* simple_secure_chat now with a proper CLI

* new: BaseChatMesh class, for abstract chat client

src/helpers/BaseChatMesh.h

@@ -0,0 +1,88 @@
+#pragma once
+
+#include <Arduino.h>   // needed for PlatformIO
+#include <Mesh.h>
+#include <helpers/AdvertDataHelpers.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;
+  uint8_t shared_secret[PUB_KEY_SIZE];
+};
+
+#define MAX_SEARCH_RESULTS   8
+
+#define MSG_SEND_FAILED       0
+#define MSG_SEND_SENT_FLOOD   1
+#define MSG_SEND_SENT_DIRECT  2
+
+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);
+};
+
+/**
+ *  \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;
+
+  mesh::Packet* composeMsgPacket(const ContactInfo& recipient, 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;
+    txt_send_timeout = 0;
+  }
+
+  // 'UI' concepts, for sub-classes to implement
+  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, bool was_flood, uint32_t sender_timestamp, 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;
+
+  // 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;
+
+public:
+  mesh::Packet* createSelfAdvert(const char* name);
+  int  sendMessage(const ContactInfo& recipient, uint8_t attempt, const char* text, uint32_t& expected_ack);
+  void resetPathTo(ContactInfo& recipient);
+  void scanRecentContacts(int last_n, ContactVisitor* visitor);
+  ContactInfo* searchContactsByPrefix(const char* name_prefix);
+  bool  addContact(const ContactInfo& contact);
+
+  void loop();
+};