/*-
 * Copyright 2016 Vsevolod Stakhov
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "config.h"
#include "rspamd.h"
#include "smtp.h"
#include "unix-std.h"

void
free_smtp_session (gpointer arg)
{
	struct smtp_session *session = arg;

	if (session) {
		if (session->task) {
			if (session->task->msg.begin) {
				munmap ((gpointer)session->task->msg.begin,
						session->task->msg.len);
			}
			rspamd_task_free (session->task);
		}
		if (session->rcpt) {
			g_list_free (session->rcpt);
		}
		if (session->dispatcher) {
			rspamd_remove_dispatcher (session->dispatcher);
		}
		close (session->sock);
		if (session->temp_name != NULL) {
			unlink (session->temp_name);
		}
		if (session->temp_fd != -1) {
			close (session->temp_fd);
		}
		rspamd_mempool_delete (session->pool);
		g_free (session);
	}
}

gboolean
create_smtp_upstream_connection (struct smtp_session *session)
{
	struct upstream *selected;

	/* Try to select upstream */
	selected = rspamd_upstream_get (session->ctx->upstreams,
			RSPAMD_UPSTREAM_ROUND_ROBIN, NULL, 0);
	if (selected == NULL) {
		msg_err ("no upstreams suitable found");
		return FALSE;
	}

	session->upstream = selected;

	/* Now try to create socket */
	session->upstream_sock = rspamd_inet_address_connect (
			rspamd_upstream_addr (selected), SOCK_STREAM, TRUE);
	if (session->upstream_sock == -1) {
		msg_err ("cannot make a connection to %s", rspamd_upstream_name (selected));
		rspamd_upstream_fail (selected);
		return FALSE;
	}
	/* Create a dispatcher for upstream connection */
	session->upstream_dispatcher = rspamd_create_dispatcher (session->ev_base,
			session->upstream_sock,
			BUFFER_LINE,
			smtp_upstream_read_socket,
			smtp_upstream_write_socket,
			smtp_upstream_err_socket,
			&session->ctx->smtp_timeout,
			session);
	session->state = SMTP_STATE_WAIT_UPSTREAM;
	session->upstream_state = SMTP_STATE_GREETING;
	rspamd_session_add_event (session->s,
		(event_finalizer_t)smtp_upstream_finalize_connection,
		session,
		g_quark_from_static_string ("smtp proxy"));
	return TRUE;
}

gboolean
smtp_send_upstream_message (struct smtp_session *session)
{
	rspamd_dispatcher_pause (session->dispatcher);
	rspamd_dispatcher_restore (session->upstream_dispatcher);

	session->upstream_state = SMTP_STATE_IN_SENDFILE;
	session->state = SMTP_STATE_WAIT_UPSTREAM;
	if (!rspamd_dispatcher_sendfile (session->upstream_dispatcher,
		session->temp_fd, session->temp_size)) {
		msg_err ("sendfile failed: %s", strerror (errno));
		goto err;
	}
	return TRUE;

err:
	session->error = SMTP_ERROR_FILE;
	session->state = SMTP_STATE_CRITICAL_ERROR;
	if (!rspamd_dispatcher_write (session->dispatcher, session->error, 0, FALSE,
		TRUE)) {
		return FALSE;
	}
	rspamd_session_destroy (session->s);
	return FALSE;
}

struct smtp_metric_callback_data {
	struct smtp_session *session;
	enum rspamd_metric_action action;
	struct metric_result *res;
	gchar *log_buf;
	gint log_offset;
	gint log_size;
	gboolean alive;
};

static void
smtp_metric_symbols_callback (gpointer key, gpointer value, void *user_data)
{
	struct smtp_metric_callback_data *cd = user_data;

	cd->log_offset += rspamd_snprintf (cd->log_buf + cd->log_offset,
			cd->log_size - cd->log_offset,
			"%s,",
			(gchar *)key);
}

static void
smtp_metric_callback (gpointer key, gpointer value, gpointer ud)
{
	struct smtp_metric_callback_data *cd = ud;
	struct metric_result *metric_res = value;
	enum rspamd_metric_action action = METRIC_ACTION_NOACTION;
	double ms = 0, rs = 0;
	gboolean is_spam = FALSE;
	struct rspamd_task *task;

	task = cd->session->task;

	/* XXX rewrite */
	ms = metric_res->metric->actions[METRIC_ACTION_REJECT].score;
	rs = metric_res->metric->actions[METRIC_ACTION_REJECT].score;
#if 0
	if (!check_metric_settings (metric_res, &ms, &rs)) {
		ms = metric_res->metric->actions[METRIC_ACTION_REJECT].score;
		rs = metric_res->metric->actions[METRIC_ACTION_REJECT].score;
	}
	if (!check_metric_action_settings (task, metric_res, metric_res->score,
		&action)) {
		action =
			check_metric_action (metric_res->score, ms, metric_res->metric);
	}
#endif
	if (metric_res->score >= ms) {
		is_spam = 1;
	}
	if (action < cd->action) {
		cd->action = action;
		cd->res = metric_res;
	}

	if (!RSPAMD_TASK_IS_SKIPPED (task)) {
		cd->log_offset += rspamd_snprintf (cd->log_buf + cd->log_offset,
				cd->log_size - cd->log_offset,
				"(%s: %c (%s): [%.2f/%.2f/%.2f] [",
				(gchar *)key,
				is_spam ? 'T' : 'F',
				rspamd_action_to_str (action),
				metric_res->score,
				ms,
				rs);
	}
	else {
		cd->log_offset += rspamd_snprintf (cd->log_buf + cd->log_offset,
				cd->log_size - cd->log_offset,
				"(%s: %c (default): [%.2f/%.2f/%.2f] [",
				(gchar *)key,
				'S',
				metric_res->score,
				ms,
				rs);

