file));

	strlcpy(session_file, getenv("HOME"), sizeof(session_file));
	strlcat(session_file, "/.telescope/session", sizeof(session_file));

	return 1;
}

int
fs_main(struct imsgbuf *b)
{
	ibuf = b;

	event_init();

	event_set(&imsgev, ibuf->fd, EV_READ | EV_PERSIST, handle_dispatch_imsg, ibuf);
	event_add(&imsgev, NULL);

	sandbox_fs_process();

	event_dispatch();
	return 0;
}



int
load_certs(struct ohash *h)
{
	char		*p, *last, *el, *line = NULL;
	const char	*errstr;
	int		 i;
	size_t		 linesize = 0;
	ssize_t		 linelen;
	FILE		*f;
	struct tofu_entry *e;

	if ((f = fopen(known_hosts_file, "r")) == NULL)
		return 0;

	while ((linelen = getline(&line, &linesize, f)) != -1) {
		if ((e = calloc(1, sizeof(*e))) == NULL)
			abort();

		i = 0;
                for ((p = strtok_r(line, " ", &last)); p;
		    (p = strtok_r(NULL, " ", &last))) {
			if (*p == '\n') {
				free(e);
				break;
			}

			switch (i) {
			case 0:
				strlcpy(e->domain, p, sizeof(e->domain));
				break;
			case 1:
				strlcpy(e->hash, p, sizeof(e->hash));
				break;
			case 2:
				if ((el = strchr(p, '\n')) == NULL)
					abort();
				*el = '\0';

				/* 0 <= verified <= 1 */
				e->verified = strtonum(p, -1, 2, &errstr);
				if (errstr != NULL)
					errx(1, "verification for %s is %s: %s",
					    e->domain, errstr, p);
				break;
			default:
				abort();
			}
			i++;
		}

		if (i != 0 && i != 3)
			abort();

		if (i != 0)
			telescope_ohash_insert(h, e);
	}

	free(line);
	return ferror(f);
}

int
load_last_session(void (*cb)(const char*))
{
	char	*nl, *line = NULL;
	int	 e;
	size_t	 linesize = 0;
	ssize_t	 linelen;
	FILE	*session;

	if ((session = fopen(session_file, "r")) == NULL)
		return 0;

	while ((linelen = getline(&line, &linesize, session)) != -1) {
                if ((nl = strchr(line, '\n')) != NULL)
			*nl = '\0';
		cb(line);
	}

	free(line);
	e = ferror(session);
	fclose(session);

	return !e;
}