smack-a-brother/src/session.h

#pragma once

#include "input.h"
#include "sim.h"
#include <map>
#include <string>

struct Game;

constexpr int SESSION_RING = 64;
// A member's connection has no ping to show.
constexpr float PING_NONE = -2;

// One tick of the room as this screen played it: the state as it started (and its checksum), and once the tick's
// events were in, who played each fighter and the controls each was given.
struct SessionTick
{
    Snapshot state;
    Controls controls[MAX_FIGHTERS];
    int owners[MAX_FIGHTERS];
    Uint32 checksum = 0;
    int tick = -1;
};

// The server's frame for a tick: every fighter's controls as it played them, after the events before them.
struct SessionFrame
{
    Controls controls[MAX_FIGHTERS];
    int count = 0;
    int events = 0;
};

// Online play: this screen runs the room it's in (the lobby's sandbox, or a game queued in it), which the server runs
// too (see server/server.cpp). It plays ahead of the server, its own controls sent for the ticks it plays and everyone
// else's guessed to keep doing what they last did. The server's frames say what everyone really did: when one differs
// from what was played, the game rewinds to that tick and plays forward again (silently). It keeps its lead over the
// server by playing a tick more, or one less, now and then, as the server says how early its controls come.
class Session
{
public:
    bool isActive = false;
    bool isJoined = false;
    bool isDesynced = false;
    // Set when the room changes, for the camera to jump.
    bool isViewChanged = false;
    int rollbacks = 0;
    int stalls = 0;

    void update(Game& game, Controls local);
    void stop(Game& game);
    bool is_wanted(Game& game);
    bool is_watching();
    bool is_playing_arena(Game& game);
    bool is_queued(Game& game);
    void arena_leave(Game& game);
    int fighter_get(Game& game, int member);
    std::string base_name_get(Game& game, int member);
    std::string name_get(Game& game, int member);
    void chat_send(Game& game, const std::string& text);
    void typing_send(Game& game, bool isTyping);
    void kick(Game& game, const std::string& name, const std::string& reason);
    int rename_wait_get();
    void queue_send(Game& game, const Rules& rules, bool isOpen = true);
    float ping_get(Game& game, int member);

private:
    SessionTick ticks[SESSION_RING];
    Controls own[SESSION_RING];
    std::map<int, SessionFrame> frames;
    // Each room's events by number, kept from before its state comes in case they come first.
    std::map<int, std::map<int, RoomEvent>> events;
    std::map<int, Uint32> checksums;
    std::map<int, Controls> held;
    // Every member's chosen name (cleaned), kept current by their renames, and the colour this screen last asked for.
    std::map<int, std::string> names;
    int room = 0;
    // The next tick to play, the first not yet confirmed, and the earliest that has to be played again.
    int tick = 0;
    int confirmed = 0;
    int rewindTo = -1;
    // How early (in ticks) this screen's controls last reached the server, and when its pace last changed.
    int lead = 0;
    int paced = 0;
    int sentColor = -1;
    // When a newcomer gives up waiting for the WebRTC link, and whether its fighter has been brought in.
    Uint64 linkDeadline = 0;
    bool isProfileSent = false;
    // With SAB_NET_STATS set, how it's keeping up goes to the log every few seconds.
    bool isStatsLogged = false;
    // Names can change only every RENAME_WAIT, so a player can't dodge being kicked by renaming: when this screen's can
    // next, and whether it's told its pending one is waiting.
    Uint64 nextRename = 0;
    bool isRenameWaiting = false;

    void start(Game& game);
    void packets_take(Game& game);
    void packet_handle(Game& game, const std::string& bytes);
    void state_load(Game& game, PacketReader& reader, int serial, int at);
    void frames_take(PacketReader& reader);
    void confirm(Game& game);
    void rewind(Game& game);
    void step(Game& game, bool isLive);
    void inputs_send(Game& game);
    void local_find(Game& game);
    void profile_watch(Game& game);
    void text_send(Game& game, PacketType type, const std::string& text);
};