From f5abd4f1d1457c1aa5560dc366261348dbffd359 Mon Sep 17 00:00:00 2001
From: ThomasV <thomasv@electrum.org>
Date: Wed, 13 Jul 2022 10:14:34 +0200
Subject: [PATCH] add command line for rebalancing channels

---
 electrum/commands.py | 18 ++++++++++++++++++
 electrum/lnworker.py | 11 ++++++++++-
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/electrum/commands.py b/electrum/commands.py
index 329fbebae..5a9ac86a7 100644
--- a/electrum/commands.py
+++ b/electrum/commands.py
@@ -1232,6 +1232,24 @@ class Commands:
         """ return the local watchtower's ctn of channel. used in regtests """
         return await self.network.local_watchtower.sweepstore.get_ctn(channel_point, None)
 
+    @command('wnl')
+    async def rebalance_channels(self, from_scid, dest_scid, amount, wallet: Abstract_Wallet = None):
+        """
+        Rebalance channels.
+        If trampoline is used, channels must be with diferent trampolines.
+        """
+        from .lnutil import ShortChannelID
+        from_scid = ShortChannelID.from_str(from_scid)
+        dest_scid = ShortChannelID.from_str(dest_scid)
+        from_channel = wallet.lnworker.get_channel_by_scid(from_scid)
+        dest_channel = wallet.lnworker.get_channel_by_scid(dest_scid)
+        amount_sat = satoshis(amount)
+        success, log = await wallet.lnworker.rebalance_channels(from_channel, dest_channel, amount_sat * 1000)
+        return {
+            'success': success,
+            'log': [x.formatted_tuple() for x in log]
+        }
+
     @command('wnpl')
     async def normal_swap(self, onchain_amount, lightning_amount, password=None, wallet: Abstract_Wallet = None):
         """
diff --git a/electrum/lnworker.py b/electrum/lnworker.py
index bfa9d8f3e..56c537fe5 100644
--- a/electrum/lnworker.py
+++ b/electrum/lnworker.py
@@ -693,6 +693,11 @@ class LNWallet(LNWorker):
     def get_channel_by_id(self, channel_id: bytes) -> Optional[Channel]:
         return self._channels.get(channel_id, None)
 
+    def get_channel_by_scid(self, scid: bytes) -> Optional[Channel]:
+        for chan in self._channels.values():
+            if chan.short_channel_id == scid:
+                return chan
+
     def diagnostic_name(self):
         return self.wallet.diagnostic_name()
 
@@ -2299,6 +2304,10 @@ class LNWallet(LNWorker):
             return (chan, swap_recv_amount)
 
     async def rebalance_channels(self, chan1, chan2, amount_msat):
+        if chan1 == chan2:
+            raise Exception('Rebalance requires two different channels')
+        if not self.channel_db and chan1.node_id == chan2.node_id:
+            raise Exception('Rebalance requires channels from different trampolines')
         lnaddr, invoice = self.create_invoice(
             amount_msat=amount_msat,
             message='rebalance',
@@ -2306,7 +2315,7 @@ class LNWallet(LNWorker):
             fallback_address=None,
             channels = [chan2]
         )
-        await self.pay_invoice(
+        return await self.pay_invoice(
             invoice, channels=[chan1])
 
     def num_sats_can_receive_no_mpp(self) -> Decimal: