#ifndef GAME_ROOT_HPP
#define GAME_ROOT_HPP

#include "game_mode.hpp"
#include "godot_cpp/classes/random_number_generator.hpp"
#include "level.hpp"
#include <godot_cpp/classes/node.hpp>
#include <godot_cpp/classes/packed_scene.hpp>
#include <godot_cpp/templates/hash_map.hpp>
#include <godot_cpp/templates/hash_set.hpp>
#include <godot_cpp/templates/pair.hpp>
#include <godot_cpp/templates/pair.hpp>
#include <godot_cpp/templates/vector.hpp>

namespace godot {
class PlayerInput;
class IPlayer;
class SpawnPoint3D;

class GameRoot3D : public Node {
    GDCLASS(GameRoot3D, Node);
    static void _bind_methods();
public:
    // get the current active singleton instance of GameRoot
    static GameRoot3D *get_singleton();
    // returns true if there is currently a singleton active for GameRoot
    static bool has_singleton();

    virtual void _enter_tree() override;
    virtual void _ready() override;
    virtual void _exit_tree() override;

    void player_input_connected();
    // force-disconnect a player
    // calls queue_free on the IPlayer instance
    void remove_player(uint32_t player_id);
    // calls remove_player for every used player input slot
    void remove_all_players();
    // initialize and register a player instance
    // the player will be added to the tree and AFTER setup_player_input will be called
    // this way the player can initialize before setting up input
    bool initialize_player(IPlayer *player, uint32_t id);

    // shorthand for set_game_mode(Ref<GameMode>())
    // unsets the gamemode
    void reset_game_mode();

    // shorthand for load_level(level, Transform3D())
    Level3D *load_level(Ref<PackedScene> level);
    // load a level, only works if 'level' is a valid scene where the root Node can cast to 'Level3D'
    // sets the level's root node's global transform
    Level3D *load_level_at(Ref<PackedScene> level, Transform3D at);
    void unload_all_levels();
    void replace_levels(Ref<PackedScene> level);

    // register a spawnpoint for use when spawning players
    void register_spawn_point(SpawnPoint3D *spawn_point);
    // remove a spawnpoint so it can't be used to spawn players
    void unregister_spawn_point(SpawnPoint3D *spawn_point);
    void place_player_at_spawnpoint(IPlayer *player);
    void player_despawned(uint32_t id);

    // ----- getter / setters -----
    // override the current gamemode
    // force-respawns all players
    void set_game_mode(Ref<GameMode> prototype);
    Ref<GameMode> get_game_mode() const;
    Ref<GameState> get_game_state() const;
    void set_first_boot_level(Ref<PackedScene> level);
    Ref<PackedScene> get_first_boot_level() const;
    HashMap<StringName, Level3D *> &get_levels();
    IPlayer *get_player(uint32_t id);
    Vector<IPlayer*> get_players();
protected:
    // attempt to make 'this' the current singleton instance
    void grab_singleton();
    // attempt to stop being the active singleton instance
    // only works if the current singleton is 'this'
    void release_singleton();
    uint32_t find_empty_player_slot() const;
    IPlayer *spawn_player(uint32_t id);
    void level_unloaded(StringName scene_path);
    static bool is_valid_level(Ref<PackedScene> &level);
protected:
    static GameRoot3D *singleton_instance;

    uint32_t next_player_id{1}; // 0 is the "invalid" player id
    HashMap<uint32_t, Pair<PlayerInput*, IPlayer*>> players{};
    Ref<GameMode> game_mode{};
private:
    RandomNumberGenerator rng{};
    HashMap<StringName, Level3D*> levels{};
    Vector<SpawnPoint3D*> spawn_points{};

    Ref<PackedScene> first_boot_level{};
};
}

#endif // !GAME_ROOT_HPP