	}
	g_hash_table_foreach (metric_res->symbols, smtp_metric_symbols_callback,
		cd);
	/* Remove last , from log buf */
	if (cd->log_buf[cd->log_offset - 1] == ',') {
		cd->log_buf[--cd->log_offset] = '\0';
	}

	cd->log_offset += rspamd_snprintf (cd->log_buf + cd->log_offset,
			cd->log_size - cd->log_offset,
			"]), len: %z, time: %s,",
			task->msg.len,
			rspamd_log_check_time (task->time_real, task->time_virtual,
					task->cfg->clock_res));
}

gboolean
make_smtp_tempfile (struct smtp_session *session)
{
	gsize r;

	r = strlen (session->cfg->temp_dir) + sizeof ("/rspamd-XXXXXX");
	session->temp_name = rspamd_mempool_alloc (session->pool, r);
	rspamd_snprintf (session->temp_name,
		r,
		"%s/rspamd-XXXXXX",
		session->cfg->temp_dir);
#ifdef HAVE_MKSTEMP
	/* Umask is set before */
	session->temp_fd = mkstemp (session->temp_name);
#else
	session->temp_fd = g_mkstemp_full (session->temp_name,
			O_RDWR,
			S_IWUSR | S_IRUSR);
#endif
	if (session->temp_fd == -1) {
		msg_err ("mkstemp error: %s", strerror (errno));

		return FALSE;
	}

	return TRUE;
}

gboolean
write_smtp_reply (struct smtp_session *session)
{
	gchar logbuf[1024], *new_subject;
	const gchar *old_subject;
	struct smtp_metric_callback_data cd;
	GMimeStream *stream;
	gint old_fd, sublen;

	/* Check metrics */
	cd.session = session;
	cd.action = METRIC_ACTION_NOACTION;
	cd.res = NULL;
	cd.log_buf = logbuf;
	cd.log_offset = rspamd_snprintf (logbuf,
			sizeof (logbuf),
			"id: <%s>, qid: <%s>, ",
			session->task->message_id,
			session->task->queue_id);
	cd.log_size = sizeof (logbuf);
	if (session->task->user) {
		cd.log_offset += rspamd_snprintf (logbuf + cd.log_offset,
				sizeof (logbuf) - cd.log_offset,
				"user: %s, ",
				session->task->user);
	}

	g_hash_table_foreach (session->task->results, smtp_metric_callback, &cd);

	msg_info ("%s", logbuf);

	if (cd.action <= METRIC_ACTION_REJECT) {
		if (!rspamd_dispatcher_write (session->dispatcher,
			session->ctx->reject_message, 0, FALSE, TRUE)) {
			return FALSE;
		}
		if (!rspamd_dispatcher_write (session->dispatcher, CRLF, sizeof (CRLF) -
			1, FALSE, TRUE)) {
			return FALSE;
		}
		rspamd_session_destroy (session->s);
		return FALSE;
	}
	else if (cd.action <= METRIC_ACTION_ADD_HEADER || cd.action <=
		METRIC_ACTION_REWRITE_SUBJECT) {
		old_fd = session->temp_fd;
		if (!make_smtp_tempfile (session)) {
			session->error = SMTP_ERROR_FILE;
			session->state = SMTP_STATE_CRITICAL_ERROR;
			rspamd_dispatcher_restore (session->dispatcher);
			if (!rspamd_dispatcher_write (session->dispatcher, session->error,
				0, FALSE, TRUE)) {
				goto err;
			}
			rspamd_session_destroy (session->s);
			return FALSE;
		}

		if (cd.action <= METRIC_ACTION_REWRITE_SUBJECT) {
			/* XXX: add this action */
			old_subject = g_mime_message_get_subject (session->task->message);
			if (old_subject != NULL) {
				sublen = strlen (old_subject) + sizeof (SPAM_SUBJECT);
				new_subject = rspamd_mempool_alloc (session->pool, sublen);
				rspamd_snprintf (new_subject,
					sublen,
					"%s%s",
					SPAM_SUBJECT,
					old_subject);
			}
			else {
				new_subject = SPAM_SUBJECT;
			}
			g_mime_message_set_subject (session->task->message, new_subject);
		}
		else if (cd.action <= METRIC_ACTION_ADD_HEADER) {
#ifndef GMIME24
			g_mime_message_add_header (session->task->message, "X-Spam",
				"true");
#else
			g_mime_object_append_header (GMIME_OBJECT (
					session->task->message), "X-Spam", "true");
#endif
		}
		stream = g_mime_stream_fs_new (session->temp_fd);
		g_mime_stream_fs_set_owner (GMIME_STREAM_FS (stream), FALSE);
		close (old_fd);

		if (g_mime_object_write_to_stream (GMIME_OBJECT (session->task->message),
			stream) == -1) {
			msg_err ("cannot write MIME object to stream: %s",
				strerror (errno));
			session->error = SMTP_ERROR_FILE;
			session->state = SMTP_STATE_CRITICAL_ERROR;
			rspamd_dispatcher_restore (session->dispatcher);
			if (!rspamd_dispatcher_write (session->dispatcher, session->error,
				0, FALSE, TRUE)) {
				goto err;
			}
			rspamd_session_destroy (session->s);
			return FALSE;
		}
		g_object_unref (stream);
	}
	/* XXX: Add other actions */
	return smtp_send_upstream_message (session);
err:
	session->error = SMTP_ERROR_FILE;
	session->state = SMTP_STATE_CRITICAL_ERROR;
	if (!rspamd_dispatcher_write (session->dispatcher, session->error, 0, FALSE,
		TRUE)) {
		return FALSE;
	}
	rspamd_session_destroy (session->s);
	return FALSE;
}