MeshCore/src/helpers/BaseChatMesh.h

#pragma once

#include <Arduino.h>   // needed for PlatformIO
#include <Mesh.h>
#include <helpers/AdvertDataHelpers.h>
#include <helpers/TxtDataHelpers.h>

#define MAX_TEXT_LEN    (10*CIPHER_BLOCK_SIZE)  // must be LESS than (MAX_PACKET_PAYLOAD - 4 - CIPHER_MAC_SIZE - 1)

struct ContactInfo {
  mesh::Identity id;
  char name[32];
  uint8_t type;   // on of ADV_TYPE_*
  uint8_t flags;
  int8_t out_path_len;
  uint8_t out_path[MAX_PATH_SIZE];
  uint32_t last_advert_timestamp;   // by THEIR clock
  uint8_t shared_secret[PUB_KEY_SIZE];
  uint32_t lastmod;  // by OUR clock
  int32_t gps_lat, gps_lon;    // 6 dec places
  uint32_t sync_since;
};

#define MAX_SEARCH_RESULTS   8

#define MSG_SEND_FAILED       0
#define MSG_SEND_SENT_FLOOD   1
#define MSG_SEND_SENT_DIRECT  2

#define REQ_TYPE_GET_STATUS      0x01   // same as _GET_STATS
#define REQ_TYPE_KEEP_ALIVE      0x02

#define RESP_SERVER_LOGIN_OK      0   // response to ANON_REQ

class ContactVisitor {
public:
  virtual void onContactVisit(const ContactInfo& contact) = 0;
};

class BaseChatMesh;

class ContactsIterator {
  int next_idx = 0;
public:
  bool hasNext(const BaseChatMesh* mesh, ContactInfo& dest);
};

#ifndef MAX_CONTACTS
  #define MAX_CONTACTS  32
#endif

#ifndef MAX_CONNECTIONS
  #define MAX_CONNECTIONS  16
#endif

struct ConnectionInfo {
  mesh::Identity server_id;
  unsigned long next_ping;
  uint32_t last_activity;
  uint32_t keep_alive_millis;
  uint32_t expected_ack;
};

struct ChannelDetails {
  mesh::GroupChannel channel;
  char name[32];
};

/**
 *  \brief  abstract Mesh class for common 'chat' client
 */
class BaseChatMesh : public mesh::Mesh {

  friend class ContactsIterator;

  ContactInfo contacts[MAX_CONTACTS];
  int num_contacts;
  int sort_array[MAX_CONTACTS];
  int matching_peer_indexes[MAX_SEARCH_RESULTS];
  unsigned long txt_send_timeout;
#ifdef MAX_GROUP_CHANNELS
  ChannelDetails channels[MAX_GROUP_CHANNELS];
  int num_channels;  // only for addChannel()
#endif
  mesh::Packet* _pendingLoopback;
  uint8_t temp_buf[MAX_TRANS_UNIT];
  ConnectionInfo connections[MAX_CONNECTIONS];

  mesh::Packet* composeMsgPacket(const ContactInfo& recipient, uint32_t timestamp, uint8_t attempt, const char *text, uint32_t& expected_ack);

protected:
  BaseChatMesh(mesh::Radio& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc, mesh::PacketManager& mgr, mesh::MeshTables& tables)
      : mesh::Mesh(radio, ms, rng, rtc, mgr, tables)
  { 
    num_contacts = 0;
  #ifdef MAX_GROUP_CHANNELS
    memset(channels, 0, sizeof(channels));
    num_channels = 0;
  #endif
    txt_send_timeout = 0;
    _pendingLoopback = NULL;
    memset(connections, 0, sizeof(connections));
  }

