-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
-- Modifications copyright (C) 2014 mrDoctorWho
-- 
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--


local st = require "util.stanza";
local dataform_new = require "util.dataforms".new;
local usermanager_user_exists = require "core.usermanager".user_exists;
local usermanager_create_user = require "core.usermanager".create_user;
local usermanager_set_password = require "core.usermanager".set_password;
local usermanager_delete_user = require "core.usermanager".delete_user;
local os_time = os.time;
local nodeprep = require "util.encodings".stringprep.nodeprep;
local jid_bare = require "util.jid".bare;
local timer = require "util.timer";


local math = require "math";
local captcha = require "captcha";



local base64 = require "util.encodings".base64.encode;
local sha1 = require "util.hashes".sha1;


local captcha_ids = {};

local config = module:get_option("captcha_config") or {};


local compat = module:get_option_boolean("registration_compat", true);
local allow_registration = module:get_option_boolean("allow_registration", false);
local additional_fields = module:get_option("additional_registration_fields", {});

local account_details = module:open_store("account_details");

local field_map = {
	username = { name = "username", type = "text-single", label = "Username", required = true };
	password = { name = "password", type = "text-private", label = "Password", required = true };
	nick = { name = "nick", type = "text-single", label = "Nickname" };
	name = { name = "name", type = "text-single", label = "Full Name" };
	first = { name = "first", type = "text-single", label = "Given Name" };
	last = { name = "last", type = "text-single", label = "Family Name" };
	email = { name = "email", type = "text-single", label = "Email" };
	address = { name = "address", type = "text-single", label = "Street" };
	city = { name = "city", type = "text-single", label = "City" };
	state = { name = "state", type = "text-single", label = "State" };
	zip = { name = "zip", type = "text-single", label = "Postal code" };
	phone = { name = "phone", type = "text-single", label = "Telephone number" };
	url = { name = "url", type = "text-single", label = "Webpage" };
	date = { name = "date", type = "text-single", label = "Birth date" };

	-- something new
	formtype = { name = "FORM_TYPE", type = "hidden"};
	captcha_text = { name = "captcha_text", type = "fixed", label = "Warning: "};
	captcha_psi = { name = "captchahidden", type = "hidden" }; -- Don't know exactly why, but it exists in ejabberd register form
	captcha_url = { name = "url", type = "text-single", label = "Captcha url"};
	from = { name = "from", type = "hidden" };
	captcha_challenge = { name = "challenge", type = "hidden" };
	sid = { name = "sid", type = "hidden" };
	ocr = { name = "ocr", label = "Enter shown text", required = true, type = "media" }
};

local registration_form = dataform_new{

	field_map.formtype;
	field_map.username;
	field_map.password;
	field_map.captcha_text;
--	field_map.captcha_psi; -- Maybe later, i really have no idea why it used in ejabberd reg form
	field_map.captcha_url;
	field_map.from;
	field_map.captcha_challenge;
	field_map.sid;
	field_map.ocr;
};


function delete_captcha(cid)
	os.remove(string.format("%s/%s.png", config.dir, cid))
	captcha_ids[cid] = nil;
end

for _, field in ipairs(additional_fields) do
	if type(field) == "table" then
		registration_form[#registration_form + 1] = field;
	else
		if field:match("%+$") then
			field = field:sub(1, #field - 1);
			field_map[field].required = true;
		end

		registration_form[#registration_form + 1] = field_map[field];
		registration_query:tag(field):up();
	end
end

module:add_feature("jabber:iq:register");

local register_stream_feature = st.stanza("register", {xmlns="http://jabber.org/features/iq-register"}):up();
module:hook("stream-features", function(event)
        local session, features = event.origin, event.features;

	-- Advertise registration to unauthorized clients only.
	if not(allow_registration) or session.type ~= "c2s_unauthed" then
		return
	end

	features:add_child(register_stream_feature);
end);

local function handle_registration_stanza(event)
	local session, stanza = event.origin, event.stanza;

	local query = stanza.tags[1];
	if stanza.attr.type == "get" then
		local reply = st.reply(stanza);
		reply:tag("query", {xmlns = "jabber:iq:register"})
			:tag("registered"):up()
			:tag("username"):text(session.username):up()
			:tag("password"):up();
		session.send(reply);
	else -- stanza.attr.type == "set"
		if query.tags[1] and query.tags[1].name == "remove" then
			local username, host = session.username, session.host;

