local id = require "util.id";

local jid = require "util.jid";

local base64 = require "util.encodings".base64;

local usermanager = require "core.usermanager";

local generate_identifier = require "util.id".short;

local token_store = module:open_store("auth_tokens", "map");

local function select_role(username, host, role)

	if role then

		return prosody.hosts[host].authz.get_role_by_name(role);

	end

	return usermanager.get_user_role(username, host);

end

function create_jid_token(actor_jid, token_jid, token_role, token_ttl, token_data, token_purpose)

	token_jid = jid.prep(token_jid);

	if not actor_jid or token_jid ~= actor_jid and not jid.compare(token_jid, actor_jid) then

		return nil, "not-authorized";

	end

	local token_username, token_host, token_resource = jid.split(token_jid);

	if token_host ~= module.host then

		return nil, "invalid-host";

	end

	if (token_data and type(token_data) ~= "table") or (token_purpose and type(token_purpose ~= "string")) then

		return nil, "bad-request";

	end

	local token_info = {

		owner = actor_jid;

		created = os.time();

		expires = token_ttl and (os.time() + token_ttl) or nil;

		jid = token_jid;

		purpose = token_purpose;

		resource = token_resource;

		role = token_role;

		data = token_data;

	};

	local token_id = id.long();

	local token = base64.encode("1;"..jid.join(token_username, token_host)..";"..token_id);

	token_store:set(token_username, token_id, token_info);

	return token, token_info;

end

local function parse_token(encoded_token)

	local token = base64.decode(encoded_token);

	if not token then return nil; end

	local token_jid, token_id = token:match("^1;([^;]+);(.+)$");

	if not token_jid then return nil; end

	local token_user, token_host = jid.split(token_jid);

	return token_id, token_user, token_host;

end

local function _get_parsed_token_info(token_id, token_user, token_host)

	if token_host ~= module.host then

		return nil, "invalid-host";

	end

	local token_info, err = token_store:get(token_user, token_id);

	if not token_info then

		if err then

			return nil, "internal-error";

		end

		return nil, "not-authorized";

	end

	if token_info.expires and token_info.expires < os.time() then

		token_store:set(token_user, token_id, nil);

		return nil, "not-authorized";

	end

	local account_info = usermanager.get_account_info(token_user, module.host);

	local password_updated_at = account_info and account_info.password_updated;

	if password_updated_at and password_updated_at > token_info.created then

		token_store:set(token_user, token_id, nil);

		return nil, "not-authorized";

	end

	return token_info

end

function get_token_info(token)

	local token_id, token_user, token_host = parse_token(token);

	if not token_id then

		return nil, "invalid-token-format";

	end

	return _get_parsed_token_info(token_id, token_user, token_host);

end

function get_token_session(token, resource)

	local token_id, token_user, token_host = parse_token(token);

	if not token_id then

		return nil, "invalid-token-format";

	end

	local token_info, err = _get_parsed_token_info(token_id, token_user, token_host);

	if not token_info then return nil, err; end

	return {

		username = token_user;

		host = token_host;

		resource = token_info.resource or resource or generate_identifier();

		role = select_role(token_user, token_host, token_info.role);

	};

end

function revoke_token(token)

	local token_id, token_user, token_host = parse_token(token);

	if not token_id then

		return nil, "invalid-token-format";

	end

	if token_host ~= module.host then

		return nil, "invalid-host";

	end

	return token_store:set(token_user, token_id, nil);

end

function sasl_handler(auth_provider, purpose, extra)

	return function (_, username, token, realm)

		local token_info, err = get_token_info(token);

		if not token_info then

			module:log("debug", "SASL handler failed to verify token: %s", err);

			return nil, nil, extra;

		end

		local token_user, token_host = jid.split(token_info.jid);

		if username ~= token_user or realm ~= token_host or (purpose and token_info.purpose ~= purpose) then

			return nil, nil, extra;

		end

		if auth_provider.is_enabled and not auth_provider.is_enabled(username) then

			return true, false, token_info;

		end

		return true, true, token_info;

	end;

end