-- complain if script is sourced in psql, rather than via CREATE EXTENSION
--\echo Use "CREATE EXTENSION anon" to load this file. \quit

--
-- Dependencies :
--  * pgcrypto ( because PG10 does not include hashing functions )
--

-- This cannot be done using `schema = anon` in anon.control
-- because we want to be able to put the dependencies in a different schema
CREATE SCHEMA IF NOT EXISTS anon;

--------------------------------------------------------------------------------
-- Security First
--------------------------------------------------------------------------------

-- Untrusted users cannot do anything inside the anon schema
REVOKE ALL ON SCHEMA anon FROM PUBLIC;
REVOKE ALL ON ALL TABLES IN SCHEMA anon FROM PUBLIC;
-- ...except calling the functions
GRANT USAGE ON SCHEMA anon TO PUBLIC;
-- other priviledge will be granted below on a case-by-case basis


--
-- By default, masking filter functions must be trusted
-- and we only trust functions from `pg_catalog` and `anon` namespaces
-- This can be bypassed by setting `anon.restrict_to_trusted_schemas` to false
--
SECURITY LABEL FOR anon ON SCHEMA pg_catalog IS 'TRUSTED';
SECURITY LABEL FOR anon ON SCHEMA anon IS 'TRUSTED';

--
-- This extension will create views based on masking functions. These functions
-- will be run as with priviledges of the owners of the views. This is prone
-- to search_path attacks: an untrusted user may be able to overide some
-- functions and gain superuser priviledges.
--
-- Therefore all functions should be defined with `SET search_path=''` even if
-- they are not SECURITY DEFINER.
--
-- More about this:
-- https://www.postgresql.org/docs/current/sql-createfunction.html#SQL-CREATEFUNCTION-SECURITY
-- https://www.cybertec-postgresql.com/en/abusing-security-definer-functions/
--

CREATE OR REPLACE FUNCTION anon.version()
RETURNS TEXT AS
$func$
  SELECT extversion FROM pg_extension WHERE extname='anon';
$func$
  LANGUAGE SQL
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-------------------------------------------------------------------------------
-- Common functions
-------------------------------------------------------------------------------

-- Returns TRUE if the column exists in the table
CREATE OR REPLACE FUNCTION anon.column_exists(
  table_relid regclass,
  column_name NAME
)
RETURNS BOOLEAN
AS $func$
  SELECT count(attname)>0
  FROM pg_catalog.pg_attribute
  WHERE attrelid = table_relid
  AND attnum > 0 -- Ordinary columns are numbered from 1 up
  AND NOT attisdropped
  AND attname = column_name;
$func$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-------------------------------------------------------------------------------
-- Noise
-------------------------------------------------------------------------------

CREATE OR REPLACE FUNCTION anon.add_noise_on_numeric_column(
  noise_table regclass,
  noise_column TEXT,
  ratio FLOAT
)
RETURNS BOOLEAN
AS $func$
BEGIN

  -- Stop if noise_column does not exist
  IF NOT anon.column_exists(noise_table,noise_column) THEN
    RAISE EXCEPTION 'Column "%" does not exist in table "%".',
                    noise_column,
                    noise_table;
    RETURN FALSE;
  END IF;

  IF ratio < 0 OR ratio > 1 THEN
    RAISE EXCEPTION 'ratio must be between 0 and 1';
    RETURN FALSE;
  END IF;

  EXECUTE format('
     UPDATE %I
     SET %I = %I *  (1+ (2 * random() - 1 ) * %L) ;
     ', noise_table, noise_column, noise_column, ratio
);
RETURN TRUE;
END;
$func$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of the EXCEPTION
  SECURITY INVOKER
; -- SET search_path='';

CREATE OR REPLACE FUNCTION anon.add_noise_on_datetime_column(
  noise_table regclass,
  noise_column TEXT,
  variation INTERVAL
)
RETURNS BOOLEAN
AS $func$
BEGIN
  -- Stop if noise_column does not exist
  IF NOT anon.column_exists(noise_table,noise_column) THEN
    RAISE EXCEPTION 'Column "%" does not exist in table "%".',
                  noise_column,
                  noise_table;
    RETURN FALSE;
  END IF;

  EXECUTE format('UPDATE %I SET %I = %I + (2 * random() - 1 ) * ''%s''::INTERVAL',
                  noise_table,
                  noise_column,
                  noise_column,
                  variation
  );
  RETURN TRUE;
END;
$func$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of the EXCEPTION
  SECURITY INVOKER
; --SET search_path='';

-------------------------------------------------------------------------------
-- "on the fly" noise
-------------------------------------------------------------------------------

-- for numerical values
CREATE OR REPLACE FUNCTION anon.noise(
  noise_value ANYELEMENT,
  ratio DOUBLE PRECISION
)
 RETURNS ANYELEMENT
AS $func$
DECLARE
  res ALIAS FOR $0;
  ran float;
BEGIN
  ran = (2.0 * random() - 1.0) * ratio;
  SELECT (noise_value * (1.0 - ran))::ANYELEMENT
    INTO res;
  RETURN res;
EXCEPTION
  WHEN numeric_value_out_of_range THEN
    SELECT (noise_value * (1.0 + ran))::ANYELEMENT
      INTO res;
    RETURN res;
END;
$func$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of the EXCEPTION
  SECURITY INVOKER
  SET search_path='';

-- for time and timestamp values
CREATE OR REPLACE FUNCTION anon.dnoise(
  noise_value ANYELEMENT,
  noise_range INTERVAL
)
 RETURNS ANYELEMENT
AS $func$
DECLARE
  res ALIAS FOR $0;
  ran INTERVAL;
BEGIN
  ran = (2.0 * random() - 1.0) * noise_range;
  SELECT (noise_value + ran)::ANYELEMENT
    INTO res;
  RETURN res;
EXCEPTION
  WHEN datetime_field_overflow THEN
    SELECT (noise_value - ran)::ANYELEMENT
      INTO res;
    RETURN res;
END;
$func$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of the EXCEPTION
  SECURITY INVOKER
  SET search_path=''
;


-------------------------------------------------------------------------------
-- Shuffle
-------------------------------------------------------------------------------

CREATE OR REPLACE FUNCTION anon.shuffle_column(
  shuffle_table regclass,
  shuffle_column NAME,
  primary_key NAME
)
RETURNS BOOLEAN
AS $func$
BEGIN
  IF NOT anon.column_exists(shuffle_table,shuffle_column) THEN
    RAISE EXCEPTION 'Column "%" does not exist in table "%".',
                  shuffle_column,
                  shuffle_table;
    RETURN FALSE;
  END IF;

  -- Stop if primary_key does not exist
  IF NOT anon.column_exists(shuffle_table,primary_key) THEN
    RAISE EXCEPTION 'Column "%" does not exist in table "%".',
                  primary_key,
                  shuffle_table;
    RETURN FALSE;
  END IF;

  -- shuffle
  EXECUTE format('
  WITH s1 AS (
    -- shuffle the primary key
    SELECT row_number() over (order by random()) n,
           %3$I AS pkey
    FROM %1$s
  ),
  s2 AS (
    -- shuffle the column
    SELECT row_number() over (order by random()) n,
           %2$I AS val
    FROM %1$s
  )
  UPDATE %1$s
  SET %2$I = s2.val
  FROM s1 JOIN s2 ON s1.n = s2.n
  WHERE %3$I = s1.pkey;
  ', shuffle_table, shuffle_column, primary_key);
  RETURN TRUE;
END;
$func$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of UPDATE
  SECURITY INVOKER
; --SET search_path='';

-------------------------------------------------------------------------------
-- Fake Data
-------------------------------------------------------------------------------

CREATE TYPE anon_fake_data_tables
AS ENUM (
  'address', 'city', 'company', 'country', 'email', 'first_name',
  'iban', 'last_name', 'lorem_ipsum', 'postcode', 'siret'
);

-- Address
DROP TABLE IF EXISTS anon.address;
CREATE TABLE anon.address (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.address CLUSTER ON address_pkey;
GRANT SELECT ON TABLE anon.address TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.address','');
SELECT pg_catalog.pg_extension_config_dump('anon.address_oid_seq','');

COMMENT ON TABLE anon.address IS 'Fake Adresses';

-- Cities
DROP TABLE IF EXISTS anon.city;
CREATE TABLE anon.city (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.city CLUSTER ON city_pkey;
GRANT SELECT ON TABLE anon.city TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.city','');
SELECT pg_catalog.pg_extension_config_dump('anon.city_oid_seq','');

