/********************************************************************\
* BitlBee -- An IRC to other IM-networks gateway                     *
*                                                                    *
* Copyright 2008 Uli Meis					     *
* Copyright 2006 Marijn Kruisselbrink and others                     *
\********************************************************************/

/* MSN module - File transfer support             */

/*
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License with
 the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
 if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
 Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "bitlbee.h"
#include "invitation.h"
#include "msn.h"
#include "lib/ftutil.h"

#ifdef debug
#undef debug
#endif
#define debug(msg ...) log_message(LOGLVL_INFO, msg)

static void msn_ftp_free(file_transfer_t *file);
static void msn_ftpr_accept(file_transfer_t *file);
static void msn_ftp_finished(file_transfer_t *file);
static void msn_ftp_canceled(file_transfer_t *file, char *reason);
static gboolean msn_ftpr_write_request(file_transfer_t *file);

static gboolean msn_ftp_connected(gpointer data, gint fd, b_input_condition cond);
static gboolean msn_ftp_read(gpointer data, gint fd, b_input_condition cond);
gboolean msn_ftps_write(file_transfer_t *file, char *buffer, unsigned int len);

/*
 * Vararg wrapper for imcb_file_canceled().
 */
gboolean msn_ftp_abort(file_transfer_t *file, char *format, ...)
{
	va_list params;

	va_start(params, format);
	char error[128];

	if (vsnprintf(error, 128, format, params) < 0) {
		sprintf(error, "internal error parsing error string (BUG)");
	}
	va_end(params);
	imcb_file_canceled(file, error);
	return FALSE;
}

/* very useful */
#define ASSERTSOCKOP(op, msg) \
	if ((op) == -1) { \
		return msn_ftp_abort(file, msg ": %s", strerror(errno)); }

void msn_ftp_invitation_cmd(struct im_connection *ic, char *who, int cookie, char *icmd,
                            char *trailer)
{
	struct msn_message *m = g_new0(struct msn_message, 1);

	m->text = g_strdup_printf("%s"
	                          "Invitation-Command: %s\r\n"
	                          "Invitation-Cookie: %u\r\n"
	                          "%s",
	                          MSN_INVITE_HEADERS,
	                          icmd,
	                          cookie,
	                          trailer);

	m->who = g_strdup(who);

	msn_sb_write_msg(ic, m);
}

void msn_ftp_cancel_invite(struct im_connection *ic, char *who,  int cookie, char *code)
{
	char buf[64];

	g_snprintf(buf, sizeof(buf), "Cancel-Code: %s\r\n", code);
	msn_ftp_invitation_cmd(ic, who, cookie, "CANCEL", buf);
}

void msn_ftp_transfer_request(struct im_connection *ic, file_transfer_t *file, char *who)
{
	unsigned int cookie = time(NULL);   /* TODO: randomize */
	char buf[2048];

	msn_filetransfer_t *msn_file = g_new0(msn_filetransfer_t, 1);

	file->data = msn_file;
	file->free = msn_ftp_free;
	file->canceled = msn_ftp_canceled;
	file->write = msn_ftps_write;
	msn_file->md = ic->proto_data;
	msn_file->invite_cookie = cookie;
	msn_file->handle = g_strdup(who);
	msn_file->dcc = file;
	msn_file->md->filetransfers = g_slist_prepend(msn_file->md->filetransfers, msn_file->dcc);
	msn_file->fd = -1;
	msn_file->sbufpos = 3;

	g_snprintf(buf, sizeof(buf),
	           "Application-Name: File Transfer\r\n"
	           "Application-GUID: {5D3E02AB-6190-11d3-BBBB-00C04F795683}\r\n"
	           "Application-File: %s\r\n"
	           "Application-FileSize: %zd\r\n",
	           file->file_name,
	           file->file_size);

	msn_ftp_invitation_cmd(msn_file->md->ic, msn_file->handle, cookie, "INVITE", buf);

