/*

 * Copyright (c) 2018 Sunil Nimmagadda <sunil@openbsd.org>

 *

 * 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.

 */

#include <sys/socket.h>

#include <sys/stat.h>

#include <arpa/telnet.h>

#include <err.h>

#include <errno.h>

#include <histedit.h>

#include <libgen.h>

#include <limits.h>

#include <pwd.h>

#include <signal.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include "ftp.h"

#define ARGVMAX	64

static void	 cmd_interrupt(int);

static int	 cmd_lookup(const char *);

static FILE	*data_fopen(const char *);

static void	 do_open(int, char **);

static void	 do_help(int, char **);

static void	 do_quit(int, char **);

static void	 do_ls(int, char **);

static void	 do_pwd(int, char **);

static void	 do_cd(int, char **);

static void	 do_get(int, char **);

static void	 do_passive(int, char **);

static void	 do_lcd(int, char **);

static void	 do_lpwd(int, char **);

static void	 do_put(int, char **);

static void	 do_mget(int, char **);

static void	 ftp_abort(void);

static char	*prompt(void);

static FILE	*ctrl_fp, *data_fp;

static struct {

	const char	 *name;

	const char	 *info;

	void		(*cmd)(int, char **);

	int		  conn_required;

} cmd_tbl[] = {

	{ "open", "connect to remote ftp server", do_open, 0 },

	{ "close", "terminate ftp session", do_quit, 1 },

	{ "help", "print local help information", do_help, 0 },

	{ "?", "print local help information", do_help, 0 },

	{ "quit", "terminate ftp session and exit", do_quit, 0 },

	{ "exit", "terminate ftp session and exit", do_quit, 0 },

	{ "ls", "list contents of remote directory", do_ls, 1 },

	{ "pwd", "print working directory on remote machine", do_pwd, 1 },

	{ "cd", "change remote working directory", do_cd, 1 },

	{ "nlist", "nlist contents of remote directory", do_ls, 1 },

	{ "get", "receive file", do_get, 1 },

	{ "passive", "toggle passive transfer mode", do_passive, 0 },

	{ "lcd", "change local working directory", do_lcd, 0 },

	{ "lpwd", "print local working directory", do_lpwd, 0 },

	{ "put", "send one file", do_put, 1 },

	{ "mget", "get multiple files", do_mget, 1 },

	{ "mput", "send multiple files", do_mget, 1 },

};

static void

cmd_interrupt(int signo)

{

	const char	msg[] = "\rwaiting for remote to finish abort\n";

	int		save_errno = errno;

	if (data_fp != NULL)

		(void)write(STDERR_FILENO, msg, sizeof(msg) - 1);

	interrupted = 1;

	errno = save_errno;

}

void

cmd(const char *host, const char *port, const char *path)

{

	HistEvent	  hev;

	EditLine	 *el;

	History		 *hist;

	const char	 *line;

	char		**ap, *argv[ARGVMAX], *cp;

	int		  count, i;

	if ((el = el_init(getprogname(), stdin, stdout, stderr)) == NULL)

		err(1, "couldn't initialise editline");

	if ((hist = history_init()) == NULL)

		err(1, "couldn't initialise editline history");

	history(hist, &hev, H_SETSIZE, 100);

	el_set(el, EL_HIST, history, hist);

	el_set(el, EL_PROMPT, prompt);

	el_set(el, EL_EDITOR, "emacs");

	el_set(el, EL_TERMINAL, NULL);

	el_set(el, EL_SIGNAL, 1);

	el_source(el, NULL);

	if (host != NULL) {

		argv[0] = "open";

		argv[1] = (char *)host;

		argv[2] = port ? (char *)port : "21";

		do_open(3, argv);

		/* If we don't have a connection, exit */

		if (ctrl_fp == NULL)

			exit(1);

		if (path != NULL) {

			argv[0] = "cd";

			argv[1] = (char *)path;

			do_cd(2, argv);

		}

	}

	for (;;) {

		signal(SIGINT, SIG_IGN);

		if ((line = el_gets(el, &count)) == NULL || count <= 0) {

			if (verbose)

				fprintf(stderr, "\n");

			argv[0] = "quit";

			do_quit(1, argv);

			break;

		}

		if (count <= 1)

			continue;

		if ((cp = strrchr(line, '\n')) != NULL)

			*cp = '\0';

		history(hist, &hev, H_ENTER, line);

		for (ap = argv; ap < &argv[ARGVMAX - 1] &&

		    (*ap = strsep((char **)&line, " \t")) != NULL;) {

			if (**ap != '\0')

				ap++;

		}

		*ap = NULL;

		if (argv[0] == NULL)

			continue;

		if ((i = cmd_lookup(argv[0])) == -1) {

			fprintf(stderr, "Invalid command.\n");

			continue;

		}

		if (cmd_tbl[i].conn_required && ctrl_fp == NULL) {

			fprintf(stderr, "Not connected.\n");

			continue;

