/*
Minetest
Copyright (C) 2010-2014 celeron55, Perttu Ahola <celeron55@gmail.com>

This program 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; either version 2.1 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser 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.
*/

#pragma once

#include "irr_v3d.h"                   // for irrlicht datatypes

#include "constants.h"
#include "serialization.h"             // for SER_FMT_VER_INVALID
#include "network/networkpacket.h"
#include "network/networkprotocol.h"
#include "porting.h"

#include <list>
#include <vector>
#include <set>
#include <mutex>

class MapBlock;
class ServerEnvironment;
class EmergeManager;

/*
 * State Transitions

      Start
  (peer connect)
        |
        v
      /-----------------\
      |                 |
      |    Created      |
      |                 |
      \-----------------/
               |                  depending of the incoming packet
               ----------------------------------------
                                                      v
                                       +-----------------------------+
                                       |IN:                          |
                                       | TOSERVER_INIT               |
                                       +-----------------------------+
                                                      | invalid playername
                                                      | or denied by mod
                                                      v
                                       +-----------------------------+
                                       |OUT:                         |
                                       | TOCLIENT_HELLO              |
                                       +-----------------------------+
                                                      |
                                                      |
                                                      v
      /-----------------\                    /-----------------\
      |                 |                    |                 |
      |  AwaitingInit2  |<---------          |    HelloSent    |
      |                 |         |          |                 |
      \-----------------/         |          \-----------------/
               |                  |                   |
+-----------------------------+   |    *-----------------------------*     Auth fails
|IN:                          |   |    |Authentication, depending on |------------------
| TOSERVER_INIT2              |   |    | packet sent by client       |                 |
+-----------------------------+   |    *-----------------------------*                 |
               |                  |                   |                                |
               |                  |                   | Authentication                 |
               v                  |                   |  successful                    |
      /-----------------\         |                   v                                |
      |                 |         |    +-----------------------------+                 |
      |    InitDone     |         |    |OUT:                         |                 |
      |                 |         |    | TOCLIENT_AUTH_ACCEPT        |                 |
      \-----------------/         |    +-----------------------------+                 |
               |                  |                   |                                |
+-----------------------------+   ---------------------                                |
|OUT:                         |                                                        |
| TOCLIENT_MOVEMENT           |                                                        |
| TOCLIENT_ITEMDEF            |                                                        |
| TOCLIENT_NODEDEF            |                                                        |
| TOCLIENT_ANNOUNCE_MEDIA     |                                                        |
| TOCLIENT_DETACHED_INVENTORY |                                                        |
| TOCLIENT_TIME_OF_DAY        |                                                        |
+-----------------------------+                                                        |
               |                                                                       |
               |                                                                       |
               |      -----------------------------                                    |
               v      |                           |                                    |
      /-----------------\                         v                                    |
      |                 |             +-----------------------------+                  |
      | DefinitionsSent |             |IN:                          |                  |
      |                 |             | TOSERVER_REQUEST_MEDIA      |                  |
      \-----------------/             |                             |                  |
               |                      +-----------------------------+                  |
               |      ^                           |                                    |
               |      -----------------------------                                    |
               v                                                                       v
+-----------------------------+                        --------------------------------+
|IN:                          |                        |                               ^
| TOSERVER_CLIENT_READY       |                        v                               |
+-----------------------------+            +------------------------+                  |
               |                           |OUT:                    |                  |
               v                           | TOCLIENT_ACCESS_DENIED |                  |
+-----------------------------+            +------------------------+                  |
|OUT:                         |                        |                               |
| TOCLIENT_MOVE_PLAYER        |                        v                               |
| TOCLIENT_PRIVILEGES         |                /-----------------\                     |
| TOCLIENT_INVENTORY_FORMSPEC |                |                 |                     |
| UpdateCrafting              |                |     Denied      |                     |
| TOCLIENT_INVENTORY          |                |                 |                     |
| TOCLIENT_HP (opt)           |                \-----------------/                     |
| TOCLIENT_BREATH             |                                                        |
| TOCLIENT_DEATHSCREEN        |                                                        |
+-----------------------------+                                                        |
              |                                                                        |
              v                                                                        |
      /-----------------\      async mod action (ban, kick)                            |
      |                 |---------------------------------------------------------------
 ---->|     Active      |
 |    |                 |----------------------------------------------
 |    \-----------------/      timeout                                v
 |       |           |                                  +-----------------------------+
 |       |           |                                  |OUT:                         |
 |       |           |                                  | TOCLIENT_DISCONNECT         |
 |       |           |                                  +-----------------------------+
 |       |           |                                                |
 |       |           v                                                v
 |       |  +-----------------------------+                    /-----------------\
 |       |  |IN:                          |                    |                 |
 |       |  | TOSERVER_DISCONNECT         |------------------->|  Disconnecting  |
 |       |  +-----------------------------+                    |                 |
 |       |                                                     \-----------------/
 |       | any auth packet which was
 |       | allowed in TOCLIENT_AUTH_ACCEPT
 |       v
 |    *-----------------------------* Auth      +-------------------------------+
 |    |Authentication, depending on | succeeds  |OUT:                           |
 |    | packet sent by client       |---------->| TOCLIENT_ACCEPT_SUDO_MODE     |
 |    *-----------------------------*           +-------------------------------+
 |                  |                                            |
 |                  | Auth fails                        /-----------------\
 |                  v                                   |                 |
 |    +-------------------------------+                 |    SudoMode     |
 |    |OUT:                           |                 |                 |
 |    | TOCLIENT_DENY_SUDO_MODE       |                 \-----------------/
 |    +-------------------------------+                          |
 |                  |                                            v
 |                  |                               +-----------------------------+
 |                  |    sets password accordingly  |IN:                          |
 -------------------+-------------------------------| TOSERVER_FIRST_SRP          |
                                                    +-----------------------------+