  // 'UI' concepts, for sub-classes to implement
  virtual bool isAutoAddEnabled() const { return true; }
  virtual void onDiscoveredContact(ContactInfo& contact, bool is_new) = 0;
  virtual bool processAck(const uint8_t *data) = 0;
  virtual void onContactPathUpdated(const ContactInfo& contact) = 0;
  virtual void onMessageRecv(const ContactInfo& contact, mesh::Packet* pkt, uint32_t sender_timestamp, const char *text) = 0;
  virtual void onCommandDataRecv(const ContactInfo& contact, mesh::Packet* pkt, uint32_t sender_timestamp, const char *text) = 0;
  virtual void onSignedMessageRecv(const ContactInfo& contact, mesh::Packet* pkt, uint32_t sender_timestamp, const uint8_t *sender_prefix, const char *text) = 0;
  virtual uint32_t calcFloodTimeoutMillisFor(uint32_t pkt_airtime_millis) const = 0;
  virtual uint32_t calcDirectTimeoutMillisFor(uint32_t pkt_airtime_millis, uint8_t path_len) const = 0;
  virtual void onSendTimeout() = 0;
  virtual void onChannelMessageRecv(const mesh::GroupChannel& channel, mesh::Packet* pkt, uint32_t timestamp, const char *text) = 0;
  virtual uint8_t onContactRequest(const ContactInfo& contact, uint32_t sender_timestamp, const uint8_t* data, uint8_t len, uint8_t* reply) = 0;
  virtual void onContactResponse(const ContactInfo& contact, const uint8_t* data, uint8_t len) = 0;

  // storage concepts, for sub-classes to override/implement
  virtual int  getBlobByKey(const uint8_t key[], int key_len, uint8_t dest_buf[]) { return 0; }  // not implemented
  virtual bool putBlobByKey(const uint8_t key[], int key_len, const uint8_t src_buf[], int len) { return false; }

  // Mesh overrides
  void onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len) override;
  int searchPeersByHash(const uint8_t* hash) override;
  void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override;
  void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, const uint8_t* secret, uint8_t* data, size_t len) override;
  bool onPeerPathRecv(mesh::Packet* packet, int sender_idx, const uint8_t* secret, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override;
  void onAckRecv(mesh::Packet* packet, uint32_t ack_crc) override;
#ifdef MAX_GROUP_CHANNELS
  int searchChannelsByHash(const uint8_t* hash, mesh::GroupChannel channels[], int max_matches) override;
#endif
  void onGroupDataRecv(mesh::Packet* packet, uint8_t type, const mesh::GroupChannel& channel, uint8_t* data, size_t len) override;

  // Connections
  bool startConnection(const ContactInfo& contact, uint16_t keep_alive_secs);
  void stopConnection(const uint8_t* pub_key);
  bool hasConnectionTo(const uint8_t* pub_key);
  void markConnectionActive(const ContactInfo& contact);
  bool checkConnectionsAck(const uint8_t* data);
  void checkConnections();

public:
  mesh::Packet* createSelfAdvert(const char* name, double lat=0.0, double lon=0.0);
  int  sendMessage(const ContactInfo& recipient, uint32_t timestamp, uint8_t attempt, const char* text, uint32_t& expected_ack, uint32_t& est_timeout);
  int  sendCommandData(const ContactInfo& recipient, uint32_t timestamp, uint8_t attempt, const char* text, uint32_t& est_timeout);
  bool sendGroupMessage(uint32_t timestamp, mesh::GroupChannel& channel, const char* sender_name, const char* text, int text_len);
  int  sendLogin(const ContactInfo& recipient, const char* password, uint32_t& est_timeout);
  int  sendRequest(const ContactInfo& recipient, uint8_t req_type, uint32_t& tag, uint32_t& est_timeout);
  bool shareContactZeroHop(const ContactInfo& contact);
  uint8_t exportContact(const ContactInfo& contact, uint8_t dest_buf[]);
  bool importContact(const uint8_t src_buf[], uint8_t len);
  void resetPathTo(ContactInfo& recipient);
  void scanRecentContacts(int last_n, ContactVisitor* visitor);
  ContactInfo* searchContactsByPrefix(const char* name_prefix);
  ContactInfo* lookupContactByPubKey(const uint8_t* pub_key, int prefix_len);
  bool  removeContact(ContactInfo& contact);
  bool  addContact(const ContactInfo& contact);
  int getNumContacts() const { return num_contacts; }
  ContactsIterator startContactsIterator();
  ChannelDetails* addChannel(const char* name, const char* psk_base64);
  bool getChannel(int idx, ChannelDetails& dest);
  bool setChannel(int idx, const ChannelDetails& src);
  int findChannelIdx(const mesh::GroupChannel& ch);

  void loop();
};