/*
 * Claws Mail -- a GTK based, lightweight, and fast e-mail client
 * Copyright (C) 1999-2022 the Claws Mail team and Hiroyuki Yamamoto
 *
 * 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 3 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
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#include "claws-features.h"
#endif

#include <glib.h>
#include <glib/gi18n.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>

#include "pop.h"
#include "md5.h"
#include "prefs_account.h"
#include "utils.h"
#include "recv.h"
#include "partial_download.h"
#include "log.h"
#include "hooks.h"
#include "file-utils.h"
#include "oauth2.h"

static gint pop3_greeting_recv		(Pop3Session *session,
					 const gchar *msg);
static gint pop3_getauth_user_send	(Pop3Session *session);
static gint pop3_getauth_pass_send	(Pop3Session *session);
static gint pop3_getauth_apop_send	(Pop3Session *session);
#ifdef USE_GNUTLS
static gint pop3_stls_send		(Pop3Session *session);
static gint pop3_stls_recv		(Pop3Session *session);
#endif
static gint pop3_getrange_stat_send	(Pop3Session *session);
static gint pop3_getrange_stat_recv	(Pop3Session *session,
					 const gchar *msg);
static gint pop3_getrange_last_send	(Pop3Session *session);
static gint pop3_getrange_last_recv	(Pop3Session *session,
					 const gchar *msg);
static gint pop3_getrange_uidl_send	(Pop3Session *session);
static gint pop3_getrange_uidl_recv	(Pop3Session *session,
					 const gchar *data,
					 guint        len);
static gint pop3_getsize_list_send	(Pop3Session *session);
static gint pop3_getsize_list_recv	(Pop3Session *session,
					 const gchar *data,
					 guint        len);
static gint pop3_retr_send		(Pop3Session *session);
static gint pop3_retr_recv		(Pop3Session *session,
					 const gchar *data,
					 guint        len);
static gint pop3_delete_send		(Pop3Session *session);
static gint pop3_delete_recv		(Pop3Session *session);
static gint pop3_logout_send		(Pop3Session *session);

static void pop3_gen_send		(Pop3Session	*session,
					 const gchar	*format, ...);

static void pop3_session_destroy	(Session	*session);

static gint pop3_write_msg_to_file	(const gchar	*file,
					 const gchar	*data,
					 guint		 len,
					 const gchar 	*prefix);

static Pop3State pop3_lookup_next	(Pop3Session	*session);
static Pop3ErrorValue pop3_ok		(Pop3Session	*session,
					 const gchar	*msg);

static gint pop3_session_recv_msg		(Session	*session,
						 const gchar	*msg);
static gint pop3_session_recv_data_finished	(Session	*session,
						 guchar		*data,
						 guint		 len);
static void pop3_get_uidl_table(PrefsAccount *ac_prefs, Pop3Session *session);

static gint pop3_greeting_recv(Pop3Session *session, const gchar *msg)
{
	session->state = POP3_GREETING;

	session->greeting = g_strdup(msg);
	return PS_SUCCESS;
}

#ifdef USE_GNUTLS
static gint pop3_stls_send(Pop3Session *session)
{
	session->state = POP3_STLS;
	pop3_gen_send(session, "STLS");
	return PS_SUCCESS;
}

static gint pop3_stls_recv(Pop3Session *session)
{
	if (session_start_tls(SESSION(session)) < 0) {
		session->error_val = PS_SOCKET;
		return -1;
	}
	return PS_SUCCESS;
}
#endif /* USE_GNUTLS */

static gint pop3_getauth_user_send(Pop3Session *session)
{
	cm_return_val_if_fail(session->user != NULL, -1);

	session->state = POP3_GETAUTH_USER;
	pop3_gen_send(session, "USER %s", session->user);
	return PS_SUCCESS;
}

static gint pop3_getauth_pass_send(Pop3Session *session)
{
	cm_return_val_if_fail(session->pass != NULL, -1);

	session->state = POP3_GETAUTH_PASS;
	pop3_gen_send(session, "PASS %s", session->pass);
	return PS_SUCCESS;
}

static gint pop3_getauth_apop_send(Pop3Session *session)
{
	gchar *start, *end;
	gchar *apop_str;
	gchar md5sum[33];

	cm_return_val_if_fail(session->user != NULL, -1);
	cm_return_val_if_fail(session->pass != NULL, -1);

	session->state = POP3_GETAUTH_APOP;

	if ((start = strchr(session->greeting, '<')) == NULL) {
		log_error(LOG_PROTOCOL, _("Required APOP timestamp not found "
			    "in greeting\n"));
		session->error_val = PS_PROTOCOL;
		return -1;
	}

	if ((end = strchr(start, '>')) == NULL || end == start + 1) {
		log_error(LOG_PROTOCOL, _("Timestamp syntax error in greeting\n"));
		session->error_val = PS_PROTOCOL;
		return -1;
	}
	*(end + 1) = '\0';

	if (!is_ascii_str(start)) {
		log_error(LOG_PROTOCOL, _("Timestamp syntax error in greeting (not ASCII)\n"));
		session->error_val = PS_PROTOCOL;
		return -1;
	}

	apop_str = g_strconcat(start, session->pass, NULL);
	md5_hex_digest(md5sum, apop_str);
	g_free(apop_str);

	pop3_gen_send(session, "APOP %s %s", session->user, md5sum);

	return PS_SUCCESS;
}

#ifdef USE_OAUTH2
static gint pop3_getauth_oauth2_send_generic(Pop3Session *session)
{
	gchar buf[MESSAGEBUFSIZE], *b64buf, *out;
	gint len;

	cm_return_val_if_fail(session->user != NULL, -1);
	cm_return_val_if_fail(session->pass != NULL, -1);

	session->state = POP3_GETAUTH_OAUTH2;
	memset(buf, 0, sizeof buf);