COMMENT ON TABLE anon.city IS 'Fake Cities';

-- Companies
DROP TABLE IF EXISTS anon.company;
CREATE TABLE anon.company (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.company CLUSTER ON company_pkey;
GRANT SELECT ON TABLE anon.company TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.company','');
SELECT pg_catalog.pg_extension_config_dump('anon.company_oid_seq','');

COMMENT ON TABLE anon.city IS 'Fake Companies';

-- Country
DROP TABLE IF EXISTS anon.country;
CREATE TABLE anon.country (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.country CLUSTER ON country_pkey;
GRANT SELECT ON TABLE anon.country TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.country','');
SELECT pg_catalog.pg_extension_config_dump('anon.country_oid_seq','');

COMMENT ON TABLE anon.country IS 'Fake Countries';

-- Email
DROP TABLE IF EXISTS anon.email;
CREATE TABLE anon.email (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.email CLUSTER ON email_pkey;
GRANT SELECT ON TABLE anon.email TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.email','');
SELECT pg_catalog.pg_extension_config_dump('anon.email_oid_seq','');

COMMENT ON TABLE anon.email IS 'Fake email adresses';

-- First names
DROP TABLE IF EXISTS anon.first_name;
CREATE TABLE anon.first_name (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.first_name CLUSTER ON first_name_pkey;
GRANT SELECT ON TABLE anon.first_name TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.first_name','');
SELECT pg_catalog.pg_extension_config_dump('anon.first_name_oid_seq','');

COMMENT ON TABLE anon.first_name IS 'Fake first names';

-- IBAN
DROP TABLE IF EXISTS anon.iban;
CREATE TABLE anon.iban (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.iban CLUSTER ON iban_pkey;
GRANT SELECT ON TABLE anon.iban TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.iban','');
SELECT pg_catalog.pg_extension_config_dump('anon.iban_oid_seq','');

COMMENT ON TABLE anon.iban IS 'Fake IBAN codes';

-- Last names
DROP TABLE IF EXISTS anon.last_name;
CREATE TABLE anon.last_name (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.last_name CLUSTER ON last_name_pkey;
GRANT SELECT ON TABLE anon.last_name TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.last_name','');
SELECT pg_catalog.pg_extension_config_dump('anon.last_name_oid_seq','');

COMMENT ON TABLE anon.last_name IS 'Fake last names';

-- Postcode
DROP TABLE IF EXISTS anon.postcode;
CREATE TABLE anon.postcode (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.postcode CLUSTER ON postcode_pkey;
GRANT SELECT ON TABLE anon.postcode TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.postcode','');
SELECT pg_catalog.pg_extension_config_dump('anon.postcode_oid_seq','');

COMMENT ON TABLE anon.postcode IS 'Fake street post codes';

-- SIRET
DROP TABLE IF EXISTS anon.siret;
CREATE TABLE anon.siret (
  oid SERIAL PRIMARY KEY,
  val TEXT
);

ALTER TABLE anon.siret CLUSTER ON siret_pkey;
GRANT SELECT ON TABLE anon.siret TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.siret','');
SELECT pg_catalog.pg_extension_config_dump('anon.siret_oid_seq','');

COMMENT ON TABLE anon.siret IS 'Fake SIRET codes';

-- Lorem Ipsum
DROP TABLE IF EXISTS anon.lorem_ipsum;
CREATE TABLE anon.lorem_ipsum (
  oid SERIAL PRIMARY KEY,
  paragraph TEXT
);

ALTER TABLE anon.lorem_ipsum CLUSTER ON lorem_ipsum_pkey;
GRANT SELECT ON TABLE anon.lorem_ipsum TO PUBLIC;
SELECT pg_catalog.pg_extension_config_dump('anon.lorem_ipsum','');
SELECT pg_catalog.pg_extension_config_dump('anon.lorem_ipsum_oid_seq','');

COMMENT ON TABLE anon.lorem_ipsum IS 'Fake text';

-- ADD NEW TABLE HERE


-------------------------------------------------------------------------------
-- Discovery / Scanning
-------------------------------------------------------------------------------

-- https://labkey.med.ualberta.ca/labkey/_webdav/REDCap%20Support/@wiki/identifiers/identifiers.html?listing=html

CREATE TABLE anon.identifiers_category(
  name TEXT UNIQUE NOT NULL,
  direct_identifier BOOLEAN,
  anon_function TEXT
);

ALTER TABLE anon.identifiers_category
  CLUSTER ON identifiers_category_name_key;
GRANT SELECT ON TABLE anon.identifiers_category TO PUBLIC;
COMMENT ON TABLE anon.identifiers_category
IS 'Generic identifiers categories based the HIPAA classification';


CREATE TABLE anon.identifier(
  lang TEXT,
  attname TEXT,
  fk_identifiers_category TEXT,
  PRIMARY KEY(attname,lang),
  FOREIGN KEY (fk_identifiers_category)
    REFERENCES anon.identifiers_category(name)
);

ALTER TABLE anon.identifier
  CLUSTER ON identifier_pkey;
GRANT SELECT ON TABLE anon.identifier TO PUBLIC;
COMMENT ON TABLE anon.identifier
IS 'Dictionnary of common identifiers field names';

CREATE OR REPLACE FUNCTION anon.detect(
  dict_lang TEXT DEFAULT 'en_US'
)
RETURNS TABLE (
  table_name REGCLASS,
  column_name NAME,
  identifiers_category TEXT,
  direct BOOLEAN
)
AS $$
BEGIN
  IF not anon.is_initialized() THEN
    RAISE NOTICE 'The dictionnary of identifiers is not present.'
      USING HINT = 'You probably need to run ''SELECT anon.init()'' ';
  END IF;

RETURN QUERY SELECT
  a.attrelid::regclass,
  a.attname,
  ic.name,
  ic.direct_identifier
FROM pg_catalog.pg_attribute a
JOIN anon.identifier fn
  ON lower(a.attname) = fn.attname
JOIN anon.identifiers_category ic
  ON fn.fk_identifiers_category = ic.name
JOIN pg_catalog.pg_class c
  ON c.oid = a.attrelid
WHERE fn.lang = dict_lang
  AND c.relnamespace IN ( -- exclude the extension tables and the catalog
        SELECT oid
        FROM pg_catalog.pg_namespace
        WHERE nspname NOT LIKE 'pg_%'
        AND nspname NOT IN  (
          'information_schema',
          'anon',
          pg_catalog.current_setting('anon.maskschema')::NAME
        )
      )
;
END;
$$
  LANGUAGE plpgsql
  PARALLEL SAFE
  STABLE
;


-------------------------------------------------------------------------------
-- Functions : INIT / RESET
-------------------------------------------------------------------------------

-- ADD unit tests in tests/sql/init.sql

CREATE OR REPLACE FUNCTION anon.load_csv(
  dest_table REGCLASS,
  csv_file TEXT
)
RETURNS BOOLEAN AS
$$
DECLARE
  csv_file_check TEXT;
  sequence TEXT;
BEGIN
-- This check does not work with PG 10 and below (absolute path not supported)
--
--  SELECT * INTO  csv_file_check
--  FROM pg_catalog.pg_stat_file(csv_file, missing_ok := TRUE );
--
--  IF csv_file_check IS NULL THEN
--    RAISE NOTICE 'Data file ''%'' is not present. Skipping.', csv_file;
--    RETURN FALSE;
--  END IF;

  -- load the csv file
  EXECUTE 'COPY ' || dest_table
      || ' FROM ' || quote_literal(csv_file);

  -- update the oid sequence (if any)
  SELECT pg_catalog.pg_get_serial_sequence(dest_table::TEXT,'oid')
  INTO sequence
  FROM pg_catalog.pg_attribute
  WHERE attname ='oid'
  AND attrelid = dest_table;

  IF sequence IS NOT NULL
  THEN
    EXECUTE format( 'SELECT pg_catalog.setval(%L, max(oid)) FROM %s',
                    sequence,
                    dest_table
    );
  END IF;

  -- clustering the table for better performance
  EXECUTE 'CLUSTER ' || dest_table;

  RETURN TRUE;

EXCEPTION

  WHEN undefined_file THEN
    RAISE NOTICE 'Data file ''%'' is not present. Skipping.', csv_file;
    RETURN FALSE;

  WHEN bad_copy_file_format THEN
    RAISE NOTICE 'Data file ''%'' has a bad CSV format. Skipping.', csv_file;
    RETURN FALSE;

