PostgreSQL functions for Croatian Personal Identification Number (OIB)

hr-pin-plpgsql.sql

-- PostgreSQL functions for Croatian Personal Identification Number (OIB)
--
-- Reference:
-- https://en.wikipedia.org/wiki/Personal_identification_number_(Croatia)
-- http://www.regos.hr/UserDocsImages/KONTROLA%20OIB-a.pdf

CREATE OR REPLACE FUNCTION hr_pin_control_number(pin_base TEXT) RETURNS INTEGER AS $$
DECLARE
	pin_digit INTEGER;
	control INTEGER;
BEGIN
	IF length(pin_base) != 10 THEN
		RAISE EXCEPTION 'Invalid input ''%''', pin_base
		USING HINT = 'Input must be exactly 10 digits long';
	END IF;

	IF NOT textregexeq(pin_base, '^[[:digit:]]+$') THEN
		RAISE EXCEPTION 'Invalid input ''%''', pin_base
		USING HINT = 'Input must contain only digits';
	END IF;

	FOR i IN 1..10 LOOP
		pin_digit := substr(pin_base, i, 1)::INTEGER;
		IF i = 1 THEN
			control := pin_digit + 10;
		ELSE
			control := pin_digit + control;
		END IF;
		control := control % 10;
		IF control = 0 THEN
			control := 10;
		END IF;
		control := control * 2;
		control := control % 11;
	END LOOP;

	control := 11 - control;
	control := control % 10;

	RETURN control;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION hr_pin_is_valid(pin TEXT) RETURNS BOOLEAN AS $$
DECLARE
	control INTEGER;
BEGIN
	IF length(pin) != 11 THEN
		RAISE EXCEPTION 'Invalid input ''%''', pin
		USING HINT = 'Input must be exactly 11 digits long';
	END IF;

	IF NOT textregexeq(pin, '^[[:digit:]]+$') THEN
		RAISE EXCEPTION 'Invalid input ''%''', pin
		USING HINT = 'Input must contain only digits';
	END IF;

	control := hr_pin_control_number(substr(pin, 1, 10));

	RETURN control = substr(pin, 11, 1)::INTEGER;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION hr_pin_generate_random() RETURNS TEXT AS $$
DECLARE
	pin_digits INTEGER[];
	pin_base TEXT;
	control INTEGER;
BEGIN
	FOR i IN 1..10 LOOP
		pin_digits[i] := floor(random() * 10);
	END LOOP;

	pin_base = array_to_string(pin_digits, '');
	control := hr_pin_control_number(pin_base);

	RETURN concat(pin_base, control);
END;
$$ LANGUAGE plpgsql;