-- general database structure
-- table to hold all rules
CREATE TABLE rules (
	netmask cidr NOT NULL,
	redirect_url text DEFAULT 'about::blank'::text NOT NULL,
	from_weekday smallint DEFAULT 0 NOT NULL,
	to_weekday smallint DEFAULT 6 NOT NULL,
	from_time time without time zone DEFAULT '00:00:00'::time without time zone NOT NULL,
	to_time time without time zone DEFAULT '23:59:59'::time without time zone NOT NULL,
	id_tag smallint NOT NULL
);

ALTER TABLE ONLY rules
	ADD CONSTRAINT rules_tag_f FOREIGN KEY (id_tag) REFERENCES tag(id_tag) MATCH FULL
	ON UPDATE RESTRICT ON DELETE RESTRICT DEFERRABLE INITIALLY DEFERRED;

-- table to hold site arrays
CREATE TABLE site (
	id_site serial,
	site text[] NOT NULL
);

ALTER TABLE ONLY site
	ADD CONSTRAINT site_pkey PRIMARY KEY (id_site);

CREATE UNIQUE INDEX site_u ON site (usort(site));

CREATE INDEX site_g ON site USING gin (site);

-- table to hold tag combinations
CREATE TABLE tag (
	id_tag serial,
	tag text[] NOT NULL
);

ALTER TABLE ONLY tag
	ADD CONSTRAINT tag_pkey PRIMARY KEY (id_tag);

CREATE UNIQUE INDEX tag_u ON tag (usort(tag));

CREATE INDEX tag_g ON tag USING gin (tag);

-- table to hold tag - site links
CREATE TABLE urls (
	date_added timestamp without time zone DEFAULT ('now'::text)::timestamp(0) without time zone NOT NULL,
	id_site smallint NOT NULL,
	id_tag smallint NOT NULL,
	regexp text
);

CREATE UNIQUE INDEX urls_pkey ON urls USING btree (id_site, regexp);

CREATE INDEX urls_id_tag ON urls USING btree (id_tag);

ALTER TABLE ONLY urls
	ADD CONSTRAINT urls_site_f FOREIGN KEY (id_site) REFERENCES site(id_site) MATCH FULL
	ON UPDATE RESTRICT ON DELETE RESTRICT DEFERRABLE INITIALLY DEFERRED;

ALTER TABLE ONLY urls
	ADD CONSTRAINT urls_tag_f FOREIGN KEY (id_tag) REFERENCES tag(id_tag) MATCH FULL
	ON UPDATE RESTRICT ON DELETE RESTRICT DEFERRABLE INITIALLY DEFERRED;

-- rule to join all tables into one to simplify access
-- automaticall uses current day and time data
CREATE VIEW site_rule AS
SELECT a.redirect_url, a.netmask, b.site, b.regexp
FROM ((
	SELECT rules.redirect_url, tag.tag AS rule_tag, rules.netmask
	FROM rules NATURAL JOIN tag
	WHERE ('now'::text)::time without time zone >= rules.from_time
		AND ('now'::text)::time without time zone <= rules.to_time
		AND date_part('dow'::text, now()) >= (rules.from_weekday)::double precision
		AND date_part('dow'::text, now()) <= (rules.to_weekday)::double precision
) a JOIN (
	SELECT site.site, tag.tag AS url_tag, regexp
	FROM urls NATURAL JOIN tag NATURAL JOIN site
) b ON (b.url_tag && a.rule_tag));

CREATE PROCEDURAL LANGUAGE plpgsql;

-- general array sorting and domain processing functions
-- sorts array
CREATE or replace FUNCTION sort(original anyarray) RETURNS anyarray
	LANGUAGE sql IMMUTABLE STRICT
	AS $_$
select array_agg(item) as result from (select unnest($1) as item order by item) a;
$_$;

		splitted[0 - pair[2]::integer] := pair[1];
		x := x - 1;
	end loop;
	return array_to_string(splitted, '.');
end;
$_$;

-- functions that works with tables
-- this functions returns id of site
create or replace function get_site(my_site text[]) returns integer
	language plpgsql strict
	as $$
declare
	site_id integer;
begin

	if not found then
		insert into tag (tag) values (usort(my_tag));
		select id_tag from tag where usort(my_tag) = tag into tag_id;
	end if;
	return tag_id;
end;
$$;