/* -*-mode: c++; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8-*- */
/*
** Copyright (C) 2008-2011 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.
**
*/

#if HAVE_CONFIG_H
#include "config.h"
#endif /*HAVE_CONFIG_H*/

#include <cstdio>
#include <xapian.h>
#include <cstring>
#include <stdexcept>

#include "mu-store.h"
#include "mu-store-priv.hh" /* _MuStore */

#include "mu-msg.h"
#include "mu-msg-part.h"
#include "mu-store.h"
#include "mu-util.h"
#include "mu-str.h"
#include "mu-date.h"
#include "mu-flags.h"
#include "mu-contacts.h"

void
_MuStore::begin_transaction ()
{
	try {
		db_writable()->begin_transaction();
			set_in_transaction (true);
	} MU_XAPIAN_CATCH_BLOCK;
}


void
_MuStore::commit_transaction () {
	try {
		set_in_transaction (false);
		db_writable()->commit_transaction();
	} MU_XAPIAN_CATCH_BLOCK;
}

void
_MuStore::rollback_transaction () {
	try {
		set_in_transaction (false);
		db_writable()->cancel_transaction();
	} MU_XAPIAN_CATCH_BLOCK;
}



/* close the old database, and write an empty one on top of it */
void
_MuStore::clear ()
{
	if (is_read_only())
		throw std::runtime_error ("database is read-only");

	// clear the database
	db_writable()->close ();
	delete _db;
	_db = new Xapian::WritableDatabase
		(path(), Xapian::DB_CREATE_OR_OVERWRITE);

		// clear the contacts cache
	if (_contacts)
		mu_contacts_clear (_contacts);
}


/* we cache these prefix strings, so we don't have to allocate the all
 * the time; this should save 10-20 string allocs per message */
G_GNUC_CONST static const std::string&
prefix (MuMsgFieldId mfid)
{
	static std::string fields[MU_MSG_FIELD_ID_NUM];
	static bool initialized = false;

	if (G_UNLIKELY(!initialized)) {
		for (int i = 0; i != MU_MSG_FIELD_ID_NUM; ++i)
			fields[i] = std::string (1, mu_msg_field_xapian_prefix
						 ((MuMsgFieldId)i));
		initialized = true;
	}

	return fields[mfid];
}


static void
add_synonym_for_flag (MuFlags flag, Xapian::WritableDatabase *db)
{
	const std::string pfx(prefix(MU_MSG_FIELD_ID_FLAGS));

	db->clear_synonyms (pfx + mu_flag_name (flag));
	db->add_synonym (pfx + mu_flag_name (flag), pfx +
			 (std::string(1, tolower(mu_flag_char (flag)))));
}


static void
add_synonym_for_prio (MuMsgPrio prio, Xapian::WritableDatabase *db)
{
	const std::string pfx (prefix(MU_MSG_FIELD_ID_PRIO));

	std::string s1 (pfx + mu_msg_prio_name (prio));
	std::string s2 (pfx + (std::string(1, mu_msg_prio_char (prio))));

	db->clear_synonyms (s1);
	db->clear_synonyms (s2);

	db->add_synonym (s1, s2);
}


static void
add_synonyms (MuStore *store)
{
	mu_flags_foreach ((MuFlagsForeachFunc)add_synonym_for_flag,
			  store->db_writable());
	mu_msg_prio_foreach ((MuMsgPrioForeachFunc)add_synonym_for_prio,
			     store->db_writable());
}


MuStore*
mu_store_new_writable (const char* xpath, const char *contacts_cache,
		       GError **err)
{
	g_return_val_if_fail (xpath, NULL);

	try {
		MuStore *store;

		store = new _MuStore (xpath, contacts_cache, false);
		add_synonyms (store);

		return store;

	} catch (const MuStoreError& merr) {
		g_set_error (err, 0, merr.mu_error(),
			     "%s", merr.what().c_str());