  WHEN invalid_text_representation THEN
    RAISE NOTICE 'Data file ''%'' has a bad CSV format. Skipping.', csv_file;
    RETURN FALSE;

END;
$$
  LANGUAGE plpgsql
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL UNSAFE -- because of the EXCEPTION
  SECURITY INVOKER
  SET search_path=''
;


-- load fake data from a given path
CREATE OR REPLACE FUNCTION anon.init(
  datapath TEXT
)
RETURNS BOOLEAN
AS $$
DECLARE
  datapath_check TEXT;
  success BOOLEAN;
BEGIN
  IF anon.is_initialized() THEN
    RAISE NOTICE 'The anon extension is already initialized.';
    RETURN TRUE;
  END IF;

  SELECT bool_or(results) INTO success
  FROM unnest(array[
    anon.load_csv('anon.identifiers_category',datapath||'/identifiers_category.csv'),
    anon.load_csv('anon.identifier',datapath ||'/identifier_fr_FR.csv'),
    anon.load_csv('anon.identifier',datapath ||'/identifier_en_US.csv'),
    anon.load_csv('anon.address',datapath ||'/address.csv'),
    anon.load_csv('anon.city',datapath ||'/city.csv'),
    anon.load_csv('anon.company',datapath ||'/company.csv'),
    anon.load_csv('anon.country',datapath ||'/country.csv'),
    anon.load_csv('anon.email', datapath ||'/email.csv'),
    anon.load_csv('anon.first_name',datapath ||'/first_name.csv'),
    anon.load_csv('anon.iban',datapath ||'/iban.csv'),
    anon.load_csv('anon.last_name',datapath ||'/last_name.csv'),
    anon.load_csv('anon.postcode',datapath ||'/postcode.csv'),
    anon.load_csv('anon.siret',datapath ||'/siret.csv'),
    anon.load_csv('anon.lorem_ipsum',datapath ||'/lorem_ipsum.csv')
  ]) results;
  RETURN success;

END;
$$
  LANGUAGE PLPGSQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL UNSAFE -- because load_csv is unsafe
  SECURITY INVOKER
  SET search_path=''
;


-- People tend to forget the anon.init() step
-- This is a friendly notice for them
CREATE OR REPLACE FUNCTION anon.notice_if_not_init()
RETURNS TEXT AS
$$
BEGIN
  IF NOT anon.is_initialized() THEN
    RAISE NOTICE 'The anon extension is not initialized.'
      USING HINT='Use ''SELECT anon.init()'' before running this function';
  END IF;
  RETURN NULL;
END;
$$
  LANGUAGE plpgsql
  STABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path='';
;


-- load() is here for backward compatibility with version 0.6
CREATE OR REPLACE FUNCTION anon.load(TEXT)
RETURNS BOOLEAN AS
$$
  SELECT anon.init($1);
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL UNSAFE -- because init() is unsafe
  SECURITY INVOKER
  SET search_path=''
;


-- If no path given, use the default data
CREATE OR REPLACE FUNCTION anon.init()
RETURNS BOOLEAN
AS $$
  WITH conf AS (
        -- find the local extension directory
        SELECT setting AS sharedir
        FROM pg_catalog.pg_config
        WHERE name = 'SHAREDIR'
    )
  SELECT anon.init(conf.sharedir || '/extension/anon/')
  FROM conf;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL UNSAFE -- because init is unsafe
  SECURITY INVOKER
  SET search_path=''
;

-- load() is here for backward compatibility with version 0.6 and below
CREATE OR REPLACE FUNCTION anon.load()
RETURNS BOOLEAN
AS $$
BEGIN
  RAISE NOTICE 'anon.load() will be deprecated in future versions.'
    USING HINT = 'you should use anon.init() instead.';
  RETURN anon.init();
END;
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because init is unsafe
  SECURITY INVOKER
  SET search_path=''
;

-- True if the fake data is already here
CREATE OR REPLACE FUNCTION anon.is_initialized()
RETURNS BOOLEAN
AS $$
  SELECT count(*)::INT::BOOLEAN
  FROM (   SELECT 1 FROM anon.address
     UNION SELECT 1 FROM anon.city
     UNION SELECT 1 FROM anon.company
     UNION SELECT 1 FROM anon.country
     UNION SELECT 1 FROM anon.email
     UNION SELECT 1 FROM anon.first_name
     UNION SELECT 1 FROM anon.iban
     UNION SELECT 1 FROM anon.last_name
     UNION SELECT 1 FROM anon.lorem_ipsum
     UNION SELECT 1 FROM anon.postcode
     UNION SELECT 1 FROM anon.siret
     -- ADD NEW TABLE HERE
     LIMIT 1
  ) t
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path=''
;

-- remove all fake data
CREATE OR REPLACE FUNCTION anon.reset()
RETURNS BOOLEAN AS
$$
    TRUNCATE anon.address;
    TRUNCATE anon.city;
    TRUNCATE anon.company;
    TRUNCATE anon.country;
    TRUNCATE anon.email;
    TRUNCATE anon.first_name;
    TRUNCATE anon.iban;
    TRUNCATE anon.last_name;
    TRUNCATE anon.lorem_ipsum;
    TRUNCATE anon.postcode;
    TRUNCATE anon.siret;
    TRUNCATE anon.identifiers_category CASCADE;
    TRUNCATE anon.identifier;
    -- ADD NEW TABLE HERE
    SELECT TRUE;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL UNSAFE -- because of TRUNCATE
  SECURITY INVOKER
  SET search_path=''
;

-- backward compatibility with version 0.6 and below
CREATE OR REPLACE FUNCTION anon.unload()
RETURNS BOOLEAN AS
$$
  SELECT anon.reset()
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL UNSAFE -- because reset is unsafe
  SECURITY INVOKER
  SET search_path=''
;

-------------------------------------------------------------------------------
--- Generic hashing
-------------------------------------------------------------------------------

-- This is a wrapper around the pgcrypto digest function
-- Standard algorithms are md5, sha1, sha224, sha256, sha384 and sha512.
-- https://www.postgresql.org/docs/current/pgcrypto.html
CREATE OR REPLACE FUNCTION anon.digest(
  seed TEXT,
  salt TEXT,
  algorithm TEXT
)
RETURNS TEXT AS
$$
  SELECT encode(@extschema@.digest(concat(seed,salt),algorithm),'hex');
$$
  LANGUAGE SQL
  IMMUTABLE
  RETURNS NULL ON NULL INPUT
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

--
-- Return a hash value for a seed
--
-- The function is a SECURIY DEFINER because `anon.salt` and `anon.algorithm`
-- are visible only to superusers.
--
CREATE OR REPLACE FUNCTION anon.hash(
  seed TEXT
)
RETURNS TEXT AS $$
  SELECT anon.digest(
    seed,
    pg_catalog.current_setting('anon.salt'),
    pg_catalog.current_setting('anon.algorithm')
  );
$$
  LANGUAGE SQL
  STABLE
  RETURNS NULL ON NULL INPUT
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path = ''
;
-- https://www.postgresql.org/docs/current/sql-createfunction.html#SQL-CREATEFUNCTION-SECURITY

-------------------------------------------------------------------------------
-- Random Generic Data
-------------------------------------------------------------------------------

CREATE OR REPLACE FUNCTION anon.random_string(
  l integer
)
RETURNS text
AS $$
  SELECT array_to_string(
    array(
        select substr('ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789',
                      ((random()*(36-1)+1)::integer)
                      ,1)
        from generate_series(1,l)
    ),''
  );
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

-- Zip code
CREATE OR REPLACE FUNCTION anon.random_zip()
RETURNS text
AS $$
  SELECT array_to_string(
         array(
                select substr('0123456789',((random()*(10-1)+1)::integer),1)
                from generate_series(1,5)
            ),''
          );
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;


-- date

CREATE OR REPLACE FUNCTION anon.random_date_between(
  date_start timestamp WITH TIME ZONE,
  date_end timestamp WITH TIME ZONE
)
RETURNS timestamp WITH TIME ZONE AS $$
    SELECT (random()*(date_end-date_start))::interval+date_start;
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.random_date()
RETURNS timestamp with time zone AS $$
  SELECT anon.random_date_between('1900-01-01'::timestamp with time zone,now());
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;