			local old_session_close = session.close;
			session.close = function(session, ...)
				session.send(st.reply(stanza));
				return old_session_close(session, ...);
			end
			
			local ok, err = usermanager_delete_user(username, host);
			
			if not ok then
				module:log("debug", "Removing user account %s@%s failed: %s", username, host, err);
				session.close = old_session_close;
				session.send(st.error_reply(stanza, "cancel", "service-unavailable", err));
				return true;
			end
			
			module:log("info", "User removed their account: %s@%s", username, host);
			module:fire_event("user-deregistered", { username = username, host = host, source = "mod_register", session = session });
		else
			local username = nodeprep(query:get_child("username"):get_text());
			local password = query:get_child("password"):get_text();
			if username and password then
				if username == session.username then
					if usermanager_set_password(username, password, session.host) then
						session.send(st.reply(stanza));
					else
						-- TODO unable to write file, file may be locked, etc, what's the correct error?
						session.send(st.error_reply(stanza, "wait", "internal-server-error"));
					end
				else
					session.send(st.error_reply(stanza, "modify", "bad-request"));
				end
			else
				session.send(st.error_reply(stanza, "modify", "bad-request"));
			end
		end
	end
	return true;
end

module:hook("iq/self/jabber:iq:register:query", handle_registration_stanza);
if compat then
	module:hook("iq/host/jabber:iq:register:query", function (event)
		local session, stanza = event.origin, event.stanza;
		if session.type == "c2s" and jid_bare(stanza.attr.to) == session.host then
			return handle_registration_stanza(event);
		end
	end);
end

local function parse_response(query)
	local form = query:get_child("x", "jabber:x:data");
	if form then
		return registration_form:data(form);
	else
		local data = {};
		local errors = {};
		for _, field in ipairs(registration_form) do
			local name, required = field.name, field.required;
			if field_map[name] then
				data[name] = query:get_child_text(name);
				if (not data[name] or #data[name] == 0) and required then
					errors[name] = "Required value missing";
				end
			end
		end
		if next(errors) then
			return data, errors;
		end
		return data;
	end
end

local recent_ips = {};
local min_seconds_between_registrations = module:get_option("min_seconds_between_registrations");
local whitelist_only = module:get_option("whitelist_registration_only");
local whitelisted_ips = module:get_option("registration_whitelist") or { "127.0.0.1" };
local blacklisted_ips = module:get_option("registration_blacklist") or {};

for _, ip in ipairs(whitelisted_ips) do whitelisted_ips[ip] = true; end
for _, ip in ipairs(blacklisted_ips) do blacklisted_ips[ip] = true; end


local function get_file(name)
	local file = io.open(name, "rb")
	local data = file:read("*all")
	file:close()
	return data
end


local function get_captcha()
	local cap = captcha.new();
	math.randomseed(os_time());
	local cid = tostring(math.random(1000, 90000)); -- random cid used for cap name
	cap:font(config.font);
	cap:scribble();
	captcha_ids[cid] = cap:write(string.format("%s/%s.png", config.dir, cid)):lower();
	timer.add_task(config.timeout, function() delete_captcha(cid) end); -- Add new function to use arguments. Is there any other way in lua? Or it even works?
	return cid
end



module:hook("stanza/iq/jabber:iq:register:query", function(event)
	local session, stanza = event.origin, event.stanza;

	if not(allow_registration) or session.type ~= "c2s_unauthed" then
		session.send(st.error_reply(stanza, "cancel", "service-unavailable"));
	else
		local query = stanza.tags[1];
		if stanza.attr.type == "get" then
			local reply = st.reply(stanza):query("jabber:iq:register");
			-- TODO: Move this in standalone function
			local challenge = get_captcha()
			local captcha_data = get_file(config.dir.."/"..challenge..".png")
			local captcha_sha = sha1(captcha_data, true) -- omg
			local captcha_base64 = base64(captcha_data) -- lol wut
			xml = registration_form:form(({FORM_TYPE = "urn:xmpp:captcha",
				from = session.host,
				ocr = {{ 
					type = "image/png",
					uri = string.format("cid:sha1+%s@bob.xmpp.org", captcha_sha) 
				}};
				url = string.format("http://%s:5280/%s/%s", session.host, config.web_path, challenge);
				captcha_text = "If you can't see an image, follow link below";
				challenge = challenge;
				sid = "1";
			}));

