commit 881085e767e7faf5a6a61e5949ecaa8d5f0d0b43
Author: Alexander PapaTutuWawa <papatutuwawa@polynom.me>
Date:   Tue Oct 27 18:05:41 2020 +0100

    mix: Initial commit

diff --git a/mod_mix/mod_mix.lua b/mod_mix/mod_mix.lua
new file mode 100644
index 0000000..1487848
--- /dev/null
+++ b/mod_mix/mod_mix.lua
@@ -0,0 +1,428 @@
+local host = module:get_host();
+if module:get_host_type() ~= "component" then
+    error("MIX should be loaded as a component", 0);
+end
+
+local st = require("util.stanza");
+local jid = require("util.jid");
+local uuid = require("util.uuid");
+local id = require("util.id");
+local datetime = require("util.datetime");
+local time = require("util.time");
+local serialization = require("util.serialization");
+local pep = module:depends("pep");
+
+local persistent_channels = module:open_store("mix_channels", "keyval");
+local persistent_channel_data = module:open_store("mix_data", "keyval");
+
+-- Default values
+local default_channel_description = module:get_option("default_description", "A MIX channel for chatting");
+local default_channel_name = module:get_option("default_name", "MIX channel");
+
+module:depends("disco");
+module:add_identity("conference", "mix", module:get_option("name", "Prosody MIX service");
+module:add_feature("http://jabber.org/protocol/disco#info");
+module:add_feature("urn:xmpp:mix:core:1");
+
+Participant = {};
+Participant.__index = Participant;
+function Participant:new(jid, nick)
+    return setmetatable({
+        jid = jid,
+        nick = nick,
+    }, Participant);
+end
+
+Channel = {}
+Channel.__index = Channel;
+function Channel:new(jid, name, description, participants, subscriptions, spid, contacts, adhoc)
+    return setmetatable({
+        jid = jid,
+        name = name,
+        description = description,
+        participants = participants,
+        subscriptions = subscriptions,
+        spid = spid,
+        contacts = contacts,
+        adhoc = adhoc,
+    }, Channel);
+end
+function Channel:from(config)
+    return setmetatable(config, Channel);
+end
+
+function Channel:get_spid(jid)
+    return self.spid[jid];
+end
+
+function Channel:debug_print()
+    module:log("debug", "Channel %s (%s)", self.jid, self.name);
+    module:log("debug", "'%s'", self.description);
+    for _, p in pairs(self.participants) do
+        module:log("debug", "=> %s (%s)", p.jid, p.nick);
+    end
+    
+    module:log("debug", "Contacts:");
+    for _, c in pairs(self.contacts) do
+        module:log("debug", "=> %s", c);
+    end
+    
+    if self.subscriptions then
+        module:log("debug", "Subscriptions:");
+        for user, subs in pairs(self.subscriptions) do
+            module:log("debug", "[%s]", user);
+            for _, sub in pairs(self.subscriptions[user]) do
+                module:log("debug", "=> %s", sub);
+            end
+        end
+    end
+end
+
+local channels = {};
+
+function get_channel(jid)
+    for i, channel in pairs(channels) do
+        if channel.jid == jid then
+            return i, channel
+        end
+    end
+end
+
+function publish_participant(service, spid, participant)
+    service:publish("urn:xmpp:mix:nodes:participants",
+                    true,
+                    spid,
+                    st.stanza("item", { id = spid, xmlns = "http://jabber.org/protocol/pubsub" })
+                        :tag("participant", { xmlns = "urn:xmpp:mix:core:1" })
+                            :tag("nick"):text(participant["nick"]):up()
+                            :tag("jid"):text(participant["jid"]));
+end
+
+function save_channels()
+    module:log("debug", "Saving channel list...");
+    local channel_list = {};
+    for _, channel in pairs(channels) do
+        table.insert(channel_list, channel.jid);