	imcb_file_recv_start(file);
}

void msn_invitation_invite(struct msn_switchboard *sb, char *handle, unsigned int cookie, char *body, int blen)
{
	char *itype = msn_findheader(body, "Application-GUID:", blen);
	char *name, *size, *invitecookie, *reject = NULL;
	user_t *u;
	size_t isize;
	file_transfer_t *file;

	if (!itype || strcmp(itype, "{5D3E02AB-6190-11d3-BBBB-00C04F795683}") != 0) {
		/* Don't know what that is - don't care */
		char *iname = msn_findheader(body, "Application-Name:", blen);
		imcb_log(sb->ic, "Received unknown MSN invitation %s (%s) from %s",
		         itype ? : "with no GUID", iname ? iname : "no application name", handle);
		g_free(iname);
		reject = "REJECT_NOT_INSTALLED";
	} else if (
	        !(name = msn_findheader(body, "Application-File:", blen)) ||
	        !(size = msn_findheader(body, "Application-FileSize:", blen)) ||
	        !(invitecookie = msn_findheader(body, "Invitation-Cookie:", blen)) ||
	        !(isize = atoll(size))) {
		imcb_log(sb->ic, "Received corrupted transfer request from %s"
		         "(name=%s, size=%s, invitecookie=%s)",
		         handle, name, size, invitecookie);
		reject = "REJECT";
	} else if (!(u = user_findhandle(sb->ic, handle))) {
		imcb_log(sb->ic, "Error in parsing transfer request, User '%s'"
		         "is not in contact list", handle);
		reject = "REJECT";
	} else if (!(file = imcb_file_send_start(sb->ic, handle, name, isize))) {
		imcb_log(sb->ic, "Error initiating transfer for request from %s for %s",
		         handle, name);
		reject = "REJECT";
	} else {
		msn_filetransfer_t *msn_file = g_new0(msn_filetransfer_t, 1);
		file->data = msn_file;
		file->accept = msn_ftpr_accept;
		file->free = msn_ftp_free;
		file->finished = msn_ftp_finished;
		file->canceled = msn_ftp_canceled;
		file->write_request = msn_ftpr_write_request;
		msn_file->md = sb->ic->proto_data;
		msn_file->invite_cookie = cookie;
		msn_file->handle = g_strdup(handle);
		msn_file->dcc = file;
		msn_file->md->filetransfers = g_slist_prepend(msn_file->md->filetransfers, msn_file->dcc);
		msn_file->fd = -1;
	}

	if (reject) {
		msn_ftp_cancel_invite(sb->ic, sb->who, cookie, reject);
	}

	g_free(name);
	g_free(size);
	g_free(invitecookie);
	g_free(itype);
}

msn_filetransfer_t* msn_find_filetransfer(struct msn_data *md, unsigned int cookie, char *handle)
{
	GSList *l;

	for (l = md->filetransfers; l; l = l->next) {
		msn_filetransfer_t *file = ((file_transfer_t *) l->data)->data;
		if (file->invite_cookie == cookie && strcmp(handle, file->handle) == 0) {
			return file;
		}
	}
	return NULL;
}

gboolean msn_ftps_connected(gpointer data, gint fd, b_input_condition cond)
{
	file_transfer_t *file = data;
	msn_filetransfer_t *msn_file = file->data;
	struct sockaddr_storage clt_addr;
	socklen_t ssize = sizeof(clt_addr);

	debug("Connected to MSNFTP client");

	ASSERTSOCKOP(msn_file->fd = accept(fd, (struct sockaddr *) &clt_addr, &ssize), "Accepting connection");

	closesocket(fd);
	fd = msn_file->fd;
	sock_make_nonblocking(fd);

	msn_file->r_event_id = b_input_add(fd, B_EV_IO_READ, msn_ftp_read, file);

	return FALSE;
}

void msn_invitations_accept(msn_filetransfer_t *msn_file, struct msn_switchboard *sb, char *handle, unsigned int cookie,
                            char *body, int blen)
{
	file_transfer_t *file = msn_file->dcc;
	char buf[1024];
	unsigned int acookie = time(NULL);
	char host[HOST_NAME_MAX + 1];
	char port[6];
	char *errmsg;