	} MU_XAPIAN_CATCH_BLOCK_G_ERROR(err,MU_ERROR_XAPIAN);

	return NULL;
}



void
mu_store_set_batch_size (MuStore *store, guint batchsize)
{
	g_return_if_fail (store);
	store->set_batch_size (batchsize);
}


gboolean
mu_store_set_metadata (MuStore *store, const char *key, const char *val)
{
	g_return_val_if_fail (store, FALSE);
	g_return_val_if_fail (key, FALSE);
	g_return_val_if_fail (val, FALSE);

	try {
		store->db_writable()->set_metadata (key, val);
		return TRUE;

	} MU_XAPIAN_CATCH_BLOCK;

	return FALSE;
}


gboolean
mu_store_clear (MuStore *store)
{
	g_return_val_if_fail (store, FALSE);

	try {
		store->clear();
		return TRUE;

	} MU_XAPIAN_CATCH_BLOCK_RETURN(FALSE);
}


void
mu_store_flush (MuStore *store)
{
	g_return_if_fail (store);

	try {
		if (store->in_transaction())
			store->commit_transaction ();
		store->db_writable()->flush (); /* => commit, post X 1.1.x */

	} MU_XAPIAN_CATCH_BLOCK;
}


static void
add_terms_values_date (Xapian::Document& doc, MuMsg *msg, MuMsgFieldId mfid)
{
	time_t t;
	const char *datestr;

	t = (time_t)mu_msg_get_field_numeric (msg, mfid);
	if (t != 0) {
		datestr = mu_date_time_t_to_str_s (t, FALSE /*UTC*/);
		doc.add_value ((Xapian::valueno)mfid, datestr);
	}
}

/* TODO: we could pre-calculate the add_term values for FLAGS */

/* pre-calculate; optimization */
G_GNUC_CONST static const std::string&
flag_val (char flagchar)
{
	static const std::string
		pfx (prefix(MU_MSG_FIELD_ID_FLAGS)),
		/* xapian wants lowercase */
		draftstr	(pfx + (char)tolower(mu_flag_char(MU_FLAG_DRAFT))),
		flaggedstr	(pfx + (char)tolower(mu_flag_char(MU_FLAG_FLAGGED))),
		passedstr	(pfx + (char)tolower(mu_flag_char(MU_FLAG_PASSED))),
		repliedstr	(pfx + (char)tolower(mu_flag_char(MU_FLAG_REPLIED))),
		seenstr		(pfx + (char)tolower(mu_flag_char(MU_FLAG_SEEN))),
		trashedstr	(pfx + (char)tolower(mu_flag_char(MU_FLAG_TRASHED))),
		newstr		(pfx + (char)tolower(mu_flag_char(MU_FLAG_NEW))),

		signedstr	(pfx + mu_flag_char(MU_FLAG_SIGNED)),
		encryptedstr	(pfx + mu_flag_char(MU_FLAG_ENCRYPTED)),
		has_attachstr	(pfx + mu_flag_char(MU_FLAG_HAS_ATTACH)),
		unreadstr	(pfx + mu_flag_char(MU_FLAG_UNREAD));

	switch (flagchar) {

	case 'D': return draftstr;
	case 'F': return flaggedstr;
	case 'P': return passedstr;
	case 'R': return repliedstr;
	case 'S': return seenstr;
	case 'T': return trashedstr;

	case 'N': return newstr;

	case 's': return signedstr;
	case 'x': return encryptedstr;
	case 'a': return has_attachstr;

	case 'u': return unreadstr;

	default:
		g_return_val_if_reached (flaggedstr);
		return flaggedstr;
	}
}




/* pre-calculate; optimization */
G_GNUC_CONST static const std::string&
prio_val (MuMsgPrio prio)
{
	static const std::string pfx (prefix(MU_MSG_FIELD_ID_PRIO));

	static const std::string
		lowstr (pfx + std::string(1, mu_msg_prio_char(MU_MSG_PRIO_LOW))),
		normalstr (pfx + std::string(1, mu_msg_prio_char(MU_MSG_PRIO_NORMAL))),
		highstr (pfx + std::string(1, mu_msg_prio_char(MU_MSG_PRIO_HIGH)));

	switch (prio) {
	case MU_MSG_PRIO_LOW:    return lowstr;
	case MU_MSG_PRIO_NORMAL: return normalstr;
	case MU_MSG_PRIO_HIGH:   return highstr;
	default:
		g_return_val_if_reached (normalstr);
		return normalstr;
	}
}



static void
add_terms_values_number (Xapian::Document& doc, MuMsg *msg, MuMsgFieldId mfid)
{
	gint64 num = mu_msg_get_field_numeric (msg, mfid);

	const std::string numstr (Xapian::sortable_serialise((double)num));
	doc.add_value ((Xapian::valueno)mfid, numstr);

	if (mfid == MU_MSG_FIELD_ID_FLAGS) {
		const char *cur = mu_flags_to_str_s
			((MuFlags)num,(MuFlagType)MU_FLAG_TYPE_ANY);
		g_return_if_fail (cur);
		while (*cur) {
			doc.add_term (flag_val(*cur));
			++cur;
		}

	} else if (mfid == MU_MSG_FIELD_ID_PRIO)
		doc.add_term (prio_val((MuMsgPrio)num));
}


/* for string and string-list */
static void
add_terms_values_str (Xapian::Document& doc, char *val,
		      MuMsgFieldId mfid)
{
	/* the value is what we'll display; the unchanged original */
	if (mu_msg_field_xapian_value(mfid))
		doc.add_value ((Xapian::valueno)mfid, val);

	/* now, let's create some search terms... */
	if (mu_msg_field_normalize (mfid))
		mu_str_normalize_in_place (val, TRUE);
	if (mu_msg_field_xapian_escape (mfid))
		mu_str_ascii_xapian_escape_in_place (val);

	if (mu_msg_field_xapian_index (mfid)) {
		Xapian::TermGenerator termgen;
		termgen.set_document (doc);
		termgen.index_text_without_positions (val, 1, prefix(mfid));
	}

	if (mu_msg_field_xapian_term(mfid))
		doc.add_term (prefix(mfid) +
			      std::string(val, 0, MU_STORE_MAX_TERM_LENGTH));
}


static void
add_terms_values_string (Xapian::Document& doc, MuMsg *msg,
			 MuMsgFieldId mfid)
{
	const char *orig;
	char *val;
	size_t len;

	if (!(orig = mu_msg_get_field_string (msg, mfid)))
		return; /* nothing to do */

	/* try stack-allocation, it's much faster*/
	len = strlen (orig);
	val = (char*)(G_LIKELY(len < 1024)?g_alloca(len+1):g_malloc(len+1));
	strcpy (val, orig);

	add_terms_values_str (doc, val, mfid);

	if (!(G_LIKELY(len < 1024)))
		g_free (val);
}



static void
add_terms_values_string_list  (Xapian::Document& doc, MuMsg *msg,
			       MuMsgFieldId mfid)
{
	const GSList *lst;

	lst = mu_msg_get_field_string_list (msg, mfid);

	if (lst && mu_msg_field_xapian_value (mfid)) {
		gchar *str;
		str = mu_str_from_list (lst, ',');
		if (str)
			doc.add_value ((Xapian::valueno)mfid, str);
		g_free (str);
	}

	if (lst && mu_msg_field_xapian_term (mfid)) {
		while (lst) {
			size_t len;
			char *val;
			/* try stack-allocation, it's much faster*/
			len = strlen ((char*)lst->data);
			if (G_LIKELY(len < 1024))
				val =  (char*)g_alloca(len+1);
			else
				val  = (char*)g_malloc(len+1);
			strcpy (val, (char*)lst->data);

			add_terms_values_str (doc, val, mfid);

			if (!(G_LIKELY(len < 1024)))
				g_free (val);

			lst = g_slist_next ((GSList*)lst);
		}
	}
}


struct PartData {
	PartData (Xapian::Document& doc, MuMsgFieldId mfid):
		_doc (doc), _mfid(mfid) {}
	Xapian::Document _doc;
	MuMsgFieldId _mfid;
};

static void
each_part (MuMsg *msg, MuMsgPart *part, PartData *pdata)
{
	if (mu_msg_part_looks_like_attachment (part, TRUE) &&
	    (part->file_name)) {

		char val[MU_STORE_MAX_TERM_LENGTH + 1];
		strncpy (val, part->file_name, sizeof(val));

