lnwallet: add a BtcWallet implementation of WalletController

This commit adds the first concrete implementation of the
WalletController interface: BtcWallet. This implementation is simply a
series of wrapper functions are the base btcwallet struct.

Additionally, for ease of use both the BlockChain IO and Signer
interface are also implemented by BtcWallet. Finally a new WalletDriver
implementation has been implemented, and will be register by the init()
method within this new package.

lnwallet/btcwallet/config.go

@@ -0,0 +1,94 @@
+package btcwallet
+
+import (
+	"path/filepath"
+
+	"github.com/roasbeef/btcd/chaincfg"
+	"github.com/roasbeef/btcd/wire"
+	"github.com/roasbeef/btcutil"
+	_ "github.com/roasbeef/btcwallet/walletdb/bdb"
+)
+
+var (
+	lnwalletHomeDir = btcutil.AppDataDir("lnwallet", false)
+	defaultDataDir  = lnwalletHomeDir
+
+	defaultLogFilename = "lnwallet.log"
+	defaultLogDirname  = "logs"
+	defaultLogDir      = filepath.Join(lnwalletHomeDir, defaultLogDirname)
+
+	btcdHomeDir        = btcutil.AppDataDir("btcd", false)
+	btcdHomedirCAFile  = filepath.Join(btcdHomeDir, "rpc.cert")
+	defaultRPCKeyFile  = filepath.Join(lnwalletHomeDir, "rpc.key")
+	defaultRPCCertFile = filepath.Join(lnwalletHomeDir, "rpc.cert")
+
+	// defaultPubPassphrase is the default public wallet passphrase which is
+	// used when the user indicates they do not want additional protection
+	// provided by having all public data in the wallet encrypted by a
+	// passphrase only known to them.
+	defaultPubPassphrase = []byte("public")
+
+	walletDbName = "lnwallet.db"
+)
+
+// Config is a struct which houses configuration paramters which modify the
+// instance of BtcWallet generated by the New() function.
+type Config struct {
+	// DataDir is the name of the directory where the wallet's persistent
+	// state should be sotred.
+	DataDir string
+
+	// LogDir is the name of the directory which should be used to store
+	// generated log files.
+	LogDir string
+
+	// DebugLevel is a string representing the level of verbosity the
+	// logger should use.
+	DebugLevel string
+
+	// RpcHost is the host and port to use to reach the rpc sever.
+	RpcHost string // localhost:18334
+
+	// RpcUser is the username which should be used to authentiate with the
+	// rpc server.
+	RpcUser string
+
+	// RpcPass is the password which should be used to authenticate the
+	// connection with the RPC server.
+	RpcPass string
+
+	// RpcNoTLS denotes if a TLS connection should be attempted when
+	// connecting to the RPC server.
+	RpcNoTLS bool
+
+	// RPCCert directory where the TLS certificate of the RPC sever is
+	// stored. If the RpcNoTLS is false, then this value will be unused.
+	RPCCert string
+	RPCKey  string
+
+	// CACert is the raw RPC cert for btcd.
+	CACert []byte
+
+	PrivatePass []byte
+	PublicPass  []byte
+	HdSeed      []byte
+
+	NetParams *chaincfg.Params
+}
+
+// networkDir returns the directory name of a network directory to hold wallet
+// files.
+func networkDir(dataDir string, chainParams *chaincfg.Params) string {
+	netname := chainParams.Name
+
+	// For now, we must always name the testnet data directory as "testnet"
+	// and not "testnet3" or any other version, as the chaincfg testnet3
+	// paramaters will likely be switched to being named "testnet3" in the
+	// future.  This is done to future proof that change, and an upgrade
+	// plan to move the testnet3 data directory can be worked out later.
+	if chainParams.Net == wire.TestNet3 {
+		netname = "testnet"
+	}
+
+	return filepath.Join(dataDir, netname)
+}