		}

		interrupted = 0;

		signal(SIGINT, cmd_interrupt);

		cmd_tbl[i].cmd(ap - argv, argv);

		if (strcmp(cmd_tbl[i].name, "quit") == 0 ||

		    strcmp(cmd_tbl[i].name, "exit") == 0)

			break;

	}

	el_end(el);

}

static int

cmd_lookup(const char *cmd)

{

	size_t	i;

	for (i = 0; i < nitems(cmd_tbl); i++)

		if (strcmp(cmd, cmd_tbl[i].name) == 0)

			return i;

	return -1;

}

static char *

prompt(void)

{

	return "ftp> ";

}

static FILE *

data_fopen(const char *mode)

{

	int	 fd;

	fd = activemode ? ftp_eprt(ctrl_fp) : ftp_epsv(ctrl_fp);

	if (fd == -1) {

		if (io_debug)

			fprintf(stderr, "Failed to open data connection");

		return NULL;

	}

	return fdopen(fd, mode);

}

static void

ftp_abort(void)

{

	char	buf[BUFSIZ];

	snprintf(buf, sizeof buf, "%c%c%c", IAC, IP, IAC);

	if (send(fileno(ctrl_fp), buf, 3, MSG_OOB) != 3)

		warn("abort");

	ftp_command(ctrl_fp, "%cABOR", DM);

}

static void

do_open(int argc, char **argv)

{

	const char	*host = NULL, *port = "21";

	char		*buf = NULL;

	size_t		 n = 0;

	int		 sock;

	if (ctrl_fp != NULL) {

		fprintf(stderr, "already connected, use close first.\n");

		return;

	}

	switch (argc) {

	case 3:

		port = argv[2];

		/* FALLTHROUGH */

	case 2:

		host = argv[1];

		break;

	default:

		fprintf(stderr, "usage: open host [port]\n");

		return;

	}

	if ((sock = tcp_connect(host, port, 0)) == -1)

		return;

	fprintf(stderr, "Connected to %s.\n", host);

	if ((ctrl_fp = fdopen(sock, "r+")) == NULL)

		err(1, "%s: fdopen", __func__);

	/* greeting */

	ftp_getline(&buf, &n, 0, ctrl_fp);

	free(buf);

	if (ftp_auth(ctrl_fp, NULL, NULL) != P_OK) {

		fclose(ctrl_fp);

		ctrl_fp = NULL;

	}

}

static void

do_help(int argc, char **argv)

{

	size_t	i;

	int	j;

	if (argc == 1) {

		for (i = 0; i < nitems(cmd_tbl); i++)

			fprintf(stderr, "%s\n", cmd_tbl[i].name);

		return;

	}

	for (i = 1; i < (size_t)argc; i++) {

		if ((j = cmd_lookup(argv[i])) == -1)

			fprintf(stderr, "invalid help command %s\n", argv[i]);

		else

			fprintf(stderr, "%s\t%s\n", argv[i], cmd_tbl[j].info);

	}

}

static void

do_quit(int argc, char **argv)

{

	if (ctrl_fp == NULL)

		return;

	ftp_command(ctrl_fp, "QUIT");

	fclose(ctrl_fp);

	ctrl_fp = NULL;

}

static void

do_ls(int argc, char **argv)

{

	FILE		*dst_fp = stdout;

	const char	*cmd, *local_fname = NULL, *remote_dir = NULL;

	char		*buf = NULL;

	size_t		 n = 0;

	ssize_t		 len;

	int		 r;

	switch (argc) {

	case 3:

		if (strcmp(argv[2], "-") != 0)

			local_fname = argv[2];

		/* FALLTHROUGH */

	case 2:

		remote_dir = argv[1];

		/* FALLTHROUGH */

	case 1:

		break;

	default:

		fprintf(stderr, "usage: ls [remote-directory [local-file]]\n");

		return;

	}

	if ((data_fp = data_fopen("r")) == NULL)

		return;

	if (local_fname && (dst_fp = fopen(local_fname, "w")) == NULL) {

		warn("fopen %s", local_fname);

		fclose(data_fp);

		data_fp = NULL;

		return;

	}

	cmd = (strcmp(argv[0], "ls") == 0) ? "LIST" : "NLST";

	if (remote_dir != NULL)

		r = ftp_command(ctrl_fp, "%s %s", cmd, remote_dir);

	else

		r = ftp_command(ctrl_fp, "%s", cmd);

	if (r != P_PRE) {

		fclose(data_fp);

		data_fp = NULL;

		if (dst_fp != stdout)

			fclose(dst_fp);

		return;

	}

	while ((len = getline(&buf, &n, data_fp)) != -1 && !interrupted) {

		buf[len - 1] = '\0';

		if (len >= 2 && buf[len - 2] == '\r')

			buf[len - 2] = '\0';