		/* now, let's create a terms... */
		mu_str_normalize_in_place (val, TRUE);
		mu_str_ascii_xapian_escape_in_place (val);

		pdata->_doc.add_term (prefix(pdata->_mfid) +
			      std::string(val, 0, MU_STORE_MAX_TERM_LENGTH));
	}
}


static void
add_terms_values_attach (Xapian::Document& doc, MuMsg *msg,
		       MuMsgFieldId mfid)
{
	PartData pdata (doc, mfid);
	mu_msg_part_foreach (msg, (MuMsgPartForeachFunc)each_part, &pdata);
}


static void
add_terms_values_body (Xapian::Document& doc, MuMsg *msg,
		       MuMsgFieldId mfid)
{
	const char *str;
	char *norm;

	if (mu_msg_get_flags(msg) & MU_FLAG_ENCRYPTED)
		return; /* ignore encrypted bodies */

	str = mu_msg_get_body_text (msg);
	if (!str) /* FIXME: html->txt fallback needed */
		str = mu_msg_get_body_html (msg);

	if (!str)
		return; /* no body... */

	Xapian::TermGenerator termgen;
	termgen.set_document(doc);

	norm = mu_str_normalize (str, TRUE);
	termgen.index_text_without_positions
		(norm, 1, prefix(mfid));

	g_free (norm);
}

struct _MsgDoc {
	Xapian::Document	*_doc;
	MuMsg			*_msg;
	MuStore                 *_store;
};
typedef struct _MsgDoc		 MsgDoc;

static void
add_terms_values (MuMsgFieldId mfid, MsgDoc* msgdoc)
{
	/* note: contact-stuff (To/Cc/From) will handled in
	 * add_contact_info, not here */
	if (!mu_msg_field_xapian_index(mfid) &&
	    !mu_msg_field_xapian_term(mfid) &&
	    !mu_msg_field_xapian_value(mfid))
		return;

	switch (mfid) {
	case MU_MSG_FIELD_ID_DATE:
		add_terms_values_date (*msgdoc->_doc, msgdoc->_msg, mfid);
		break;
	case MU_MSG_FIELD_ID_BODY_TEXT:
		add_terms_values_body (*msgdoc->_doc, msgdoc->_msg, mfid);
		break;
	case MU_MSG_FIELD_ID_ATTACH:
		add_terms_values_attach (*msgdoc->_doc, msgdoc->_msg, mfid);
		break;
	default:
		if (mu_msg_field_is_numeric (mfid))
			add_terms_values_number (*msgdoc->_doc, msgdoc->_msg,
						 mfid);
		else if (mu_msg_field_is_string (mfid))
			add_terms_values_string (*msgdoc->_doc,
						 msgdoc->_msg,
						 mfid);
		else if (mu_msg_field_is_string_list(mfid))
			add_terms_values_string_list (*msgdoc->_doc,
						      msgdoc->_msg,
						      mfid);
		else
			g_return_if_reached ();
	}
}


static const std::string&
xapian_pfx (MuMsgContact *contact)
{
	static const std::string empty;

	/* use ptr to string to prevent copy... */
	switch (contact->type) {
	case MU_MSG_CONTACT_TYPE_TO:
		return prefix(MU_MSG_FIELD_ID_TO);
	case MU_MSG_CONTACT_TYPE_FROM:
		return prefix(MU_MSG_FIELD_ID_FROM);
	case MU_MSG_CONTACT_TYPE_CC:
		return prefix(MU_MSG_FIELD_ID_CC);
	case MU_MSG_CONTACT_TYPE_BCC:
		return prefix(MU_MSG_FIELD_ID_BCC);
	default:
		g_warning ("unsupported contact type %u",
			   (unsigned)contact->type);
		return empty;
	}
}


static void
each_contact_info (MuMsgContact *contact, MsgDoc *msgdoc)
{
	const std::string pfx (xapian_pfx(contact));
	if (pfx.empty())
		return; /* unsupported contact type */

	if (!mu_str_is_empty(contact->name)) {
		Xapian::TermGenerator termgen;
		termgen.set_document (*msgdoc->_doc);
		char *norm = mu_str_normalize (contact->name, TRUE);
		termgen.index_text_without_positions (norm, 1, pfx);
		g_free (norm);
	}

