add interface section formatting

vpn_manager/__init__.py

@@ -1,2 +1 @@
 from .__main__ import *
-

vpn_manager/__main__.py

@@ -1,19 +1,55 @@
 from dataclasses import dataclass
+from textwrap import dedent
+
 
 @dataclass
-class StaticPeer:
+class Peer:
     public_key: str
-    endpoint: str
+    private_key: str
+    address_cidr: str
     port: str
+    endpoint: str = None
 
 
 def format_static_peer(static_peer, routes, keepalive=30):
-    return f'''[Peer]
+    return f"""
+[Peer]
 PublicKey = {static_peer.public_key}
 AllowedIPs = {routes}
 Endpoint = {static_peer.endpoint}:{static_peer.port}
-PersistentKeepAlive = {keepalive}'''
-    
+PersistentKeepAlive = {keepalive}
+""".strip()
+
+
+def format_interface(peer, dns, forward=False):
+    if forward:
+        forward = dedent(
+            """\
+            PostUp = iptables -A FORWARD -i wg0 -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
+            PostDown = iptables -D FORWARD -i wg0 -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE
+            """
+        )
+        # wg0 always?
+        # eth0 always?
+    else:
+        forward = ""
+    if peer.port:
+        port = f"ListenPort = {peer.port}\n"
+    else:
+        port = ""
+    dns = f"DNS = {dns}\n"
+    return f"""
+[Interface]
+PrivateKey = {peer.private_key}
+Address = {peer.address_cidr}
+{port}\
+{dns}\
+{forward}\
+""".strip()
+
+
+def remove_empty_lines(text):
+    return "\n".join([s for s in text.splitlines() if s.strip()])
 
 
 def main():