	/* "user=" {User} "^Aauth=Bearer " {Access Token} "^A^A" */
	/* session->pass contains the OAUTH2 Access Token */
	len = sprintf(buf, "user=%s\1auth=Bearer %s\1\1", session->user, session->pass);
	b64buf = g_base64_encode(buf, len);
	out = g_strconcat("AUTH XOAUTH2 ", b64buf, NULL);
	g_free(b64buf);

	pop3_gen_send(session, "%s", out);
	/* Any error response contains base64({JSON-Body}) containing three values: status, schemes, and scope */
	/* This could be dealt with but is currently written to the log in a fairly graceful fail - not crucial */
	g_free(out);
	return PS_SUCCESS;
}

/* Microsoft requires authentication to be split in two lines */
static gint pop3_getauth_oauth2_send_microsoft_1(Pop3Session *session)
{
	cm_return_val_if_fail(session->user != NULL, -1);
	cm_return_val_if_fail(session->pass != NULL, -1);

	session->state = POP3_GETAUTH_USER_PHASE2;

	pop3_gen_send(session, "AUTH XOAUTH2");

	return PS_SUCCESS;
}

static gint pop3_getauth_oauth2_send_microsoft_2(Pop3Session *session)
{
	gchar buf[MESSAGEBUFSIZE], *b64buf;
	gint len;

	cm_return_val_if_fail(session->user != NULL, -1);
	cm_return_val_if_fail(session->pass != NULL, -1);

	session->state = POP3_GETAUTH_OAUTH2;
	memset(buf, 0, sizeof buf);

	/* "user=" {User} "^Aauth=Bearer " {Access Token} "^A^A"*/
	/* session->pass contains the OAUTH2 Access Token*/
	len = sprintf(buf, "user=%s\1auth=Bearer %s\1\1", session->user, session->pass);
	b64buf = g_base64_encode(buf, len);

	pop3_gen_send(session, "%s", b64buf);

	g_free(b64buf);
	/* Any error response contains base64({JSON-Body}) containing three values: status, schemes, and scope */
	/* This could be dealt with but is currently written to the log in a fairly graceful fail - not crucial */
	return PS_SUCCESS;
}

static gint pop3_getauth_oauth2_send(Pop3Session *session)
{
	gint oauth2_provider = session->ac_prefs->oauth2_provider;
	return (  oauth2_provider == OAUTH2AUTH_OUTLOOK ||
		  oauth2_provider == OAUTH2AUTH_EXCHANGE ||
		  oauth2_provider == OAUTH2AUTH_MICROSOFT_GCCHIGH
		? pop3_getauth_oauth2_send_microsoft_1(session)
		: pop3_getauth_oauth2_send_generic(session)
		);
}
#endif

static gint pop3_getrange_stat_send(Pop3Session *session)
{
	session->state = POP3_GETRANGE_STAT;
	pop3_gen_send(session, "STAT");
	return PS_SUCCESS;
}

static gint pop3_getrange_stat_recv(Pop3Session *session, const gchar *msg)
{
	if (sscanf(msg, "%d %d", &session->count, &session->total_bytes) != 2) {
		log_error(LOG_PROTOCOL, _("POP protocol error\n"));
		session->error_val = PS_PROTOCOL;
		return -1;
	} else {
		if (session->count == 0) {
			session->uidl_is_valid = TRUE;
		} else {
			session->msg = g_new0(Pop3MsgInfo, session->count + 1);
			session->cur_msg = 1;
		}
	}

	return PS_SUCCESS;
}

static gint pop3_getrange_last_send(Pop3Session *session)
{
	session->state = POP3_GETRANGE_LAST;
	pop3_gen_send(session, "LAST");
	return PS_SUCCESS;
}

static gint pop3_getrange_last_recv(Pop3Session *session, const gchar *msg)
{
	gint last;

	if (sscanf(msg, "%d", &last) == 0) {
		log_warning(LOG_PROTOCOL, _("POP protocol error\n"));
		session->error_val = PS_PROTOCOL;
		return -1;
	} else {
		if (session->count > last) {
			session->new_msg_exist = TRUE;
			session->cur_msg = last + 1;
		} else
			session->cur_msg = 0;
	}

	return PS_SUCCESS;
}

static gint pop3_getrange_uidl_send(Pop3Session *session)
{
	session->state = POP3_GETRANGE_UIDL;
	pop3_gen_send(session, "UIDL");
	return PS_SUCCESS;
}

