From c9bc01cbb10d3ecb0acfa739653f337302b24eec Mon Sep 17 00:00:00 2001
From: MMGen <mmgen@tuta.io>
Date: Fri, 8 Jun 2018 10:20:33 +0000
Subject: [PATCH] Altcoin module loading magic

---
 mmgen/globalvars.py |  1 +
 mmgen/tw.py         | 24 ++++++------------------
 mmgen/tx.py         | 10 ++++------
 mmgen/util.py       |  9 +++++++++
 4 files changed, 20 insertions(+), 24 deletions(-)

diff --git a/mmgen/globalvars.py b/mmgen/globalvars.py
index fed00ad7..01e12b48 100755
--- a/mmgen/globalvars.py
+++ b/mmgen/globalvars.py
@@ -65,6 +65,7 @@ class g(object):
 	# Constant vars - some of these might be overriden in opts.py, but they don't change thereafter
 
 	coin                 = 'BTC'
+	token                = ''
 	debug                = False
 	debug_opts           = False
 	debug_rpc            = False
diff --git a/mmgen/tw.py b/mmgen/tw.py
index c0972d36..0618d4a6 100755
--- a/mmgen/tw.py
+++ b/mmgen/tw.py
@@ -28,6 +28,9 @@ CUR_HOME,ERASE_ALL = '\033[H','\033[0J'
 
 class TwUnspentOutputs(MMGenObject):
 
+	def __new__(cls,*args,**kwargs):
+		return MMGenObject.__new__(altcoin_subclass(cls,'tw','TwUnspentOutputs'),*args,**kwargs)
+
 	txid_w = 64
 	show_txid = True
 	can_group = True
@@ -61,12 +64,6 @@ watch-only wallet using '{}-addrimport' and then re-run this program.
 """.strip().format(g.proj_name.lower())
 	}
 
-	def __new__(cls,*args,**kwargs):
-		if g.coin == 'ETH':
-			from mmgen.altcoins.eth.tw import EthereumTwUnspentOutputs
-			cls = EthereumTwUnspentOutputs
-		return MMGenObject.__new__(cls,*args,**kwargs)
-
 	def __init__(self,minconf=1):
 		self.unspent      = self.MMGenTwOutputList()
 		self.fmt_display  = ''
@@ -350,10 +347,7 @@ watch-only wallet using '{}-addrimport' and then re-run this program.
 class TwAddrList(MMGenDict):
 
 	def __new__(cls,*args,**kwargs):
-		if g.coin == 'ETH':
-			from mmgen.altcoins.eth.tw import EthereumTwAddrList
-			cls = EthereumTwAddrList
-		return MMGenDict.__new__(cls,*args,**kwargs)
+		return MMGenDict.__new__(altcoin_subclass(cls,'tw','TwAddrList'),*args,**kwargs)
 
 	def __init__(self,usr_addr_list,minconf,showempty,showbtcaddrs,all_labels):
 
@@ -474,10 +468,7 @@ class TwAddrList(MMGenDict):
 class TrackingWallet(MMGenObject):
 
 	def __new__(cls,*args,**kwargs):
-		if g.coin == 'ETH':
-			from mmgen.altcoins.eth.tw import EthereumTrackingWallet
-			cls = EthereumTrackingWallet
-		return MMGenObject.__new__(cls,*args,**kwargs)
+		return MMGenObject.__new__(altcoin_subclass(cls,'tw','TrackingWallet'),*args,**kwargs)
 
 	def import_label(self,coinaddr,lbl):
 		# NOTE: this works because importaddress() removes the old account before
@@ -546,10 +537,7 @@ class TwGetBalance(MMGenObject):
 	fs = '{w:13} {u:<16} {p:<16} {c}\n'
 
 	def __new__(cls,*args,**kwargs):
-		if g.coin == 'ETH':
-			from mmgen.altcoins.eth.tw import EthereumTwGetBalance
-			cls = EthereumTwGetBalance
-		return MMGenObject.__new__(cls,*args,**kwargs)
+		return MMGenObject.__new__(altcoin_subclass(cls,'tw','TwGetBalance'),*args,**kwargs)
 
 	def __init__(self,minconf,quiet):
 
diff --git a/mmgen/tx.py b/mmgen/tx.py
index b49d4637..97ada6b9 100755
--- a/mmgen/tx.py
+++ b/mmgen/tx.py
@@ -219,6 +219,10 @@ txio_attrs = {
 }
 
 class MMGenTX(MMGenObject):
+
+	def __new__(cls,*args,**kwargs):
+		return MMGenObject.__new__(altcoin_subclass(cls,'tx','MMGenTX'),*args,**kwargs)
+
 	ext      = 'rawtx'
 	raw_ext  = 'rawtx'
 	sig_ext  = 'sigtx'
@@ -269,12 +273,6 @@ class MMGenTX(MMGenObject):
 		desc = 'transaction outputs'
 		member_type = 'MMGenTxOutput'
 
-	def __new__(cls,*args,**kwargs):
-		if g.coin == 'ETH':
-			from mmgen.altcoins.eth.tx import EthereumMMGenTX
-			cls = EthereumMMGenTX
-		return MMGenObject.__new__(cls,*args,**kwargs)
-
 	def __init__(self,filename=None,coin_sym_only=False,caller=None,silent_open=False):
 		self.inputs      = self.MMGenTxInputList()
 		self.outputs     = self.MMGenTxOutputList()
diff --git a/mmgen/util.py b/mmgen/util.py
index f5bdb629..82cffc99 100755
--- a/mmgen/util.py
+++ b/mmgen/util.py
@@ -891,3 +891,12 @@ def format_par(s,indent=0,width=80,as_list=False):
 			line += ('',' ')[bool(line)] + words.pop(0)
 		lines.append(' '*indent + line)
 	return lines if as_list else '\n'.join(lines) + '\n'
+
+def altcoin_subclass(cls,mod_id,cls_name):
+	if cls.__name__ != cls_name: return cls
+	pn = capfirst(g.proto.name)
+	tn = 'Token' if g.token else ''
+	e1 = 'from mmgen.altcoins.{}.{} import {}{}{}'.format(g.coin.lower(),mod_id,pn,tn,cls_name)
+	e2 = 'cls = {}{}{}'.format(pn,tn,cls_name)
+	try: exec e1; exec e2; return cls
+	except ImportError: return cls