/* message-property.cc - Properties are like tags, but (key,value) pairs.
 * keys are allowed to repeat.
 *
 * This file is part of notmuch.
 *
 * Copyright © 2016 David Bremner
 *
 * 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/ .
 *
 * Author: David Bremner <david@tethera.net>
 */

#include "notmuch-private.h"
#include "database-private.h"
#include "message-private.h"

struct _notmuch_message_property_list {
    Xapian::TermIterator *iterator;
    notmuch_message_t *message;
    const char *prefix;
    char *current;
};

static int
_notmuch_message_property_list_destroy (notmuch_message_property_list_t *list)
{
    delete list->iterator;
    return 0;
}

notmuch_status_t
notmuch_message_get_property (notmuch_message_t *message, const char *key, const char **value)
{
    notmuch_private_status_t private_status;
    char *term = NULL;

    if (! value)
	return NOTMUCH_STATUS_NULL_POINTER;

    term = talloc_asprintf (message, "%s%s=",
			    _find_prefix ("property"), key);
    if (term == NULL) {
	private_status = NOTMUCH_PRIVATE_STATUS_OUT_OF_MEMORY;
	goto DONE;
    }

    private_status = _notmuch_message_get_prefixed_term (message, term, value);
    if (private_status == NOTMUCH_PRIVATE_STATUS_NO_TERM_FOUND) {
	*value = NULL;
	private_status = NOTMUCH_PRIVATE_STATUS_SUCCESS;
    }

  DONE:
    if (term)
	talloc_free (term);

    if (private_status)
	return COERCE_STATUS (private_status,
			      "Unhandled error retrieving message property");
    return NOTMUCH_STATUS_SUCCESS;
}

static notmuch_status_t
_notmuch_message_modify_property (notmuch_message_t *message, const char *key, const char *value,
				  notmuch_bool_t delete_it)
{
    notmuch_private_status_t private_status;
    notmuch_status_t status;
    char *term = NULL;

    status = _notmuch_database_ensure_writable (_notmuch_message_database (message));
    if (status)
	return status;

    if (key == NULL || value== NULL)
	return NOTMUCH_STATUS_NULL_POINTER;

    if (index (key, '=') || index (value, '='))
	return NOTMUCH_STATUS_ILLEGAL_ARGUMENT;

    term = talloc_asprintf (message, "%s=%s", key, value);

    /* this invalidates all of the property, which it currently shouldn't */
    if (delete_it)
	private_status = _notmuch_message_remove_term (message, "property", term);
    else
	private_status = _notmuch_message_add_term (message, "property", term);

    if (private_status)
	return COERCE_STATUS (private_status,
			      "Unhandled error modifying message property");

    _notmuch_message_sync (message);

    if (term)
	talloc_free (term);

    return NOTMUCH_STATUS_SUCCESS;
}

notmuch_status_t
notmuch_message_add_property (notmuch_message_t *message, const char *key, const char *value)
{
    return _notmuch_message_modify_property (message, key, value, FALSE);
}

notmuch_status_t
notmuch_message_remove_property (notmuch_message_t *message, const char *key, const char *value)
{
    return _notmuch_message_modify_property (message, key, value, TRUE);
}

notmuch_status_t
notmuch_message_get_property_list (notmuch_message_t *message,
				  const char *key,
				  notmuch_message_property_list_t **out)
{
    notmuch_message_property_list_t *list = NULL;
    notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
    notmuch_database_t *notmuch = _notmuch_message_database (message);

    const char *term;

    list = talloc (message, notmuch_message_property_list_t);
    if (! list) {
	status = NOTMUCH_STATUS_OUT_OF_MEMORY;
	goto DONE;
    }

    talloc_set_destructor (list, _notmuch_message_property_list_destroy);
    list->current = NULL;
    list->message = message;


    term = talloc_asprintf (message, "%s%s=",
			    _find_prefix ("property"), key);

    list->prefix = talloc_strdup (list, term);

    if (term == NULL) {
	status = NOTMUCH_STATUS_OUT_OF_MEMORY;
	goto DONE;
    }

    try {

	/* force copying onto the heap */
	list->iterator = new Xapian::TermIterator;
	*list->iterator = message->doc.termlist_begin ();

	(*list->iterator).skip_to (term);

    } catch (const Xapian::Error &error) {
	_notmuch_database_log (notmuch, "A Xapian exception occurred getting property iterator: %s.\n",
			       error.get_msg().c_str());
	notmuch->exception_reported = TRUE;
	status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
    }

    *out = list;

  DONE:
    if (status && list)
	talloc_free (list);

    return status;
}

notmuch_bool_t
notmuch_message_property_list_valid (notmuch_message_property_list_t *list)
{
    if (*(list->iterator) == list->message->doc.termlist_end ())
	return FALSE;

    if (strncmp (list->prefix, (**list->iterator).c_str (), strlen(list->prefix)) != 0)
	return FALSE;

    return TRUE;
}

const char *
notmuch_message_property_list_value (notmuch_message_property_list_t *list)
{

    if (list->current)
	talloc_free (list->current);

    list->current = talloc_strdup (list, (**list->iterator).c_str () + strlen (list->prefix));

    return list->current;
}

void
notmuch_message_property_list_move_to_next (notmuch_message_property_list_t *list)
{
    (*(list->iterator))++;
}

void
notmuch_message_property_list_destroy (notmuch_message_property_list_t *list)
{
    talloc_free (list);
}