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

local datamanager = require "util.datamanager";
local log = require "util.logger".init("usermanager");
local type = type;
local error = error;
local ipairs = ipairs;
local hashes = require "util.hashes";
local jid_bare = require "util.jid".bare;
local saltedPasswordSHA1 = require "util.sasl.scram".saltedPasswordSHA1;
local config = require "core.configmanager";
local usermanager = require "core.usermanager";
local generate_uuid = require "util.uuid".generate;
local new_sasl = require "util.sasl".new;
local nodeprep = require "util.encodings".stringprep.nodeprep;
local hosts = hosts;

local prosody = _G.prosody;

local is_cyrus = usermanager.is_cyrus;

-- Default; can be set per-user
local iteration_count = 4096;

function new_hashpass_provider(host)
	local provider = { name = "internal_hashed" };
	log("debug", "initializing hashpass authentication provider for host '%s'", host);

	function provider.test_password(username, password)
		if is_cyrus(host) then return nil, "Legacy auth not supported with Cyrus SASL."; end
		local credentials = datamanager.load(username, host, "accounts") or {};
	
		if credentials.password ~= nil and string.len(credentials.password) ~= 0 then
			if credentials.password ~= password then
				return nil, "Auth failed. Provided password is incorrect.";
			end

			if provider.set_password(username, credentials.password) == nil then
				return nil, "Auth failed. Could not set hashed password from plaintext.";
			else
				return true;
			end
		end

		if credentials.iteration_count == nil or credentials.salt == nil or string.len(credentials.salt) == 0 then
			return nil, "Auth failed. Stored salt and iteration count information is not complete.";
		end

		local valid, binpass = saltedPasswordSHA1(password, credentials.salt, credentials.iteration_count);
		local hexpass = binpass:gsub(".", function (c) return ("%02x"):format(c:byte()); end);

		if valid and hexpass == credentials.hashpass then
			return true;
		else
			return nil, "Auth failed. Invalid username, password, or password hash information.";
		end
	end

	function provider.set_password(username, password)
		if is_cyrus(host) then return nil, "Passwords unavailable for Cyrus SASL."; end
		local account = datamanager.load(username, host, "accounts");
		if account then
			if account.iteration_count == nil then
				account.iteration_count = iteration_count;
			end

			if account.salt == nil then
				account.salt = generate_uuid();
			end

			local valid, binpass = saltedPasswordSHA1(password, account.salt, account.iteration_count);
			local hexpass = binpass:gsub(".", function (c) return ("%02x"):format(c:byte()); end);
			account.hashpass = hexpass;

			account.password = nil;
			return datamanager.store(username, host, "accounts", account);
		end
		return nil, "Account not available.";
	end

	function provider.user_exists(username)
		if is_cyrus(host) then return true; end
		local account = datamanager.load(username, host, "accounts");
		if not account then
			log("debug", "account not found for username '%s' at host '%s'", username, module.host);
			return nil, "Auth failed. Invalid username";
		end
		if (account.hashpass == nil or string.len(account.hashpass) == 0) and (account.password == nil or string.len(account.password) == 0) then
			log("debug", "account password not set or zero-length for username '%s' at host '%s'", username, module.host);
			return nil, "Auth failed. Password invalid.";
		end
		return true;
	end

	function provider.create_user(username, password)
		if is_cyrus(host) then return nil, "Account creation/modification not available with Cyrus SASL."; end
		local salt = generate_uuid();
		local valid, binpass = saltedPasswordSHA1(password, salt, iteration_count);
		local hexpass = binpass:gsub(".", function (c) return ("%02x"):format(c:byte()); end);
		return datamanager.store(username, host, "accounts", {hashpass = hexpass, salt = salt, iteration_count = iteration_count});
	end

	function provider.get_sasl_handler()
		local realm = module:get_option("sasl_realm") or module.host;
		local testpass_authentication_profile = {
			plain_test = function(username, password, realm)
				local prepped_username = nodeprep(username);
				if not prepped_username then
					log("debug", "NODEprep failed on username: %s", username);
					return "", nil;
				end
				return usermanager.test_password(prepped_username, password, realm), true;
			end,
			scram_sha_1 = function(username, realm)
				local credentials = datamanager.load(username, host, "accounts") or {};
				if credentials.password then
					usermanager.set_password(username, credentials.password);
					credentials = datamanager.load(username, host, "accounts") or {};
				end
				local salted_password, iteration_count, salt = credentials.hashpass, credentials.iteration_count, credentials.salt;
				salted_password = salted_password and salted_password:gsub("..", function(x) return string.char(tonumber(x, 16)); end);
				return salted_password, iteration_count, salt, true;
			end
		};
		return new_sasl(realm, testpass_authentication_profile);
	end

	function provider.is_admin(jid)
		local admins = config.get(host, "core", "admins");
		if admins ~= config.get("*", "core", "admins") and type(admins) == "table" then
			jid = jid_bare(jid);
			for _,admin in ipairs(admins) do
				if admin == jid then return true; end
			end
		elseif admins then
			log("error", "Option 'admins' for host '%s' is not a table", host);
		end
		return is_admin(jid); -- Test whether it's a global admin instead
	end
	return provider;
end

module:add_item("auth-provider", new_hashpass_provider(module.host));