-- sorts array and removes duplicates
CREATE or replace FUNCTION usort(original anyarray) RETURNS anyarray
	LANGUAGE sql IMMUTABLE STRICT
	AS $_$
select array_agg(item) as result from (select distinct unnest($1) as item order by item) a;
$_$;







































































-- transforms domain into ordered array for indexing
CREATE or replace FUNCTION tripdomain(url text) RETURNS text[]
	LANGUAGE plpgsql IMMUTABLE STRICT
	AS $_$
declare
	result text[];
	splitted text[];

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

-- this functions returns id of site
create or replace function get_site(my_site text[]) returns integer
	language plpgsql strict
	as $$
declare
	site_id integer;
begin
	select id_site from site where my_site = site into site_id;
	if not found then
		insert into site (site) values (my_site);
		select id_site from site where my_site = site into site_id;
	end if;
	return site_id;
end;
$$;

create or replace function get_site(domain text) returns integer
	language sql immutable strict
	as $$
select get_site(tripdomain($1)) as result;
$$;

-- this function adds tag to site by site id
CREATE or replace FUNCTION mark(my_id_site integer, new_tag text) RETURNS integer
	LANGUAGE plpgsql STRICT
	AS $$
declare
	-- maybe check should be added to make sure supplied site id really exists
	my_tag text[];
	my_tag_id integer;
begin
	-- selecting tags site already have and adding new tag to them
	-- note that tags should be sorted to eliminate permutations
	select coalesce(tag, '{}'::text[]) from urls natural left join tag where id_site = my_id_site into my_tag;
	if not found then
		-- no records found - creating new tag
		insert into urls (id_site, id_tag) values (my_id_site, get_tag(array[new_tag]));
	else
		-- joining tags
		select usort(my_tag || array[new_tag]) into my_tag;
		-- updating existing record
		update urls set id_tag = get_tag(my_tag || array[new_tag]) where id_site = my_id_site;
	end if;
	return my_id_site;
end;
$$;

-- this function adds tag to domain
CREATE or replace FUNCTION mark(domain text, new_tag text) RETURNS integer
	LANGUAGE sql immutable STRICT
	AS $$
select mark(get_site($1), $2) as result;
$$;

-- this function returns id of tag array
create or replace function get_tag(my_tag text[]) returns integer
	language plpgsql strict
	as $$
declare
	tag_id integer;
begin
	select id_tag from tag where usort(my_tag) = tag into tag_id;
	if not found then
		insert into tag (tag) values (usort(my_tag));
		select id_tag from tag where usort(my_tag) = tag into tag_id;
	end if;
	return tag_id;
end;
$$;

-- 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,

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
);

ALTER TABLE ONLY urls
	ADD CONSTRAINT urls_pkey PRIMARY KEY (date_added);

CREATE UNIQUE INDEX urls_id_site ON urls USING btree (id_site);