static gint pop3_getrange_uidl_recv(Pop3Session *session, const gchar *data,
				    guint len)
{
	gchar id[IDLEN + 1];
	gchar buf[POPBUFSIZE];
	gint buf_len;
	guint32 num;
	time_t recv_time;
	gint partial_recv;
	const gchar *p = data;
	const gchar *lastp = data + len;
	const gchar *newline;

	while (p < lastp) {
		if ((newline = memchr(p, '\r', lastp - p)) == NULL)
			return -1;
		buf_len = MIN(newline - p, sizeof(buf) - 1);
		memcpy(buf, p, buf_len);
		buf[buf_len] = '\0';

		p = newline + 1;
		if (p < lastp && *p == '\n') p++;

		if (sscanf(buf, "%d %" Xstr(IDLEN) "s", &num, id) != 2 ||
		    num <= 0 || num > session->count) {
			log_warning(LOG_PROTOCOL, _("invalid UIDL response: %s\n"), buf);
			continue;
		}

		session->msg[num].uidl = g_strdup(id);

		recv_time = (time_t)(GPOINTER_TO_INT(g_hash_table_lookup(
					session->uidl_table, id)));
		session->msg[num].recv_time = recv_time;

		if (recv_time != RECV_TIME_NONE) {
			debug_print("num %d uidl %s: already got it\n", num, id);
		} else {
			debug_print("num %d uidl %s: unknown\n", num, id);
		}

		partial_recv = (gint)(GPOINTER_TO_INT(g_hash_table_lookup(
					session->partial_recv_table, id)));

		if (recv_time != RECV_TIME_NONE
		|| partial_recv != POP3_TOTALLY_RECEIVED) {
			session->msg[num].received =
				(partial_recv != POP3_MUST_COMPLETE_RECV);
			session->msg[num].partial_recv = partial_recv;
			if (partial_recv == POP3_MUST_COMPLETE_RECV)
				session->new_msg_exist = TRUE;
		}
		if (!session->new_msg_exist &&
		    (recv_time == RECV_TIME_NONE ||
		     session->ac_prefs->rmmail)) {
			session->cur_msg = num;
			session->new_msg_exist = TRUE;
		}
	}

	session->uidl_is_valid = TRUE;
	return PS_SUCCESS;
}

static gint pop3_getsize_list_send(Pop3Session *session)
{
	session->state = POP3_GETSIZE_LIST;
	pop3_gen_send(session, "LIST");
	return PS_SUCCESS;
}

static gint pop3_getsize_list_recv(Pop3Session *session, const gchar *data,
				   guint len)
{
	gchar buf[POPBUFSIZE];
	gint buf_len;
	guint num, size;
	const gchar *p = data;
	const gchar *lastp = data + len;
	const gchar *newline;

	while (p < lastp) {
		if ((newline = memchr(p, '\r', lastp - p)) == NULL)
			return -1;
		buf_len = MIN(newline - p, sizeof(buf) - 1);
		memcpy(buf, p, buf_len);
		buf[buf_len] = '\0';

		p = newline + 1;
		if (p < lastp && *p == '\n') p++;

		if (sscanf(buf, "%u %u", &num, &size) != 2) {
			session->error_val = PS_PROTOCOL;
			return -1;
		}

		if (num > 0 && num <= session->count)
			session->msg[num].size = size;
		if (num > 0 && num < session->cur_msg)
			session->cur_total_bytes += size;
	}

	return PS_SUCCESS;
}

static gint pop3_retr_send(Pop3Session *session)
{
	session->state = POP3_RETR;
	debug_print("retrieving %d [%s]\n", session->cur_msg,
		session->msg[session->cur_msg].uidl ?
		 session->msg[session->cur_msg].uidl:" ");
	pop3_gen_send(session, "RETR %d", session->cur_msg);
	return PS_SUCCESS;
}

static gint pop3_retr_recv(Pop3Session *session, const gchar *data, guint len)
{
	gchar *file;
	gint drop_ok;
	MailReceiveData mail_receive_data;

	/* NOTE: we allocate a slightly larger buffer with a zero terminator
	 * because some plugins may think that it has a C string. */
	mail_receive_data.session  = session;
	mail_receive_data.data     = g_new0(gchar, len + 1);
	mail_receive_data.data_len = len;
	memcpy(mail_receive_data.data, data, len);

	hooks_invoke(MAIL_RECEIVE_HOOKLIST, &mail_receive_data);

	file = get_tmp_file();
	if (pop3_write_msg_to_file(file, mail_receive_data.data,
				   mail_receive_data.data_len, NULL) < 0) {
		g_free(file);
		g_free(mail_receive_data.data);
		session->error_val = PS_IOERR;
		return -1;
	}
	g_free(mail_receive_data.data);

	if (session->msg[session->cur_msg].partial_recv
	    == POP3_MUST_COMPLETE_RECV) {
		gchar *old_file = partial_get_filename(
				session->ac_prefs->recv_server,
				session->ac_prefs->userid,
				session->msg[session->cur_msg].uidl);

		if (old_file) {
			partial_delete_old(old_file);
			g_free(old_file);
		}
	}

	/* drop_ok: 0: success 1: don't receive -1: error */
	drop_ok = session->drop_message(session, file);

	g_free(file);
	if (drop_ok < 0) {
		session->error_val = PS_IOERR;
		return -1;
	}