	msn_file->auth_cookie = acookie;

	if ((msn_file->fd = ft_listen(NULL, host, port, FALSE, &errmsg)) == -1) {
		msn_ftp_abort(file, "Failed to listen locally, check your ft_listen setting in bitlbee.conf: %s",
		              errmsg);
		return;
	}

	msn_file->r_event_id = b_input_add(msn_file->fd, B_EV_IO_READ, msn_ftps_connected, file);

	g_snprintf(buf, sizeof(buf),
	           "IP-Address: %s\r\n"
	           "Port: %s\r\n"
	           "AuthCookie: %d\r\n"
	           "Launch-Application: FALSE\r\n"
	           "Request-Data: IP-Address:\r\n\r\n",
	           host,
	           port,
	           msn_file->auth_cookie);

	msn_ftp_invitation_cmd(msn_file->md->ic, handle, msn_file->invite_cookie, "ACCEPT", buf);
}

void msn_invitationr_accept(msn_filetransfer_t *msn_file, struct msn_switchboard *sb, char *handle, unsigned int cookie,
                            char *body, int blen)
{
	file_transfer_t *file = msn_file->dcc;
	char *authcookie, *ip, *port;

	if (!(authcookie = msn_findheader(body, "AuthCookie:", blen)) ||
	    !(ip = msn_findheader(body, "IP-Address:", blen)) ||
	    !(port = msn_findheader(body, "Port:", blen))) {
		msn_ftp_abort(file, "Received invalid accept reply");
	} else if (
	        (msn_file->fd = proxy_connect(ip, atoi(port), msn_ftp_connected, file))
	        < 0) {
		msn_ftp_abort(file, "Error connecting to MSN client");
	} else {
		msn_file->auth_cookie = strtoul(authcookie, NULL, 10);
	}

	g_free(authcookie);
	g_free(ip);
	g_free(port);
}

void msn_invitation_accept(struct msn_switchboard *sb, char *handle, unsigned int cookie, char *body, int blen)
{
	msn_filetransfer_t *msn_file = msn_find_filetransfer(sb->ic->proto_data, cookie, handle);
	file_transfer_t *file = msn_file ? msn_file->dcc : NULL;

	if (!msn_file) {
		imcb_log(sb->ic, "Received invitation ACCEPT message for unknown invitation (already aborted?)");
	} else if (file->sending) {
		msn_invitations_accept(msn_file, sb, handle, cookie, body, blen);
	} else {
		msn_invitationr_accept(msn_file, sb, handle, cookie, body, blen);
	}
}

void msn_invitation_cancel(struct msn_switchboard *sb, char *handle, unsigned int cookie, char *body, int blen)
{
	msn_filetransfer_t *msn_file = msn_find_filetransfer(sb->ic->proto_data, cookie, handle);

	if (!msn_file) {
		imcb_log(sb->ic, "Received invitation CANCEL message for unknown invitation (already aborted?)");
	} else {
		msn_ftp_abort(msn_file->dcc, msn_findheader(body, "Cancel-Code:", blen));
	}
}

int msn_ftp_write(file_transfer_t *file, char *format, ...)
{
	msn_filetransfer_t *msn_file = file->data;
	va_list params;
	int st;
	char *s;

	va_start(params, format);
	s = g_strdup_vprintf(format, params);
	va_end(params);

	st = write(msn_file->fd, s, strlen(s));
	if (st != strlen(s)) {
		return msn_ftp_abort(file, "Error sending data over MSNFTP connection: %s",
		                     strerror(errno));
	}

	g_free(s);
	return 1;
}

gboolean msn_ftp_connected(gpointer data, gint fd, b_input_condition cond)
{
	file_transfer_t *file = data;
	msn_filetransfer_t *msn_file = file->data;

	debug("Connected to MSNFTP server, starting authentication");
	if (!msn_ftp_write(file, "VER MSNFTP\r\n")) {
		return FALSE;
	}

