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

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

local usermanager = require "core.usermanager";

local http = require "util.http";

local extra_fields = {

	nick = true; name = true; first = true; last = true; email = true;

	address = true; city = true; state = true; zip = true;

	phone = true; url = true; date = true;

}

function template(data)

	-- Like util.template, but deals with plain text

	return { apply = function(values) return (data:gsub("{([^}]+)}", values)); end }

end

local function get_template(name)

	local fh = assert(module:load_resource("templates/"..name..".html"));

	local data = assert(fh:read("*a"));

	fh:close();

	return template(data);

end

local function render(template, data)

	return tostring(template.apply(data));

end

local register_tpl = get_template "register";

local success_tpl = get_template "success";

if next(captcha_options) ~= nil then

	local recaptcha_tpl = get_template "recaptcha";

	function generate_captcha(display_options)

		return recaptcha_tpl.apply(setmetatable({

	  		recaptcha_display_error = display_options and display_options.recaptcha_error

	  			and ("&error="..display_options.recaptcha_error) or "";

	  	}, {

	  		__index = function (t, k)

	  			if captcha_options[k] then return captcha_options[k]; end

	  			module:log("error", "Missing parameter from captcha_options: %s", k);

			end

		}));

	end

	function verify_captcha(request, form, callback)

		http.request("https://www.google.com/recaptcha/api/verify", {

			body = http.formencode {

				privatekey = captcha_options.recaptcha_private_key;

				remoteip = request.conn:ip();

				challenge = form.recaptcha_challenge_field;

				response = form.recaptcha_response_field;

			};

		}, function (verify_result, code)

			local verify_ok, verify_err = verify_result:match("^([^\n]+)\n([^\n]+)");

			if verify_ok == "true" then

				callback(true);

			else

				callback(false, verify_err)

			end

		end);

	end

else

	module:log("debug", "No Recaptcha options set, using fallback captcha")

	local random = math.random;

	local hmac_sha1 = require "util.hashes".hmac_sha1;

	local secret = require "util.uuid".generate()

	local ops = { '+', '-' };

	local captcha_tpl = get_template "simplecaptcha";

	function generate_captcha()

		local op = ops[random(1, #ops)];

		local x, y = random(1, 9)

		repeat

			y = random(1, 9);

		until x ~= y;

		local answer;

		if op == '+' then

			answer = x + y;

		elseif op == '-' then

			if x < y then

				-- Avoid negative numbers

				x, y = y, x;

			end

			answer = x - y;

		end

		local challenge = hmac_sha1(secret, answer, true);

		return captcha_tpl.apply {

			op = op, x = x, y = y, challenge = challenge;

		};

	end

	function verify_captcha(request, form, callback)

		if hmac_sha1(secret, form.captcha_reply, true) == form.captcha_challenge then

			callback(true);

		else

			callback(false, "Captcha verification failed");

		end

	end

end

function generate_page(event, display_options)

	local request = event.request;

	return render(register_tpl, {

		path = request.path; hostname = module.host;

		notice = display_options and display_options.register_error or "";

		captcha = generate_captcha(display_options);

	})

end

function register_user(form)

	local prepped_username = nodeprep(form.username);

	if not prepped_username then

		return nil, "Username contains forbidden characters";

	end

	if usermanager.user_exists(prepped_username, module.host) then

		return nil, "Username already taken";

	end

	local ok, err = usermanager.create_user(prepped_username, form.password, module.host);

	if ok then

		local extra_data = {};

		for field in pairs(extra_fields) do

			local field_value = form[field];

			if field_value and #field_value > 0 then

				extra_data[field] = field_value;

			end

		end

		if next(first) ~= nil then

			datamanager.store(prepped_username, module.host, "account_details", extra_data);

		end

		module:fire_event("user-registered", {

			username = prepped_username,

			host = module.host,

			source = module.name

		});

	end

	return ok, err;

end

function generate_success(event, form)

	return render(success_tpl, { jid = nodeprep(form.username).."@"..module.host });

end

function generate_register_response(event, form, ok, err)

	local message;

	if ok then

		return generate_success(event, form);

	else

		return generate_page(event, { register_error = err });

	end

end

function handle_form(event)

	local request, response = event.request, event.response;

	local form = http.formdecode(request.body);

	verify_captcha(request, form, function (ok, err)

		if ok then

			local register_ok, register_err = register_user(form);

			response:send(generate_register_response(event, form, register_ok, register_err));

		else

			response:send(generate_page(event, { register_error = err }));

		end

	end);

	return true; -- Leave connection open until we respond above

end

module:provides("http", {

	route = {

		GET = generate_page;

		POST = handle_form;

	};

});