+
+        persistent_channel_data:set(channel.jid, channel);
+    end
+
+    persistent_channels:set("channels", channel_list);
+    module:log("debug", "Saving channel list done.");
+end
+
+function Channel:save_state()
+    -- Saving the entire state everything one channel seems stupid,
+    -- so we just save the changed channel
+    module:log("debug", "Saving state of channel %s...", self.jid);
+    persistent_channel_data:set(self.jid, self);
+    module:log("debug", "Saving state done.", self.jid);
+end
+
+function module.load()
+    module:log("info", "Loading MIX channels...");
+    
+    local channel_list = persistent_channels:get("channels");
+    if channel_list then
+        for _, channel in pairs(channel_list) do
+            table.insert(channels, Channel:from(persistent_channel_data:get(channel)));
+            module:log("debug", "MIX channel %s loaded", channel);
+        end
+    else
+        module:log("debug", "No MIX channels found.");
+    end
+    module:log("debug", "Loading MIX channels done.");
+end
+
+module:hook("host-disco-items", function(event)
+    module:log("debug", "host-disco-items called");
+    local reply = event.reply;
+    for _, channel in pairs(channels) do
+        -- Adhoc channels are supposed to be invisible
+        if not channel.adhoc then
+            reply:tag("item", { jid = channel.jid }):up();
+        end
+    end 
+end);
+
+module:hook("iq/bare/http://jabber.org/protocol/disco#items:query", function(event)
+    module:log("debug", "IQ-GET disco#items");
+
+    local origin, stanza = event.origin, event.stanza;
+    local _, channel = get_channel(staza.attr.to);
+    if not channel then
+        -- TODO: Send error message
+    end
+    local reply = st.reply(stanza):tag("query", { xmlns = "http://jabber.org/protocol/disco#items", node = "mix" });
+    for _, node in pairs({"urn:xmpp:mix:nodes:messages", "urn:xmpp:mix:nodes:participants", "urn:xmpp:mix:nodes:info"}) do
+        reply:tag("item", { jid = channel.jid, node = node }):up();
+    end
+
+    origin.send(reply);
+    return true;
+end);
+
+module:hook("iq/bare/http://jabber.org/protocol/disco#info:query", function(event)
+    module:log("debug", "IQ-GET disco#info");
+
+    local origin, stanza = event.origin, event.stanza;
+    local _, channel = get_channel(stanza.attr.to);
+    if not channel then
+        -- TODO: Send error message 
+    end
+    local reply = st.reply(stanza):tag("query", { xmlns = "http://jabber.org/protocol/disco#info" });
+    reply:tag("identity", { category = "conference", name = channel.name, type = "mix" }):up();
+    reply:tag("feature", { var = "urn:xmpp:mix:core:1" }):up();
+    -- TODO: Do something here
+    reply:tag("feature", { var = "urn:xmpp:mix:core:1#create-channel" }):up();
+    reply:tag("feature", { var = "http://jabber.org/protocol/disco#info" }):up();
+    origin.send(reply);
+    return true;
+end);
+
+function find_participant(table, jid)
+    for i, v in pairs(table) do
+        if v.jid == jid then
+            return i
+        end
+    end
+
+    return -1
+end
+
+module:hook("iq-set/bare/urn:xmpp:mix:core:1:leave", function(event)
+    module:log("debug", "MIX leave received");
+    local origin, stanza = event.origin, event.stanza;
+    local from = jid.bare(stanza.attr.from);
+    local i, channel = get_channel(stanza.attr.to);
+    if not channel then
+        -- TODO: Return error
+    end
+
+    local participant_index = find_participant(channel.participants, from);
+    if participant_index == -1 then
+        channel:debug_print();
+        module:log("debug", "%s is not a participant in %s", from, channel.jid);
+        return;
+    end
+
+    -- Remove the user as a participant by...
+    -- Unsubscribing
+    local srv = pep.get_pep_service(channel.jid);
+    for _, node in pairs(channel.subscriptions[from]) do
+        srv:remove_subscription(node, true, from);
+        module:log("debug", "Unsubscribed %s from %s on %s", from, node, channel.jid);
+    end
+    channels[i].subscriptions[from] = nil;
+    -- Retracting the participation
+    srv:retract("urn:xmpp:mix:nodes:participants", true, channel.spid[from], true);
+    -- Removing the user
+    table.remove(channels[i].participants, participant_index);
+    channel:save_state();
+
+    origin.send(st.reply(stanza):tag("leave", { xmlns = "urn:xmpp:mix:core:1" }));
+    return true;
+end);
+
+module:hook("iq-set/bare/urn:xmpp:mix:core:1:join", function(event)
+    module:log("debug", "MIX join received");
+
+    local origin, stanza = event.origin, event.stanza;
+    local i, channel = get_channel(stanza.attr.to);
+    if not channel then
+        -- TODO: Return error
+        return
+    end
+    local from = jid.bare(stanza.attr.from);
+    local spid = channel.spid[from] or uuid.generate(); -- Stable Participant ID
+    local reply = st.reply(stanza)
+                    :tag("join", { xmlns = "urn:xmpp:mix:core:1", id = spid });
+    local srv = pep.get_pep_service(jid.node(stanza.attr.to));
+    local join = stanza:get_child("join", "urn:xmpp:mix:core:1");
+    local nick = join:get_child("nick");
+    module:log("debug", "User joining as nick %s", nick:get_text());
+    
+    local nodes = {};
+    -- TODO: The spec says that an error sould be returned when no nodes can be subscribed to
+    for subscribe in join:childtags("subscribe") do
+        module:log("debug", "Subscribing user to node %s", subscribe.attr.node);
+        local ok, err = srv:add_subscription(subscribe.attr.node, true, from);
+        if not ok then
+            module:log("debug", "Error during subscription: %s", err);
+        else
+            table.insert(nodes, subscribe.attr.node);
+            reply:tag("subscribe", { node = subscribe.attr.node }):up();
+        end
+    end
+    channels[i].subscriptions[from] = nodes;
+    
+    local participant = Participant:new(jid.bare(from), nick:get_text())
+    table.insert(channels[i].participants, participant)
+    channels[i].spid[jid.bare(stanza.attr.from)] = spid;
+    publish_participant(srv, spid, participant);
+    channels[i]:save_state();
+
+    reply:add_child(nick);
+    origin.send(reply);
+    return true
+end);
+
+module:hook("iq-set/bare/urn:xmpp:mix:core:1:setnick", function(event)
+    module:log("debug", "MIX setnick received");
+    local origin, stanza = event.origin, event.stanza;
+    local from = jid.bare(stanza.attr.from);
+    local i, channel = get_channel(stanza.attr.to);
+    if not channel then
+        -- TODO: Return error
+    end
+
+    local participant_index = find_participant(channel.participants, from);
+    if participant_index == -1 then
+        channel:debug_print();
+        module:log("debug", "%s is not a participant in %s", from, channel.jid);
+        return;
+    end
+
+    local setnick = stanza:get_child("setnick", "urn:xmpp:mix:core:1");
+    -- TODO: Error handling
+    local nick = setnick:get_child("nick"):get_text();
+    
+    -- Change the nick
+    channels[i].participants[participant_index].nick = nick;
+    -- Inform all other members
+    local srv = pep.get_pep_service(channel.jid);
+    local participant = channel.participants[participant_index];
+    publish_participant(srv, channel:get_spid(participant.jid), participant);
+
+    origin.send(st.reply(stanza)
+                    :tag("setnick", { xmlns = "urn:xmpp:mix:core:1" })
+                        :tag("nick"):text(nick));
+    channel:save_state();
+    return true;
+end);
+
+function Channel:publish_info(srv)
+    srv:publish("urn:xmpp:mix:nodes:info", true, timestamp,
+                st.stanza("item", { id = timestamp, xmlns = "http://jabber.org/protocol/pubsub" })
+                    :tag("x", { xmlns = "jabber:x:data", type = "result" })
+                        :tag("field", { var = "FORM_TYPE", type = "hidden" })
+                            :tag("value"):text("urn:xmpp:mix:core:1"):up():up()
+                        :tag("field", { var = "Name" })
