/*
** Copyright (C) 2011-2017 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
**
** 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, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**
*/
#include <string.h>
#include <ctype.h>

#include "mu-str.h"
#include "mu-msg.h"
#include "mu-msg-iter.h"
#include "mu-msg-part.h"
#include "mu-maildir.h"

static void
append_sexp_attr_list (GString *gstr, const char* elm, const GSList *lst)
{
	const GSList *cur;

	if (!lst)
		return; /* empty list, don't include */

	g_string_append_printf (gstr, "\t:%s ( ", elm);

	for (cur = lst; cur; cur = g_slist_next(cur)) {
		char *str;
		str = mu_str_escape_c_literal
			((const gchar*)cur->data, TRUE);
		g_string_append_printf (gstr, "%s ", str);
		g_free (str);
	}

	g_string_append (gstr, ")\n");
}

static void
append_sexp_attr (GString *gstr, const char* elm, const char *str)
{
	gchar *esc, *utf8, *cur;

	if (!str || strlen(str) == 0)
		return; /* empty: don't include */


	utf8 = mu_str_utf8ify (str);

	for (cur = utf8; *cur; ++cur)
		if (iscntrl(*cur))
			*cur = ' ';

	esc = mu_str_escape_c_literal (utf8, TRUE);
	g_free (utf8);

	g_string_append_printf (gstr, "\t:%s %s\n", elm, esc);
	g_free (esc);
}

static void
append_sexp_body_attr (GString *gstr, const char* elm, const char *str)
{
	gchar *esc;

	if (!str || strlen(str) == 0)
		return; /* empty: don't include */

	esc = mu_str_escape_c_literal (str, TRUE);

	g_string_append_printf (gstr, "\t:%s %s\n", elm, esc);
	g_free (esc);
}

struct _ContactData {
	gboolean from, to, cc, bcc, reply_to;
	GString *gstr;
	MuMsgContactType prev_ctype;
};
typedef struct _ContactData ContactData;

static gchar*
get_name_email_pair (MuMsgContact *c)
{
	gchar *name, *email, *pair;

	name  = (char*)mu_msg_contact_name(c);
	email = (char*)mu_msg_contact_email(c);

	name  = name ? mu_str_escape_c_literal (name, TRUE) : NULL;
	email = email ? mu_str_escape_c_literal (email, TRUE) : NULL;

	pair = g_strdup_printf ("(%s . %s)",
				name ? name : "nil",
				email ? email : "nil");
	g_free (name);
	g_free (email);

	return pair;
}


static void
add_prefix_maybe (GString *gstr, gboolean *field, const char *prefix)
{
	/* if there's nothing in the field yet, add the prefix */
	if (!*field)
		g_string_append (gstr, prefix);

	*field = TRUE;
}

static gboolean
each_contact (MuMsgContact *c, ContactData *cdata)
{
	char *pair;
	MuMsgContactType ctype;

	ctype = mu_msg_contact_type (c);

	/* if the current type is not the previous type, close the
	 * previous first */
	if (cdata->prev_ctype != ctype && cdata->prev_ctype != (unsigned)-1)
		g_string_append (cdata->gstr, ")\n");

	switch (ctype) {

	case MU_MSG_CONTACT_TYPE_FROM:
		add_prefix_maybe (cdata->gstr, &cdata->from, "\t:from (");
		break;
	case MU_MSG_CONTACT_TYPE_TO:
		add_prefix_maybe (cdata->gstr, &cdata->to, "\t:to (");
		break;
	case MU_MSG_CONTACT_TYPE_CC:
		add_prefix_maybe (cdata->gstr, &cdata->cc, "\t:cc (");
		break;
	case MU_MSG_CONTACT_TYPE_BCC:
		add_prefix_maybe (cdata->gstr, &cdata->bcc, "\t:bcc (");
		break;
	case MU_MSG_CONTACT_TYPE_REPLY_TO:
		add_prefix_maybe (cdata->gstr, &cdata->reply_to,
				  "\t:reply-to (");
		break;
	default: g_return_val_if_reached (FALSE);
	}

	cdata->prev_ctype = ctype;

	pair = get_name_email_pair (c);
	g_string_append (cdata->gstr, pair);
	g_free (pair);

	return TRUE;
}


static void
maybe_append_list_post_as_reply_to (GString *gstr, MuMsg *msg)
{
	/* some mailing lists do not set the reply-to; see pull #1278. So for
	 * those cases, check the List-Post address and use that instead */