	session->cur_total_bytes += session->msg[session->cur_msg].size;
	session->cur_total_recv_bytes += session->msg[session->cur_msg].size;
	session->cur_total_num++;

	session->msg[session->cur_msg].received = TRUE;
	session->msg[session->cur_msg].partial_recv = POP3_TOTALLY_RECEIVED;

	session->msg[session->cur_msg].recv_time =
		drop_ok == 1 ? RECV_TIME_KEEP : session->current_time;

	return PS_SUCCESS;
}

static gint pop3_top_send(Pop3Session *session, gint max_size)
{
	gint num_lines = (max_size*1024)/82; /* consider lines to be 80 chars */
	session->state = POP3_TOP;
	pop3_gen_send(session, "TOP %d %d", session->cur_msg, num_lines);
	return PS_SUCCESS;
}

static gint pop3_top_recv(Pop3Session *session, const gchar *data, guint len)
{
	gchar *file;
	gint drop_ok;
	MailReceiveData mail_receive_data;
	gchar *partial_notice = NULL;

	/* NOTE: we allocate a slightly larger buffer with a zero terminator
	 * because some plugins may think that it has a C string. */
	mail_receive_data.session  = session;
	mail_receive_data.data     = g_new0(gchar, len + 1);
	mail_receive_data.data_len = len;
	memcpy(mail_receive_data.data, data, len);

	hooks_invoke(MAIL_RECEIVE_HOOKLIST, &mail_receive_data);

	partial_notice = g_strdup_printf("SC-Marked-For-Download: 0\n"
					 "SC-Partially-Retrieved: %s\n"
					 "SC-Account-Server: %s\n"
					 "SC-Account-Login: %s\n"
					 "SC-Message-Size: %d",
					 session->msg[session->cur_msg].uidl,
					 session->ac_prefs->recv_server,
					 session->ac_prefs->userid,
					 session->msg[session->cur_msg].size);
	file = get_tmp_file();
	if (pop3_write_msg_to_file(file, mail_receive_data.data,
				   mail_receive_data.data_len,
				   partial_notice) < 0) {
		g_free(file);
		g_free(mail_receive_data.data);
		session->error_val = PS_IOERR;
		g_free(partial_notice);
		return -1;
	}
	g_free(mail_receive_data.data);
	g_free(partial_notice);

	/* drop_ok: 0: success 1: don't receive -1: error */
	drop_ok = session->drop_message(session, file);
	g_free(file);
	if (drop_ok < 0) {
		session->error_val = PS_IOERR;
		return -1;
	}

	session->cur_total_bytes += session->msg[session->cur_msg].size;
	session->cur_total_recv_bytes += session->msg[session->cur_msg].size;
	session->cur_total_num++;

	session->msg[session->cur_msg].received = TRUE;
	session->msg[session->cur_msg].partial_recv = POP3_PARTIALLY_RECEIVED;
	session->msg[session->cur_msg].recv_time =
		drop_ok == 1 ? RECV_TIME_KEEP : session->current_time;

	return PS_SUCCESS;
}

static gint pop3_delete_send(Pop3Session *session)
{
	session->state = POP3_DELETE;
	pop3_gen_send(session, "DELE %d", session->cur_msg);
	return PS_SUCCESS;
}

static gint pop3_delete_recv(Pop3Session *session)
{
	session->msg[session->cur_msg].deleted = TRUE;
	return PS_SUCCESS;
}

static gint pop3_logout_send(Pop3Session *session)
{
	session->state = POP3_LOGOUT;
	pop3_gen_send(session, "QUIT");
	return PS_SUCCESS;
}

static void pop3_gen_send(Pop3Session *session, const gchar *format, ...)
{
	gchar buf[POPBUFSIZE + 1];
	int length;
	va_list args;

	va_start(args, format);
	length = g_vsnprintf(buf, sizeof(buf) - 2, format, args);
	va_end(args);
	if (length > POPBUFSIZE)
		g_warning("POP buffer length overflow! (wanted to write = %d > %d = buf size)\n", length, POPBUFSIZE);

	if (!g_ascii_strncasecmp(buf, "PASS ", 5))
		log_print(LOG_PROTOCOL, "POP> PASS ********\n");
#ifdef USE_OAUTH2
	else if  (!g_ascii_strncasecmp(buf, "AUTH XOAUTH2", 12))
		log_print(LOG_PROTOCOL, "POP> AUTH XOAUTH2  ********\n");
#endif
	else if (length > 128)
		log_print(LOG_PROTOCOL, "POP> %.128s... (truncated from %d)\n", buf, length);
	else
		log_print(LOG_PROTOCOL, "POP> %s\n", buf);

	session_send_msg(SESSION(session), buf);
}

Session *pop3_session_new(PrefsAccount *account)
{
	Pop3Session *session;

	cm_return_val_if_fail(account != NULL, NULL);

	account->receive_in_progress = TRUE;

	session = g_new0(Pop3Session, 1);

	session_init(SESSION(session), account, FALSE);

	SESSION(session)->type = SESSION_POP3;

	SESSION(session)->recv_msg = pop3_session_recv_msg;
	SESSION(session)->recv_data_finished = pop3_session_recv_data_finished;
	SESSION(session)->send_data_finished = NULL;
	SESSION(session)->ssl_cert_auto_accept = account->ssl_certs_auto_accept;
	SESSION(session)->destroy = pop3_session_destroy;