*/
namespace con {
	class Connection;
}


// Also make sure to update the ClientInterface::statenames
// array when modifying these enums

enum ClientState
{
	CS_Invalid,
	CS_Disconnecting,
	CS_Denied,
	CS_Created,
	CS_AwaitingInit2,
	CS_HelloSent,
	CS_InitDone,
	CS_DefinitionsSent,
	CS_Active,
	CS_SudoMode
};

enum ClientStateEvent
{
	CSE_Hello,
	CSE_AuthAccept,
	CSE_InitLegacy,
	CSE_GotInit2,
	CSE_SetDenied,
	CSE_SetDefinitionsSent,
	CSE_SetClientReady,
	CSE_SudoSuccess,
	CSE_SudoLeave,
	CSE_Disconnect
};

/*
	Used for queueing and sorting block transfers in containers

	Lower priority number means higher priority.
*/
struct PrioritySortedBlockTransfer
{
	PrioritySortedBlockTransfer(float a_priority, const v3s16 &a_pos, session_t a_peer_id)
	{
		priority = a_priority;
		pos = a_pos;
		peer_id = a_peer_id;
	}
	bool operator < (const PrioritySortedBlockTransfer &other) const
	{
		return priority < other.priority;
	}
	float priority;
	v3s16 pos;
	session_t peer_id;
};

class RemoteClient
{
public:
	// peer_id=0 means this client has no associated peer
	// NOTE: If client is made allowed to exist while peer doesn't,
	//       this has to be set to 0 when there is no peer.
	//       Also, the client must be moved to some other container.
	session_t peer_id = PEER_ID_INEXISTENT;
	// The serialization version to use with the client
	u8 serialization_version = SER_FMT_VER_INVALID;
	//
	u16 net_proto_version = 0;

	/* Authentication information */
	std::string enc_pwd = "";
	bool create_player_on_auth_success = false;
	AuthMechanism chosen_mech  = AUTH_MECHANISM_NONE;
	void *auth_data = nullptr;
	u32 allowed_auth_mechs = 0;
	u32 allowed_sudo_mechs = 0;

	bool isSudoMechAllowed(AuthMechanism mech)
	{ return allowed_sudo_mechs & mech; }
	bool isMechAllowed(AuthMechanism mech)
	{ return allowed_auth_mechs & mech; }

	RemoteClient();
	~RemoteClient() = default;

	/*
		Finds block that should be sent next to the client.
		Environment should be locked when this is called.
		dtime is used for resetting send radius at slow interval
	*/
	void GetNextBlocks(ServerEnvironment *env, EmergeManager* emerge,
			float dtime, std::vector<PrioritySortedBlockTransfer> &dest);

	void GotBlock(v3s16 p);

	void SentBlock(v3s16 p);

	void SetBlockNotSent(v3s16 p);
	void SetBlocksNotSent(std::map<v3s16, MapBlock*> &blocks);

	/**
	 * tell client about this block being modified right now.
	 * this information is required to requeue the block in case it's "on wire"
	 * while modification is processed by server
	 * @param p position of modified block
	 */
	void ResendBlockIfOnWire(v3s16 p);

	u32 getSendingCount() const { return m_blocks_sending.size(); }

	bool isBlockSent(v3s16 p) const
	{
		return m_blocks_sent.find(p) != m_blocks_sent.end();
	}

	// Increments timeouts and removes timed-out blocks from list