	GMatchInfo	*minfo;
	GRegex		*rx;
	const char*	 list_post;

	list_post = mu_msg_get_header (msg, "List-Post");
	if (!list_post)
		return;

	rx = g_regex_new ("^(<?mailto:)?([a-z0-9%+@.-]+)>?", G_REGEX_CASELESS, 0, NULL);
	g_return_if_fail(rx);

	if (g_regex_match (rx, list_post, 0, &minfo)) {
		char	*addr;
		addr = g_match_info_fetch (minfo, 2);
		g_string_append_printf (gstr,"\t:reply-to ((nil . \"%s\"))\n", addr);
		g_free(addr);
	}

	g_match_info_free (minfo);
	g_regex_unref (rx);
}



static void
append_sexp_contacts (GString *gstr, MuMsg *msg)
{
	ContactData cdata;

	cdata.from	 = cdata.to = cdata.cc = cdata.bcc
			 = cdata.reply_to = FALSE;
	cdata.gstr	 = gstr;
	cdata.prev_ctype = (unsigned)-1;

	mu_msg_contact_foreach (msg, (MuMsgContactForeachFunc)each_contact,
				&cdata);
	if (cdata.from || cdata.to || cdata.cc || cdata.bcc || cdata.reply_to)
		gstr = g_string_append (gstr, ")\n");

	if (!cdata.reply_to)
		maybe_append_list_post_as_reply_to (gstr, msg);
}

struct _FlagData {
	char *flagstr;
	MuFlags msgflags;
};
typedef struct _FlagData FlagData;

static void
each_flag (MuFlags flag, FlagData *fdata)
{
	if (!(flag & fdata->msgflags))
		return;

	if (!fdata->flagstr)
		fdata->flagstr = g_strdup (mu_flag_name(flag));
	else {
		gchar *tmp;
		tmp = g_strconcat (fdata->flagstr, " ",
				   mu_flag_name(flag), NULL);
		g_free (fdata->flagstr);
		fdata->flagstr = tmp;
	}
}

static void
append_sexp_flags (GString *gstr, MuMsg *msg)
{
	FlagData fdata;

	fdata.msgflags = mu_msg_get_flags (msg);
	fdata.flagstr  = NULL;

	mu_flags_foreach ((MuFlagsForeachFunc)each_flag, &fdata);
	if (fdata.flagstr)
		g_string_append_printf (gstr, "\t:flags (%s)\n",
					fdata.flagstr);
	g_free (fdata.flagstr);
}

static char*
get_temp_file (MuMsg *msg, MuMsgOptions opts, unsigned index)
{
	char *path;
	GError *err;

	err = NULL;
	path = mu_msg_part_get_cache_path (msg, opts, index, &err);
	if (!path)
		goto errexit;

	if (!mu_msg_part_save (msg, opts, path, index, &err))
		goto errexit;

	return path;

errexit:
	g_warning ("failed to save mime part: %s",
		   err->message ? err->message : "something went wrong");
	g_clear_error (&err);
	g_free (path);
	return NULL;
}


static gchar*
get_temp_file_maybe (MuMsg *msg, MuMsgPart *part, MuMsgOptions opts)
{
	char *tmp, *tmpfile;

	opts |= MU_MSG_OPTION_USE_EXISTING;