-- integer

CREATE OR REPLACE FUNCTION anon.random_int_between(
  int_start INTEGER,
  int_stop INTEGER
)
RETURNS INTEGER AS $$
    SELECT CAST ( random()*(int_stop-int_start)+int_start AS INTEGER );
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.random_bigint_between(
  int_start BIGINT,
  int_stop BIGINT
)
RETURNS BIGINT AS $$
    SELECT CAST ( random()*(int_stop-int_start)+int_start AS BIGINT );
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.random_phone(
  phone_prefix TEXT DEFAULT '0'
)
RETURNS TEXT AS $$
  SELECT  phone_prefix
          || CAST(anon.random_int_between(100000000,999999999) AS TEXT)
          AS "phone";
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

--
-- hashing a seed with a random salt
--
CREATE OR REPLACE FUNCTION anon.random_hash(
  seed TEXT
)
RETURNS TEXT AS
$$
  SELECT anon.digest(
    seed,
    anon.random_string(6),
    pg_catalog.current_setting('anon.algorithm')
  );
$$
  LANGUAGE SQL
  VOLATILE
  SECURITY DEFINER
  PARALLEL RESTRICTED -- because random
  SET search_path = ''
  RETURNS NULL ON NULL INPUT
;

-- Array
CREATE OR REPLACE FUNCTION anon.random_in(
  a ANYARRAY
)
RETURNS ANYELEMENT AS
$$
  SELECT a[pg_catalog.floor(pg_catalog.random()*array_length(a,1)+1)]
$$
  LANGUAGE SQL
  VOLATILE
  RETURNS NULL ON NULL INPUT
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;


-------------------------------------------------------------------------------
-- FAKE data
-------------------------------------------------------------------------------

-- We avoid using the floor() function in the function below because it is
-- way too slow. Instead we're using the mod operator like this:
--    (pg_catalog.random()*last_value)::INTEGER%last_value
-- See Issue #223 for more details
-- https://gitlab.com/dalibo/postgresql_anonymizer/-/merge_requests/223

CREATE OR REPLACE FUNCTION anon.fake_first_name()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.first_name_oid_seq
  )
  SELECT COALESCE(f.val,anon.notice_if_not_init())
  FROM anon.first_name f
  JOIN random r ON f.oid=r.oid;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_last_name()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.last_name_oid_seq
  )
  SELECT COALESCE(l.val,anon.notice_if_not_init())
  FROM anon.last_name l
  JOIN random r ON l.oid=r.oid;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_email()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.email_oid_seq
  )
  SELECT COALESCE(e.val,anon.notice_if_not_init())
  FROM anon.email e
  JOIN random r ON e.oid=r.oid;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_address()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.address_oid_seq
  )
  SELECT COALESCE(a.val,anon.notice_if_not_init())
  FROM anon.address a
  JOIN random r ON a.oid = r.oid
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_city()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.city_oid_seq
  )
  SELECT COALESCE(c.val,anon.notice_if_not_init())
  FROM anon.city c
  JOIN random r ON c.oid=r.oid;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_company()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.company_oid_seq
  )
  SELECT COALESCE(c.val,anon.notice_if_not_init())
  FROM anon.company c
  JOIN random r ON c.oid = r.oid
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_country()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.country_oid_seq
  )
  SELECT COALESCE(c.val,anon.notice_if_not_init())
  FROM anon.country c
  JOIN random r ON c.oid = r.oid
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_iban()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.iban_oid_seq
  )
  SELECT COALESCE(i.val,anon.notice_if_not_init())
  FROM anon.iban i
  JOIN random r ON i.oid = r.oid;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_postcode()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.postcode_oid_seq
  )
  SELECT COALESCE(p.val,anon.notice_if_not_init())
  FROM anon.postcode p
  JOIN random r ON p.oid = r.oid
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.fake_siret()
RETURNS TEXT AS $$
  WITH random AS (
    SELECT (pg_catalog.random()*last_value)::INTEGER%last_value+1 AS oid
    FROM anon.siret_oid_seq
  )
  SELECT COALESCE(s.val,anon.notice_if_not_init())
  FROM anon.siret s
  JOIN random r ON s.oid = r.oid;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

-- Lorem Ipsum
-- Usage:
--   `SELECT anon.lorem_ipsum()` returns 5 paragraphs
--   `SELECT anon.lorem_ipsum(2)` returns 2 paragraphs
--   `SELECT anon.lorem_ipsum( paragraph := 4 )` returns 4 paragraphs
--   `SELECT anon.lorem_ipsum( words := 20 )` returns 20 words
--   `SELECT anon.lorem_ipsum( characters := 7 )` returns 7 characters
--
CREATE OR REPLACE FUNCTION anon.lorem_ipsum(
  paragraphs INTEGER DEFAULT 5,
  words INTEGER DEFAULT 0,
  characters INTEGER DEFAULT 0
)
RETURNS TEXT AS $$
WITH
-- First let's shuffle the lorem_ipsum table
randomized_lorem_ipsum AS (
  SELECT *
  FROM anon.lorem_ipsum
  ORDER BY RANDOM()
),
-- if `characters` is defined,
-- then the limit is the number of characters
-- else return NULL
cte_characters AS (
  SELECT
    CASE characters
      WHEN 0
      THEN NULL
      ELSE substring( c.agg_paragraphs for characters )
    END AS n_characters
  FROM (
    SELECT string_agg(paragraph,E'\n') AS agg_paragraphs
    FROM randomized_lorem_ipsum
  ) AS c
),
-- if `characters` is not defined and if `words` defined,
-- then the limit is the number of words
-- else return NULL
cte_words AS (
  SELECT
    CASE words
      WHEN 0
      THEN NULL
      ELSE string_agg(w.unnested_words,' ')
    END AS n_words
  FROM (
    SELECT unnest(string_to_array(p.agg_paragraphs,' ')) as unnested_words
    FROM (
      SELECT string_agg(paragraph,E' \n') AS agg_paragraphs
      FROM randomized_lorem_ipsum
      ) AS p
    LIMIT words
  ) as w
),
-- if `characters` is notdefined and `words` is not defined,
-- then the limit is the number of paragraphs
cte_paragraphs AS (
  SELECT string_agg(l.paragraph,E'\n') AS n_paragraphs
  FROM (
    SELECT *
    FROM randomized_lorem_ipsum
    LIMIT paragraphs
  ) AS l
)
SELECT COALESCE(
  cte_characters.n_characters,
  cte_words.n_words,
  cte_paragraphs.n_paragraphs,
  anon.notice_if_not_init()
)
FROM
  cte_characters,
  cte_words,
  cte_paragraphs
;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL RESTRICTED -- because random
  SECURITY INVOKER
  SET search_path=''
;

-------------------------------------------------------------------------------
-- Pseudonymized data
-------------------------------------------------------------------------------

--
-- Convert an hexadecimal value to an integer
--
CREATE OR REPLACE FUNCTION anon.hex_to_int(
  hexval TEXT
)
RETURNS INT AS $$
DECLARE
    result  INT;
BEGIN
    EXECUTE 'SELECT x' || quote_literal(hexval) || '::INT' INTO result;
    RETURN result;
END;
$$
  LANGUAGE plpgsql
  IMMUTABLE
  STRICT
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

--
-- Return a deterministic value inside a range of OID for a given seed+salt
--
CREATE OR REPLACE FUNCTION anon.projection_to_oid(
  seed ANYELEMENT,
  salt TEXT,
  last_oid BIGINT
)
RETURNS INT AS $$
  --
  -- get a md5 hash of the seed and then project it on a 0-to-1 scale
  -- then multiply by the latest oid
  -- which give a deterministic oid inside the range
  --
  -- This works because MD5 signatures values have a uniform distribution
  -- see https://crypto.stackexchange.com/questions/14967/distribution-for-a-subset-of-md5
  --
  SELECT CAST(
    -- we use only the 6 first characters of the md5 signature
    -- and we divide by the max value : x'FFFFFF' = 16777215
    last_oid * anon.hex_to_int(md5(seed::TEXT||salt)::char(6)) / 16777215.0
  AS INT )
$$
  LANGUAGE SQL
  IMMUTABLE
  RETURNS NULL ON NULL INPUT
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;


--
-- the pseudo function are declared as SECURTY DEFINER because the access
-- the anon.salt which is only visible to superusers.
--
-- If a masked role can read the salt, he/she can run a brute force attack to
-- retrieve the original data based on the pseudonymized data
--

CREATE OR REPLACE FUNCTION anon.pseudo_first_name(
  seed ANYELEMENT,
  salt TEXT DEFAULT NULL
)
RETURNS TEXT AS $$
  SELECT COALESCE(val,anon.notice_if_not_init())
  FROM anon.first_name
  WHERE oid = anon.projection_to_oid(
    seed,
    COALESCE(salt, pg_catalog.current_setting('anon.salt')),
    (SELECT max(oid) FROM anon.first_name)
  );
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path = pg_catalog,pg_temp
;

