Adds peer discovery

internal/engine/peers.go

@@ -0,0 +1,81 @@
+// MIT License
+//
+// Copyright 2020-2021 Kompendium, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+
+package engine
+
+import (
+	"fmt"
+	"sync"
+)
+
+// Peer represents a connected remote node.
+type Peer struct {
+	addr    uint32
+	hash    string
+	version string
+}
+
+// PeerStore holds active Peers, managing them in a concurrency safe
+// manner and providing lookup via various functions
+type PeerStore struct {
+	mtx       sync.RWMutex
+	peers     map[string]*Peer // hash -> peer
+	connected map[string]int   // (ip|ip:port) -> count
+	current   []*Peer
+	incoming  int
+	outgoing  int
+}
+
+// NewPeerStore initializes a new peer store
+func NewPeerStore() *PeerStore {
+	ps := new(PeerStore)
+	ps.peers = make(map[string]*Peer)
+	ps.connected = make(map[string]int)
+	return ps
+}
+
+// Add a peer to be managed. Returns an error if a peer with that hash
+// is already tracked
+func (ps *PeerStore) Add(p *Peer) error {
+	if p == nil {
+		return fmt.Errorf("trying to add nil")
+	}
+	ps.mtx.Lock()
+	defer ps.mtx.Unlock()
+
+	if _, ok := ps.peers[p.hash]; ok {
+		return fmt.Errorf("peer already exists")
+	}
+	ps.current = nil
+	ps.peers[p.hash] = p
+	ps.connected[fmt.Sprint(p.addr)]++
+	ps.connected[p.version]++
+
+	return nil
+}
+
+// Get list of all peers available on the Network
+func GetPeers() []Peer {
+	// do network discovery
+
+	return []Peer{}
+}