From e779a669c8ef95386ac846ebc829332dfbfae642 Mon Sep 17 00:00:00 2001
From: John Livingston <git@john-livingston.fr>
Date: Sat, 29 Jun 2024 19:33:37 +0200
Subject: [PATCH] Poll WIP (#231):

* poll backend WIP
---
 prosody-modules/mod_muc_poll/mod_muc_poll.lua |  4 +
 prosody-modules/mod_muc_poll/poll.lib.lua     | 88 ++++++++++++++++++-
 2 files changed, 90 insertions(+), 2 deletions(-)

diff --git a/prosody-modules/mod_muc_poll/mod_muc_poll.lua b/prosody-modules/mod_muc_poll/mod_muc_poll.lua
index 2af76e34..5b1ac707 100644
--- a/prosody-modules/mod_muc_poll/mod_muc_poll.lua
+++ b/prosody-modules/mod_muc_poll/mod_muc_poll.lua
@@ -18,6 +18,7 @@ local get_room_from_jid = mod_muc.get_room_from_jid;
 local xmlns_poll = module:require("constants").xmlns_poll;
 local send_form = module:require("form").send_form;
 local process_form = module:require("form").process_form;
+local handle_groupchat = module:require("poll").handle_groupchat;
 
 -- new poll creation, get form
 module:hook("iq-get/bare/" .. xmlns_poll .. ":query", function (event)
@@ -66,3 +67,6 @@ end);
 module:hook("muc-disco#info", function (event)
 	event.reply:tag("feature", { var = xmlns_poll }):up();
 end);
+
+-- on groupchat messages, we check if this is a vote for the current poll
+module:hook("muc-occupant-groupchat", handle_groupchat);
diff --git a/prosody-modules/mod_muc_poll/poll.lib.lua b/prosody-modules/mod_muc_poll/poll.lib.lua
index 8b1607e8..4ff76658 100644
--- a/prosody-modules/mod_muc_poll/poll.lib.lua
+++ b/prosody-modules/mod_muc_poll/poll.lib.lua
@@ -1,6 +1,7 @@
 -- SPDX-FileCopyrightText: 2024 John Livingston <https://www.john-livingston.fr/>
 -- SPDX-License-Identifier: AGPL-3.0-only
 
+local st = require "util.stanza";
 local get_time = require "util.time".now;
 
 local function end_current_poll (room)
@@ -8,17 +9,100 @@ local function end_current_poll (room)
     return;
   end
   -- TODO: compute and send last result.
+  module:log("debug", "Ending the current poll for room %s", room.jid);
   room._data.current_poll = nil;
 end
 
 local function create_poll(room, fields)
+  module:log("debug", "Creating a new poll for room %s", room.jid);
   room._data.current_poll = fields;
-  room._data.current_poll.end_timestamp = now() + (60 * fields["muc#roompoll_duration"]);
-  room._data.current_poll.votes = {};
+  room._data.current_poll.end_timestamp = get_time() + (60 * fields["muc#roompoll_duration"]);
+  room._data.current_poll.votes_by_occupant = {};
+  room._data.current_poll.votes_by_choices = {};
+  for field, _ in pairs(fields) do
+    local c = field:match("^muc#roompoll_choice(%d+)$");
+    if c then
+      if fields["muc#roompoll_choice" .. c]:find("%S") then
+        room._data.current_poll.votes_by_choices[c] = 0;
+      end
+    end
+  end
   -- TODO: create and send poll message.
 end
 
+local function handle_groupchat(event)
+  local origin, stanza = event.origin, event.stanza;
+  local room = event.room;
+  if not room._data.current_poll then
+    return;
+  end
+
+  -- There is a current poll. Is this a vote?
+  local body = stanza:get_child_text("body")
+  if not body or #body < 1 then
+    return;
+  end
+  local choice = body:match("^%s*!(%d+)%s*$");
+  if not choice then
+    return;
+  end
+
+  -- Ok, seems it is a vote.
+
+  if get_time() > room._data.current_poll.end_timestamp then
+    module:log("debug", "Got a vote for a finished poll, not counting it.");
+    -- Note: we keep bouncing messages a few seconds/minutes after the poll end
+    -- to be sure any user that send the vote too late won't expose his choice.
+    origin.send(st.error_reply(
+      stanza,
+      -- error_type = 'cancel' (see descriptions in RFC 6120 https://xmpp.org/rfcs/rfc6120.html#stanzas-error-syntax)
+      "cancel",
+      -- error_condition = 'not-allowed' (see RFC 6120 Defined Error Conditions https://xmpp.org/rfcs/rfc6120.html#stanzas-error-conditions)
+      "not-allowed",
+      "This poll is over."
+      ));
+    return true; -- stop!
+  end
+
+  -- We must check that the choice is valid:
+  if room._data.current_poll.votes_by_choices[choice] == nil then
+    module:log("debug", "Invalid vote, bouncing it.");
+    origin.send(st.error_reply(
+      stanza,
+      -- error_type = 'cancel' (see descriptions in RFC 6120 https://xmpp.org/rfcs/rfc6120.html#stanzas-error-syntax)
+      "cancel",
+      -- error_condition = 'not-allowed' (see RFC 6120 Defined Error Conditions https://xmpp.org/rfcs/rfc6120.html#stanzas-error-conditions)
+      "bad-request",
+      "This choice is not valid."
+    ));
+    return true; -- stop!
+  end
+
+  -- Ok, we can count the vote.
+  local occupant = event.occupant;
+  local id = occupant.jid; -- FIXME: is this the correct value? or bare_jid?
+  module:log("debug", "Counting a new vote for room %s: choice %i, voter %s", room.jid, choice, id);
+
+  -- TODO: count the vote.
+
+  -- When the poll is anonymous, we bounce the messages (but count the votes).
+  local must_bounce = room._data.current_poll["muc#roompoll_anonymous"] == true;
+  if must_bounce then
+    module:log("debug", "Invalid vote, bouncing it.");
+    origin.send(st.error_reply(
+      stanza,
+      -- error_type
+      "continue",
+      -- error_condition
+      "undefined-condition",
+      "You vote is taken into account. Votes are anonymous, it will not be shown to other participants."
+    ));
+    return true; -- stop!
+  end
+end
+
 return {
   end_current_poll = end_current_poll;
   create_poll = create_poll;
+  handle_groupchat = handle_groupchat;
 };