CREATE OR REPLACE FUNCTION anon.pseudo_last_name(
  seed ANYELEMENT,
  salt TEXT DEFAULT NULL
)
RETURNS TEXT AS $$
  SELECT COALESCE(val,anon.notice_if_not_init())
  FROM anon.last_name
  WHERE oid = anon.projection_to_oid(
    seed,
    COALESCE(salt, pg_catalog.current_setting('anon.salt')),
    (SELECT max(oid) FROM anon.last_name)
  );
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path = pg_catalog,pg_temp
;


CREATE OR REPLACE FUNCTION anon.pseudo_email(
  seed ANYELEMENT,
  salt TEXT DEFAULT NULL
)
RETURNS TEXT AS $$
  SELECT COALESCE(val,anon.notice_if_not_init())
  FROM anon.email
  WHERE oid = anon.projection_to_oid(
    seed,
    COALESCE(salt, pg_catalog.current_setting('anon.salt')),
    (SELECT MAX(oid) FROM anon.email)
  );
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path=''
;


CREATE OR REPLACE FUNCTION anon.pseudo_city(
  seed ANYELEMENT,
  salt TEXT DEFAULT NULL
)
RETURNS TEXT AS $$
  SELECT COALESCE(val,anon.notice_if_not_init())
  FROM anon.city
  WHERE oid = anon.projection_to_oid(
    seed,
    COALESCE(salt, pg_catalog.current_setting('anon.salt')),
    (SELECT MAX(oid) FROM anon.city)
  );
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.pseudo_country(
  seed ANYELEMENT,
  salt TEXT DEFAULT NULL
)
RETURNS TEXT AS $$
  SELECT COALESCE(val,anon.notice_if_not_init())
  FROM anon.country
  WHERE oid = anon.projection_to_oid(
    seed,
    COALESCE(salt, pg_catalog.current_setting('anon.salt')),
    (SELECT MAX(oid) FROM anon.city)
  );
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.pseudo_company(
  seed ANYELEMENT,
  salt TEXT DEFAULT NULL
)
RETURNS TEXT AS $$
  SELECT COALESCE(val,anon.notice_if_not_init())
  FROM anon.company
  WHERE oid = anon.projection_to_oid(
    seed,
    COALESCE(salt, pg_catalog.current_setting('anon.salt')),
    (SELECT MAX(oid) FROM anon.company)
  );
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.pseudo_iban(
  seed ANYELEMENT,
  salt TEXT DEFAULT NULL
)
RETURNS TEXT AS $$
  SELECT COALESCE(val,anon.notice_if_not_init())
  FROM anon.iban
  WHERE oid = anon.projection_to_oid(
    seed,
    COALESCE(salt, pg_catalog.current_setting('anon.salt')),
    (SELECT MAX(oid) FROM anon.iban)
  );
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.pseudo_siret(
  seed ANYELEMENT,
  salt TEXT DEFAULT NULL
)
RETURNS TEXT AS $$
  SELECT COALESCE(val,anon.notice_if_not_init())
  FROM anon.siret
  WHERE oid = anon.projection_to_oid(
    seed,
    COALESCE(salt, pg_catalog.current_setting('anon.salt')),
    (SELECT MAX(oid) FROM anon.siret)
  );
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path=''
;




-------------------------------------------------------------------------------
-- Partial Scrambling
-------------------------------------------------------------------------------

-- partial('abcdefgh',1,'xxxx',3) will return 'axxxxfgh';
CREATE OR REPLACE FUNCTION anon.partial(
  ov TEXT,
  prefix INT,
  padding TEXT,
  suffix INT
)
RETURNS TEXT AS $$
  SELECT substring(ov FROM 1 FOR prefix)
      || padding
      || substring(ov FROM (length(ov)-suffix+1) FOR suffix);
$$
  LANGUAGE SQL
  IMMUTABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

--
-- partial_email('daamien@gmail.com') will becomme 'da******@gm******.com'
--
CREATE OR REPLACE FUNCTION anon.partial_email(
  ov TEXT
)
RETURNS TEXT AS $$
-- This is an oversimplistic way to scramble an email address
-- The main goal is to avoid any complex regexp
-- by splitting the job into simpler tasks
  SELECT substring(regexp_replace(ov, '@.*', '') FROM 1 FOR 2) -- da
      || '******'
      || '@'
      || substring(regexp_replace(ov, '.*@', '') FROM 1 FOR 2) -- gm
      || '******'
      || '.'
      || regexp_replace(ov, '.*\.', '') -- com
  ;
$$
  LANGUAGE SQL
  IMMUTABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;


-------------------------------------------------------------------------------
-- Masking Rules Management
-- This is the common metadata used by the 3 main features :
-- anonymize(), dump() and dynamic masking engine
-------------------------------------------------------------------------------


-- See tests in tests/sql/get_function_schema.sql
CREATE OR REPLACE FUNCTION anon.get_function_schema(text)
RETURNS TEXT
AS 'MODULE_PATHNAME', 'get_function_schema'
  LANGUAGE C
  IMMUTABLE
  STRICT
  PARALLEL SAFE
;

-- Register a SECURITY LABEL provider
-- /!\ there's no way to "unregister" a label, the label will remain forever in
-- the database.
CREATE OR REPLACE FUNCTION anon.register_label(TEXT)
RETURNS BOOLEAN
AS 'MODULE_PATHNAME', 'register_label'
  LANGUAGE C
  VOLATILE
  STRICT
  PARALLEL UNSAFE
;

--
-- Create an additional masking policy
--
CREATE OR REPLACE FUNCTION anon.register_masking_policy(
  policy TEXT
)
RETURNS BOOLEAN
AS $$
BEGIN
  PERFORM anon.register_label(policy);
  EXECUTE format('SECURITY LABEL FOR %I ON SCHEMA pg_catalog IS ''TRUSTED'';',
                    policy);
  EXECUTE format('SECURITY LABEL FOR %I ON SCHEMA anon IS ''TRUSTED'';',
                    policy);
  RETURN True;
END;
$$
  LANGUAGE plpgsql
  VOLATILE
  STRICT
  PARALLEL UNSAFE
;



CREATE OR REPLACE FUNCTION anon.trg_check_trusted_schemas()
RETURNS event_trigger
AS $$
DECLARE
  untrusted_schema TEXT;
BEGIN
  -- This will return nothing if the schema is to be trusted
  SELECT anon.get_function_schema(masking_function)
  INTO untrusted_schema
  FROM anon.pg_masking_rules
  WHERE pg_catalog.current_setting('anon.restrict_to_trusted_schemas')::BOOLEAN
  AND masking_function IS NOT NULL
  AND NOT trusted_schema
  LIMIT 1;

  IF untrusted_schema = '' THEN
    RAISE 'The schema of the masking filter must be defined'
      USING HINT = 'Check the anon.restrict_to_trusted_schemas parameter';
  ELSIF length(untrusted_schema) > 0 THEN
    RAISE '% is not a trusted schema.', untrusted_schema
      USING HINT = 'You must add a TRUSTED security label to this schema.';
  END IF;
END;
$$
  LANGUAGE plpgsql
  PARALLEL SAFE
  SECURITY DEFINER
  SET search_path=''
;

-- Check each new masking rule
CREATE EVENT TRIGGER anon_trg_check_trusted_schemas
  ON ddl_command_end
  WHEN TAG IN ('SECURITY LABEL')
  EXECUTE PROCEDURE anon.trg_check_trusted_schemas();
  -- EXECUTE FUNCTION is not supported by PG10 and below

