local modulemanager = require "core.modulemanager";

local usermanager = require "core.usermanager";

local array = require "util.array";

local dt = require "util.datetime";

local id = require "util.id";

local it = require "util.iterators";

local jid = require "util.jid";

local st = require "util.stanza";

local strict = module:get_option_boolean("enforce_client_ids", false);

local tokenauth = module:depends("tokenauth");

local mod_fast = module:depends("sasl2_fast");

local client_store = assert(module:open_store("clients", "keyval+"));

--[[{

	id = id;

	first_seen =

	last_seen =

	user_agent = {

		name =

		os =

	}

--}]]

local xmlns_sasl2 = "urn:xmpp:sasl:2";

local function get_user_agent(sasl_handler, token_info)

	local sasl_agent = sasl_handler and sasl_handler.user_agent;

	local token_agent = token_info and token_info.data and token_info.data.oauth2_client;

	if not (sasl_agent or token_agent) then return; end

	return {

		software = sasl_agent and sasl_agent.software or token_agent and token_agent.name or nil;

		uri = token_agent and token_agent.uri or nil;

		device = sasl_agent and sasl_agent.device or nil;

	};

end

module:hook("sasl2/c2s/success", function (event)

	local session = event.session;

	local username, client_id = session.username, session.client_id;

	local mechanism = session.sasl_handler.selected;

	local token_info = session.sasl_handler.token_info;

	local token_id = token_info and token_info.id or nil;

	local now = os.time();

	if client_id then -- SASL2, have client identifier

		local is_new_client;

		local client_state = client_store:get_key(username, client_id);

		if not client_state then

			is_new_client = true;

			client_state = {

				id = client_id;

				first_seen = now;

				user_agent = get_user_agent(session.sasl_handler, token_info);

				full_jid = nil;

				last_seen = nil;

				mechanisms = {};

			};

		end

		-- Update state

		client_state.full_jid = session.full_jid;

		client_state.last_seen = now;

		client_state.mechanisms[mechanism] = now;

		if session.sasl_handler.fast_auth then

			client_state.fast_auth = now;

		end

		if token_id then

			client_state.auth_token_id = token_id;

		end

		-- Store updated state

		client_store:set_key(username, client_id, client_state);

		if is_new_client then

			module:fire_event("client_management/new-client", { client = client_state });

		end

	end

end);

local function find_client_by_resource(username, resource)

	local full_jid = jid.join(username, module.host, resource);

	local clients = client_store:get(username);

	if not clients then return; end

	for _, client_state in pairs(clients) do

		if client_state.full_jid == full_jid then

			return client_state;

		end

	end

end

module:hook("resource-bind", function (event)

	local session = event.session;

	if session.client_id then return; end

	local is_new_client;

	local client_state = find_client_by_resource(event.session.username, event.session.resource);

	local now = os.time();

	if not client_state then

		is_new_client = true;

		client_state = {

			id = id.short();

			first_seen = now;

			user_agent = nil;

			full_jid = nil;

			last_seen = nil;

			mechanisms = {};

			legacy = true;

		};

	end

	-- Update state

	local legacy_info = session.client_management_info;

	client_state.full_jid = session.full_jid;

	client_state.last_seen = now;

	client_state.mechanisms[legacy_info.mechanism] = now;

	if legacy_info.fast_auth then

		client_state.fast_auth = now;

	end

	local token_id = legacy_info.token_info and legacy_info.token_info.id;

	if token_id then

		client_state.auth_token_id = token_id;

	end

	-- Store updated state

	client_store:set_key(session.username, client_state.id, client_state);

	if is_new_client then

		module:fire_event("client_management/new-client", { client = client_state });

	end

end);

if strict then

	module:hook_tag(xmlns_sasl2, "authenticate", function (session, auth)

		local user_agent = auth:get_child("user-agent");

		if not user_agent or not user_agent.attr.id then

			local failure = st.stanza("failure", { xmlns = xmlns_sasl2 })

				:tag("malformed-request", { xmlns = "urn:ietf:params:xml:ns:xmpp-sasl" }):up()

				:text_tag("text", "Client identifier required but not supplied");

			session.send(failure);

			return true;

		end

	end, 500);

	if modulemanager.get_modules_for_host(module.host):contains("saslauth") then

		module:log("error", "mod_saslauth is enabled, but enforce_client_ids is enabled and will prevent it from working");

	end

	module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", function (event)

		-- Block legacy SASL, if for some reason it is being used (either mod_saslauth is loaded,

		-- or clients try it without advertisement)

		module:log("warn", "Blocking legacy SASL authentication because enforce_client_ids is enabled");

		local failure = st.stanza("failure", { xmlns = xmlns_sasl2 })

			:tag("malformed-request", { xmlns = "urn:ietf:params:xml:ns:xmpp-sasl" }):up()

			:text_tag("text", "Legacy SASL authentication is not available on this server");

		event.session.send(failure);

		return true;

	end);

else

	-- Legacy client compat code

	module:hook("authentication-success", function (event)

		local session = event.session;

		if session.client_id then return; end -- SASL2 client

		local sasl_handler = session.sasl_handler;

		session.client_management_info = {

			mechanism = sasl_handler.selected;

			token_info = sasl_handler.token_info;

			fast_auth = sasl_handler.fast_auth;