#ifdef USE_GNUTLS
	if (account->set_gnutls_priority && account->gnutls_priority &&
			strlen(account->gnutls_priority) != 0)
		SESSION(session)->gnutls_priority = g_strdup(account->gnutls_priority);
	SESSION(session)->use_tls_sni = account->use_tls_sni;
#endif

	session->state = POP3_READY;
	session->ac_prefs = account;
	session->pop_before_smtp = FALSE;
	pop3_get_uidl_table(account, session);
	session->current_time = time(NULL);
	session->error_val = PS_SUCCESS;
	session->error_msg = NULL;

	return SESSION(session);
}

static void pop3_session_destroy(Session *session)
{
	Pop3Session *pop3_session = POP3_SESSION(session);
	gint n;

	cm_return_if_fail(session != NULL);

	for (n = 1; n <= pop3_session->count; n++)
		g_free(pop3_session->msg[n].uidl);
	g_free(pop3_session->msg);

	if (pop3_session->uidl_table) {
		hash_free_strings(pop3_session->uidl_table);
		g_hash_table_destroy(pop3_session->uidl_table);
	}

	if (pop3_session->partial_recv_table) {
		hash_free_strings(pop3_session->partial_recv_table);
		g_hash_table_destroy(pop3_session->partial_recv_table);
	}

	g_free(pop3_session->greeting);
	g_free(pop3_session->user);
	g_free(pop3_session->pass);
	g_free(pop3_session->error_msg);

	pop3_session->ac_prefs->receive_in_progress = FALSE;
}

static void pop3_get_uidl_table(PrefsAccount *ac_prefs, Pop3Session *session)
{
	GHashTable *table;
	GHashTable *partial_recv_table;
	gchar *path;
	FILE *fp;
	gchar buf[POPBUFSIZE];
	gchar uidl[POPBUFSIZE];
	time_t recv_time;
	time_t now;
	gint partial_recv;
	gchar *sanitized_uid = g_strdup(ac_prefs->userid);

	subst_for_filename(sanitized_uid);

	table = g_hash_table_new(g_str_hash, g_str_equal);
	partial_recv_table = g_hash_table_new(g_str_hash, g_str_equal);

	path = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
			   "uidl", G_DIR_SEPARATOR_S, ac_prefs->recv_server,
			   "-", sanitized_uid, NULL);

	g_free(sanitized_uid);
	if ((fp = claws_fopen(path, "rb")) == NULL) {
		if (ENOENT != errno) FILE_OP_ERROR(path, "claws_fopen");
		g_free(path);
		path = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
				   "uidl-", ac_prefs->recv_server,
				   "-", ac_prefs->userid, NULL);
		if ((fp = claws_fopen(path, "rb")) == NULL) {
			if (ENOENT != errno) FILE_OP_ERROR(path, "claws_fopen");
			g_free(path);
			session->uidl_table = table;
			session->partial_recv_table = partial_recv_table;
			return;
		}
	}
	g_free(path);

	now = time(NULL);

	while (claws_fgets(buf, sizeof(buf), fp) != NULL) {
		gchar tmp[POPBUFSIZE];
		strretchomp(buf);
		recv_time = RECV_TIME_NONE;
		partial_recv = POP3_TOTALLY_RECEIVED;

		if (sscanf(buf, "%s\t%ld\t%s", uidl, (long int *) &recv_time, tmp) < 3) {
			if (sscanf(buf, "%s\t%ld", uidl, (long int *) &recv_time) != 2) {
				if (sscanf(buf, "%s", uidl) != 1)
					continue;
				else {
					recv_time = now;
					strcpy(tmp, "0");
				}
			} else {
				strcpy(tmp, "0");
			}
		}

		if (recv_time == RECV_TIME_NONE)
			recv_time = RECV_TIME_RECEIVED;
		g_hash_table_insert(table, g_strdup(uidl),
				    GINT_TO_POINTER(recv_time));
		if (strlen(tmp) == 1)
			partial_recv = atoi(tmp); /* totally received ?*/
		else
			partial_recv = POP3_MUST_COMPLETE_RECV;

		g_hash_table_insert(partial_recv_table, g_strdup(uidl),
				    GINT_TO_POINTER(partial_recv));
	}

	claws_fclose(fp);
	session->uidl_table = table;
	session->partial_recv_table = partial_recv_table;

	return;
}

#define TRY(func) \
if (!(func)) \
{ \
	g_warning("failed to write"); \
	goto err_write;			\
} \

gint pop3_write_uidl_list(Pop3Session *session)
{
	gchar *path, *tmp_path;
	FILE *fp;
	Pop3MsgInfo *msg;
	gint n;
	gchar *sanitized_uid = g_strdup(session->ac_prefs->userid);

	subst_for_filename(sanitized_uid);

	if (!session->uidl_is_valid) {
		g_free(sanitized_uid);
		return 0;
	}

	path = g_strconcat(get_rc_dir(), G_DIR_SEPARATOR_S,
			   "uidl", G_DIR_SEPARATOR_S,
			   session->ac_prefs->recv_server,
			   "-", sanitized_uid, NULL);
	tmp_path = g_strconcat(path, ".tmp", NULL);

