-- Publishes Twitter search results over pubsub

--

-- Config:

-- Component "pubsub.example.com" "pubsub"

-- modules_enabled = {

--   "pubsub_twitter";

-- }

-- twitter_searches = { -- node -> query

--   prosody = "prosody xmpp";

-- }

-- twitter_pull_interval = 20 -- minutes

--

local pubsub = module:depends"pubsub";

local json = require "util.json";

local http = require "net.http";

local set = require "util.set";

local it = require "util.iterators";

local array = require "util.array";

local st = require "util.stanza";

--local dump = require"util.serialization".serialize;

local xmlns_atom = "http://www.w3.org/2005/Atom";

local twitter_searches = module:get_option("twitter_searches", {});

local refresh_interval = module:get_option_number("twitter_pull_interval", 20) * 60;

local api_url = module:get_option_string("twitter_search_url", "http://search.twitter.com/search.json");

local month_number = {

	Jan = "01", Feb = "02", Mar = "03";

	Apr = "04", May = "05", Jun = "06";

	Jul = "07", Aug = "08", Sep = "09";

	Oct = "10", Nov = "11", Dec = "12";

};

local active_searches = {};

local function publish_result(search_name, result)

	local node, id = search_name, result.id_str;

	--"Tue, 02 Apr 2013 15:40:54 +0000"

	local timestamp_date, timestamp_month, timestamp_year, timestamp_time =

		result.created_at:match(" (%d+) (%a+) (%d+) (%d%d:%d%d:%d%d)");

	local timestamp = ("%s-%s-%sT%sZ"):format(timestamp_year, month_number[timestamp_month], timestamp_date, timestamp_time);

	local item = st.stanza("item", { xmlns = "http://jabber.org/protocol/pubsub", id = id })

		:tag("entry", { xmlns = xmlns_atom })

			:tag("id"):text(id):up()

			:tag("author")

				:tag("name"):text(result.from_user_name.." (@"..result.from_user..")"):up()

				:tag("uri"):text("http://twitter.com/"..result.from_user):up()

				:up()

			:tag("published"):text(timestamp):up()

			:tag("title"):text(result.text):up()

			:tag("link", { rel = "alternate" , href = "https://twitter.com/"..result.from_user.."/status/"..id}):up();

	module:log("debug", "Publishing Twitter result: %s", tostring(item));

	local ok, err = pubsub.service:publish(node, true, id, item);

	if not ok then

		if err == "item-not-found" then -- try again

			local ok, err = pubsub.service:create(node, true);

			if not ok then

				module:log("error", "could not create node %s: %s", node, err);

				return;

			end

			local ok, err = pubsub.service:publish(node, true, id, item);

			if not ok then

				module:log("error", "could not create or publish node %s: %s", node, err);

				return

			end

		else

			module:log("error", "publishing %s failed: %s", node, err);

		end

	end

end

local function is_retweet(tweet)

	return not not tweet.text:match("^RT ");

end

function update_all()

	module:log("debug", "Updating all searches");

	for name, search in pairs(active_searches) do

		module:log("debug", "Fetching new results for '%s'", name);

		http.request(search.refresh_url or search.url, nil, function (result_json, code)

			if code ~= 200 then

				module:log("warn", "Twitter search query '%s' failed with code %d", name, code);

				return;

			end

			local response = json.decode(result_json);

			module:log("debug", "Processing %d results for %s", #response.results, name);

			search.refresh_url = api_url..response.refresh_url;

			for _, result in ipairs(response.results) do

				if not is_retweet(result) then

					publish_result(name, result);

				end

			end

		end);

	end

	return refresh_interval;

end

function module.load()

	local config_searches = set.new(array.collect(it.keys(twitter_searches)));

	local current_searches = set.new(array.collect(it.keys(active_searches)));

	local disable_searches = current_searches - config_searches;

	local new_searches = config_searches - current_searches;

	for search_name in disable_searches do

		module:log("debug", "Disabled old Twitter search '%s'", search_name);

		active_searches[search_name] = nil;

	end

	for search_name in new_searches do

		module:log("debug", "Created new Twitter search '%s'", search_name);

		local query = twitter_searches[search_name];

		active_searches[search_name] = {

			url = api_url.."?q="..http.urlencode(query);

		};

	end

end

module:add_timer(5, update_all);