local id = require "util.id";

local it = require "util.iterators";

local url = require "socket.url";

local jid_node = require "util.jid".node;

local jid_split = require "util.jid".split;

local default_ttl = module:get_option_number("invite_expiry", 86400 * 7);

local token_storage;

if prosody.process_type == "prosody" or prosody.shutdown then

	token_storage = module:open_store("invite_token", "map");

end

local function get_uri(action, jid, token, params) --> string

	return url.build({

			scheme = "xmpp",

			path = jid,

			query = action..";preauth="..token..(params and (";"..params) or ""),

		});

end

local function create_invite(invite_action, invite_jid, allow_registration, additional_data, ttl, reusable)

	local token = id.medium();

	local created_at = os.time();

	local expires = created_at + (ttl or default_ttl);

	local invite_params = (invite_action == "roster" and allow_registration) and "ibr=y" or nil;

	local invite = {

		type = invite_action;

		jid = invite_jid;

		token = token;

		allow_registration = allow_registration;

		additional_data = additional_data;

		uri = get_uri(invite_action, invite_jid, token, invite_params);

		created_at = created_at;

		expires = expires;

		reusable = reusable;

	};

	module:fire_event("invite-created", invite);

	if allow_registration then

		local ok, err = token_storage:set(nil, token, invite);

		if not ok then

			module:log("warn", "Failed to store account invite: %s", err);

			return nil, "internal-server-error";

		end

	end

	if invite_action == "roster" then

		local username = jid_node(invite_jid);

		local ok, err = token_storage:set(username, token, expires);

		if not ok then

			module:log("warn", "Failed to store subscription invite: %s", err);

			return nil, "internal-server-error";

		end

	end

	return invite;

end

-- Create invitation to register an account (optionally restricted to the specified username)

function create_account(account_username, additional_data, ttl) --luacheck: ignore 131/create_account

	local jid = account_username and (account_username.."@"..module.host) or module.host;

	return create_invite("register", jid, true, additional_data, ttl);

end

-- Create invitation to reset the password for an account

function create_account_reset(account_username, ttl) --luacheck: ignore 131/create_account_reset

	return create_account(account_username, { allow_reset = account_username }, ttl or 86400);

end

-- Create invitation to become a contact of a local user

function create_contact(username, allow_registration, additional_data, ttl) --luacheck: ignore 131/create_contact

	return create_invite("roster", username.."@"..module.host, allow_registration, additional_data, ttl);

end

-- Create invitation to register an account and join a user group

-- If explicit ttl is passed, invite is valid for multiple signups

-- during that time period

function create_group(group_ids, additional_data, ttl) --luacheck: ignore 131/create_group

	local merged_additional_data = {

		groups = group_ids;

	};

	if additional_data then

		for k, v in pairs(additional_data) do

			merged_additional_data[k] = v;

		end

	end

	return create_invite("register", module.host, true, merged_additional_data, ttl, not not ttl);

end

-- Iterates pending (non-expired, unused) invites that allow registration

function pending_account_invites() --luacheck: ignore 131/pending_account_invites

	local store = module:open_store("invite_token");

	local now = os.time();

	local function is_valid_invite(_, invite)

		return invite.expires > now;

	end

	return it.filter(is_valid_invite, pairs(store:get(nil) or {}));

end

function get_account_invite_info(token) --luacheck: ignore 131/get_account_invite_info

	if not token then

		return nil, "no-token";

	end

	-- Fetch from host store (account invite)

	local token_info = token_storage:get(nil, token);

	if not token_info then

		return nil, "token-invalid";

	elseif os.time() > token_info.expires then

		return nil, "token-expired";

	end

	return token_info;

end

function delete_account_invite(token) --luacheck: ignore 131/delete_account_invite

	if not token then

		return nil, "no-token";

	end

	return token_storage:set(nil, token, nil);

end

local valid_invite_methods = {};

local valid_invite_mt = { __index = valid_invite_methods };

function valid_invite_methods:use()

	if self.reusable then

		return true;

	end

	if self.username then

		-- Also remove the contact invite if present, on the

		-- assumption that they now have a mutual subscription

		token_storage:set(self.username, self.token, nil);

	end

	token_storage:set(nil, self.token, nil);

	return true;

end

-- Get a validated invite (or nil, err). Must call :use() on the

-- returned invite after it is actually successfully used

-- For "roster" invites, the username of the local user (who issued

-- the invite) must be passed.