		};

	end);

end

local function is_password_mechanism(mech_name)

	if mech_name == "OAUTHBEARER" then return false; end

	if mech_name:match("^HT%-") then return false; end

	return true;

end

local function is_client_active(client)

	local username, host = jid.split(client.full_jid);

	local account_info = usermanager.get_account_info(username, host);

	local last_password_change = account_info and account_info.password_updated;

	local status = {};

	-- Check for an active token grant that has been previously used by this client

	if client.auth_token_id then

		local grant = tokenauth.get_grant_info(client.auth_token_id);

		if grant then

			status.grant = grant;

		end

	end

	-- Check for active FAST tokens

	if client.fast_auth then

		if mod_fast.is_client_fast(username, client.id, last_password_change) then

			status.fast = client.fast_auth;

		end

	end

	-- Client has access if any password-based SASL mechanisms have been used since last password change

	for mech, mech_last_used in pairs(client.mechanisms) do

		if is_password_mechanism(mech) and mech_last_used >= last_password_change then

			status.password = mech_last_used;

		end

	end

	if prosody.full_sessions[client.full_jid] then

		status.connected = true;

	end

	if next(status) == nil then

		return nil;

	end

	return status;

end

-- Public API

--luacheck: ignore 131

function get_active_clients(username)

	local clients = client_store:get(username);

	local active_clients = {};

	local used_grants = {};

	-- Go through known clients, check whether they could possibly log in

	for client_id, client in pairs(clients or {}) do --luacheck: ignore 213/client_id

		local active = is_client_active(client);

		if active then

			client.type = "session";

			client.id = "client/"..client.id;

			client.active = active;

			table.insert(active_clients, client);

			if active.grant then

				used_grants[active.grant.id] = true;

			end

		end

	end

	-- Next, account for any grants that have been issued, but never actually logged in

	for grant_id, grant in pairs(tokenauth.get_user_grants(username) or {}) do

		if not used_grants[grant_id] then -- exclude grants already accounted for

			table.insert(active_clients, {

				id = "grant/"..grant_id;

				type = "access";

				first_seen = grant.created;

				last_seen = grant.accessed;

				active = {

					grant = grant;

				};

				user_agent = get_user_agent(nil, grant);

			});

		end

	end

	table.sort(active_clients, function (a, b)

		if a.last_seen and b.last_seen then

			return a.last_seen < b.last_seen;

		elseif not (a.last_seen or b.last_seen) then

			if a.first_seen and b.first_seen then

				return a.first_seen < b.first_seen;

			end

		elseif b.last_seen then

			return true;

		elseif a.last_seen then

			return false;

		end

		return a.id < b.id;

	end);

	return active_clients;

end

function revoke_client_access(username, client_selector)

	if client_selector.id then

		local c_type, c_id = client_selector.id:match("^(%w+)/(.+)$");

		if c_type == "client" then

			local client = client_store:get_key(username, c_id);

			if not client then

				return nil, "item-not-found";

			end

			local status = is_client_active(client);

			if status.connected then

				local ok, err = prosody.full_sessions[client.full_jid]:close();

				if not ok then return ok, err; end

			end

			if status.fast then

				local ok = mod_fast.revoke_fast_tokens(username, client.id);

				if not ok then return nil, "internal-server-error"; end

			end

			if status.grant then

				local ok = tokenauth.revoke_grant(username, status.grant.id);

				if not ok then return nil, "internal-server-error"; end

			end

			if status.password then

				return nil, "password-reset-required";

			end

			return true;

		elseif c_type == "grant" then

			local grant = tokenauth.get_grant_info(username, c_id);

			if not grant then

				return nil, "item-not-found";

			end

			local ok = tokenauth.revoke_grant(username, c_id);

			if not ok then return nil, "internal-server-error"; end

			return true;

		end

	end

	return nil, "item-not-found";

end

-- Protocol

local xmlns_manage_clients = "xmpp:prosody.im/protocol/manage-clients";

module:hook("iq-get/self/xmpp:prosody.im/protocol/manage-clients:list", function (event)

	local origin, stanza = event.origin, event.stanza;

	if not module:may(":list-clients", event) then

		origin.send(st.error_reply(stanza, "auth", "forbidden"));

		return true;

	end

	local reply = st.reply(stanza)

		:tag("clients", { xmlns = xmlns_manage_clients });

	local active_clients = get_active_clients(event.origin.username);

	for _, client in ipairs(active_clients) do

		local auth_type = st.stanza("auth");

		if client.active then

			if client.active.password then

				auth_type:text_tag("password");

			end

			if client.active.grant then

				auth_type:text_tag("bearer-token");

			end

			if client.active.fast then

				auth_type:text_tag("fast");

			end

		end

		local user_agent = st.stanza("user-agent");

		if client.user_agent then

			if client.user_agent.software then

				user_agent:text_tag("software", client.user_agent.software);

			end

			if client.user_agent.device then

				user_agent:text_tag("device", client.user_agent.device);

			end

			if client.user_agent.uri then

				user_agent:text_tag("uri", client.user_agent.uri);

			end

		end

		local connected = client.active and client.active.connected;

		reply:tag("client", { id = client.id, connected = connected and "true" or "false", type = client.type })

			:text_tag("first-seen", dt.datetime(client.first_seen))

			:text_tag("last-seen", dt.datetime(client.last_seen))

			:add_child(auth_type)

			:add_child(user_agent)

			:up();

	end

	reply:up();

	origin.send(reply);

	return true;

end);