/*  MasqMail
    Copyright (C) 1999-2001 Oliver Kurth
    Copyright (C) 2010 markus schnalke <meillo@marmaro.de>

    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
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#include "masqmail.h"
#include "readsock.h"

/* must match PROT_* in masqmail.h */
gchar *prot_names[] = {
	"local",
	"SMTP",
	"ESMTP",
	"(unknown)"  /* should not happen, but better than crashing. */
};

static gchar*
string_base62(gchar * res, guint value, gchar len)
{
	static gchar base62_chars[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
	gchar *p = res + len;
	*p = '\0';
	while (p > res) {
		*(--p) = base62_chars[value % 62];
		value /= 62;
	}
	return res;
}

static gint
_g_list_addr_isequal(gconstpointer a, gconstpointer b)
{
	address *addr1 = (address *) a;
	address *addr2 = (address *) b;
	int ret;

	if ((ret = strcasecmp(addr1->domain, addr2->domain)) == 0) {
		return strcmp(addr1->local_part, addr2->local_part);
	}
	return ret;
}

/* accept message from anywhere.
   A message from local is indicated by msg->recieved_host == NULL

   The -t option: With the ACC_RCPT_FROM_HEAD flag the addrs found found
   in To/Cc/Bcc headers are added to the recipient list.
*/

accept_error
accept_message_stream(FILE * in, message * msg, guint flags)
{
	gchar *line, *line1;
	int line_size = MAX_DATALINE;
	gboolean in_headers = TRUE;
	header *hdr = NULL;
	gint line_cnt = 0, data_size = 0;

	line = g_malloc(line_size);
	line[0] = '\0';

	while (TRUE) {
		int len = read_sockline1(in, &line, &line_size, 5 * 60, READSOCKL_CVT_CRLF);

		line1 = line;

		if ((line[0] == '.') && (!(flags & ACC_DOT_IGNORE))) {
			if (line[1] == '\n') {
				g_free(line);
				break;
			}
			line1++;
		}

		if ((len == -1) && (flags & (ACC_DOT_IGNORE | ACC_NODOT_RELAX))) {
			/* we got an EOF, and the last line was not terminated by a CR */
			gint len1 = strlen(line1);
			if (len1 > 0) {  /* == 0 is 'normal' (EOF after a CR) */
				if (line1[len1 - 1] != '\n') {  /* some mail clients allow unterminated lines */
					line1[len1] = '\n';
					line1[len1 + 1] = '\0';
					msg->data_list = g_list_prepend(msg->data_list, g_strdup(line1));
					data_size += strlen(line1);
					line_cnt++;
				}
			}
			break;

		} else if (len == -1) {
			g_free(line);
			return AERR_EOF;

		} else if (len == -2) {
			/* should not happen any more */
			g_free(line);
			return AERR_OVERFLOW;

		} else if (len == -3) {
			g_free(line);
			return AERR_TIMEOUT;

		} else if (len <= 0) {
			/* does not happen */
			g_free(line);
			DEBUG(5) debugf("read_sockline returned %d\n", len);
			return AERR_UNKNOWN;

		}

		if (in_headers) {

			/* some pop servers send the 'From ' line, skip it: */
			if (!msg->hdr_list && strncmp(line1, "From ", 5) == 0) {
				continue;
			}

			if (line1[0] == ' ' || line1[0] == '\t') {
				/* continuation of 'folded' header: */
				if (hdr) {
					char* cp;
					cp = g_strconcat(hdr->header, line1, NULL);
					hdr->value = cp + (hdr->value - hdr->header);
					free(hdr->header);
					hdr->header = cp;
				}

			} else if (line1[0] == '\n') {
				/* an empty line marks end of headers */
				in_headers = FALSE;
			} else {
				/* in all other cases we expect another header */
				if ((hdr = get_header(line1))) {
					msg->hdr_list = g_list_append(msg->hdr_list, hdr);
				} else {
					/* if get_header() returns NULL, no header was recognized,
					   so this seems to be the first data line of a broken mailer
					   which does not send an empty line after the headers */
					in_headers = FALSE;
					msg->data_list = g_list_prepend(msg->data_list, g_strdup(line1));
				}
			}
		} else {
			/* message body */
			msg->data_list = g_list_prepend(msg->data_list, g_strdup(line1));
			data_size += strlen(line1);
			line_cnt++;
		}

		if (conf.max_msg_size && (data_size > conf.max_msg_size)) {
			DEBUG(4) debugf("accept_message_stream(): "
					"received %d bytes (conf.max_msg_size=%d)\n",
			                data_size, conf.max_msg_size);
			return AERR_SIZE;
		}

	}

	DEBUG(4) debugf("received %d lines of data (%d bytes)\n", line_cnt, data_size);

	if (!msg->data_list) {
		/* make sure data list is not NULL: */
		msg->data_list = g_list_append(NULL, g_strdup(""));
	}
	msg->data_list = g_list_reverse(msg->data_list);

