# HG changeset patch
# User Jonas Schäfer <jonas@wielicki.name>
# Date 1622294225 -7200
# Node ID b305814bd93016a6a7a6fb97535e3884922aca19
# Parent  d95fcde6e39d6aea7ceb54289823a792a6c0b328
mod_muc_dicebot: A thing to roll dice

Do you see what happens, Jitsi? Do you see what happens when you
make it hard for me to use a proper bot? This is what happens,
Jitsi. This is what happens when you meet a stranger in the alps!

Ahem. In all seriousness, this is more of a quick hack than
anything else. It will look for `.r` in MUC messages and if it
finds it, it'll interpret it as an instruction to roll a few
dice. Injects the results in the body of the message. Eats the
message alive if it is malformed.

diff -r d95fcde6e39d -r b305814bd930 mod_muc_dicebot/mod_muc_dicebot.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_muc_dicebot/mod_muc_dicebot.lua	Sat May 29 15:17:05 2021 +0200
@@ -0,0 +1,70 @@
+local muc = module:depends("muc");
+local rand = require"util.random";
+
+local s_match = string.match;
+local s_gmatch = string.gmatch;
+local t_insert = table.insert;
+local t_concat = table.concat;
+
+local rooms = module:get_option_set("muc_dicebot_rooms", nil);
+local xmlns_nick = "http://jabber.org/protocol/nick";
+
+local function is_room_affected(roomjid)
+	return not rooms or rooms:contains(roomjid)
+end
+
+local function roll(sides)
+	if sides > 256 then
+		return nil, "too many sides"
+	end
+	local factor = math.floor(256 / sides);
+	local cutoff = sides * factor;
+	module:log("error", "%d -> %d %d %d", sides, max, factor, cutoff);
+	for i=1,10 do
+		local randomness = string.byte(rand.bytes(1), 1);
+		module:log("error", "%d", randomness);
+		if randomness < cutoff then
+			return (randomness % sides) + 1
+		end
+	end
+	return nil, "failed to find valid number"
+end
+
+local function muc_broadcast_message(event)
+	if not is_room_affected(event.room.jid) then
+		return
+	end
+
+	local stanza = event.stanza;
+	local body = stanza:get_child("body");
+	local text = body:get_text();
+	module:log("error", "%q %q %q", stanza, body, text);
+	local dice = s_match(text, "^[%.!]r%s(.+)$");
+	if not dice or dice == "" then
+		return
+	end
+
+	local results = {};
+	local count = 0;
+	local sum = 0;
+	for ndice, sep, sides in s_gmatch(dice, "(%d*)([wd]?)(%d+)") do
+		if not sep or sep == "" then
+			sides = ndice .. sides
+			ndice = "1"
+		end
+		local ndice = tonumber(ndice);
+		count = count + ndice;
+		if count > 100 then
+			return true
+		end
+		local sides = tonumber(sides);
+		for i=1,ndice do
+			local value = roll(sides);
+			t_insert(results, tostring(value));
+			sum = sum + value;
+		end
+	end
+	body:text("\n⇒ "..t_concat(results, " ").." (sum: "..sum..")");
+end
+
+module:hook("muc-broadcast-message", muc_broadcast_message);