	/* don't normalize e-mail address, but do lowercase it */
	if (!mu_str_is_empty(contact->address)) {
		char *escaped = mu_str_ascii_xapian_escape (contact->address);
		msgdoc->_doc->add_term
			(std::string  (pfx + escaped, 0,
				       MU_STORE_MAX_TERM_LENGTH));
		g_free (escaped);

		/* store it also in our contacts cache */
		if (msgdoc->_store->contacts())
			mu_contacts_add (msgdoc->_store->contacts(),
					 contact->address, contact->name,
					 mu_msg_get_date(msgdoc->_msg));
	}
}


gboolean
mu_store_store_msg (MuStore *store, MuMsg *msg, gboolean replace)
{
	g_return_val_if_fail (store, FALSE);
	g_return_val_if_fail (msg, FALSE);

	try {
		Xapian::Document newdoc;
		Xapian::docid id;
		MsgDoc msgdoc = { &newdoc, msg, store };
		const std::string uid(store->get_message_uid(msg));

		if (!store->in_transaction())
			store->begin_transaction();

		/* we must add a unique term, so we can replace
		 * matching documents */
		newdoc.add_term (uid);
		mu_msg_field_foreach
			((MuMsgFieldForEachFunc)add_terms_values, &msgdoc);
		/* also store the contact-info as separate terms */
		mu_msg_contact_foreach
			(msg,
			 (MuMsgContactForeachFunc)each_contact_info,
			 &msgdoc);

		/* add_document is slightly
		   faster, we can use it when
		 * we know the document does not exist yet, eg., in
		 * case of a rebuild */
		if (replace) /* we replace all existing documents for this file */
			id = store->db_writable()->replace_document (uid, newdoc);
		else
			id = store->db_writable()->add_document (newdoc);

		if (store->inc_processed() % store->batch_size() == 0)
			store->commit_transaction();

		return TRUE;

	} MU_XAPIAN_CATCH_BLOCK;

	if (store->in_transaction())
		store->rollback_transaction();

	return FALSE;
}


gboolean
mu_store_store_path (MuStore *store, const char *path)
{
	MuMsg *msg;
	GError *err;
	gboolean rv;

	g_return_val_if_fail (store, FALSE);
	g_return_val_if_fail (path, FALSE);

	err = NULL;
	msg = mu_msg_new_from_file (path, NULL, &err);

	if (!msg) {
		if (err) {
			g_warning ("failed to create message %s to store: %s",
				   path, err->message);
			g_error_free (err);
		} else
			g_warning ("failed to create message %s to store", path);

		return FALSE;
	}

	rv = mu_store_store_msg (store, msg, TRUE);
	if (!rv)
		g_warning ("failed to store %s", path);

	mu_msg_unref (msg);

	return rv;
}


XapianWritableDatabase*
mu_store_get_writable_database (MuStore *store)
{
	g_return_val_if_fail (store, NULL);

	return (XapianWritableDatabase*)store->db_writable();
}


gboolean
mu_store_remove_path (MuStore *store, const char *msgpath)
{
	g_return_val_if_fail (store, FALSE);
	g_return_val_if_fail (msgpath, FALSE);

	try {
		const std::string uid (store->get_message_uid (msgpath));

		store->db_writable()->delete_document (uid);
		store->inc_processed();

		return TRUE;

	} MU_XAPIAN_CATCH_BLOCK_RETURN (FALSE);
}


gboolean
mu_store_set_timestamp (MuStore *store, const char* msgpath,
			time_t stamp)
{
	char buf[21];

	g_return_val_if_fail (store, FALSE);
	g_return_val_if_fail (msgpath, FALSE);

	sprintf (buf, "%" G_GUINT64_FORMAT, (guint64)stamp);
	return mu_store_set_metadata (store, msgpath, buf);
}