-- List of all the masked columns
CREATE OR REPLACE VIEW anon.pg_masking_rules AS
WITH const AS (
  SELECT
    -- #" is the escape-double-quote separator
    '%MASKED +WITH +FUNCTION +#"%#(%#)#"%'::TEXT
      AS pattern_mask_column_function,
    'MASKED +WITH +VALUE +#"%#" ?'::TEXT
      AS pattern_mask_column_value
),
rules_from_default AS (
SELECT
  c.oid AS attrelid,
  a.attnum  AS attnum,
  c.relnamespace::REGNAMESPACE,
  c.relname,
  a.attname,
  pg_catalog.format_type(a.atttypid, a.atttypmod),
  NULL AS col_description,
  NULL AS masking_function,
  COALESCE(pg_catalog.pg_get_expr(d.adbin, d.adrelid),'NULL') AS masking_value,
  0 AS priority -- lowest priority for the default value
FROM pg_catalog.pg_class c
JOIN pg_catalog.pg_namespace n ON n.oid=c.relnamespace
JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid
LEFT JOIN pg_catalog.pg_attrdef d ON (a.attrelid, a.attnum) = (d.adrelid, d.adnum)
WHERE a.attnum > 0
AND n.nspname NOT IN ('information_schema', 'pg_catalog', 'pg_toast','anon')
AND NOT a.attisdropped
AND pg_catalog.current_setting('anon.privacy_by_default')::BOOLEAN
),
rules_from_seclabels AS (
SELECT
  sl.objoid AS attrelid,
  sl.objsubid  AS attnum,
  c.relnamespace::REGNAMESPACE,
  c.relname,
  a.attname,
  pg_catalog.format_type(a.atttypid, a.atttypmod),
  sl.label AS col_description,
  trim(substring( sl.label FROM k.pattern_mask_column_function FOR '#'))
    AS masking_function,
  trim(substring(sl.label FROM k.pattern_mask_column_value FOR '#'))
    AS masking_value,
  100 AS priority -- high priority for the security label syntax
FROM const k,
     pg_catalog.pg_seclabel sl
JOIN pg_catalog.pg_class c ON sl.classoid = c.tableoid AND sl.objoid = c.oid
JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid AND sl.objsubid = a.attnum
WHERE a.attnum > 0
--  TODO : Filter out the catalog tables
AND NOT a.attisdropped
AND (   sl.label SIMILAR TO k.pattern_mask_column_function ESCAPE '#'
    OR  sl.label SIMILAR TO k.pattern_mask_column_value ESCAPE '#'
    )
AND sl.provider = 'anon' -- this is hard-coded in anon.c
),
rules_from_all AS (
SELECT * FROM rules_from_default
UNION
SELECT * FROM rules_from_seclabels
)
-- DISTINCT will keep just the 1st rule for each column based on priority,
SELECT
  DISTINCT ON (attrelid, attnum) *,
  COALESCE(masking_function,masking_value) AS masking_filter,
  (
    -- Aggregate with count and bool_and to handle the cases
    -- when the schema is not delared
    SELECT COUNT(label)>0 and bool_and(label='TRUSTED')
    FROM pg_seclabel sl,
         anon.get_function_schema(masking_function) f("schema")
    WHERE f.schema != ''
    AND   sl.objoid=f.schema::REGNAMESPACE
  ) AS trusted_schema

FROM rules_from_all
ORDER BY attrelid, attnum, priority DESC
;

GRANT SELECT ON anon.pg_masking_rules TO PUBLIC;

--
-- Unmask all the role at once
--
CREATE OR REPLACE FUNCTION anon.remove_masks_for_all_columns()
RETURNS BOOLEAN AS
$$
DECLARE
  r RECORD;
BEGIN
  FOR r IN SELECT relnamespace, relname, attname
           FROM anon.pg_masking_rules
  LOOP
    EXECUTE format('SECURITY LABEL FOR anon ON COLUMN %I.%I.%I IS NULL',
                    r.relnamespace,
                    r.relname,
                    r.attname
    );
  END LOOP;
  RETURN TRUE;
END
$$
  LANGUAGE plpgsql
  PARALLEL UNSAFE -- because of SECURITY LABEL
  SECURITY INVOKER
  SET search_path=''
;


-- Compatibility with version 0.3 and earlier
CREATE OR REPLACE VIEW anon.pg_masks AS
SELECT * FROM anon.pg_masking_rules
;


-------------------------------------------------------------------------------
-- Static Masking
-------------------------------------------------------------------------------

-- Return SQL assigment which replace masked data in a column or null when no masking rule was found
CREATE OR REPLACE FUNCTION anon.build_anonymize_column_assignment(
  tablename REGCLASS,
  colname NAME
)
RETURNS TEXT AS
$$
DECLARE
  mf TEXT; -- masking_filter can be either a function or a value
  mf_is_a_faking_function BOOLEAN;
BEGIN
  SET CONSTRAINTS ALL DEFERRED;
  SELECT masking_filter INTO mf
  FROM anon.pg_masking_rules
  WHERE attrelid = tablename::OID
  AND attname = colname;

  IF mf IS NULL THEN
    RAISE WARNING 'There is no masking rule for column % in table %',
                  colname,
                  tablename;
    RETURN null;
  END IF;

  SELECT mf LIKE 'anon.fake_%' INTO mf_is_a_faking_function;
  IF mf_is_a_faking_function AND not anon.is_initialized() THEN
    RAISE NOTICE 'The faking data is not present.'
      USING HINT = 'You probably need to run ''SELECT anon.init()'' ';
  END IF;

  RETURN format('%I = %s', colname, mf);
END;
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- Replace masked data in a column
CREATE OR REPLACE FUNCTION anon.anonymize_column(
  tablename REGCLASS,
  colname NAME
)
RETURNS BOOLEAN AS
$$
DECLARE
  sql TEXT;
BEGIN
  SET CONSTRAINTS ALL DEFERRED;
  sql := anon.build_anonymize_column_assignment(tablename, colname);
  IF sql IS NULL THEN
    RETURN FALSE;
  END IF;
  RAISE DEBUG 'Anonymize % with %', tablename, sql;
  EXECUTE format('UPDATE %s SET %s', tablename, sql);
  RETURN TRUE;
END;
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of UPDATE
  SECURITY INVOKER
  SET search_path=''
;

-- Replace masked data in a table
CREATE OR REPLACE FUNCTION anon.anonymize_table(tablename REGCLASS)
RETURNS BOOLEAN AS
$$
DECLARE sql TEXT;
BEGIN
  SELECT string_agg(anon.build_anonymize_column_assignment(tablename, attname), ',') INTO sql
  FROM anon.pg_masking_rules
  WHERE attrelid::regclass = tablename;

  IF sql != '' THEN
    RAISE DEBUG 'Anonymize table % with %', tablename, sql;
    EXECUTE format('UPDATE %s SET %s', tablename, sql);
    RETURN true;
  END IF;

  RETURN NULL;

EXCEPTION
  WHEN not_null_violation THEN
    RAISE EXCEPTION 'Cannot mask a "NOT NULL" column with a NULL value'
          USING HINT = 'If privacy_by_design is enabled, add a default value to the column';
END;
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of UPDATE
  SECURITY INVOKER
  SET search_path = ''
;

-- Walk through all tables with masked columns and execute anonymize_table on them
CREATE OR REPLACE FUNCTION anon.anonymize_database()
RETURNS BOOLEAN AS
$$
  SELECT bool_or(anon.anonymize_table(t.regclass))
  FROM (
      SELECT distinct attrelid::REGCLASS as regclass
      FROM anon.pg_masking_rules
  ) as t;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL UNSAFE -- because of UPDATE
  SECURITY INVOKER
  SET search_path=''
;



-------------------------------------------------------------------------------
-- Dynamic Masking
-------------------------------------------------------------------------------

-- ADD TEST IN FILES:
--   * tests/sql/masking.sql
--   * tests/sql/hasmask.sql

-- True if the role is masked
CREATE OR REPLACE FUNCTION anon.hasmask(
  role REGROLE,
  masking_policy TEXT DEFAULT 'anon'
)
RETURNS BOOLEAN AS
$$
SELECT bool_or(m.masked)
FROM (
  -- Rule from SECURITY LABEL
  SELECT label ILIKE 'MASKED' AS masked
  FROM pg_catalog.pg_shseclabel
  WHERE  objoid = role
  AND provider = masking_policy
  UNION
  -- return FALSE if the SELECT above is empty
  SELECT FALSE as masked --
) AS m
$$
  LANGUAGE SQL
  STABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- DEPRECATED : use directly `hasmask(oid::REGROLE)` instead
-- Adds a `hasmask` column to the pg_roles catalog
CREATE OR REPLACE VIEW anon.pg_masked_roles AS
SELECT r.*, anon.hasmask(r.oid::REGROLE)
FROM pg_catalog.pg_roles r
;

