From c66c7473bf792d547500673a4ec13e1ac03c503f Mon Sep 17 00:00:00 2001
From: Olaoluwa Osuntokun <laolu32@gmail.com>
Date: Tue, 2 May 2017 19:49:14 -0700
Subject: [PATCH] lnd: register selected chain within chainRegistry on boot

This commit modifies the initialization logic within lnd.go to
recognize which chain was selected by the user and to set the
parameters accordingly. With this commit, lnd is now able to switch
between chains within nothing more than a toggle of config paramters!
---
 lnd.go | 51 ++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 15 deletions(-)

diff --git a/lnd.go b/lnd.go
index e76ceee1..b25d7589 100644
--- a/lnd.go
+++ b/lnd.go
@@ -8,7 +8,6 @@ import (
 	"net/http"
 	_ "net/http/pprof"
 	"os"
-	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
@@ -29,8 +28,9 @@ import (
 )
 
 var (
-	cfg             *config
-	shutdownChannel = make(chan struct{})
+	cfg              *config
+	shutdownChannel  = make(chan struct{})
+	registeredChains = newChainRegistry()
 )
 
 // lndMain is the true entry point for lnd. This function is required since
@@ -64,22 +64,31 @@ func lndMain() error {
 	// network related metadata.
 	chanDB, err := channeldb.Open(cfg.DataDir)
 	if err != nil {
-		fmt.Println("unable to open channeldb: ", err)
+		ltndLog.Errorf("unable to open channeldb: ", err)
 		return err
 	}
 	defer chanDB.Close()
 
+	// Set the RPC config from the "home" chain. Multi-chain isn't yet
+	// active, so we'll restrict usage to a particular chain for now.
+	homeChainConfig := cfg.Bitcoin
+	if registeredChains.PrimaryChain() == litecoinChain {
+		homeChainConfig = cfg.Litecoin
+	}
+	ltndLog.Infof("Primary chain is set to: %v",
+		registeredChains.PrimaryChain())
+
 	// Next load btcd's TLS cert for the RPC connection. If a raw cert was
 	// specified in the config, then we'll set that directly. Otherwise, we
 	// attempt to read the cert from the path specified in the config.
 	var rpcCert []byte
-	if cfg.RawRPCCert != "" {
-		rpcCert, err = hex.DecodeString(cfg.RawRPCCert)
+	if homeChainConfig.RawRPCCert != "" {
+		rpcCert, err = hex.DecodeString(homeChainConfig.RawRPCCert)
 		if err != nil {
 			return err
 		}
 	} else {
-		certFile, err := os.Open(cfg.RPCCert)
+		certFile, err := os.Open(homeChainConfig.RPCCert)
 		if err != nil {
 			return err
 		}
@@ -96,14 +105,14 @@ func lndMain() error {
 	// specified, then we use that directly. Otherwise, we assume the
 	// default port according to the selected chain parameters.
 	var btcdHost string
-	if strings.Contains(cfg.RPCHost, ":") {
-		btcdHost = cfg.RPCHost
+	if strings.Contains(homeChainConfig.RPCHost, ":") {
+		btcdHost = homeChainConfig.RPCHost
 	} else {
-		btcdHost = fmt.Sprintf("%v:%v", cfg.RPCHost, activeNetParams.rpcPort)
+		btcdHost = fmt.Sprintf("%v:%v", homeChainConfig.RPCHost, activeNetParams.rpcPort)
 	}
 
-	btcdUser := cfg.RPCUser
-	btcdPass := cfg.RPCPass
+	btcdUser := homeChainConfig.RPCUser
+	btcdPass := homeChainConfig.RPCPass
 
 	// TODO(roasbeef): parse config here and select chosen notifier instead
 	rpcConfig := &btcrpcclient.ConnConfig{
@@ -124,10 +133,10 @@ func lndMain() error {
 	// TODO(roasbeef): parse config here select chosen WalletController
 	walletConfig := &btcwallet.Config{
 		PrivatePass: []byte("hello"),
-		DataDir:     filepath.Join(cfg.DataDir, "lnwallet"),
+		DataDir:     homeChainConfig.ChainDir,
 		RPCHost:     btcdHost,
-		RPCUser:     cfg.RPCUser,
-		RPCPass:     cfg.RPCPass,
+		RPCUser:     homeChainConfig.RPCUser,
+		RPCPass:     homeChainConfig.RPCPass,
 		CACert:      rpcCert,
 		NetParams:   activeNetParams.Params,
 	}
@@ -160,6 +169,18 @@ func lndMain() error {
 		net.JoinHostPort("", strconv.Itoa(cfg.PeerPort)),
 	}
 
+	// Finally before we start the server, we'll register the "holy
+	// trinity" of interface for our current "home chain" with the active
+	// chainRegistry interface.
+	primaryChain := registeredChains.PrimaryChain()
+	registeredChains.RegisterChain(primaryChain, &chainControl{
+		chainIO:       bio,
+		chainNotifier: notifier,
+		wallet:        wallet,
+	})
+
+	// With all the relevant chains initialized, we can finally start the
+	// server itself.
 	server, err := newServer(defaultListenAddrs, notifier, bio,
 		fundingSigner, wallet, chanDB)
 	if err != nil {