	if  (!(opts & MU_MSG_OPTION_EXTRACT_IMAGES) ||
	     g_ascii_strcasecmp (part->type, "image") != 0)
		return NULL;

	tmp = get_temp_file (msg, opts, part->index);
	if (!tmp)
		return NULL;

	tmpfile = mu_str_escape_c_literal (tmp, TRUE);
	g_free (tmp);
	return tmpfile;
}


struct _PartInfo {
	char        *parts;
	MuMsgOptions opts;
};
typedef struct _PartInfo PartInfo;

static char*
sig_verdict (MuMsgPart *mpart)
{
	char				*signers, *s;
	const char			*verdict;
	MuMsgPartSigStatusReport	*report;

	report = mpart->sig_status_report;
	if (!report)
		return g_strdup ("");

	switch (report->verdict) {
	case MU_MSG_PART_SIG_STATUS_GOOD:
		verdict = ":signature verified";
		break;
	case MU_MSG_PART_SIG_STATUS_BAD:
		verdict = ":signature bad";
		break;
	case MU_MSG_PART_SIG_STATUS_ERROR:
		verdict = ":signature unverified";
		break;
	default:
		verdict = "";
		break;
	}

	if (!report->signers)
		return g_strdup (verdict);

	signers = mu_str_escape_c_literal (report->signers, TRUE);
	s	= g_strdup_printf ("%s :signers %s", verdict, signers);
	g_free (signers);

	return s;
}

static const char*
dec_verdict (MuMsgPart *mpart)
{
	MuMsgPartType ptype;

	ptype = mpart->part_type;

	if (ptype & MU_MSG_PART_TYPE_DECRYPTED)
		return ":decryption succeeded";
	else if (ptype & MU_MSG_PART_TYPE_ENCRYPTED)
		return ":decryption failed";
	else
		return "";
}


static gchar *
get_part_type_string (MuMsgPartType ptype)
{
	GString *gstr;
	unsigned u;
	struct PartTypes {
		MuMsgPartType ptype;
		const char* name;
	} ptypes[] = {
		{ MU_MSG_PART_TYPE_LEAF,       "leaf" },
		{ MU_MSG_PART_TYPE_MESSAGE,    "message" },
		{ MU_MSG_PART_TYPE_INLINE,     "inline" },
		{ MU_MSG_PART_TYPE_ATTACHMENT, "attachment" },
		{ MU_MSG_PART_TYPE_SIGNED,     "signed" },
		{ MU_MSG_PART_TYPE_ENCRYPTED,  "encrypted" }
	};

	gstr = g_string_sized_new (100); /* more than enough */
	gstr = g_string_append_c (gstr, '(');

	for (u = 0; u!= G_N_ELEMENTS(ptypes); ++u) {
		if (ptype & ptypes[u].ptype) {
			if (gstr->len > 1)
				gstr = g_string_append_c (gstr, ' ');
			gstr = g_string_append (gstr, ptypes[u].name);
		}
	}

	gstr = g_string_append_c (gstr, ')');

	return g_string_free (gstr, FALSE);
}


static void
each_part (MuMsg *msg, MuMsgPart *part, PartInfo *pinfo)
{
	char		*name, *encname, *tmp, *parttype;
	char		*tmpfile, *cidesc, *verdict;
	const char	*cid;

	name     = mu_msg_part_get_filename (part, TRUE);
	encname  = name ?
		mu_str_escape_c_literal(name, TRUE) :
		g_strdup("\"noname\"");
	g_free (name);

	tmpfile  = get_temp_file_maybe (msg, part, pinfo->opts);
	parttype = get_part_type_string (part->part_type);
	verdict  = sig_verdict (part);

	cid    = mu_msg_part_get_content_id(part);
	cidesc = cid ? mu_str_escape_c_literal(cid, TRUE) : NULL;

