-- Expose a simple servlet to handle user registrations from web pages

-- via JSON.

--

-- A Good chunk of the code is from mod_data_access.lua by Kim Alvefur

-- aka Zash.

local jid_prep = require "util.jid".prep

local jid_split = require "util.jid".split

local usermanager = usermanager

local b64_decode = require "util.encodings".base64.decode

local json_decode = require "util.json".decode

local os_time = os.time

local nodeprep = require "util.encodings".stringprep.nodeprep

module:depends("http")

-- Pick up configuration.

local secure = module:get_option_boolean("reg_servlet_secure", false)

local set_realm_name = module:get_option_string("reg_servlet_realm", "Restricted")

local base_path = module:get_option_string("reg_servlet_base", "/register_account/")

local throttle_time = module:get_option_number("reg_servlet_ttime", nil)

local whitelist = module:get_option_set("reg_servlet_wl", {})

local blacklist = module:get_option_set("reg_servlet_bl", {})

local recent_ips = {}

-- Begin

local function http_response(event, code, message, headers)

	local response = event.response

	if headers then

		for header, data in pairs(headers) do response.headers[header] = data end

	end

	response.headers.content_type = "application/json"

	response.status_code = code

	response:send(message)

end

local function handle_req(event)

	local request = event.request

	local body = request.body

	if secure and not request.secure then return nil end

	if request.method ~= "POST" then

		return http_response(event, 405, "Bad method...", {["Allow"] = "POST"})

	end

	if not request.headers["authorization"] then

		return http_response(event, 401, "No... No...", {["WWW-Authenticate"]='Basic realm="'.. set_realm_name ..'"'})

	end

	local user, password = b64_decode(request.headers.authorization:match("[^ ]*$") or ""):match("([^:]*):(.*)")

	user = jid_prep(user)

	if not user or not password then return http_response(event, 400, "What's this..?") end

	local user_node, user_host = jid_split(user)

	if not hosts[user_host] then return http_response(event, 401, "Negative.") end

	module:log("warn", "%s is authing to submit a new user registration data", user)

	if not usermanager.test_password(user_node, user_host, password) then

		module:log("warn", "%s failed authentication", user)

		return http_response(event, 401, "Who the hell are you?! Guards!")

	end

	local req_body

	-- We check that what we have is valid JSON wise else we throw an error...

	if not pcall(function() req_body = json_decode(body) end) then

		module:log("debug", "JSON data submitted for user registration by %s failed to Decode.", user)

		return http_response(event, 400, "JSON Decoding failed.")

	else

		-- Decode JSON data and check that all bits are there else throw an error

		if req_body["username"] == nil or req_body["password"] == nil or req_body["host"] == nil or req_body["ip"] == nil then

			module:log("debug", "%s supplied an insufficent number of elements or wrong elements for the JSON registration", user)

			return http_response(event, 400, "Invalid syntax.")

		end

		-- Check if user is an admin of said host

		if not usermanager.is_admin(user, req_body["host"]) then

			module:log("warn", "%s tried to submit registration data for %s but he's not an admin", user, req_body["host"])

			return http_response(event, 401, "I obey only to my masters... Have a nice day.")

		else	

			-- Blacklist can be checked here.

			if blacklist:contains(req_body["ip"]) then module:log("warn", "Attempt of reg. submission to the JSON servlet from blacklisted address: %s", req_body["ip"]) ; return http_response(403, "The specified address is blacklisted, sorry sorry.") end

			-- We first check if the supplied username for registration is already there.

			-- And nodeprep the username

			local username = nodeprep(req_body["username"])

			if not username then

				module:log("debug", "An username containing invalid characters was supplied: %s", user)

				return http_response(event, 406, "Supplied username contains invalid characters, see RFC 6122.")

			else

				if not usermanager.user_exists(username, req_body["host"]) then

					-- if username fails to register successive requests shouldn't be throttled until one is successful.

					if throttle_time and not whitelist:contains(req_body["ip"]) then

						if not recent_ips[req_body["ip"]] then

							recent_ips[req_body["ip"]] = os_time()

						else

							if os_time() - recent_ips[req_body["ip"]] < throttle_time then

								recent_ips[req_body["ip"]] = os_time()

								module:log("warn", "JSON Registration request from %s has been throttled.", req_body["ip"])

								return http_response(event, 503, "Woah... How many users you want to register..? Request throttled, wait a bit and try again.")

							end

							recent_ips[req_body["ip"]] = os_time()

						end

					end

					local ok, error = usermanager.create_user(username, req_body["password"], req_body["host"])

					if ok then 

						hosts[req_body["host"]].events.fire_event("user-registered", { username = username, host = req_body["host"], source = "mod_register_json", session = { ip = req_body["ip"] } })

						module:log("debug", "%s registration data submission for %s@%s is successful", user, username, req_body["host"])

						return http_response(event, 200, "Done.")

					else

						module:log("error", "user creation failed: "..error)

						return http_response(event, 500, "Encountered server error while creating the user: "..error)

					end

				else

					module:log("debug", "%s registration data submission for %s failed (user already exists)", user, username)

					return http_response(event, 409, "User already exists.")

				end

			end

		end

	end

end

-- Set it up!

module:provides("http", {

	default_path = base_path,

        route = {

                ["GET /"] = handle_req,

		["POST /"] = handle_req

        }

})