From e2afc9eae28def55cfe7d2d0eef915034d5c9b59 Mon Sep 17 00:00:00 2001
From: Sir Darkrengarius <darkren92@gmail.com>
Date: Thu, 12 Sep 2019 14:11:22 +0300
Subject: [PATCH] Add RPC server for server

---
 pkg/app2/server_rpc.go | 191 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 191 insertions(+)
 create mode 100644 pkg/app2/server_rpc.go

diff --git a/pkg/app2/server_rpc.go b/pkg/app2/server_rpc.go
new file mode 100644
index 000000000..ba73f4fe8
--- /dev/null
+++ b/pkg/app2/server_rpc.go
@@ -0,0 +1,191 @@
+package app2
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"sync"
+
+	"github.com/skycoin/dmsg"
+
+	"github.com/skycoin/skywire/pkg/routing"
+)
+
+type ServerRPC struct {
+	dmsgC       *dmsg.Client
+	conns       map[uint16]net.Conn
+	connsMx     sync.RWMutex
+	lstConnID   uint16
+	listeners   map[uint16]*dmsg.Listener
+	listenersMx sync.RWMutex
+	lstLisID    uint16
+}
+
+func (r *ServerRPC) nextConnID() (*uint16, error) {
+	r.connsMx.Lock()
+
+	connID := r.lstConnID + 1
+	for ; connID < r.lstConnID; connID++ {
+		if _, ok := r.conns[connID]; !ok {
+			break
+		}
+	}
+
+	if connID == r.lstConnID {
+		r.connsMx.Unlock()
+		return nil, errors.New("no more available conns")
+	}
+
+	r.conns[connID] = nil
+	r.lstConnID = connID
+
+	r.connsMx.Unlock()
+	return &connID, nil
+}
+
+func (r *ServerRPC) nextLisID() (*uint16, error) {
+	r.listenersMx.Lock()
+
+	lisID := r.lstLisID + 1
+	for ; lisID < r.lstLisID; lisID++ {
+		if _, ok := r.listeners[lisID]; !ok {
+			break
+		}
+	}
+
+	if lisID == r.lstLisID {
+		r.listenersMx.Unlock()
+		return nil, errors.New("no more available listeners")
+	}
+
+	r.listeners[lisID] = nil
+	r.lstLisID = lisID
+
+	r.listenersMx.Unlock()
+	return &lisID, nil
+}
+
+func (r *ServerRPC) setConn(connID uint16, conn net.Conn) error {
+	r.connsMx.Lock()
+
+	if c, ok := r.conns[connID]; ok && c != nil {
+		r.connsMx.Unlock()
+		return errors.New("conn already exists")
+	}
+
+	r.conns[connID] = conn
+
+	r.connsMx.Unlock()
+	return nil
+}
+
+func (r *ServerRPC) setListener(lisID uint16, lis *dmsg.Listener) error {
+	r.listenersMx.Lock()
+
+	if l, ok := r.listeners[lisID]; ok && l != nil {
+		r.listenersMx.Unlock()
+		return errors.New("listener already exists")
+	}
+
+	r.listeners[lisID] = lis
+
+	r.listenersMx.Unlock()
+	return nil
+}
+
+func (r *ServerRPC) getConn(connID uint16) (net.Conn, bool) {
+	r.connsMx.RLock()
+	conn, ok := r.conns[connID]
+	r.connsMx.RUnlock()
+	return conn, ok
+}
+
+func (r *ServerRPC) getListener(lisID uint16) (*dmsg.Listener, bool) {
+	r.listenersMx.RLock()
+	lis, ok := r.listeners[lisID]
+	r.listenersMx.RUnlock()
+	return lis, ok
+}
+
+type DialReq struct {
+	Remote routing.Addr
+}
+
+func (r *ServerRPC) Dial(req *DialReq, connID *uint16) error {
+	connID, err := r.nextConnID()
+	if err != nil {
+		return err
+	}
+
+	tp, err := r.dmsgC.Dial(context.TODO(), req.Remote.PubKey, uint16(req.Remote.Port))
+	if err != nil {
+		return err
+	}
+
+	if err := r.setConn(*connID, tp); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+type ListenReq struct {
+	Local routing.Addr
+}
+
+func (r *ServerRPC) Listen(req *ListenReq, lisID *uint16) error {
+	lisID, err := r.nextLisID()
+	if err != nil {
+		return err
+	}
+
+	dmsgL, err := r.dmsgC.Listen(uint16(req.Local.Port))
+	if err != nil {
+		return err
+	}
+
+	if err := r.setListener(*lisID, dmsgL); err != nil {
+		// TODO: close listener
+		return err
+	}
+
+	return nil
+}
+
+func (r *ServerRPC) Accept(lisID *uint16, connID *uint16) error {
+	lis, ok := r.getListener(*lisID)
+	if !ok {
+		return fmt.Errorf("not listener with id %d", *lisID)
+	}
+
+	connID, err := r.nextConnID()
+	if err != nil {
+		return err
+	}
+
+	tp, err := lis.Accept()
+	if err != nil {
+		return err
+	}
+
+	if err := r.setConn(*connID, tp); err != nil {
+		// TODO: close conn
+		return err
+	}
+
+	return nil
+}
+
+type WriteReq struct {
+	ConnID uint16
+	B      []byte
+}
+
+func (r *ServerRPC) Write(req *WriteReq, n *int) error {
+	conn, ok := r.getConn(req.ConnID)
+	if !ok {
+		return fmt.Errorf("not conn with id %d", req.ConnID)
+	}
+
+}