Default to using the bitcoin mainnet network subdirectory

To ease migration for c-lightning v0.8.0 users.

See ElementsProject/lightning-charge#69

Resolves ElementsProject/lightning-charge#70
and shesek/spark-wallet#130

index.js

@@ -2,22 +2,36 @@
 
 const path = require('path');
 const net = require('net');
+const fs = require('fs');
 const readline = require('readline');
 const debug = require('debug')('clightning-client');
 const {EventEmitter} = require('events');
 const LightningError = require('error/typed')({ type: 'lightning', message: 'lightning-client error' })
 const methods = require('./methods');
 
 const defaultRpcPath = path.join(require('os').homedir(), '.lightning')
+    , fStat = (...p) => fs.statSync(path.join(...p))
+    , fExists = (...p) => fs.existsSync(path.join(...p))
 
 class LightningClient extends EventEmitter {
     constructor(rpcPath=defaultRpcPath) {
         if (!path.isAbsolute(rpcPath)) {
             throw new Error('The rpcPath must be an absolute path');
         }
 
-        if (rpcPath.slice(-14) !== '/lightning-rpc') {
-            rpcPath = path.join(rpcPath, '/lightning-rpc');
+        if (!fExists(rpcPath) || !fStat(rpcPath).isSocket()) {
+          // network directory provided, use the lightning-rpc within in
+          if (fExists(rpcPath, 'lightning-rpc')) {
+            rpcPath = path.join(rpcPath, 'lightning-rpc');
+          }
+
+          // main data directory provided, default to using the bitcoin mainnet subdirectory
+          // to be removed in v0.2.0
+          else if (fExists(rpcPath, 'bitcoin', 'lightning-rpc')) {
+            console.error(`WARN: ${rpcPath}/lightning-rpc is missing, using the bitcoin mainnet subdirectory at ${rpcPath}/bitcoin instead.`)
+            console.error(`WARN: specifying the main lightning data directory is deprecated, please specify the network directory explicitly with "--ln-path ${rpcPath}/<network>".\n`)
+            rpcPath = path.join(rpcPath, 'bitcoin', 'lightning-rpc')
+          }
         }
 
         debug(`Connecting to ${rpcPath}`);