local st = require "util.stanza";

local jid_bare = require "util.jid".bare;

local jid_split = require "util.jid".split;

local xmlns_carbons = "urn:xmpp:carbons:1";

local xmlns_forward = "urn:xmpp:forward:0";

local host_sessions = hosts[module.host].sessions;

module:hook("iq/self/"..xmlns_carbons..":enable", function(event)

	local origin, stanza = event.origin, event.stanza;

	if stanza.attr.type == "set" then

		module:log("debug", "%s enabled carbons", origin.full_jid);

		origin.want_carbons = true;

		origin.send(st.reply(stanza));

		return true

	end

end);

module:hook("iq/self/"..xmlns_carbons..":disable", function(event)

	local origin, stanza = event.origin, event.stanza;

	if stanza.attr.type == "set" then

		module:log("debug", "%s disabled carbons", origin.full_jid);

		origin.want_carbons = nil;

		origin.send(st.reply(stanza));

		return true

	end

end);

local function message_handler(event, c2s)

	local origin, stanza = event.origin, event.stanza;

	local orig_type = stanza.attr.type;

	local orig_to = stanza.attr.to;

	local orig_from = stanza.attr.from;

	if not (orig_type == nil

			or orig_type == "normal"

			or orig_type == "chat") then

		return -- No carbons for messages of type error or headline

	end

	local bare_jid, user_sessions;

	local no_carbon_to = {};

	module:log("debug", "origin (%s) type: %s", tostring(origin), origin.type)

	if c2s then -- Stanza sent by a local client

		bare_jid = (origin.username.."@"..origin.host)

		user_sessions = host_sessions[origin.username];

	else -- Stanza about to be delivered to a local client

		local username, hostname, resource = jid_split(orig_to);

		bare_jid = jid_bare(orig_to);

		user_sessions = host_sessions[username];

		if resource then

			no_carbon_to[resource] = true;

		else

			local top_resources = user_sessions.top_resources;

			for _, session in ipairs(top_resources) do

				no_carbon_to[session.resource] = true;

			end

		end

	end

	if not c2s and stanza:get_child("private", xmlns_carbons) then

		stanza:maptags(function(tag)

			return tag.attr.xmlns == xmlns_carbons

				and tag.name == "private" and tag or nil;

		end);

		return

	end

	if not stanza:get_child("forwarded", xmlns_forward) then

		user_sessions = user_sessions and user_sessions.sessions;

		for resource, session in pairs(user_sessions) do

			local full_jid = bare_jid .. "/" .. resource;

			if session.want_carbons then

				if (c2s and session ~= origin) or (not c2s and not no_carbon_to[resource]) then

					local msg = st.clone(stanza);

					msg.attr.xmlns = msg.attr.xmlns or "jabber:client";

					local fwd = st.message{

								from = bare_jid,

								to = full_jid,

								type = orig_type,

							}

						:tag("forwarded", { xmlns = xmlns_forward })

							:tag(c2s and "sent" or "received", { xmlns = xmlns_carbons }):up()

							:add_child(msg);

					core_post_stanza(origin, fwd);

				end

			end

		end

	end

end

local function c2s_message_handler(event)

	return message_handler(event, true)

end

-- Stanzas sent by local clients

module:hook("pre-message/bare", c2s_message_handler, 1);

module:hook("pre-message/full", c2s_message_handler, 1);

-- Stanzas to local clients

module:hook("message/bare", message_handler, 1);

module:hook("message/full", message_handler, 1);

module:add_feature(xmlns_carbons);