			data = st.stanza("data", 
				{xmlns = "urn:xmpp:bob", 
				cid = string.format("sha1+%s@bob.xmpp.org", captcha_sha), 
				type = "image/png", 
				["max-age"] = config.timeout})
			:text(captcha_base64);
			
			reply = reply:add_child(xml);
			reply = reply:add_child(data);
			session.send(reply);

		elseif stanza.attr.type == "set" then
			if query.tags[1] and query.tags[1].name == "remove" then
				session.send(st.error_reply(stanza, "auth", "registration-required"));
			else
				local data, errors = parse_response(query);
				if errors then
					session.send(st.error_reply(stanza, "modify", "not-acceptable"));
				else
					-- Check that the user is not blacklisted or registering too often
					if not session.ip then
						module:log("debug", "User's IP not known; can't apply blacklist/whitelist");
					elseif blacklisted_ips[session.ip] or (whitelist_only and not whitelisted_ips[session.ip]) then
						session.send(st.error_reply(stanza, "cancel", "not-acceptable", "You are not allowed to register an account."));
						return true;
					elseif min_seconds_between_registrations and not whitelisted_ips[session.ip] then
						if not recent_ips[session.ip] then
							recent_ips[session.ip] = { time = os_time(), count = 1 };
						else
							local ip = recent_ips[session.ip];
							ip.count = ip.count + 1;
							
							if os_time() - ip.time < min_seconds_between_registrations then
								ip.time = os_time();
								session.send(st.error_reply(stanza, "wait", "not-acceptable"));
								return true;
							end
							ip.time = os_time();
						end
					end
					local host = module.host;
					local ocr = data.ocr:lower();
					local challenge = data.challenge;
					local username, password = nodeprep(data.username), data.password;
					data.username, data.password = nil, nil; 

					if challenge == nil or captcha_ids[challenge] == nil then
						session.send(st.error_reply(stanza, "modify", "not-acceptable", "Captcha id is invalid or it has expired"));
						delete_captcha(challenge);
						return true;
					elseif ocr ~= captcha_ids[challenge] then
						session.send(st.error_reply(stanza, "modify", "not-acceptable", "Invalid captcha text"));
						delete_captcha(challenge);
						return true;
					end
					if not username or username == "" then
						session.send(st.error_reply(stanza, "modify", "not-acceptable", "The requested username is invalid."));
						delete_captcha(challenge);
						return true;
					end
					local user = { username = username , host = host, allowed = true }
					module:fire_event("user-registering", user);
					if not user.allowed then
						delete_captcha(challenge);
						session.send(st.error_reply(stanza, "modify", "not-acceptable", "The requested username is forbidden."));
					elseif usermanager_user_exists(username, host) then
						delete_captcha(challenge)
						session.send(st.error_reply(stanza, "cancel", "conflict", "The requested username already exists."));
					else
						-- TODO unable to write file, file may be locked, etc, what's the correct error?
						local error_reply = st.error_reply(stanza, "wait", "internal-server-error", "Failed to write data to disk.");
						if usermanager_create_user(username, password, host) then
							if next(data) and not account_details:set(username, data) then
								delete_captcha(challenge);
								usermanager_delete_user(username, host);
								session.send(error_reply);
								return true;
							end
							session.send(st.reply(stanza)); -- user created!
							module:log("info", "User account created: %s@%s", username, host);
							module:fire_event("user-registered", {
								username = username, host = host, source = "mod_register",
								session = session });
						else
							delete_captcha(challenge);
							session.send(error_reply);
						end
					end
				end
			end
		end
	end
	return true;
end);

function string:split(sep)
	local sep, fields = sep or ":", {}
	local pattern = string.format("([^%s]+)", sep)
	self:gsub(pattern, function(c) fields[#fields+1] = c end)
	return fields
end


function handle_http_request(event) 
	local request = event.request;
	local path = request.path;
	local cid = path:split("/")[2];
	if cid == nil or captcha_ids[cid] == nil then
		return nil;
	end
	request.response = {
		status_code = 200;
		headers = {	
			content_type = "image/png" 
		};
		body = get_file(string.format("%s/%s.png", config.dir, cid));
	};
	return request.response;


end;

module:provides("http", {
	default_path = "/"..config.web_path;
	route = {
		["GET /*"] = handle_http_request;
	};
});