/*************************************************************************/
/*  multiplayer_replicator.h                                             */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
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/*************************************************************************/

#ifndef MULTIPLAYER_REPLICATOR_H
#define MULTIPLAYER_REPLICATOR_H

#include "core/multiplayer/multiplayer_api.h"

#include "core/io/resource_uid.h"
#include "core/templates/hash_map.h"
#include "core/variant/typed_array.h"

class MultiplayerReplicator : public Object {
	GDCLASS(MultiplayerReplicator, Object);

public:
	enum {
		SPAWN_CMD_OFFSET = 9,
		SYNC_CMD_OFFSET = 9,
	};

	enum ReplicationMode {
		REPLICATION_MODE_NONE,
		REPLICATION_MODE_SERVER,
		REPLICATION_MODE_CUSTOM,
	};

	struct SceneConfig {
		ReplicationMode mode;
		uint64_t sync_interval = 0;
		uint64_t sync_last = 0;
		uint8_t sync_recv = 0;
		List<StringName> properties;
		List<StringName> sync_properties;
		Callable on_spawn_despawn_send;
		Callable on_spawn_despawn_receive;
		Callable on_sync_send;
		Callable on_sync_receive;
	};

protected:
	static void _bind_methods();

private:
	enum {
		BYTE_OR_ZERO_SHIFT = MultiplayerAPI::CMD_FLAG_0_SHIFT,
	};

	enum {
		BYTE_OR_ZERO_FLAG = 1 << BYTE_OR_ZERO_SHIFT,
	};

	MultiplayerAPI *multiplayer = nullptr;
	Vector<uint8_t> packet_cache;
	Map<ResourceUID::ID, SceneConfig> replications;
	Map<ObjectID, ResourceUID::ID> replicated_nodes;
	HashMap<ResourceUID::ID, List<ObjectID>> tracked_objects;

	// Encoding
	Error _get_state(const List<StringName> &p_properties, const Object *p_obj, List<Variant> &r_variant);
	Error _encode_state(const List<Variant> &p_variants, uint8_t *p_buffer, int &r_len, bool *r_raw = nullptr);
	Error _decode_state(const List<StringName> &p_cfg, Object *p_obj, const uint8_t *p_buffer, int p_len, int &r_len, bool p_raw = false);

	// Spawn
	Error _spawn_despawn(ResourceUID::ID p_scene_id, Object *p_obj, int p_peer, bool p_spawn);
	Error _send_spawn_despawn(int p_peer_id, const ResourceUID::ID &p_scene_id, const Variant &p_data, bool p_spawn);
	void _process_default_spawn_despawn(int p_from, const ResourceUID::ID &p_scene_id, const uint8_t *p_packet, int p_packet_len, bool p_spawn);
	Error _send_default_spawn_despawn(int p_peer_id, const ResourceUID::ID &p_scene_id, Object *p_obj, const NodePath &p_path, bool p_spawn);

	// Sync
	void _process_default_sync(const ResourceUID::ID &p_id, const uint8_t *p_packet, int p_packet_len);
	Error _sync_all_default(const ResourceUID::ID &p_scene_id, int p_peer);
	void _track(const ResourceUID::ID &p_scene_id, Object *p_object);
	void _untrack(const ResourceUID::ID &p_scene_id, Object *p_object);

public:
	void clear();

	// Encoding
	PackedByteArray encode_state(const ResourceUID::ID &p_scene_id, const Object *p_node, bool p_initial);
	Error decode_state(const ResourceUID::ID &p_scene_id, Object *p_node, PackedByteArray p_data, bool p_initial);

	// Spawn
	Error spawn_config(const ResourceUID::ID &p_id, ReplicationMode p_mode, const TypedArray<StringName> &p_props = TypedArray<StringName>(), const Callable &p_on_send = Callable(), const Callable &p_on_recv = Callable());
	Error spawn(ResourceUID::ID p_scene_id, Object *p_obj, int p_peer = 0);
	Error despawn(ResourceUID::ID p_scene_id, Object *p_obj, int p_peer = 0);
	Error send_despawn(int p_peer_id, const ResourceUID::ID &p_scene_id, const Variant &p_data = Variant(), const NodePath &p_path = NodePath());
	Error send_spawn(int p_peer_id, const ResourceUID::ID &p_scene_id, const Variant &p_data = Variant(), const NodePath &p_path = NodePath());

	// Sync
	Error sync_config(const ResourceUID::ID &p_id, uint64_t p_interval, const TypedArray<StringName> &p_props = TypedArray<StringName>(), const Callable &p_on_send = Callable(), const Callable &p_on_recv = Callable());
	Error sync_all(const ResourceUID::ID &p_scene_id, int p_peer);
	Error send_sync(int p_peer_id, const ResourceUID::ID &p_scene_id, PackedByteArray p_data, Multiplayer::TransferMode p_mode, int p_channel);
	void track(const ResourceUID::ID &p_scene_id, Object *p_object);
	void untrack(const ResourceUID::ID &p_scene_id, Object *p_object);

	// Used by MultiplayerAPI
	void spawn_all(int p_peer);
	void process_spawn_despawn(int p_from, const uint8_t *p_packet, int p_packet_len, bool p_spawn);
	void process_sync(int p_from, const uint8_t *p_packet, int p_packet_len);
	void scene_enter_exit_notify(const String &p_scene, Node *p_node, bool p_enter);
	void poll();

	MultiplayerReplicator(MultiplayerAPI *p_multiplayer) {
		multiplayer = p_multiplayer;
	}
};

VARIANT_ENUM_CAST(MultiplayerReplicator::ReplicationMode);

#endif // MULTIPLAYER_REPLICATOR_H