	tmp = g_strdup_printf
		("%s(:index %d :name %s :mime-type \"%s/%s\"%s%s "
		 ":type %s "
		 ":attachment %s %s%s :size %i %s %s)",
		 pinfo->parts ? pinfo->parts: "",
		 part->index,
		 encname,
		 part->type ? part->type : "application",
		 part->subtype ? part->subtype : "octet-stream",
		 tmpfile ? " :temp" : "", tmpfile ? tmpfile : "",
		 parttype,
		 mu_msg_part_maybe_attachment (part) ? "t" : "nil",
		 cidesc ? " :cid" : "", cidesc ? cidesc : "",
		 (int)part->size,
		 verdict,
		 dec_verdict (part));

	g_free (encname);
	g_free (tmpfile);
	g_free (parttype);
	g_free (verdict);
	g_free (cidesc);

	g_free (pinfo->parts);
	pinfo->parts = tmp;
}


static void
append_sexp_parts (GString *gstr, MuMsg *msg, MuMsgOptions opts)
{
	PartInfo pinfo;

	pinfo.parts = NULL;
	pinfo.opts  = opts;

	if (!mu_msg_part_foreach (msg, opts, (MuMsgPartForeachFunc)each_part,
				  &pinfo)) {
		/* do nothing */
	} else if (pinfo.parts) {
		g_string_append_printf (gstr, "\t:parts (%s)\n", pinfo.parts);
		g_free (pinfo.parts);
	}
}

static void
append_sexp_thread_info (GString *gstr, const MuMsgIterThreadInfo *ti)
{
	g_string_append_printf
		(gstr, "\t:thread (:path \"%s\" :level %u%s%s%s%s%s)\n",
		 ti->threadpath,
		 ti->level,
		 ti->prop & MU_MSG_ITER_THREAD_PROP_FIRST_CHILD  ?
		 " :first-child t" : "",
		 ti->prop & MU_MSG_ITER_THREAD_PROP_LAST_CHILD   ?
		 " :last-child t" : "",
		 ti->prop & MU_MSG_ITER_THREAD_PROP_EMPTY_PARENT ?
		 " :empty-parent t" : "",
		 ti->prop & MU_MSG_ITER_THREAD_PROP_DUP          ?
		 " :duplicate t" : "",
		 ti->prop & MU_MSG_ITER_THREAD_PROP_HAS_CHILD    ?
		 " :has-child t" : "");
}

static void
append_sexp_param (GString *gstr, const GSList *param)
{
	for (;param; param = g_slist_next (param)) {
		const char *str;
		char *key, *value;

		str   = param->data;
		key   = str ? mu_str_escape_c_literal (str, FALSE) : g_strdup ("");

		param = g_slist_next (param);
		str   = param->data;
		value = str ? mu_str_escape_c_literal (str, FALSE) : g_strdup ("");

		g_string_append_printf (gstr, "(\"%s\" . \"%s\")", key, value);
		g_free (key);
		g_free (value);

		if (param->next)
			g_string_append_c (gstr, ' ');
	}
}

static void
append_message_file_parts (GString *gstr, MuMsg *msg, MuMsgOptions opts)
{
	const char	*str;
	GError		*err;
	const GSList    *params;

	err = NULL;

	if (!mu_msg_load_msg_file (msg, &err)) {
		g_warning ("failed to load message file: %s",
			   err ? err->message : "some error occurred");
		g_clear_error (&err);
		return;
	}

	append_sexp_parts (gstr, msg, opts);
	append_sexp_contacts (gstr, msg);

