-- Allow Slack-style incoming and outgoing hooks to MUC rooms

-- Based on mod_muc_intercom and mod_post_msg

-- Copyright 2016-2017 Nathan Whitehorn <nwhitehorn@physics.ucla.edu>

--

-- This file is MIT/X11 licensed.

module:depends"http"

local host_session = prosody.hosts[module.host];

local msg = require "util.stanza".message;

local jid = require "util.jid";

local now = require "util.datetime".datetime;

local json = require "util.json"

local formdecode = require "net.http".formdecode;

local http = require "net.http";

local dataform = require "util.dataforms";

local function get_room_from_jid(mod_muc, room_jid)

	if mod_muc.get_room_from_jid then

		return mod_muc.get_room_from_jid(room_jid);

	elseif mod_muc.rooms then

		return mod_muc.rooms[room_jid]; -- COMPAT 0.9, 0.10

	end

end

local button_ns = "xmpp:prosody.im/community/mod_slack_webhooks#buttons";

local routing = module:get_option("outgoing_webhook_routing") or {};

local listen_path = module:get_option("incoming_webhook_path") or "/webhook";

local default_from_nick = module:get_option("incoming_webhook_default_nick") or "Bot";

function postcallback(_, code)

	module:log("debug", "HTTP result %d", code)

end

function check_message(data)

	local stanza = data.stanza;

	local mod_muc = host_session.muc;

	if not mod_muc then return; end

	local this_room = get_room_from_jid(mod_muc, stanza.attr.to);

	if not this_room then return; end -- no such room

	local from_room_jid = this_room._jid_nick[stanza.attr.from];

	if not from_room_jid then return; end -- no such nick

	local from_room, from_host, from_nick = jid.split(from_room_jid);

	local body = stanza:get_child("body");

	if not body then return; end -- No body, like topic changes

	body = body and body:get_text(); -- I feel like I want to do `or ""` there :/

	if not routing[from_room] then

		return;

	end

	local json_out = {

		channel_name = from_room,

		timestamp = now(),

		text = body,

		team_domain = from_host,

		user_name = from_nick,

	};

	local form = stanza:get_child("x", "jabber:x:form");

	if form and form.attr.type == "submit" then

		local callback_id, button_name, button_value;

		for field in form:childtags("field") do

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

				button_name = field:get_child_text("text");

			elseif field.attr.var == "button_name" then

				button_name = field:get_child_text("text");

			elseif field.attr.var ~= "FORM_TYPE" or field:get_child_text("text") ~= button_ns then

				callback_id, button_name, button_value = nil, nil, nil;

				break;

			end

		end

		if callback_id and button_name and button_value then

			json_out.callback_id = callback_id;

			json_out.actions = {

				{ type = "button", name = button_name, value = button_value }

			};

		end

	end

	local stanzaid = stanza:get_child("id");

	if stanzaid and string.sub(stanzaid,1,string.len("webhookbot"))=="webhookbot" then

		json_out["bot_id"] = "webhookbot";

	end

	json_out = json.encode(json_out)

	local url = routing[from_room];

	module:log("debug", "message from %s in %s to %s", from_nick, from_room, url);

	if url == "DEBUG" then

		module:log("debug", "json_out = %s", json_out);

		return;

	end

	local headers = {

		["Content-Type"] = "application/json",

	};

	http.request(url, { method = "POST", body = json_out, headers = headers }, postcallback)

end

module:hook("message/bare", check_message, 10);

local function route_post(f)

	return function(event, path)

		local bare_room = jid.join(path, module.host);

		local mod_muc = host_session.muc;

		if not get_room_from_jid(mod_muc, bare_room) then

			module:log("warn", "mod_slack_webhook: invalid JID: %s", bare_room);

			return 404;

		end

		-- Check secret?

		return f(event, path)

	end

end

local function handle_post(event, path)

	local mod_muc = host_session.muc;

	local request = event.request;

	local headers = request.headers;

	local body_type = headers.content_type;

	local post_body;

	if body_type == "application/x-www-form-urlencoded" then

		post_body = formdecode(request.body);

	elseif body_type == "application/json" then

		post_body = json.decode(request.body)

		if not post_body then

			return 420;

		end

	else

		return 422;

	end

	local bare_room = jid.join(path, module.host);

	local dest_room = get_room_from_jid(mod_muc, bare_room);

	local from_nick = default_from_nick;

	if post_body["username"] then

		from_nick = post_body["username"];

	end

	local sender = jid.join(path, module.host, from_nick);

	module:log("debug", "message to %s from %s", bare_room, sender);

	module:log("debug", "body: %s", post_body["text"]);

	local message = msg({ to = bare_room, from = sender, type = "groupchat", id="webhookbot" .. now()},post_body["text"]);

	if type(post_body["attachments"]) == "table" then -- Buttons?

		-- luacheck: ignore 631

		-- defensive against JSON having whatever data in it, enjoy

		for _, attachment in ipairs(post_body["attachments"]) do

			if type(attachment) == "table" and type(attachment.actions) == "table" and type(attachment.callback_id) == "string" then

				local buttons = {};

				local button_name;

				for _, action in ipairs(attachment.actions) do

					if type(attachment.text) == "string" then

						buttons.label = attachment.text;

					end

					if type(action) == "table" and action.type == "button" and type(action.name) == "string" and type(action.value) == "string" then

						if not button_name then

							button_name = action.name;

						end

						if button_name == action.name then

							local button = {

								value = action.value;

							};

							if type(action.text) == "string" then

								button.label = action.text;

							end

							table.insert(buttons, button);

						end

					end

				end

				if button_name then

					message:add_direct_child(dataform.new({

						{

							type = "hidden", name = "FORM_TYPE",

							value = button_ns,

						},

						{

							type = "hidden", name = "callback_id",

							value = attachment.callback_id,

						},

						{

							type = "hidden", name = "button_name",

							value = button_name,

						},

						{

							type = "list-single", name = "buttons",

							value = "", -- FIXME util.dataforms can't do options without a value

							options = buttons;

						}

					}):form());

					break;

				end

			end

		end

	end

	dest_room:broadcast_message(message, true);

	return 201;

end

module:provides("http", {

	default_path = listen_path;

	route = {

		["POST /*"] = route_post(handle_post);

		OPTIONS = function(e)

			local headers = e.response.headers;

			headers.allow = "POST";

			headers.accept = "application/x-www-form-urlencoded, application/json";

			return 200;

		end;

	}

});