-- If no username is passed, but the registration is a roster invite

-- from a local user, the "inviter" field of the returned invite will

-- be set to their username.

function get(token, username)

	if not token then

		return nil, "no-token";

	end

	local valid_until, inviter;

	-- Fetch from host store (account invite)

	local token_info = token_storage:get(nil, token);

	if username then -- token being used for subscription

		-- Fetch from user store (subscription invite)

		valid_until = token_storage:get(username, token);

	else -- token being used for account creation

		valid_until = token_info and token_info.expires;

		if token_info and token_info.type == "roster" then

			username = jid_node(token_info.jid);

			inviter = username;

		end

	end

	if not valid_until then

		module:log("debug", "Got unknown token: %s", token);

		return nil, "token-invalid";

	elseif os.time() > valid_until then

		module:log("debug", "Got expired token: %s", token);

		return nil, "token-expired";

	end

	return setmetatable({

		token = token;

		username = username;

		inviter = inviter;

		type = token_info and token_info.type or "roster";

		uri = token_info and token_info.uri or get_uri("roster", username.."@"..module.host, token);

		additional_data = token_info and token_info.additional_data or nil;

		reusable = token_info.reusable;

	}, valid_invite_mt);

end

function use(token) --luacheck: ignore 131/use

	local invite = get(token);

	return invite and invite:use();

end

--- shell command

do

	-- Since the console is global this overwrites the command for

	-- each host it's loaded on, but this should be fine.

	local get_module = require "core.modulemanager".get_module;

	local console_env = module:shared("/*/admin_shell/env");

	-- luacheck: ignore 212/self

	console_env.invite = {};

	function console_env.invite:create_account(user_jid)

		local username, host = jid_split(user_jid);

		local mod_invites, err = get_module(host, "invites");

		if not mod_invites then return nil, err or "mod_invites not loaded on this host"; end

		local invite, err = mod_invites.create_account(username);

		if not invite then return nil, err; end

		return true, invite.landing_page or invite.uri;

	end

	function console_env.invite:create_contact(user_jid, allow_registration)

		local username, host = jid_split(user_jid);

		local mod_invites, err = get_module(host, "invites");

		if not mod_invites then return nil, err or "mod_invites not loaded on this host"; end

		local invite, err = mod_invites.create_contact(username, allow_registration);

		if not invite then return nil, err; end

		return true, invite.landing_page or invite.uri;

	end

end

--- prosodyctl command

function module.command(arg)

	if #arg < 2 or arg[1] ~= "generate" then

		print("usage: prosodyctl mod_"..module.name.." generate example.com");

		return 2;

	end

	table.remove(arg, 1); -- pop command

	local sm = require "core.storagemanager";

	local mm = require "core.modulemanager";

	local host = arg[1];

	assert(prosody.hosts[host], "Host "..tostring(host).." does not exist");

	sm.initialize_host(host);

	table.remove(arg, 1); -- pop host

	module.host = host; --luacheck: ignore 122/module

	token_storage = module:open_store("invite_token", "map");

	-- Load mod_invites

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

	-- Optional community module that if used, needs to be loaded here

	local invites_page_module = module:get_option_string("invites_page_module", "invites_page");

	if mm.get_modules_for_host(host):contains(invites_page_module) then

		module:depends(invites_page_module);

	end

	local allow_reset;

	local roles;

	local groups = {};

	while #arg > 0 do

		local value = arg[1];

		table.remove(arg, 1);

		if value == "--help" then

			print("usage: prosodyctl mod_"..module.name.." generate DOMAIN --reset USERNAME")

			print("usage: prosodyctl mod_"..module.name.." generate DOMAIN [--admin] [--role ROLE] [--group GROUPID]...")

			print()

			print("This command has two modes: password reset and new account.")

			print("If --reset is given, the command operates in password reset mode and in new account mode otherwise.")

			print()

			print("required arguments in password reset mode:")

			print()

			print("    --reset USERNAME  Generate a password reset link for the given USERNAME.")

			print()

			print("optional arguments in new account mode:")

			print()

			print("    --admin           Make the new user privileged")

			print("                      Equivalent to --role prosody:admin")

			print("    --role ROLE       Grant the given ROLE to the new user")

			print("    --group GROUPID   Add the user to the group with the given ID")

			print("                      Can be specified multiple times")

			print()

			print("--role and --admin override each other; the last one wins")

			print("--group can be specified multiple times; the user will be added to all groups.")

			print()

			print("--reset and the other options cannot be mixed.")

			return 2

		elseif value == "--reset" then

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

			local username = nodeprep(arg[1])

			table.remove(arg, 1);

			if not username then

				print("Please supply a valid username to generate a reset link for");

				return 2;

			end

			allow_reset = username;

		elseif value == "--admin" then

			roles = { ["prosody:admin"] = true };

		elseif value == "--role" then

			local rolename = arg[1];

			if not rolename then

				print("Please supply a role name");

				return 2;

			end

			roles = { [rolename] = true };

			table.remove(arg, 1);

		elseif value == "--group" or value == "-g" then

			local groupid = arg[1];

			if not groupid then

				print("Please supply a group ID")

				return 2;

			end

			table.insert(groups, groupid);

			table.remove(arg, 1);

		else

			print("unexpected argument: "..value)

		end

	end

	local invite;

	if allow_reset then

		if roles then

			print("--role/--admin and --reset are mutually exclusive")

			return 2;

		end

		if #groups > 0 then

			print("--group and --reset are mutually exclusive")

		end

		invite = assert(invites.create_account_reset(allow_reset));

	else

		invite = assert(invites.create_account(nil, {

			roles = roles,

			groups = groups

		}));

	end

	print(invite.landing_page or invite.uri);

end