	sock_make_nonblocking(msn_file->fd);
	msn_file->r_event_id = b_input_add(msn_file->fd, B_EV_IO_READ, msn_ftp_read, file);

	return FALSE;
}

gboolean msn_ftp_handle_command(file_transfer_t *file, char* line)
{
	msn_filetransfer_t *msn_file = file->data;
	char **cmd = msn_linesplit(line);
	int count = 0;

	if (cmd[0]) {
		while (cmd[++count]) {
			;
		}
	}

	if (count < 1) {
		return msn_ftp_abort(file, "Missing command in MSNFTP communication");
	}

	if (strcmp(cmd[0], "VER") == 0) {
		if (strcmp(cmd[1], "MSNFTP") != 0) {
			return msn_ftp_abort(file, "Unsupported filetransfer protocol: %s", cmd[1]);
		}
		if (file->sending) {
			msn_ftp_write(file, "VER MSNFTP\r\n");
		} else {
			msn_ftp_write(file, "USR %s %u\r\n", msn_file->md->ic->acc->user, msn_file->auth_cookie);
		}
	} else if (strcmp(cmd[0], "FIL") == 0) {
		if (strtoul(cmd[1], NULL, 10) != file->file_size) {
			return msn_ftp_abort(file,
			                     "FIL reply contains a different file size than the size in the invitation");
		}
		msn_ftp_write(file, "TFR\r\n");
		msn_file->status |= MSN_TRANSFER_RECEIVING;
	} else if (strcmp(cmd[0], "USR") == 0) {
		if ((strcmp(cmd[1], msn_file->handle) != 0) ||
		    (strtoul(cmd[2], NULL, 10) != msn_file->auth_cookie)) {
			msn_ftp_abort(file, "Authentication failed. "
			              "Expected handle: %s (got %s), cookie: %u (got %s)",
			              msn_file->handle, cmd[1],
			              msn_file->auth_cookie, cmd[2]);
		}
		msn_ftp_write(file, "FIL %zu\r\n", file->file_size);
	} else if (strcmp(cmd[0], "TFR") == 0) {
		file->write_request(file);
	} else if (strcmp(cmd[0], "BYE") == 0) {
		unsigned int retcode = count > 1 ? atoi(cmd[1]) : 1;

		if ((retcode == 16777989) || (retcode == 16777987)) {
			imcb_file_finished(file);
		} else if (retcode == 2147942405) {
			imcb_file_canceled(file, "Failure: receiver is out of disk space");
		} else if (retcode == 2164261682) {
			imcb_file_canceled(file, "Failure: receiver cancelled the transfer");
		} else if (retcode == 2164261683) {
			imcb_file_canceled(file, "Failure: sender has cancelled the transfer");
		} else if (retcode == 2164261694) {
			imcb_file_canceled(file, "Failure: connection is blocked");
		} else {
			char buf[128];

			sprintf(buf, "Failure: unknown BYE code: %d", retcode);
			imcb_file_canceled(file, buf);
		}
	} else if (strcmp(cmd[0], "CCL") == 0) {
		imcb_file_canceled(file, "Failure: receiver cancelled the transfer");
	} else {
		msn_ftp_abort(file, "Received invalid command %s from msn client", cmd[0]);
	}
	return TRUE;
}

gboolean msn_ftp_send(gpointer data, gint fd, b_input_condition cond)
{
	file_transfer_t *file = data;
	msn_filetransfer_t *msn_file = file->data;

	msn_file->w_event_id = 0;

	file->write_request(file);

	return FALSE;
}

/*
 * This should only be called if we can write, so just do it.
 * Add a write watch so we can write more during the next cycle (if possible).
 * This got a bit complicated because (at least) amsn expects packets of size 2045.
 */
gboolean msn_ftps_write(file_transfer_t *file, char *buffer, unsigned int len)
{
	msn_filetransfer_t *msn_file = file->data;
	int ret, overflow;

	/* what we can't send now */
	overflow = msn_file->sbufpos + len - MSNFTP_PSIZE;

