mte/include/sql/0002-recoup_refresh.sql

--
-- This file is part of TALER
-- Copyright (C) 2025 Taler Systems SA
--
-- TALER is free software; you can redistribute it and/or modify it under the
-- terms of the GNU General Public License as published by the Free Software
-- Foundation; either version 3, or (at your option) any later version.
--
-- TALER is distributed in the hope that it will be useful, but WITHOUT ANY
-- WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-- A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License along with
-- TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
--


CREATE FUNCTION create_table_recoup_refresh(
  IN partition_suffix TEXT DEFAULT NULL
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  table_name TEXT DEFAULT 'recoup_refresh';
BEGIN
  PERFORM create_partitioned_table(
    'CREATE TABLE %I'
    '(recoup_refresh_uuid BIGINT GENERATED BY DEFAULT AS IDENTITY'
    ',coin_pub BYTEA NOT NULL CHECK (LENGTH(coin_pub)=32)'
    ',known_coin_id BIGINT NOT NULL'
    ',coin_sig BYTEA NOT NULL CHECK(LENGTH(coin_sig)=64)'
    ',coin_blind BYTEA NOT NULL CHECK(LENGTH(coin_blind)=32)'
    ',amount taler_amount NOT NULL'
    ',recoup_timestamp INT8 NOT NULL'
    ',refresh_id INT8 NOT NULL'
    ') %s ;'
    ,table_name
    ,'PARTITION BY HASH (coin_pub)'
    ,partition_suffix
  );
  PERFORM comment_partitioned_table(
     'Table of coins that originated from a refresh operation and that were recouped. Links the (fresh) coin to the melted operation (and thus the old coin). A recoup on a refreshed coin credits the old coin and debits the fresh coin.'
    ,table_name
    ,partition_suffix
  );
  PERFORM comment_partitioned_column(
     'Refreshed coin of a revoked denomination where the residual value is credited to the old coin. Do not CASCADE ON DROP on the coin_pub, as we may keep the coin alive!'
    ,'coin_pub'
    ,table_name
    ,partition_suffix
  );
  PERFORM comment_partitioned_column(
     'Used for garbage collection (in the absence of foreign constraints, in the future)'
    ,'known_coin_id'
    ,table_name
    ,partition_suffix
  );
  PERFORM comment_partitioned_column(
     'Link to the refresh operation. Also identifies the h_blind_ev of the recouped coin (as h_coin_ev).'
    ,'refresh_id'
    ,table_name
    ,partition_suffix
  );
  PERFORM comment_partitioned_column(
     'Denomination blinding key used when creating the blinded coin from the planchet. Secret revealed during the recoup to provide the linkage between the coin and the refresh operation.'
    ,'coin_blind'
    ,table_name
    ,partition_suffix
  );
END
$$;


CREATE FUNCTION constrain_table_recoup_refresh(
  IN partition_suffix TEXT
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  table_name TEXT DEFAULT 'recoup_refresh';
BEGIN
  table_name = concat_ws('_', table_name, partition_suffix);

  EXECUTE FORMAT (
    'CREATE INDEX ' || table_name || '_by_refresh_id_index'
    ' ON ' || table_name || ' '
    '(refresh_id);'
  );
  EXECUTE FORMAT (
    'COMMENT ON INDEX ' || table_name || '_by_refresh_id_index '
    'IS ' || quote_literal('used in exchange_do_melt for zombie coins (rare)') || ';'
  );

  EXECUTE FORMAT (
    'CREATE INDEX ' || table_name || '_by_coin_pub_index'
    ' ON ' || table_name || ' '
    '(coin_pub);'
  );
  EXECUTE FORMAT (
    'ALTER TABLE ' || table_name ||
    ' ADD CONSTRAINT ' || table_name || '_recoup_refresh_uuid_key'
    ' UNIQUE (recoup_refresh_uuid) '
  );
END
$$;


CREATE FUNCTION foreign_table_recoup_refresh()
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  table_name TEXT DEFAULT 'recoup_refresh';
BEGIN
  EXECUTE FORMAT (
    'ALTER TABLE ' || table_name ||
    ' ADD CONSTRAINT ' || table_name || '_foreign_coin_pub'
    ' FOREIGN KEY (coin_pub) '
    ' REFERENCES known_coins (coin_pub)'
    ',ADD CONSTRAINT ' || table_name || '_foreign_known_coin_id'
    ' FOREIGN KEY (known_coin_id) '
    ' REFERENCES known_coins (known_coin_id) ON DELETE CASCADE'
    ',ADD CONSTRAINT ' || table_name || '_foreign_refresh_id'
    ' FOREIGN KEY (refresh_id) '
    ' REFERENCES refresh (refresh_id) ON DELETE CASCADE'
  );
END
$$;


CREATE OR REPLACE FUNCTION recoup_refresh_insert_trigger()
  RETURNS trigger
  LANGUAGE plpgsql
  AS $$
BEGIN
  INSERT INTO exchange.coin_history
    (coin_pub
    ,table_name
    ,serial_id)
  VALUES
     (NEW.coin_pub
    ,'recoup_refresh::NEW'
    ,NEW.recoup_refresh_uuid);
  INSERT INTO exchange.coin_history
    (coin_pub
    ,table_name
    ,serial_id)
  SELECT
     refresh.old_coin_pub
    ,'recoup_refresh::OLD'
    ,NEW.recoup_refresh_uuid
    FROM refresh
    WHERE refresh.refresh_id = NEW.refresh_id;
  RETURN NEW;
END $$;
COMMENT ON FUNCTION coin_deposits_insert_trigger()
  IS 'Automatically generate coin history entry.';


CREATE FUNCTION master_table_recoup_refresh()
RETURNS VOID
LANGUAGE plpgsql
AS $$
BEGIN
  CREATE TRIGGER recoup_refresh_on_insert
    AFTER INSERT
     ON recoup_refresh
     FOR EACH ROW EXECUTE FUNCTION recoup_refresh_insert_trigger();
END $$;



INSERT INTO exchange_tables
    (name
    ,version
    ,action
    ,partitioned
    ,by_range)
  VALUES
    ('recoup_refresh'
    ,'exchange-0002'
    ,'create'
    ,TRUE
    ,FALSE),
    ('recoup_refresh'
    ,'exchange-0002'
    ,'constrain'
    ,TRUE
    ,FALSE),
    ('recoup_refresh'
    ,'exchange-0002'
    ,'foreign'
    ,TRUE
    ,FALSE),
    ('recoup_refresh'
    ,'exchange-0002'
    ,'master'
    ,TRUE
    ,FALSE);