32blit-pico/multiplayer.cpp

#include <cstring>
#include "multiplayer.hpp"

#include "usb.hpp"

#include "engine/api_private.hpp"

static bool multiplayer_enabled = false;
static bool peer_connected = false;

static uint16_t mp_buffer_len, mp_buffer_off;
static uint8_t *mp_buffer = nullptr;

CDCCommand::Status CDCHandshakeCommand::update() {
  uint8_t b;
  usb_cdc_read(&b, 1);
  peer_connected = b != 0;

  if(peer_connected)
    send_multiplayer_handshake(true);

  return Status::Done;
}

void CDCUserCommand::init() {
  mp_buffer_off = 0;
}

CDCCommand::Status CDCUserCommand::update() {
  // read length
  if(!mp_buffer) {
    if(usb_cdc_read_available() < 2)
        return Status::Continue;

    usb_cdc_read((uint8_t *)&mp_buffer_len, 2);
    mp_buffer = new uint8_t[mp_buffer_len];
  }

  // read data
  mp_buffer_off += usb_cdc_read(mp_buffer + mp_buffer_off, mp_buffer_len - mp_buffer_off);

  if(mp_buffer_off == mp_buffer_len) {
    if(blit::api_data.message_received)
      blit::api_data.message_received(mp_buffer, mp_buffer_len);

    delete[] mp_buffer;
    mp_buffer = nullptr;
    return Status::Done;
  }

  return Status::Continue;
}

void send_multiplayer_handshake(bool is_reply) {
  uint8_t val = 0;
  if(multiplayer_enabled)
    val = is_reply ? 2 : 1;

  uint8_t buf[]{'3', '2', 'B', 'L', 'M', 'L', 'T','I', val};
  usb_cdc_write(buf, 9);
  usb_cdc_flush_write();
}

void update_multiplayer() {
  if(!usb_cdc_connected()) {
    peer_connected = false;
  }
}

bool is_multiplayer_connected() {
  return multiplayer_enabled && peer_connected;
}

void set_multiplayer_enabled(bool enabled) {
  multiplayer_enabled = enabled;

  if(!enabled)
    send_multiplayer_handshake();
}

void send_multiplayer_message(const uint8_t *data, uint16_t len) {
  if(!peer_connected)
    return;

  uint8_t buf[]{'3', '2', 'B', 'L', 'U', 'S', 'E','R',
    uint8_t(len & 0xFF), uint8_t(len >> 8)
  };
  usb_cdc_write(buf, 10);

  usb_cdc_write((uint8_t *)data, len);

  usb_cdc_flush_write();
}