From d05ac5074195e08cb0d79b51e1620b463089345e Mon Sep 17 00:00:00 2001
From: Luke Murphy <lukewm@riseup.net>
Date: Sat, 1 Aug 2020 18:53:28 +0200
Subject: [PATCH] Spec out basics on send/send_batch once again

---
 simple_message_channels/smc.py | 58 +++++++++++++++-------------------
 test/test_smc.py               |  5 ---
 2 files changed, 26 insertions(+), 37 deletions(-)

diff --git a/simple_message_channels/smc.py b/simple_message_channels/smc.py
index 4f3ac83..aff548e 100644
--- a/simple_message_channels/smc.py
+++ b/simple_message_channels/smc.py
@@ -1,46 +1,40 @@
 """Sans I/O wire protocol for Hypercore"""
-from typing import List, Optional
+from typing import List, Tuple
 
 import attr
-import pyvarint
+from pyvarint import encode, encoding_length
 
 __all__ = ["SimpleMessageChannel"]
 
+
 @attr.s(auto_attribs=True)
 class SimpleMessageChannel:
     """A simple message channel."""
 
-    message: Optional[bytes] = None
-    ptr: int = 0
-    varint: int = 0
-    factor: int = 1
-    length: int = 0
-    header: int = 0
-    state: int = 0
-    consumed: int = 0
-    max_size: int = 8 * 1024 * 1024
-    types: List = attr.Factory(list)
-
-    receiving: bool = False
-    destroyed: bool = False
-    error: Optional[Exception] = None
-
-    # TODO(decentral1se): context, onmessage, onmissing
-
     async def send(self, channel: int, type: int, message: bytes) -> bytes:
-        """Produce data that can be sent over the channel."""
+        """Encode a channel, type and message data to be sent.
+
+        :param channel: the message channel identifier
+        :param type: the type of message
+        :param message: the message data
+        """
         header = channel << 4 or type
-        length = self.encoding_length(type, message) + pyvarint.encoding_length(header)
-        # TODO(decentral1se): implement offset in pyvarint encode/decode
+        length = len(message) + encoding_length(header)
+        return encode(length) + encode(header) + message
 
-    async def recv(self, data: bytes) -> bool:
-        """Receive data sent over a channel."""
-        pass
-
-    def destroy(self) -> None:
-        """Mark message channel as destroyed."""
-        self.destroyed = True
-
-    def encoding_length(self, type:int, message: bytes) -> int:
-        """TODO"""
+    async def send_batch(self, messages: List[Tuple[int, int, bytes]]) -> bytes:
+        """Encodes a series of messages into a single payload of bytes.
+
+        :param messages: Several data messages
+        """
+        payload = b""
+        for (channel, type, message) in messages:
+            payload += await self.send(channel, type, message)
+        return payload
+
+    async def recv(self, data: bytes) -> Tuple[int, int, bytes]:
+        """Encode a channel, type, message to be sent.
+
+        :param data: the message data
+        """
         pass
diff --git a/test/test_smc.py b/test/test_smc.py
index 384364b..e69de29 100644
--- a/test/test_smc.py
+++ b/test/test_smc.py
@@ -1,5 +0,0 @@
-async def test_send_produces_bytes(smc):
-    channel, type, message = 0, 0, b"abc"
-
-    payload = await smc.send(channel, type, message)
-    assert isinstance(payload, bytes)