	g_free(sanitized_uid);

	if ((fp = claws_fopen(tmp_path, "wb")) == NULL) {
		FILE_OP_ERROR(tmp_path, "claws_fopen");
		goto err_write;
	}

	for (n = 1; n <= session->count; n++) {
		msg = &session->msg[n];
		if (msg->uidl && msg->received &&
		    (!msg->deleted || session->state != POP3_DONE))
			TRY(fprintf(fp, "%s\t%ld\t%d\n",
				msg->uidl, (long int)
				msg->recv_time,
				msg->partial_recv)
			    > 0);
	}

	if (claws_safe_fclose(fp) == EOF) {
		FILE_OP_ERROR(tmp_path, "claws_fclose");
		fp = NULL;
		goto err_write;
	}
	fp = NULL;
#ifdef G_OS_WIN32
	claws_unlink(path);
#endif
	if (g_rename(tmp_path, path) < 0) {
		FILE_OP_ERROR(path, "rename");
		goto err_write;
	}
	g_free(path);
	g_free(tmp_path);
	return 0;
err_write:
	if (fp)
		claws_fclose(fp);
	g_free(path);
	g_free(tmp_path);
	return -1;
}

#undef TRY

static gint pop3_write_msg_to_file(const gchar *file, const gchar *data,
				   guint len, const gchar *prefix)
{
	FILE *fp;
	const gchar *prev, *cur;

	cm_return_val_if_fail(file != NULL, -1);

	if ((fp = claws_fopen(file, "wb")) == NULL) {
		FILE_OP_ERROR(file, "claws_fopen");
		return -1;
	}

	if (change_file_mode_rw(fp, file) < 0)
		FILE_OP_ERROR(file, "chmod");

	if (prefix != NULL) {
		if (fprintf(fp, "%s\n", prefix) < 0) {
			FILE_OP_ERROR(file, "fprintf");
			claws_fclose(fp);
			claws_unlink(file);
			return -1;
		}
	}

	/* +------------------+----------------+--------------------------+ *
	 * ^data              ^prev            ^cur             data+len-1^ */

	prev = data;
	while ((cur = (gchar *)my_memmem(prev, len - (prev - data), "\r\n", 2))
	       != NULL) {
		if ((cur > prev && claws_fwrite(prev, 1, cur - prev, fp) < 1) ||
		    claws_fputc('\n', fp) == EOF) {
			FILE_OP_ERROR(file, "claws_fwrite");
			g_warning("can't write to file: %s", file);
			claws_fclose(fp);
			claws_unlink(file);
			return -1;
		}

		if (cur == data + len - 1) {
			prev = cur + 1;
			break;
		}

		if (*(cur + 1) == '\n')
			prev = cur + 2;
		else
			prev = cur + 1;

		if (prev - data < len - 1 && *prev == '.' && *(prev + 1) == '.')
			prev++;

		if (prev - data >= len)
			break;
	}

	if (prev - data < len &&
	    claws_fwrite(prev, 1, len - (prev - data), fp) < 1) {
		FILE_OP_ERROR(file, "claws_fwrite");
		g_warning("can't write to file: %s", file);
		claws_fclose(fp);
		claws_unlink(file);
		return -1;
	}
	if (data[len - 1] != '\r' && data[len - 1] != '\n') {
		if (claws_fputc('\n', fp) == EOF) {
			FILE_OP_ERROR(file, "claws_fputc");
			g_warning("can't write to file: %s", file);
			claws_fclose(fp);
			claws_unlink(file);
			return -1;
		}
	}

	if (claws_safe_fclose(fp) == EOF) {
		FILE_OP_ERROR(file, "claws_fclose");
		claws_unlink(file);
		return -1;
	}

	return 0;
}

static Pop3State pop3_lookup_next(Pop3Session *session)
{
	Pop3MsgInfo *msg;
	PrefsAccount *ac = session->ac_prefs;
	gint size;
	gboolean size_limit_over;

	for (;;) {
		msg = &session->msg[session->cur_msg];
		size = msg->size;
		size_limit_over =
		    (ac->enable_size_limit &&
		     ac->size_limit > 0 &&
		     size > ac->size_limit * 1024);

		if (ac->rmmail &&
		    msg->recv_time != RECV_TIME_NONE &&
		    msg->recv_time != RECV_TIME_KEEP &&
		    msg->partial_recv == POP3_TOTALLY_RECEIVED &&
		    session->current_time - msg->recv_time >=
		    ((ac->msg_leave_time * 24 * 60 * 60) +
		     (ac->msg_leave_hour * 60 * 60))) {
			log_message(LOG_PROTOCOL,
					_("POP: Deleting expired message %d [%s]\n"),
					session->cur_msg, msg->uidl?msg->uidl:" ");
			session->cur_total_bytes += size;
			pop3_delete_send(session);
			return POP3_DELETE;
		}

		if (size_limit_over) {
			if (!msg->received && msg->partial_recv !=
			    POP3_MUST_COMPLETE_RECV) {
				pop3_top_send(session, ac->size_limit);
				return POP3_TOP;
			} else if (msg->partial_recv == POP3_MUST_COMPLETE_RECV)
				break;

