/** 
 * @file llcachename.h
 * @brief A cache of names from UUIDs.
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLCACHENAME_H
#define LL_LLCACHENAME_H

#include <boost/bind.hpp>
#include <boost/signals2.hpp>

class LLMessageSystem;
class LLHost;
class LLUUID;


typedef boost::signals2::signal<void (const LLUUID& id,
                                      const std::string& first_name,
                                      const std::string& last_name,
                                      BOOL is_group)> LLCacheNameSignal;
typedef LLCacheNameSignal::slot_type LLCacheNameCallback;

// Old callback with user data for compatability
typedef void (*old_callback_t)(const LLUUID&, const std::string&, const std::string&, BOOL, void*);

// Here's the theory:
// If you request a name that isn't in the cache, it returns "waiting"
// and requests the data.  After the data arrives, you get that on 
// subsequent calls.
// If the data hasn't been updated in an hour, it requests it again,
// but keeps giving you the old value until new data arrives.
// If you haven't requested the data in an hour, it releases it.
class LLCacheName
{
public:
	LLCacheName(LLMessageSystem* msg);
	LLCacheName(LLMessageSystem* msg, const LLHost& upstream_host);
	~LLCacheName();

	// registers the upstream host
	// for viewers, this is the currently connected simulator
	// for simulators, this is the data server
	void setUpstream(const LLHost& upstream_host);

	boost::signals2::connection addObserver(const LLCacheNameCallback& callback);

	// janky old format. Remove after a while. Phoenix. 2008-01-30
	void importFile(LLFILE* fp);

	// storing cache on disk; for viewer, in name.cache
	bool importFile(std::istream& istr);
	void exportFile(std::ostream& ostr);

	// If available, copies the first and last name into the strings provided.
	// first must be at least DB_FIRST_NAME_BUF_SIZE characters.
	// last must be at least DB_LAST_NAME_BUF_SIZE characters.
	// If not available, copies the string "waiting".
	// Returns TRUE iff available.
	BOOL getName(const LLUUID& id, std::string& first, std::string& last);
	BOOL getFullName(const LLUUID& id, std::string& fullname);
	
	// Reverse lookup of UUID from name
	BOOL getUUID(const std::string& first, const std::string& last, LLUUID& id);
	BOOL getUUID(const std::string& fullname, LLUUID& id);
	
	// If available, this method copies the group name into the string
	// provided. The caller must allocate at least
	// DB_GROUP_NAME_BUF_SIZE characters. If not available, this
	// method copies the string "waiting". Returns TRUE iff available.
	BOOL getGroupName(const LLUUID& id, std::string& group);

	// Call the callback with the group or avatar name.
	// If the data is currently available, may call the callback immediatly
	// otherwise, will request the data, and will call the callback when
	// available.  There is no garuntee the callback will ever be called.
	boost::signals2::connection get(const LLUUID& id, BOOL is_group, const LLCacheNameCallback& callback);
	
	// LEGACY
	boost::signals2::connection get(const LLUUID& id, BOOL is_group, old_callback_t callback, void* user_data);
	// This method needs to be called from time to time to send out
	// requests.
	void processPending();

	// Expire entries created more than "secs" seconds ago.
	void deleteEntriesOlderThan(S32 secs);

	// Debugging
	void dump();		// Dumps the contents of the cache
	void dumpStats();	// Dumps the sizes of the cache and associated queues.

	static std::string getDefaultName();
	static void LocalizeCacheName(std::string key, std::string value);
	static std::map<std::string, std::string> sCacheName;
private:

	class Impl;
	Impl& impl;
};



extern LLCacheName* gCacheName;

#endif