/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-disco-store.c: abstract class for a disconnectable remote store */

/*
 *  Authors: Dan Winship <danw@ximian.com>
 *
 *  Copyright 2001 Ximian, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * 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.
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "camel-disco-store.h"
#include "camel-disco-diary.h"
#include "camel-exception.h"
#include "camel-session.h"

#define CDS_CLASS(o) (CAMEL_DISCO_STORE_CLASS (CAMEL_OBJECT_GET_CLASS (o)))

static CamelRemoteStoreClass *remote_store_class = NULL;

static void disco_construct (CamelService *service, CamelSession *session,
			     CamelProvider *provider, CamelURL *url,
			     CamelException *ex);
static gboolean disco_connect (CamelService *service, CamelException *ex);
static void disco_cancel_connect (CamelService *service);
static gboolean disco_disconnect (CamelService *service, gboolean clean, CamelException *ex);
static CamelFolder *disco_get_folder (CamelStore *store, const char *name,
				      guint32 flags, CamelException *ex);
static CamelFolderInfo *disco_get_folder_info (CamelStore *store,
					       const char *top, guint32 flags,
					       CamelException *ex);
static void set_status (CamelDiscoStore *disco_store,
			CamelDiscoStoreStatus status,
			CamelException *ex);
static gboolean can_work_offline (CamelDiscoStore *disco_store);

static void
camel_disco_store_class_init (CamelDiscoStoreClass *camel_disco_store_class)
{
	CamelServiceClass *camel_service_class =
		CAMEL_SERVICE_CLASS (camel_disco_store_class);
	CamelStoreClass *camel_store_class =
		CAMEL_STORE_CLASS (camel_disco_store_class);

	remote_store_class = CAMEL_REMOTE_STORE_CLASS (camel_type_get_global_classfuncs (camel_remote_store_get_type ()));

	/* virtual method definition */
	camel_disco_store_class->set_status = set_status;
	camel_disco_store_class->can_work_offline = can_work_offline;

	/* virtual method overload */
	camel_service_class->construct = disco_construct;
	camel_service_class->connect = disco_connect;
	camel_service_class->disconnect = disco_disconnect;
	camel_service_class->cancel_connect = disco_cancel_connect;

	camel_store_class->get_folder = disco_get_folder;
	camel_store_class->get_folder_info = disco_get_folder_info;
}

CamelType
camel_disco_store_get_type (void)
{
	static CamelType camel_disco_store_type = CAMEL_INVALID_TYPE;

	if (camel_disco_store_type == CAMEL_INVALID_TYPE) {
		camel_disco_store_type = camel_type_register (
			CAMEL_REMOTE_STORE_TYPE, "CamelDiscoStore",
			sizeof (CamelDiscoStore),
			sizeof (CamelDiscoStoreClass),
			(CamelObjectClassInitFunc) camel_disco_store_class_init,
			NULL,
			NULL,
			NULL);
	}

	return camel_disco_store_type;
}

static void
disco_construct (CamelService *service, CamelSession *session,
		 CamelProvider *provider, CamelURL *url,
		 CamelException *ex)
{
	CamelDiscoStore *disco = CAMEL_DISCO_STORE (service);

	CAMEL_SERVICE_CLASS (remote_store_class)->construct (service, session, provider, url, ex);
	if (camel_exception_is_set (ex))
		return;

	disco->status = camel_session_is_online (session) ?
		CAMEL_DISCO_STORE_ONLINE : CAMEL_DISCO_STORE_OFFLINE;
}

static gboolean
disco_connect (CamelService *service, CamelException *ex)
{
	CamelDiscoStore *store = CAMEL_DISCO_STORE (service);
	CamelDiscoStoreStatus status;

	status = camel_disco_store_status (store);
	if (status != CAMEL_DISCO_STORE_OFFLINE) {
		if (!CAMEL_SERVICE_CLASS (remote_store_class)->connect (service, ex)) {
			status = camel_disco_store_status (store);
			if (status != CAMEL_DISCO_STORE_OFFLINE)
				return FALSE;
			camel_exception_clear (ex);
		}
	}

	switch (status) {
	case CAMEL_DISCO_STORE_ONLINE:
	case CAMEL_DISCO_STORE_RESYNCING:
		if (!CDS_CLASS (service)->connect_online (service, ex))
			return FALSE;
		if (camel_disco_diary_empty (store->diary))
			return TRUE;

		/* Need to resync */
		store->status = CAMEL_DISCO_STORE_RESYNCING;
		camel_disco_diary_replay (store->diary, ex);
		store->status = CAMEL_DISCO_STORE_ONLINE;
		if (camel_exception_is_set (ex))
			return FALSE;

		if (!camel_service_disconnect (service, TRUE, ex))
			return FALSE;
		return camel_service_connect (service, ex);

	case CAMEL_DISCO_STORE_OFFLINE:
		return CDS_CLASS (service)->connect_offline (service, ex);
	}

	g_assert_not_reached ();
	return FALSE;
}

static void
disco_cancel_connect (CamelService *service)
{
	CamelDiscoStore *store = CAMEL_DISCO_STORE (service);

	/* Fall back */
	store->status = CAMEL_DISCO_STORE_OFFLINE;

	CAMEL_SERVICE_CLASS (remote_store_class)->cancel_connect (service);
}

static gboolean
disco_disconnect (CamelService *service, gboolean clean, CamelException *ex)
{
	CamelDiscoStore *store = CAMEL_DISCO_STORE (service);

	switch (camel_disco_store_status (store)) {
	case CAMEL_DISCO_STORE_ONLINE:
	case CAMEL_DISCO_STORE_RESYNCING:
		if (!CDS_CLASS (service)->disconnect_online (service, clean, ex))
			return FALSE;
		break;

	case CAMEL_DISCO_STORE_OFFLINE:
		if (!CDS_CLASS (service)->disconnect_offline (service, clean, ex))
			return FALSE;
		break;