			log_message(LOG_PROTOCOL,
					_("POP: Skipping message %d [%s] (%d bytes)\n"),
					session->cur_msg, msg->uidl?msg->uidl:" ", size);
		}

		if (size == 0 || msg->received || size_limit_over) {
			session->cur_total_bytes += size;
			if (session->cur_msg == session->count) {
				pop3_logout_send(session);
				return POP3_LOGOUT;
			} else
				session->cur_msg++;
		} else
			break;
	}

	pop3_retr_send(session);
	return POP3_RETR;
}

static Pop3ErrorValue pop3_ok(Pop3Session *session, const gchar *msg)
{
	Pop3ErrorValue ok;

	log_print(LOG_PROTOCOL, "POP< %s\n", msg);

	/* exchange replies '+' in response to first line of auth xoauth */
	if (!strncmp(msg, "+OK", 3) || !strncmp(msg, "+", 1))
		ok = PS_SUCCESS;
	else if (!strncmp(msg, "-ERR", 4)) {
		if (strstr(msg + 4, "lock") ||
		    strstr(msg + 4, "Lock") ||
		    strstr(msg + 4, "LOCK") ||
		    strstr(msg + 4, "wait")) {
			log_error(LOG_PROTOCOL, _("mailbox is locked\n"));
			ok = PS_LOCKBUSY;
		} else if (strcasestr(msg + 4, "timeout")) {
			log_error(LOG_PROTOCOL, _("Session timeout\n"));
			ok = PS_ERROR;
		} else {
			switch (session->state) {
#ifdef USE_GNUTLS
			case POP3_STLS:
				log_error(LOG_PROTOCOL, _("couldn't start STARTTLS session\n"));
				ok = PS_ERROR;
				break;
#endif
			case POP3_GETAUTH_USER:
			case POP3_GETAUTH_PASS:
			case POP3_GETAUTH_APOP:
				log_error(LOG_PROTOCOL, _("error occurred on authentication\n"));
				ok = PS_AUTHFAIL;
				break;
			case POP3_GETRANGE_LAST:
			case POP3_GETRANGE_UIDL:
			case POP3_TOP:
				log_warning(LOG_PROTOCOL, _("command not supported\n"));
				ok = PS_NOTSUPPORTED;
				break;

			default:
				log_error(LOG_PROTOCOL, _("error occurred on POP session\n"));
				ok = PS_ERROR;
			}
		}

		g_free(session->error_msg);
		session->error_msg = g_strdup(msg);
		g_printerr("POP: %s\n", msg);
	} else
		ok = PS_PROTOCOL;

	session->error_val = ok;
	return ok;
}

static gint pop3_session_recv_msg(Session *session, const gchar *msg)
{
	Pop3Session *pop3_session = POP3_SESSION(session);
	Pop3ErrorValue val = PS_SUCCESS;
	const gchar *body;

	body = msg;
	if (pop3_session->state != POP3_GETRANGE_UIDL_RECV &&
	    pop3_session->state != POP3_GETSIZE_LIST_RECV) {
		val = pop3_ok(pop3_session, msg);
		if (val != PS_SUCCESS) {
			if (val != PS_NOTSUPPORTED) {
				pop3_session->state = POP3_ERROR;
				return -1;
			}
		}

		if (*body == '+' || *body == '-')
			body++;
		while (g_ascii_isalpha(*body))
			body++;
		while (g_ascii_isspace(*body))
			body++;
	}