	/* we get here after we succesfully received the mail data */

	msg->data_size = data_size;
	msg->received_time = time(NULL);

	return AERR_OK;
}

accept_error
accept_message_prepare(message * msg, guint flags)
{
	struct passwd *passwd = NULL;
	time_t rec_time = time(NULL);

	DEBUG(5) debugf("accept_message_prepare()\n");

	/* create unique message id */
	msg->uid = g_malloc(14);
	string_base62(msg->uid, rec_time, 6);
	msg->uid[6] = '-';
	string_base62(msg->uid + 7, getpid(), 3);
	msg->uid[10] = '-';
	string_base62(msg->uid + 11, msg->transfer_id, 2);
	msg->uid[13] = '\0';

	/* if local, get password entry and set return path if missing */
	if (!msg->received_host) {
		passwd = g_memdup(getpwuid(geteuid()), sizeof(struct passwd));
		msg->ident = g_strdup(passwd->pw_name);
		if (!msg->return_path) {
			gchar *path = g_strdup_printf("<%s@%s>", passwd->pw_name, conf.host_name);
			DEBUG(3) debugf("setting return_path for local accept: %s\n", path);
			msg->return_path = create_address(path, TRUE);
			g_free(path);
		}
	}

	/* scan headers */
	{
		gboolean has_id = FALSE;
		gboolean has_date = FALSE;
		gboolean has_sender = FALSE;
		gboolean has_from = FALSE;
		gboolean has_to_or_cc = FALSE;
		GList *hdr_node, *hdr_node_next;
		header *hdr;

		for (hdr_node = g_list_first(msg->hdr_list);
		     hdr_node;
		     hdr_node = hdr_node_next) {
			hdr_node_next = g_list_next(hdr_node);
			hdr = ((header *) (hdr_node->data));
			DEBUG(5) debugf("scanning headers: %s", hdr->header);
			switch (hdr->id) {
			case HEAD_MESSAGE_ID:
				has_id = TRUE;
				break;
			case HEAD_DATE:
				has_date = TRUE;
				break;
			case HEAD_FROM:
				has_from = TRUE;
				break;
			case HEAD_SENDER:
				has_sender = TRUE;
				break;
			case HEAD_TO:
			case HEAD_CC:
				has_to_or_cc = TRUE;
				/* fall through */
			case HEAD_BCC:
				if (flags & ACC_RCPT_FROM_HEAD) {
					/* -t option (see comment above) */
					DEBUG(5) debugf("hdr->value = %s\n", hdr->value);
					if (hdr->value) {
						msg->rcpt_list = addr_list_append_rfc822(msg->rcpt_list, hdr->value, conf.host_name);
					}
				}
				if (hdr->id == HEAD_BCC) {
					DEBUG(3) debugf("removing 'Bcc' header\n");
					msg->hdr_list = g_list_remove_link(msg->hdr_list, hdr_node);
					g_list_free_1(hdr_node);
					destroy_header(hdr);
				}
				break;
			case HEAD_ENVELOPE_TO:
				if (flags & ACC_SAVE_ENVELOPE_TO) {
					DEBUG(3) debugf("creating 'X-Orig-Envelope-To' header\n");
					msg->hdr_list = g_list_prepend(msg->hdr_list, create_header(HEAD_UNKNOWN,
					                               "X-Orig-Envelope-To: %s", hdr->value));
				}
				DEBUG(3) debugf("removing 'Envelope-To' header\n");
				msg->hdr_list = g_list_remove_link(msg->hdr_list, hdr_node);
				g_list_free_1(hdr_node);
				destroy_header(hdr);
				break;
			case HEAD_RETURN_PATH:
				if (flags & ACC_MAIL_FROM_HEAD) {
					/* usually POP3 accept */
					msg->return_path = create_address_qualified(hdr->value, TRUE, msg->received_host);
					DEBUG(3) debugf("setting return_path to %s\n", addr_string(msg->return_path));
				}
				DEBUG(3) debugf("removing 'Return-Path' header\n");
				msg->hdr_list = g_list_remove_link(msg->hdr_list, hdr_node);
				g_list_free_1(hdr_node);
				destroy_header(hdr);
				break;
			default:
				break;  /* make compiler happy */
			}
		}

		if (!msg->return_path) {
			/* TODO: do we still need this as we don't fetch
			         mail anymore? */
			/* this can happen for pop3 accept only and if no
			   Return-Path: header was given */
			GList *hdr_list;
			header *hdr;

			DEBUG(3) debugf("return_path == NULL\n");

			hdr_list = find_header(msg->hdr_list, HEAD_SENDER, NULL);
			if (!hdr_list) {
				hdr_list = find_header(msg->hdr_list, HEAD_FROM, NULL);
			}
			if (hdr_list) {
				gchar *addr;
				hdr = (header *) (g_list_first(hdr_list)->data);