-- Display all columns of the relation with the masking function (if any)
CREATE OR REPLACE FUNCTION anon.mask_columns(
  source_relid OID
)
RETURNS TABLE (
    attname NAME,
    masking_filter TEXT,
    format_type TEXT
) AS
$$
SELECT
  a.attname::NAME, -- explicit cast for PG 9.6
  m.masking_filter,
  m.format_type
FROM pg_catalog.pg_attribute a
LEFT JOIN  anon.pg_masking_rules m
        ON m.attrelid = a.attrelid
        AND m.attname = a.attname
WHERE  a.attrelid = source_relid
AND    a.attnum > 0 -- exclude ctid, cmin, cmax
AND    NOT a.attisdropped
ORDER BY a.attnum
;
$$
  LANGUAGE SQL
  VOLATILE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- get the "select filters" that will mask the real data of a table
CREATE OR REPLACE FUNCTION anon.mask_filters(
  relid OID
)
RETURNS TEXT AS
$$
DECLARE
    m RECORD;
    expression TEXT;
    comma TEXT;
BEGIN
    expression := '';
    comma := '';
    FOR m IN SELECT * FROM anon.mask_columns(relid)
    LOOP
        expression := expression || comma;
        IF m.masking_filter IS NULL THEN
            -- No masking rule found
            expression := expression || quote_ident(m.attname);
        ELSE
            -- use the masking filter instead of the original value
            -- the masking filter is casted into the column type
            expression := expression || format('CAST(%s AS %s) AS %s',
                                                m.masking_filter,
                                                m.format_type,
                                                quote_ident(m.attname)
                                              );
        END IF;
        comma := ',';
    END LOOP;
  RETURN expression;
END
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- Build a masked view for a table
CREATE OR REPLACE FUNCTION anon.mask_create_view(
  relid OID
)
RETURNS BOOLEAN AS
$$
BEGIN
  EXECUTE format( 'CREATE OR REPLACE VIEW %I.%s AS SELECT %s FROM %s',
                  pg_catalog.current_setting('anon.maskschema'),
                  -- FIXME quote_ident(relid::REGCLASS::TEXT) ?
                  ( SELECT quote_ident(relname)
                    FROM pg_catalog.pg_class
                    WHERE relid = oid
                  ),
                  anon.mask_filters(relid),
                  relid::REGCLASS
  );
  RETURN TRUE;
END
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of CREATE
  SECURITY INVOKER
  SET search_path=''
;

-- Remove a masked view for a given table
CREATE OR REPLACE FUNCTION anon.mask_drop_view(
  relid OID
)
RETURNS BOOLEAN AS
$$
BEGIN
  EXECUTE format('DROP VIEW %I.%s;',
                  pg_catalog.current_setting('anon.maskschema'),
                  -- FIXME quote_ident(relid::REGCLASS::TEXT) ?
                  ( SELECT quote_ident(relname)
                    FROM pg_catalog.pg_class
                    WHERE relid = oid
                  )
  );
  RETURN TRUE;
END
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of DROP
  SECURITY INVOKER
  SET search_path=''
;

-- Activate the masking engine
CREATE OR REPLACE FUNCTION anon.start_dynamic_masking(
  autoload BOOLEAN DEFAULT TRUE
)
RETURNS BOOLEAN AS
$$
DECLARE
  r RECORD;
BEGIN

  SELECT current_setting('is_superuser') = 'on' AS su INTO r;
  IF NOT r.su THEN
    RAISE EXCEPTION 'Only supersusers can start the dynamic masking engine.';
  END IF;

  -- Load faking data
  SELECT anon.is_initialized() AS init INTO r;
  IF NOT autoload THEN
    RAISE DEBUG 'Autoload is disabled.';
  ELSEIF r.init THEN
    RAISE DEBUG 'Anon extension is already initiliazed.';
  ELSE
    PERFORM anon.init();
  END IF;

  EXECUTE format('CREATE SCHEMA IF NOT EXISTS %I',
                  pg_catalog.current_setting('anon.maskschema')::NAME
  );

  PERFORM anon.mask_update();

  RETURN TRUE;

  EXCEPTION
    WHEN invalid_name THEN
       RAISE EXCEPTION '% is not a valid name',
                        pg_catalog.current_setting('anon.maskschema')::NAME;

END
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of UPDATE
  SECURITY INVOKER
  SET search_path=''
;


-- this is opposite of start_dynamic_masking()
CREATE OR REPLACE FUNCTION anon.stop_dynamic_masking()
RETURNS BOOLEAN AS
$$
DECLARE
  r RECORD;
BEGIN

  SELECT current_setting('is_superuser') = 'on' AS su INTO r;
  IF NOT r.su THEN
    RAISE EXCEPTION 'Only supersusers can stop the dynamic masking engine.';
  END IF;

  -- Walk through all tables in the source schema and drop the masking view
  PERFORM anon.mask_drop_view(oid)
  FROM pg_catalog.pg_class
  WHERE relnamespace=quote_ident(pg_catalog.current_setting('anon.sourceschema'))::REGNAMESPACE
  AND relkind IN ('r','p','f') -- relations or partitions or foreign tables
  ;

  -- Walk through all masked roles and remove their mask
  PERFORM anon.unmask_role(oid::REGROLE)
  FROM pg_catalog.pg_roles
  WHERE anon.hasmask(oid::REGROLE);

  -- Drop the masking schema, it should be empty
  EXECUTE format('DROP SCHEMA %I',
                  pg_catalog.current_setting('anon.maskschema')
  );

  RETURN TRUE;
END
$$
  LANGUAGE plpgsql
  VOLATILE
  PARALLEL UNSAFE -- because of DROP
  SECURITY INVOKER
  SET search_path=''
;



-- This is run after any changes in the data model
CREATE OR REPLACE FUNCTION anon.trg_mask_update()
RETURNS EVENT_TRIGGER AS
$$
-- SQL Functions cannot return EVENT_TRIGGER,
-- we're forced to write a plpgsql function
BEGIN
  PERFORM anon.mask_update();
END
$$
  LANGUAGE plpgsql
  PARALLEL UNSAFE -- because of UPDATE
  SECURITY INVOKER
  SET search_path=''
;


-- Mask a specific role
CREATE OR REPLACE FUNCTION anon.mask_role(
  maskedrole REGROLE
)
RETURNS BOOLEAN AS
$$
DECLARE
  sourceschema REGNAMESPACE;
  maskschema REGNAMESPACE;
BEGIN
  SELECT quote_ident(pg_catalog.current_setting('anon.sourceschema'))::REGNAMESPACE
    INTO sourceschema;
  SELECT quote_ident(pg_catalog.current_setting('anon.maskschema'))::REGNAMESPACE
    INTO maskschema;
  RAISE DEBUG 'Mask role % (% -> %)', maskedrole, sourceschema, maskschema;
  -- The masked role cannot read the authentic data in the source schema
  EXECUTE format('REVOKE ALL ON SCHEMA %s FROM %s', sourceschema, maskedrole);
  -- The masked role can use the anon schema
  EXECUTE format('GRANT USAGE ON SCHEMA anon TO %s', maskedrole);
  EXECUTE format('GRANT SELECT ON ALL TABLES IN SCHEMA anon TO %s', maskedrole);
  EXECUTE format('GRANT SELECT ON ALL SEQUENCES IN SCHEMA anon TO %s', maskedrole);
  -- The masked role can use the masking schema
  EXECUTE format('GRANT USAGE ON SCHEMA %s TO %s', maskschema, maskedrole);
  EXECUTE format('GRANT SELECT ON ALL TABLES IN SCHEMA %s TO %s', maskschema, maskedrole);
  -- This is how we "trick" the masked role
  EXECUTE format('ALTER ROLE %s SET search_path TO %s,%s;', maskedrole, maskschema,sourceschema);
  RETURN TRUE;
END
$$
  LANGUAGE plpgsql
  PARALLEL UNSAFE -- because of ALTER
  SECURITY INVOKER
  SET search_path=''
;

-- Remove (partially) the mask of a specific role
CREATE OR REPLACE FUNCTION anon.unmask_role(
  maskedrole REGROLE
)
RETURNS BOOLEAN AS
$$
BEGIN
  -- we dont know what priviledges this role had before putting his mask on
  -- so we keep most of the priviledges as they are and let the
  -- administrator restore the correct access right.
  RAISE NOTICE 'The previous priviledges of ''%'' are not restored. You need to grant them manually.', maskedrole;
  -- restore default search_path
  EXECUTE format('ALTER ROLE %s RESET search_path;', maskedrole);
  RETURN TRUE;
END
$$
  LANGUAGE plpgsql
  PARALLEL UNSAFE -- because of UPDATE
  SECURITY INVOKER
  SET search_path=''
;

CREATE OR REPLACE FUNCTION anon.mask_update()
RETURNS BOOLEAN AS
$$
BEGIN
  -- Check if dynamic masking is enabled
  PERFORM nspname
  FROM pg_catalog.pg_namespace
  WHERE nspname = pg_catalog.current_setting('anon.maskschema')::NAME;

