syntax = "proto3";
package lnex;

// ─── HANDSHAKE ──────────────────────────────────────────────────────────────

// Server → Client on TCP connect (packet_id = 0x0001)
message Hello {
  string lnex_version    = 1;  // "v1"
  bytes  server_pubkey   = 2;  // 32-byte Ed25519 public key
  bytes  challenge_nonce = 3;  // 32-byte random challenge
  string node_name       = 4;
}

// Client → Server (packet_id = 0x0002)
message Auth {
  bytes  client_pubkey  = 1;  // 32-byte Ed25519 public key
  string nickname       = 2;
  string lnex_version   = 3;
  bytes  signature      = 4;  // Ed25519 sig over challenge_nonce
}

// Server → Client on success (packet_id = 0x0003)
message Session {
  string session_id  = 1;
  string token       = 2;
  int64  expires_at  = 3;  // Unix ms, 0 = no expiry
}

// ─── KEEPALIVE ──────────────────────────────────────────────────────────────

// Either direction (0x0004 / 0x0005)
message Ping {
  int64 timestamp = 1;  // Unix ms
}

message Pong {
  int64 timestamp = 1;  // Echo of Ping.timestamp
}

// ─── CHANNELS ───────────────────────────────────────────────────────────────

// Client → Gateway (0x0030)
message JoinChannel {
  string channel_id = 1;
}

// Client → Gateway (0x0031)
message LeaveChannel {
  string channel_id = 1;
}

// Gateway → Client (0x0032) — full channel snapshot on join
message ChannelState {
  string          channel_id     = 1;
  string          channel_name   = 2;
  ChannelKind     kind           = 3;
  repeated Member members        = 4;
  string          voice_endpoint = 5;  // host:port of voice-node UDP

  enum ChannelKind {
    TEXT  = 0;
    VOICE = 1;
  }

  message Member {
    string user_id   = 1;
    string nickname  = 2;
    bool   in_voice  = 3;
  }
}

// Broadcast → all channel members (0x0040 / 0x0041)
message UserJoin {
  string channel_id = 1;
  string user_id    = 2;
  string nickname   = 3;
}

message UserLeave {
  string channel_id = 1;
  string user_id    = 2;
}

// ─── CHAT ───────────────────────────────────────────────────────────────────

// Client → Gateway, broadcast to channel (0x0020)
message ChatMessage {
  string message_id  = 1;  // UUID v4, generated by client
  string channel_id  = 2;
  string sender_id   = 3;  // sender pubkey short form
  string content     = 4;
  int64  timestamp   = 5;  // Unix ms
}

// Gateway → Client on join (0x0021) — recent history
message ChatHistory {
  string              channel_id = 1;
  repeated ChatMessage messages  = 2;
}

// ─── VOICE STATE ────────────────────────────────────────────────────────────

// Broadcast on voice state change (0x0011)
message VoiceState {
  string user_id    = 1;
  string channel_id = 2;

  enum State {
    SILENT   = 0;
    SPEAKING = 1;
    MUTED    = 2;
    DEAFENED = 3;
  }

  State state = 3;
}

// ─── ERRORS ─────────────────────────────────────────────────────────────────

// Any direction (0x00F0)
message Error {
  uint32 code    = 1;  // ErrorCode enum value
  string message = 2;
}

// ─── DISCONNECT ─────────────────────────────────────────────────────────────

// Any direction (0x00FF) — graceful close
message Disconnect {
  string reason = 1;  // optional human-readable reason
}