	}

	return CAMEL_SERVICE_CLASS (remote_store_class)->disconnect (service, clean, ex);
}

static CamelFolder *
disco_get_folder (CamelStore *store, const char *name,
		  guint32 flags, CamelException *ex)
{
	CamelDiscoStore *disco_store = CAMEL_DISCO_STORE (store);
	
	switch (camel_disco_store_status (disco_store)) {
	case CAMEL_DISCO_STORE_ONLINE:
		return CDS_CLASS (store)->get_folder_online (store, name, flags, ex);
		
	case CAMEL_DISCO_STORE_OFFLINE:
		return CDS_CLASS (store)->get_folder_offline (store, name, flags, ex);
		
	case CAMEL_DISCO_STORE_RESYNCING:
		return CDS_CLASS (store)->get_folder_resyncing (store, name, flags, ex);	
	}
	
	g_assert_not_reached ();
	return NULL;
}

static CamelFolderInfo *
disco_get_folder_info (CamelStore *store, const char *top,
		       guint32 flags, CamelException *ex)
{
	CamelDiscoStore *disco_store = CAMEL_DISCO_STORE (store);

	/* Do this first so if we get forced offline, we'll switch to
	 * the correct branch below. (FIXME: This only works because
	 * we know that get_folder_info is the first call that the
	 * mailer makes on a store.)
	 */
	if (CAMEL_SERVICE (store)->status == CAMEL_SERVICE_DISCONNECTED) {
		if (!camel_service_connect (CAMEL_SERVICE (store), ex))
			return NULL;
	}

	switch (camel_disco_store_status (disco_store)) {
	case CAMEL_DISCO_STORE_ONLINE:
		return CDS_CLASS (store)->get_folder_info_online (store, top, flags, ex);
		
	case CAMEL_DISCO_STORE_OFFLINE:
		/* Can't edit subscriptions while offline */
		if ((store->flags & CAMEL_STORE_SUBSCRIPTIONS) &&
		    !(flags & CAMEL_STORE_FOLDER_INFO_SUBSCRIBED)) {
			camel_disco_store_check_online (disco_store, ex);
			return NULL;
		}
		
		return CDS_CLASS (store)->get_folder_info_offline (store, top, flags, ex);
		
	case CAMEL_DISCO_STORE_RESYNCING:
		return CDS_CLASS (store)->get_folder_info_resyncing (store, top, flags, ex);
	}
	
	g_assert_not_reached ();
	return NULL;
}


/**
 * camel_disco_store_status:
 * @store: a disconnectable store
 *
 * Return value: the current online/offline status of @store.
 **/
CamelDiscoStoreStatus
camel_disco_store_status (CamelDiscoStore *store)
{
	CamelService *service = CAMEL_SERVICE (store);

	g_return_val_if_fail (CAMEL_IS_DISCO_STORE (store), CAMEL_DISCO_STORE_ONLINE);

	if (service->status == CAMEL_SERVICE_CONNECTING &&
	    store->status == CAMEL_DISCO_STORE_ONLINE &&
	    !camel_session_is_online (service->session))
		store->status = CAMEL_DISCO_STORE_OFFLINE;

	return store->status;
}


static void
set_status (CamelDiscoStore *disco_store, CamelDiscoStoreStatus status,
	    CamelException *ex)
{
	if (disco_store->status == status)
		return;

	camel_store_sync (CAMEL_STORE (disco_store), ex);
	if (camel_exception_is_set (ex))
		return;
	if (!camel_service_disconnect (CAMEL_SERVICE (disco_store), TRUE, ex))
		return;

	disco_store->status = status;
	camel_service_connect (CAMEL_SERVICE (disco_store), ex);
}

/**
 * camel_disco_store_set_status:
 * @store: a disconnectable store
 * @status: the new status
 * @ex: a CamelException
 *
 * Sets @store to @status. If an error occurrs and the status cannot
 * be set to @status, @ex will be set.
 **/
void
camel_disco_store_set_status (CamelDiscoStore *store,
			      CamelDiscoStoreStatus status,
			      CamelException *ex)
{
	CDS_CLASS (store)->set_status (store, status, ex);
}


static gboolean
can_work_offline (CamelDiscoStore *disco_store)
{
	g_warning ("CamelDiscoStore::can_work_offline not implemented for `%s'",
		   camel_type_to_name (CAMEL_OBJECT_GET_TYPE (disco_store)));
	return FALSE;
}

/**
 * camel_disco_store_can_work_offline:
 * @store: a disconnectable store
 *
 * Return value: whether or not @store can be used offline. (Will be
 * %FALSE if the store is not caching data to local disk, for example.)
 **/
gboolean
camel_disco_store_can_work_offline (CamelDiscoStore *store)
{
	return CDS_CLASS (store)->can_work_offline (store);
}


/**
 * camel_disco_store_check_online:
 * @store: a disconnectable store
 * @ex: a CamelException
 *
 * This checks that @store is online, and sets @ex if it is not. This
 * can be used as a simple way to set a generic error message in @ex
 * for operations that won't work offline.
 *
 * Return value: whether or not @store is online.
 **/
gboolean
camel_disco_store_check_online (CamelDiscoStore *store, CamelException *ex)
{
	if (camel_disco_store_status (store) != CAMEL_DISCO_STORE_ONLINE) {
		camel_exception_set (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
				     _("You must be working online to "
				       "complete this operation"));
		return FALSE;
	}

	return TRUE;
}