	/* append what we can do the send buffer */
	memcpy(msn_file->sbuf + msn_file->sbufpos, buffer, MIN(len, MSNFTP_PSIZE - msn_file->sbufpos));
	msn_file->sbufpos += MIN(len, MSNFTP_PSIZE - msn_file->sbufpos);

	/* if we don't have enough for a full packet and there's more wait for it */
	if ((msn_file->sbufpos < MSNFTP_PSIZE) &&
	    (msn_file->data_sent + msn_file->sbufpos - 3 < file->file_size)) {
		if (!msn_file->w_event_id) {
			msn_file->w_event_id = b_input_add(msn_file->fd, B_EV_IO_WRITE, msn_ftp_send, file);
		}
		return TRUE;
	}

	/* Accumulated enough data, lets send something out */

	msn_file->sbuf[0] = 0;
	msn_file->sbuf[1] = (msn_file->sbufpos - 3) & 0xff;
	msn_file->sbuf[2] = ((msn_file->sbufpos - 3) >> 8) & 0xff;

	ASSERTSOCKOP(ret = send(msn_file->fd, msn_file->sbuf, msn_file->sbufpos, 0), "Sending");

	msn_file->data_sent += ret - 3;

	/* TODO: this should really not be fatal */
	if (ret < msn_file->sbufpos) {
		return msn_ftp_abort(file, "send() sent %d instead of %d (send buffer full!)", ret, msn_file->sbufpos);
	}

	msn_file->sbufpos = 3;

	if (overflow > 0) {
		while (overflow > (MSNFTP_PSIZE - 3)) {
			if (!msn_ftps_write(file, buffer + len - overflow, MSNFTP_PSIZE - 3)) {
				return FALSE;
			}
			overflow -= MSNFTP_PSIZE - 3;
		}
		return msn_ftps_write(file, buffer + len - overflow, overflow);
	}

	if (msn_file->data_sent == file->file_size) {
		if (msn_file->w_event_id) {
			b_event_remove(msn_file->w_event_id);
			msn_file->w_event_id = 0;
		}
	} else {
		/* we might already be listening if this is data from an overflow */
		if (!msn_file->w_event_id) {
			msn_file->w_event_id = b_input_add(msn_file->fd, B_EV_IO_WRITE, msn_ftp_send, file);
		}
	}

	return TRUE;
}

/* Binary part of the file transfer protocol */
gboolean msn_ftpr_read(file_transfer_t *file)
{
	msn_filetransfer_t *msn_file = file->data;
	int st;
	unsigned char buf[3];

	if (msn_file->data_remaining) {
		msn_file->r_event_id = 0;

		ASSERTSOCKOP(st = read(msn_file->fd, file->buffer, MIN(sizeof(file->buffer),
		                                                       msn_file->data_remaining)), "Receiving");

		if (st == 0) {
			return msn_ftp_abort(file, "Remote end closed connection");
		}

		msn_file->data_sent += st;

		msn_file->data_remaining -= st;

		file->write(file, file->buffer, st);

		if (msn_file->data_sent >= file->file_size) {
			imcb_file_finished(file);
		}

		return FALSE;
	} else {
		ASSERTSOCKOP(st = read(msn_file->fd, buf, 1), "Receiving");
		if (st == 0) {
			return msn_ftp_abort(file, "read returned EOF while reading data header from msn client");
		} else if (buf[0] == '\r' || buf[0] == '\n') {
			debug("Discarding extraneous newline");
		} else if (buf[0] != 0) {
			msn_ftp_abort(file, "Remote end canceled the transfer");
			/* don't really care about these last 2 (should be 0,0) */
			read(msn_file->fd, buf, 2);
			return FALSE;
		} else {
			unsigned int size;
			ASSERTSOCKOP(st = read(msn_file->fd, buf, 2), "Receiving");
			if (st < 2) {
				return msn_ftp_abort(file,
				                     "read returned EOF while reading data header from msn client");
			}

			size = buf[0] + ((unsigned int) buf[1] << 8);
			msn_file->data_remaining = size;
		}
	}
	return TRUE;
}