	switch (pop3_session->state) {
	case POP3_READY:
	case POP3_GREETING:
		pop3_greeting_recv(pop3_session, body);
#ifdef USE_GNUTLS
		if (pop3_session->ac_prefs->ssl_pop == SSL_STARTTLS)
			val = pop3_stls_send(pop3_session);
		else
#endif
#ifdef USE_OAUTH2
		if (pop3_session->ac_prefs->use_pop_auth && pop3_session->ac_prefs->pop_auth_type == POPAUTH_OAUTH2)
			val = pop3_getauth_oauth2_send(pop3_session);
		else
#endif
		if (pop3_session->ac_prefs->use_pop_auth && pop3_session->ac_prefs->pop_auth_type == POPAUTH_APOP)
			val = pop3_getauth_apop_send(pop3_session);
		else
			val = pop3_getauth_user_send(pop3_session);
		break;
#ifdef USE_GNUTLS
	case POP3_STLS:
		if (pop3_stls_recv(pop3_session) != PS_SUCCESS)
			return -1;
		if (pop3_session->ac_prefs->use_pop_auth && pop3_session->ac_prefs->pop_auth_type == POPAUTH_APOP)
			val = pop3_getauth_apop_send(pop3_session);
#ifdef USE_OAUTH2
		else if (pop3_session->ac_prefs->use_pop_auth && pop3_session->ac_prefs->pop_auth_type == POPAUTH_OAUTH2)
			val = pop3_getauth_oauth2_send(pop3_session);
#endif
		else
			val = pop3_getauth_user_send(pop3_session);
		break;
#endif
	case POP3_GETAUTH_USER:
		val = pop3_getauth_pass_send(pop3_session);
		break;
#ifdef USE_OAUTH2
	case POP3_GETAUTH_USER_PHASE2:
		val = pop3_getauth_oauth2_send_microsoft_2(pop3_session);
		break;
#endif
	case POP3_GETAUTH_PASS:
	case POP3_GETAUTH_APOP:
#ifdef USE_OAUTH2
	case POP3_GETAUTH_OAUTH2:
#endif
		if (!pop3_session->pop_before_smtp)
			val = pop3_getrange_stat_send(pop3_session);
		else
			val = pop3_logout_send(pop3_session);
		break;
	case POP3_GETRANGE_STAT:
		if (pop3_getrange_stat_recv(pop3_session, body) < 0)
			return -1;
		if (pop3_session->count > 0)
			val = pop3_getrange_uidl_send(pop3_session);
		else
			val = pop3_logout_send(pop3_session);
		break;
	case POP3_GETRANGE_LAST:
		if (val == PS_NOTSUPPORTED)
			pop3_session->error_val = PS_SUCCESS;
		else if (pop3_getrange_last_recv(pop3_session, body) < 0)
			return -1;
		if (pop3_session->cur_msg > 0)
			val = pop3_getsize_list_send(pop3_session);
		else
			val = pop3_logout_send(pop3_session);
		break;
	case POP3_GETRANGE_UIDL:
		if (val == PS_NOTSUPPORTED) {
			pop3_session->error_val = PS_SUCCESS;
			val = pop3_getrange_last_send(pop3_session);
		} else {
			pop3_session->state = POP3_GETRANGE_UIDL_RECV;
			session_recv_data(session, 0, ".\r\n");
		}
		break;
	case POP3_GETSIZE_LIST:
		pop3_session->state = POP3_GETSIZE_LIST_RECV;
		session_recv_data(session, 0, ".\r\n");
		break;
	case POP3_RETR:
		pop3_session->state = POP3_RETR_RECV;
		session_recv_data(session, 0, ".\r\n");
		break;
	case POP3_TOP:
		if (val == PS_NOTSUPPORTED) {
			pop3_session->error_val = PS_SUCCESS;
		} else {
			pop3_session->state = POP3_TOP_RECV;
			session_recv_data(session, 0, ".\r\n");
		}
		break;
	case POP3_DELETE:
		pop3_delete_recv(pop3_session);
		if (pop3_session->cur_msg == pop3_session->count)
			val = pop3_logout_send(pop3_session);
		else {
			pop3_session->cur_msg++;
			if (pop3_lookup_next(pop3_session) == POP3_ERROR)
				return -1;
		}
		break;
	case POP3_LOGOUT:
		pop3_session->state = POP3_DONE;
		session_disconnect(session);
		break;
	case POP3_ERROR:
	default:
		return -1;
	}

	return val == PS_SUCCESS?0:-1;
}

static gint pop3_session_recv_data_finished(Session *session, guchar *data,
					    guint len)
{
	Pop3Session *pop3_session = POP3_SESSION(session);
	Pop3ErrorValue val = PS_SUCCESS;

	switch (pop3_session->state) {
	case POP3_GETRANGE_UIDL_RECV:
		val = pop3_getrange_uidl_recv(pop3_session, data, len);
		if (val == PS_SUCCESS) {
			if (pop3_session->new_msg_exist)
				pop3_getsize_list_send(pop3_session);
			else
				pop3_logout_send(pop3_session);
		} else
			return -1;
		break;
	case POP3_GETSIZE_LIST_RECV:
		val = pop3_getsize_list_recv(pop3_session, data, len);
		if (val == PS_SUCCESS) {
			if (pop3_lookup_next(pop3_session) == POP3_ERROR)
				return -1;
		} else
			return -1;
		break;
	case POP3_RETR_RECV:
		if (pop3_retr_recv(pop3_session, data, len) < 0)
			return -1;

		if (pop3_session->ac_prefs->rmmail &&
		    pop3_session->ac_prefs->msg_leave_time == 0 &&
		    pop3_session->ac_prefs->msg_leave_hour == 0 &&
		    pop3_session->msg[pop3_session->cur_msg].recv_time
		    != RECV_TIME_KEEP)
			pop3_delete_send(pop3_session);
		else if (pop3_session->cur_msg == pop3_session->count)
			pop3_logout_send(pop3_session);
		else {
			pop3_session->cur_msg++;
			if (pop3_lookup_next(pop3_session) == POP3_ERROR)
				return -1;
		}
		break;
	case POP3_TOP_RECV:
		if (pop3_top_recv(pop3_session, data, len) < 0)
			return -1;

		if (pop3_session->cur_msg == pop3_session->count)
			pop3_logout_send(pop3_session);
		else {
			pop3_session->cur_msg++;
			if (pop3_lookup_next(pop3_session) == POP3_ERROR)
				return -1;
		}
		break;
	case POP3_TOP:
		log_warning(LOG_PROTOCOL, _("TOP command unsupported\n"));
		if (pop3_session->cur_msg == pop3_session->count)
			pop3_logout_send(pop3_session);
		else {
			pop3_session->cur_msg++;
			if (pop3_lookup_next(pop3_session) == POP3_ERROR)
				return -1;
		}
		break;
	case POP3_ERROR:
	default:
		return -1;
	}

	return 0;
}