  IF NOT FOUND THEN
    -- Dynamic masking is disabled, no need to go further
    RETURN FALSE;
  END IF;

  -- Walk through all tables in the source schema
  -- and build a dynamic masking view
  PERFORM anon.mask_create_view(oid)
  FROM pg_catalog.pg_class
  WHERE relnamespace=quote_ident(pg_catalog.current_setting('anon.sourceschema'))::REGNAMESPACE
  AND relkind IN ('r','p','f') -- relations or partitions or foreign tables
  ;

  -- Walk through all masked roles and apply the restrictions
  PERFORM anon.mask_role(oid::REGROLE)
  FROM pg_catalog.pg_roles
  WHERE anon.hasmask(oid::REGROLE);

  RETURN TRUE;
END
$$
  LANGUAGE plpgsql
  PARALLEL UNSAFE -- because of UPDATE
  SECURITY DEFINER
  SET search_path=''
;


--
-- Unmask all the role at once
--
CREATE OR REPLACE FUNCTION anon.remove_masks_for_all_roles()
RETURNS BOOLEAN AS
$$
DECLARE
  r RECORD;
BEGIN
  FOR r IN SELECT rolname
           FROM anon.pg_masked_roles
           WHERE hasmask
  LOOP
    EXECUTE format('SECURITY LABEL FOR anon ON ROLE %I IS NULL', r.rolname);
  END LOOP;
  RETURN TRUE;
END
$$
  LANGUAGE plpgsql
  PARALLEL UNSAFE -- because of SECURITY LABEL
  SECURITY INVOKER
  SET search_path=''
;


--
-- Trigger the mask_update on any major schema changes
--
-- Complete list of TAGs is available here:
-- https://www.postgresql.org/docs/current/event-trigger-matrix.html
--
CREATE EVENT TRIGGER anon_trg_mask_update
  ON ddl_command_end
  WHEN TAG IN (
    'ALTER TABLE', 'CREATE TABLE', 'CREATE TABLE AS', 'DROP TABLE',
    'ALTER MATERIALIZED VIEW', 'CREATE MATERIALIZED VIEW', 'DROP MATERIALIZED VIEW',
    'ALTER FOREIGN TABLE', 'CREATE FOREIGN TABLE', 'DROP FOREIGN TABLE',
    'SECURITY LABEL', 'SELECT INTO'
  )
  EXECUTE PROCEDURE anon.trg_mask_update()
  -- EXECUTE FUNCTION not supported by PG10 and below
;


-------------------------------------------------------------------------------
-- Generalization
-------------------------------------------------------------------------------

-- ADD TEST IN FILES:
--   * tests/sql/generalization.sql

-- Transform an integer into a range of integer
CREATE OR REPLACE FUNCTION anon.generalize_int4range(
  val INTEGER,
  step INTEGER default 10
)
RETURNS INT4RANGE
AS $$
SELECT int4range(
    val / step * step,
    ((val / step)+1) * step
  );
$$
  LANGUAGE SQL
  IMMUTABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- Transform a bigint into a range of bigint
CREATE OR REPLACE FUNCTION anon.generalize_int8range(
  val BIGINT,
  step BIGINT DEFAULT 10
)
RETURNS INT8RANGE
AS $$
SELECT int8range(
    val / step * step,
    ((val / step)+1) * step
  );
$$
  LANGUAGE SQL
  IMMUTABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- Transform a numeric into a range of numeric
CREATE OR REPLACE FUNCTION anon.generalize_numrange(
  val NUMERIC,
  step INTEGER DEFAULT 10
)
RETURNS NUMRANGE
AS $$
WITH i AS (
  SELECT anon.generalize_int4range(val::INTEGER,step) as r
)
SELECT numrange(
    lower(i.r)::NUMERIC,
    upper(i.r)::NUMERIC
  )
FROM i
;
$$
  LANGUAGE SQL
  IMMUTABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- Transform a timestamp with out timezone (ts) into a range of ts
-- the `step` option can have the following values
--        microseconds,milliseconds,second,minute,hour,day,week,
--        month,year,decade,century,millennium
CREATE OR REPLACE FUNCTION anon.generalize_tsrange(
  val TIMESTAMP WITHOUT TIME ZONE,
  step TEXT DEFAULT 'decade'
)
RETURNS TSRANGE
AS $$
SELECT tsrange(
    date_trunc(step, val)::TIMESTAMP WITHOUT TIME ZONE,
    date_trunc(step, val)::TIMESTAMP WITHOUT TIME ZONE + ('1 '|| step)::INTERVAL
  );
$$
  LANGUAGE SQL
  IMMUTABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- tstzrange
CREATE OR REPLACE FUNCTION anon.generalize_tstzrange(
  val TIMESTAMP WITH TIME ZONE,
  step TEXT DEFAULT 'decade'
)
RETURNS TSTZRANGE
AS $$
WITH lowerbound AS (
  SELECT date_trunc(step, val)::TIMESTAMP WITH TIME ZONE AS d
)
SELECT tstzrange( d, d + ('1 '|| step)::INTERVAL )
FROM lowerbound
;
$$
  LANGUAGE SQL
  IMMUTABLE
  PARALLEL SAFE
  SECURITY INVOKER
  SET search_path=''
;

-- daterange — Range of date
CREATE OR REPLACE FUNCTION anon.generalize_daterange(
  val DATE,
  step TEXT DEFAULT 'decade'
)
RETURNS DATERANGE
AS $$
SELECT daterange(
    date_trunc(step, val)::DATE,
    (date_trunc(step, val) + ('1 '|| step)::INTERVAL)::DATE
  );
$$
  LANGUAGE SQL
  PARALLEL SAFE
  IMMUTABLE
  SECURITY INVOKER
  SET search_path=''
;

-------------------------------------------------------------------------------
-- Risk Evaluation
-------------------------------------------------------------------------------

-- ADD TEST IN FILES:
--   * tests/sql/k_anonymity.sql

-- This is an attempt to implement various anonymity assessment methods.
-- These functions should be used with care.

CREATE OR REPLACE VIEW anon.pg_identifiers AS
WITH const AS (
  SELECT
    '%(quasi|indirect) identifier%'::TEXT AS pattern_indirect_identifier
)
SELECT
  sl.objoid AS attrelid,
  sl.objsubid  AS attnum,
  c.relname,
  a.attname,
  pg_catalog.format_type(a.atttypid, a.atttypmod),
  sl.label AS col_description,
  lower(sl.label) SIMILAR TO k.pattern_indirect_identifier ESCAPE '#'  AS indirect_identifier,
  100 AS priority -- high priority for the security label syntax
FROM const k,
     pg_catalog.pg_seclabel sl
JOIN pg_catalog.pg_class c ON sl.classoid = c.tableoid AND sl.objoid = c.oid
JOIN pg_catalog.pg_attribute a ON a.attrelid = c.oid AND sl.objsubid = a.attnum
WHERE a.attnum > 0
--  TODO : Filter out the catalog tables
AND NOT a.attisdropped
AND lower(sl.label) SIMILAR TO k.pattern_indirect_identifier ESCAPE '#'
AND sl.provider = 'anon' -- this is hard-coded in anon.c
;


-- see https://en.wikipedia.org/wiki/K-anonymity
CREATE OR REPLACE FUNCTION  anon.k_anonymity(
  relid REGCLASS
)
RETURNS INTEGER
AS $$
DECLARE
  identifiers TEXT;
  result INTEGER;
BEGIN
  SELECT string_agg(attname,',')
  INTO identifiers
  FROM anon.pg_identifiers
  WHERE relname::REGCLASS = relid;

  IF identifiers IS NULL THEN
    RAISE WARNING 'There is no identifier declared for relation ''%''.',
                  relid::REGCLASS
    USING HINT = 'Use SECURITY LABEL FOR anon ... to declare which columns are '
              || 'indirect identifiers.';
    RETURN NULL;
  END IF;

  EXECUTE format(E'
    SELECT min(c) AS k_anonymity
    FROM (
      SELECT COUNT(*) as c
      FROM %s
      GROUP BY %s
    ) AS k;
  ',
  relid::REGCLASS,
  identifiers
  )
  INTO result;
  RETURN result;
END
$$
  LANGUAGE plpgsql
  IMMUTABLE
  PARALLEL SAFE
  SECURITY INVOKER
; --SET search_path='';

-- TODO : https://en.wikipedia.org/wiki/L-diversity

-- TODO : https://en.wikipedia.org/wiki/T-closeness