/* Text mode part of the file transfer protocol */
gboolean msn_ftp_txtproto(file_transfer_t *file)
{
	msn_filetransfer_t *msn_file = file->data;
	int i = msn_file->tbufpos, st;
	char *tbuf = msn_file->tbuf;

	ASSERTSOCKOP(st = read(msn_file->fd,
	                       tbuf + msn_file->tbufpos,
	                       sizeof(msn_file->tbuf) - msn_file->tbufpos),
	             "Receiving");

	if (st == 0) {
		return msn_ftp_abort(file, "read returned EOF while reading text from msn client");
	}

	msn_file->tbufpos += st;

	do {
		for (; i < msn_file->tbufpos; i++) {
			if (tbuf[i] == '\n' || tbuf[i] == '\r') {
				tbuf[i] = '\0';
				if (i > 0) {
					msn_ftp_handle_command(file, tbuf);
				} else {
					while (tbuf[i] == '\n' || tbuf[i] == '\r') {
						i++;
					}
				}
				memmove(tbuf, tbuf + i + 1, msn_file->tbufpos - i - 1);
				msn_file->tbufpos -= i + 1;
				i = 0;
				break;
			}
		}
	} while (i < msn_file->tbufpos);

	if (msn_file->tbufpos == sizeof(msn_file->tbuf)) {
		return msn_ftp_abort(file,
		                     "Line exceeded %d bytes in text protocol",
		                     sizeof(msn_file->tbuf));
	}
	return TRUE;
}

gboolean msn_ftp_read(gpointer data, gint fd, b_input_condition cond)
{
	file_transfer_t *file = data;
	msn_filetransfer_t *msn_file = file->data;

	if (msn_file->status & MSN_TRANSFER_RECEIVING) {
		return msn_ftpr_read(file);
	} else {
		return msn_ftp_txtproto(file);
	}
}

void msn_ftp_free(file_transfer_t *file)
{
	msn_filetransfer_t *msn_file = file->data;

	if (msn_file->r_event_id) {
		b_event_remove(msn_file->r_event_id);
	}

	if (msn_file->w_event_id) {
		b_event_remove(msn_file->w_event_id);
	}

	if (msn_file->fd != -1) {
		closesocket(msn_file->fd);
	}

	msn_file->md->filetransfers = g_slist_remove(msn_file->md->filetransfers, msn_file->dcc);

	g_free(msn_file->handle);

	g_free(msn_file);
}

void msn_ftpr_accept(file_transfer_t *file)
{
	msn_filetransfer_t *msn_file = file->data;

	msn_ftp_invitation_cmd(msn_file->md->ic, msn_file->handle, msn_file->invite_cookie, "ACCEPT",
	                       "Launch-Application: FALSE\r\n"
	                       "Request-Data: IP-Address:\r\n");
}

void msn_ftp_finished(file_transfer_t *file)
{
	msn_ftp_write(file, "BYE 16777989\r\n");
}

void msn_ftp_canceled(file_transfer_t *file, char *reason)
{
	msn_filetransfer_t *msn_file = file->data;

	msn_ftp_cancel_invite(msn_file->md->ic, msn_file->handle,
	                      msn_file->invite_cookie,
	                      file->status & FT_STATUS_TRANSFERRING ?
	                      "FTTIMEOUT" :
	                      "FAIL");

	imcb_log(msn_file->md->ic, "File transfer aborted: %s", reason);
}

gboolean msn_ftpr_write_request(file_transfer_t *file)
{
	msn_filetransfer_t *msn_file = file->data;

	if (msn_file->r_event_id != 0) {
		msn_ftp_abort(file,
		              "BUG in MSN file transfer:"
		              "write_request called when"
		              "already watching for input");
		return FALSE;
	}

	msn_file->r_event_id =
	        b_input_add(msn_file->fd, B_EV_IO_READ, msn_ftp_read, file);

	return TRUE;
}