				DEBUG(5) debugf("hdr->value = '%s'\n", hdr->value);

				addr = g_strdup(hdr->value);
				g_strchomp(addr);

				msg->return_path = create_address_qualified(addr, FALSE, msg->received_host);
				if (msg->return_path) {
					DEBUG(3) debugf("setting return_path to %s\n", addr_string(msg->return_path));
					msg->hdr_list = g_list_append( msg->hdr_list, create_header(HEAD_UNKNOWN, "X-Warning: return path set from %s address\n", hdr->id == HEAD_SENDER ? "Sender:" : "From:"));
				}
				g_free(addr);
			}
			if (!msg->return_path) {
				/* no Sender: or From: or
				   create_address_qualified failed */
				msg->return_path = create_address_qualified("postmaster", TRUE, conf.host_name);
				DEBUG(3) debugf("setting return_path to %s\n", addr_string(msg->return_path));
				msg->hdr_list = g_list_append(msg->hdr_list, create_header(HEAD_UNKNOWN, "X-Warning: real return path is unknown\n"));
			}
		}

		/* here we should have our recipients, fail if not: */
		if (!msg->rcpt_list) {
			logwrite(LOG_WARNING, "no recipients found in message\n");
			return AERR_NORCPT;
		}

		if (!has_sender && !has_from) {
			DEBUG(3) debugf("adding 'From:' header\n");
			if (msg->full_sender_name) {
				msg->hdr_list = g_list_append(msg->hdr_list, create_header(HEAD_FROM, "From: \"%s\" <%s@%s>\n", msg->full_sender_name, msg->return_path->local_part, msg->return_path->domain));
			} else {
				msg->hdr_list = g_list_append(msg->hdr_list, create_header(HEAD_FROM, "From: <%s@%s>\n", msg->return_path->local_part, msg->return_path->domain));
			}
		}
		if (!has_to_or_cc) {
			DEBUG(3) debugf("no To: or Cc: header, hence adding `To: undisclosed recipients:;'\n");
			msg->hdr_list = g_list_append(msg->hdr_list, create_header(HEAD_TO, "To: undisclosed-recipients:;\n"));
		}
		if (!has_date) {
			DEBUG(3) debugf("adding 'Date:' header\n");
			msg->hdr_list = g_list_append(msg->hdr_list, create_header(HEAD_DATE, "Date: %s\n", rec_timestamp()));
		}
		if (!has_id) {
			DEBUG(3) debugf("adding 'Message-ID:' header\n");
			msg->hdr_list = g_list_append(msg->hdr_list, create_header(HEAD_MESSAGE_ID, "Message-ID: <%s@%s>\n", msg->uid, conf.host_name));
		}
	}

	/* Received header: */
	/* At this point because we have to know the rcpts for the 'for' part */
	/* The `for' part will only be used if exactly one rcpt is present. */
	gchar *for_string = NULL;
	header *hdr = NULL;

	DEBUG(3) debugf("adding 'Received:' header\n");

	if (g_list_length(msg->rcpt_list) == 1) {
		address *addr = (address *) (g_list_first(msg->rcpt_list)->data);
		for_string = g_strdup_printf("\n\tfor %s", addr_string(addr));
	}

	if (!msg->received_host) {
		/* received locally */
		hdr = create_header(HEAD_RECEIVED,
		    "Received: by %s (%s %s, from userid %d)\n\tid %s%s; %s\n",
		    conf.host_name, PACKAGE, VERSION, geteuid(),
		    msg->uid, for_string ? for_string : "", rec_timestamp());
	} else {
		/* received from remote */
#ifdef ENABLE_IDENT
		DEBUG(5) debugf("adding 'Received:' header (5)\n");
		hdr = create_header(HEAD_RECEIVED,
		    "Received: from %s (ident=%s)\n\tby %s with %s (%s %s)\n\tid %s%s; %s\n",
		    msg->received_host, msg->ident ? msg->ident : "unknown",
		    conf.host_name, prot_names[msg->received_prot], PACKAGE,
		    VERSION, msg->uid, for_string ? for_string : "",
		    rec_timestamp());
#else
		hdr = create_header(HEAD_RECEIVED,
		    "Received: from %s\n\tby %s with %s (%s %s)\n\tid %s%s; %s\n",
		    msg->received_host, conf.host_name,
		    prot_names[msg->received_prot], PACKAGE, VERSION,
		    msg->uid, for_string ? for_string : "", rec_timestamp());
#endif
	}
	msg->hdr_list = g_list_prepend(msg->hdr_list, hdr);

	if (for_string)
		g_free(for_string);

	return AERR_OK;
}

accept_error
accept_message(FILE * in, message * msg, guint flags)
{
	accept_error err;

	err = accept_message_stream(in, msg, flags);
	if (err == AERR_OK) {
		err = accept_message_prepare(msg, flags);
	}

	return err;
}