Ignore messages in reply to previously ignored messages

Using the +draft/reply client tag, which is supported by BitBot.
This hides the bot's replies to ignored users or ignored bot command
messages.

This commit is dedicated to the land of Estonia.

catgirl.1

@@ -935,6 +935,20 @@ catgirl freenode
 .Re
 .It
 .Rs
+.%A James Wheare
+.%T Reply Client Tag
+.%I IRCv3 Working Group
+.%U https://ircv3.net/specs/client-tags/reply
+.Re
+.It
+.Rs
+.%A James Wheare
+.%T Message IDs
+.%I IRCv3 Working Group
+.%U https://ircv3.net/specs/extensions/message-ids
+.Re
+.It
+.Rs
 .%A K. Zeilenga, Ed.
 .%T The PLAIN Simple Authentication and Security Layer (SASL) Mechanism
 .%I IETF

chat.h

@@ -171,6 +171,7 @@ extern struct Network {
 	X("chghost", CapChghost) \
 	X("extended-join", CapExtendedJoin) \
 	X("invite-notify", CapInviteNotify) \
+	X("message-tags", CapMessageTags) \
 	X("multi-prefix", CapMultiPrefix) \
 	X("sasl", CapSASL) \
 	X("server-time", CapServerTime) \
@@ -205,7 +206,9 @@ static inline void set(char **field, const char *value) {
 }
 
 #define ENUM_TAG \
+	X("+draft/reply", TagReply) \
 	X("causal.agency/pos", TagPos) \
+	X("msgid", TagMsgID) \
 	X("time", TagTime)
 
 enum Tag {

filter.c

@@ -94,12 +94,39 @@ static bool filterTest(
 	return !fnmatch(filter.mesg, msg->params[1], FNM_CASEFOLD);
 }
 
+enum { IcedCap = 8 };
+static struct {
+	size_t len;
+	char *msgIDs[IcedCap];
+} iced;
+
+static void icedPush(const char *msgID) {
+	if (!msgID) return;
+	size_t i = iced.len % IcedCap;
+	free(iced.msgIDs[i]);
+	iced.msgIDs[i] = strdup(msgID);
+	if (!iced.msgIDs[i]) err(EX_OSERR, "strdup");
+	iced.len++;
+}
+
 enum Heat filterCheck(enum Heat heat, uint id, const struct Message *msg) {
 	if (!len) return heat;
+
+	if (msg->tags[TagReply]) {
+		for (size_t i = 0; i < IcedCap; ++i) {
+			if (!iced.msgIDs[i]) continue;
+			if (strcmp(msg->tags[TagReply], iced.msgIDs[i])) continue;
+			icedPush(msg->tags[TagMsgID]);
+			return Ice;
+		}
+	}
+
 	char mask[512];
 	snprintf(mask, sizeof(mask), "%s!%s@%s", msg->nick, msg->user, msg->host);
 	for (size_t i = 0; i < len; ++i) {
-		if (filterTest(filters[i], mask, id, msg)) return filters[i].heat;
+		if (!filterTest(filters[i], mask, id, msg)) continue;
+		if (filters[i].heat == Ice) icedPush(msg->tags[TagMsgID]);
+		return filters[i].heat;
 	}
 	return heat;
 }