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

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

local st = require "util.stanza";

local hosts = hosts;

local user_exists = require "core.usermanager".user_exists;

local is_contact_subscribed = require "core.rostermanager".is_contact_subscribed;

local pairs, ipairs = pairs, ipairs;

local next = next;

local type = type;

local load_roster = require "core.rostermanager".load_roster;

local sha1 = require "util.hashes".sha1;

local base64 = require "util.encodings".base64.encode;

local NULL = {};

local data = {};

local recipients = {};

local hash_map = {};

module:add_identity("pubsub", "pep");

module:add_feature("http://jabber.org/protocol/pubsub#publish");

local function publish(session, node, item)

	local disable = #item.tags ~= 1 or #item.tags[1].tags == 0;

	local bare = session.username..'@'..session.host;

	local stanza = st.message({from=bare, type='headline'})

		:tag('event', {xmlns='http://jabber.org/protocol/pubsub#event'})

			:tag('items', {node=node})

				:add_child(item)

			:up()

		:up();

	-- store for the future

	local user_data = data[bare];

	if disable then

		if user_data then

			user_data[node] = nil;

			if not next(user_data) then data[bare] = nil; end

		end

	else

		if not user_data then user_data = {}; data[bare] = user_data; end

		user_data[node] = stanza;

	end

	-- broadcast

	for recipient, notify in pairs(recipients[bare] or NULL) do

		if notify[node] then

			stanza.attr.to = recipient;

			core_post_stanza(session, stanza);

		end

	end

end

local function publish_all(user, recipient, session)

	local d = data[user];

	local notify = recipients[user] and recipients[user][recipient];

	if d and notify then

		for node in pairs(notify) do

			local message = d[node];

			if message then

				message.attr.to = recipient;

				session.send(message);

			end

		end

	end

end

local function get_caps_hash_from_presence(stanza, current)

	local t = stanza.attr.type;

	if not t then

		for _, child in pairs(stanza.tags) do

			if child.name == "c" and child.attr.xmlns == "http://jabber.org/protocol/caps" then

				local attr = child.attr;

				if attr.hash then -- new caps

					if attr.hash == 'sha-1' and attr.node and attr.ver then return attr.ver, attr.node.."#"..attr.ver; end

				else -- legacy caps

					if attr.node and attr.ver then return attr.node.."#"..attr.ver.."#"..(attr.ext or ""), attr.node.."#"..attr.ver; end

				end

				return; -- bad caps format

			end

		end

	elseif t == "unavailable" or t == "error" then

		return;

	end

	return current; -- no caps, could mean caps optimization, so return current

end

module:hook("presence/bare", function(event)

	-- inbound presence to bare JID recieved

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

	local user = stanza.attr.to or (origin.username..'@'..origin.host);

	local bare = jid_bare(stanza.attr.from);

	local item = load_roster(jid_split(user))[bare];

	if not stanza.attr.to or (item and (item.subscription == 'from' or item.subscription == 'both')) then

		local recipient = stanza.attr.from;

		local current = recipients[user] and recipients[user][recipient];

		local hash = get_caps_hash_from_presence(stanza, current);

		if current == hash then return; end

		if not hash then

			if recipients[user] then recipients[user][recipient] = nil; end

		else

			recipients[user] = recipients[user] or {};

			if hash_map[hash] then

				recipients[user][recipient] = hash_map[hash];

				publish_all(user, recipient, origin);

			else

				recipients[user][recipient] = hash;

				origin.send(

					st.stanza("iq", {from=stanza.attr.to, to=stanza.attr.from, id="disco", type="get"})

						:query("http://jabber.org/protocol/disco#info")

				);

			end

		end

	end

end, 10);

module:hook("iq/bare/http://jabber.org/protocol/pubsub:pubsub", function(event)

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

	if stanza.attr.type == 'set' and (not stanza.attr.to or jid_bare(stanza.attr.from) == stanza.attr.to) then

		local payload = stanza.tags[1];

		if payload.name == 'pubsub' then -- <pubsub xmlns='http://jabber.org/protocol/pubsub'>

			payload = payload.tags[1];

			if payload and payload.name == 'publish' and payload.attr.node then -- <publish node='http://jabber.org/protocol/tune'>

				local node = payload.attr.node;

				payload = payload.tags[1];

				if payload then -- <item>

					publish(session, node, payload);

					return true;

				end

			end

		end

	end

end);

local function calculate_hash(disco_info)

	local identities, features, extensions = {}, {}, {};

	for _, tag in pairs(disco_info) do

		if tag.name == "identity" then

			table.insert(identities, (tag.attr.category or "").."\0"..(tag.attr.type or "").."\0"..(tag.attr["xml:lang"] or "").."\0"..(tag.attr.name or ""));

		elseif tag.name == "feature" then

			table.insert(features, tag.attr.var or "");

		elseif tag.name == "x" and tag.attr.xmlns == "jabber:x:data" then

			local form = {};

			local FORM_TYPE;

			for _, field in pairs(tag.tags) do

				if field.name == "field" and field.attr.var then

					local values = {};

					for _, val in pairs(field.tags) do

						val = #val.tags == 0 and table.concat(val); -- FIXME use get_text?

						if val then table.insert(values, val); end

					end

					table.sort(values);

					if field.attr.var == "FORM_TYPE" then

						FORM_TYPE = values[1];

					elseif #values > 0 then

						table.insert(form, field.attr.var.."\0"..table.concat(values, "<"));

					else

						table.insert(form, field.attr.var);

					end

				end

			end

			table.sort(form);

			form = table.concat(form, "<");

			if FORM_TYPE then form = FORM_TYPE.."\0"..form; end

			table.insert(extensions, form);

		end

	end

	table.sort(identities);

	table.sort(features);

	table.sort(extensions);

	if #identities > 0 then identities = table.concat(identities, "<"):gsub("%z", "/").."<"; else identities = ""; end

	if #features > 0 then features = table.concat(features, "<").."<"; else features = ""; end

	if #extensions > 0 then extensions = table.concat(extensions, "<"):gsub("%z", "<").."<"; else extensions = ""; end

	local S = identities..features..extensions;

	local ver = base64(sha1(S));

	return ver, S;

end

module:hook("iq/bare/disco", function(event)

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

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

		local disco = stanza.tags[1];

		if disco and disco.name == "query" and disco.attr.xmlns == "http://jabber.org/protocol/disco#info" then

			-- Process disco response

			local user = stanza.attr.to or (session.username..'@'..session.host);

			local contact = stanza.attr.from;

			local current = recipients[user] and recipients[user][contact];

			if type(current) ~= "string" then return; end -- check if waiting for recipient's response

			local ver = current;

			if not string.find(current, "#") then

				ver = calculate_hash(disco.tags); -- calculate hash

			end

			local notify = {};

			for _, feature in pairs(disco.tags) do

				if feature.name == "feature" and feature.attr.var then

					if nfeature then notify[nfeature] = true; end

				end

			end

			hash_map[ver] = notify; -- update hash map

			recipients[user][contact] = notify; -- set recipient's data to calculated data

			-- send messages to recipient

			publish_all(user, contact, session);

		end

	end

end);