	/* add the user-agent / x-mailer */
	str = mu_msg_get_header (msg, "User-Agent");
	if (str || (str = mu_msg_get_header (msg, "X-Mailer")))
		append_sexp_attr (gstr, "user-agent", str);

	params = mu_msg_get_body_text_content_type_parameters (msg, opts);
	if (params) {
		g_string_append_printf (gstr, "\t:body-txt-params (");
		append_sexp_param (gstr, params);
		g_string_append_printf (gstr, ")\n");
	}

	append_sexp_body_attr (gstr, "body-txt",
			  mu_msg_get_body_text(msg, opts));
	append_sexp_body_attr (gstr, "body-html",
			  mu_msg_get_body_html(msg, opts));
}

static void
append_sexp_date_and_size (GString *gstr, MuMsg *msg)
{
	time_t t;
	size_t s;

	t = mu_msg_get_date (msg);
	if (t == (time_t)-1)  /* invalid date? */
		t = 0;

	s = mu_msg_get_size (msg);
	if (s == (size_t)-1)   /* invalid size? */
		s = 0;

	g_string_append_printf
		(gstr,
		 "\t:date (%d %u 0)\n\t:size %u\n",
		 (unsigned)(t >> 16),
		 (unsigned)(t & 0xffff),
		 (unsigned)s);
}


static void
append_sexp_tags (GString *gstr, MuMsg *msg)
{
	const GSList *tags, *t;
	gchar *tagesc;
	GString *tagstr = g_string_new("");

	tags = mu_msg_get_tags (msg);

	for(t = tags; t; t = t->next) {
		if (t != tags)
			g_string_append(tagstr, " ");

		tagesc = mu_str_escape_c_literal((const gchar *)t->data, TRUE);
		g_string_append(tagstr, tagesc);

		g_free(tagesc);
	}

	if (tagstr->len > 0)
		g_string_append_printf (gstr, "\t:tags (%s)\n",
					tagstr->str);
	g_string_free (tagstr, TRUE);
}

char*
mu_msg_to_sexp (MuMsg *msg, unsigned docid, const MuMsgIterThreadInfo *ti,
		MuMsgOptions opts)
{
	GString *gstr;

	g_return_val_if_fail (msg, NULL);
	g_return_val_if_fail (!((opts & MU_MSG_OPTION_HEADERS_ONLY) &&
				(opts & MU_MSG_OPTION_EXTRACT_IMAGES)),NULL);
	gstr = g_string_sized_new
		((opts & MU_MSG_OPTION_HEADERS_ONLY) ?  1024 : 8192);

	if (docid == 0)
		g_string_append (gstr, "(\n");
	else
		g_string_append_printf (gstr, "(\n\t:docid %u\n", docid);

	if (ti)
		append_sexp_thread_info (gstr, ti);

	append_sexp_attr (gstr, "subject", mu_msg_get_subject (msg));

	/* in the no-headers-only case (see below) we get a more complete list
	 * of contacts, so no need to get them here if that's the case */
	if (opts & MU_MSG_OPTION_HEADERS_ONLY)
		append_sexp_contacts (gstr, msg);

	append_sexp_date_and_size (gstr, msg);

	append_sexp_attr (gstr, "message-id", mu_msg_get_msgid (msg));
	append_sexp_attr (gstr, "mailing-list",
			  mu_msg_get_mailing_list (msg));
	append_sexp_attr (gstr, "path",	 mu_msg_get_path (msg));
	append_sexp_attr (gstr, "maildir", mu_msg_get_maildir (msg));
	g_string_append_printf (gstr, "\t:priority %s\n",
				mu_msg_prio_name(mu_msg_get_prio(msg)));
	append_sexp_flags (gstr, msg);
	append_sexp_tags  (gstr, msg);

	append_sexp_attr_list (gstr, "references",
			       mu_msg_get_references (msg));
	append_sexp_attr (gstr, "in-reply-to",
			  mu_msg_get_header (msg, "In-Reply-To"));

	/* headers are retrieved from the database, views from the
	 * message file file attr things can only be gotten from the
	 * file (ie., mu view), not from the database (mu find).  */
	if (!(opts & MU_MSG_OPTION_HEADERS_ONLY))
		append_message_file_parts (gstr, msg, opts);

	g_string_append (gstr, ")\n");
	return g_string_free (gstr, FALSE);
}