+                            :tag("value"):text(self.name):up()
+                        :tag("field", { var = "Contact" })
+                            :tag("value"):text(self.contacts));
+end
+
+function create_channel(node, creator, adhoc)
+    local channel = Channel:new(string.format("%s@%s", node, host),
+                                default_channel_name,
+                                default_channel_description,
+                                {},
+                                {},
+                                {},
+                                { creator },
+                                adhoc);
+    -- Create the PEP nodes
+    local srv = pep.get_pep_service(node);
+    local timestamp = datetime.datetime(time.now());
+    srv:create("urn:xmpp:mix:nodes:info", true, { ["access_model"] = "open" });
+    channel:publish_info(srv);
+    -- TODO: This seems bad
+    srv:create("urn:xmpp:mix:nodes:participants", true, { ["access_model"] = "open"});
+    table.insert(channels, channel);
+end
+
+module:hook("iq-set/host/urn:xmpp:mix:core:1:create", function(event)
+    module:log("debug", "MIX create received");
+    local origin, stanza = event.origin, event.stanza;
+    local from = jid.bare(stanza.attr.from);
+
+    local create = stanza:get_child("create", "urn:xmpp:mix:core:1");
+    local node;
+    if create.attr.channel ~= nil then
+        -- Create non-adhoc channel
+        node = create.attr.channel;
+        local _, channel = get_channel(stanza.attr.to);
+        if channel then
+            -- TODO: Return error
+        end
+
+        create_channel(create.attr.channel, from, false);
+    else
+        -- Create adhoc channel
+        -- TODO: Check for a collision
+        node = id.short();
+        create_channel(node, from, true);
+    end
+    module:log("debug", "Channel %s created with %s as owner", node, from);
+
+    origin.send(st.reply(stanza)
+                :tag("create", { xmlns = "urn:xmpp:mix:core:1", channel = node }));
+    save_channels();
+    return true;
+end);
+
+module:hook("iq-set/host/urn:xmpp:mix:core:1:destroy", function(event)
+    module:log("debug", "MIX destroy received");
+    local origin, stanza = event.origin, event.stanza;
+    local from = jid.bare(stanza.attr.from);
+
+    local destroy = stanza:get_child("create", "urn:xmpp:mix:core:1");
+    local node = destory.attr.channel;
+    local node_jid = string.format("%s@%s", node, host);
+    local i, channel = get_channel(node_jid);
+    if not channel then
+        -- TODO: Error
+    end
+    -- TODO: Check permissions
+    
+    -- Remove all registered nodes
+    local srv = pep.get_pep_service(node);
+    for _, pep_node in pairs({ "urn:xmpp:mix:nodes:participants", "urn:xmpp:mix:nodes:info" }) do
+        srv:delete(pep_node, true);
+    end
+    table.remove(channels, i);
+     
+    module:log("debug", "Channel %s destroyed", node);
+
+    origin.send(st.reply(stanza));
+    save_channels();
+    return true;
+end);
+
+module:hook("message/bare", function(event)
+    module:log("debug", "MIX message detected");
+    local stanza = event.stanza;
+
+    if stanza.attr.type ~= "groupchat" then
+        -- TODO: Error handling
+    end
+
+    local from = jid.bare(stanza.attr.from);
+    local i, channel = get_channel(stanza.attr.to);
+    if not channel then
+        -- TODO: Error handlung
+    end
+    
+    local participant_index = find_participant(channel.participants, from);
+    if participant_index == -1 then
+        -- TODO: Error not in channel
+        return;
+    end
+    local participant = channel.participants[participant_index];
+
+    local msg = st.clone(stanza);
+    msg:add_child(st.stanza("mix", { xmlns = "urn:xmpp:mix:core:1" })
+                    :tag("nick"):text(participant.nick):up()
+                    :tag("jid"):text(participant.jid):up());
+    msg.attr.from = channel.jid.."/"..channel.spid[from];
+    for _, p in pairs(channel.participants) do
+        if p.jid ~= participant.jid then
+            msg.attr.to = p.jid;
+            module:send(msg);
+            module:log("debug", msg:pretty_print());
+            module:log("debug", "Message from %s sent to %s", participant.jid, p.jid);
+        end
+    end
+    return true;
+end);