Add lastread command

mmcli.py

@@ -151,6 +151,9 @@ def resolve_team_channel(mm_api: mattermost.MMApi, query: str) -> Dict:
 	if not team:
 		raise NotFound("team", query_parts[0])
 
+	if query_parts[1].startswith("id:"):
+		channel = mm_api.get_channel(query_parts[1][3:])
+	else:
 		channel = resolve_channel(mm_api, team["id"], query_parts[1])
 	if not channel:
 		return NotFound("channel", query_parts[1])
@@ -443,6 +446,23 @@ def customstatus(mm_api: mattermost.MMApi, cmdline_args):
 		mm_api._delete(f"/v4/users/me/status/custom")
 
 
+def lastread(mm_api: mattermost.MMApi, cmdline_args):
+	team, channel = resolve_team_channel(mm_api, cmdline_args.channel) if cmdline_args.channel is not None else (None, None)
+	assert channel is not None
+	response = mm_api._get(f"/v4/users/me/channels/{channel['id']}/posts/unread?limit_after=1&limit_before=0")
+
+	if response["order"]:
+		assert len(response["order"]) == 1
+		last_read_id = response["order"][0]
+	else:
+		last_read_id = None
+
+	if cmdline_args.format == "json":
+		print(json.dumps(last_read_id))
+	if cmdline_args.format == "tsv":
+		print(last_read_id or "null")
+
+
 def tsv_escape(text):
 	return text.replace("\\", "\\\\").replace("\t", r"\t").replace("\n", r"\n")
 
@@ -488,6 +508,7 @@ ACTIONS = {
 	"edit": {"function": edit},
 	"status": {"function": status},
 	"customstatus": {"function": customstatus},
+	"lastread": {"function": lastread},
 }
 
 FORMATTERS = { "json", "tsv" }
@@ -597,6 +618,9 @@ The input format accepted on stdin is one JSON object per line. The possible fie
 	parser_customstatus.add_argument("--emoji", help="Name of emoji (without colons), e.g. coffee")
 	parser_customstatus.add_argument("text" ,   help="Text for the status", nargs="?")
 
+	parser_lastread = subparsers.add_parser("lastread", help="last read message in channel; will be null if all messages are read")
+	parser_lastread.add_argument("channel", help="URL names of team and channel: '<team>/<channel>'")
+
 	parsed = argparser.parse_args()
 
 	if not parsed.server: