mte/include/sql/0002-recoup.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(
  IN partition_suffix TEXT DEFAULT NULL
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  table_name TEXT DEFAULT 'recoup';
BEGIN

  PERFORM create_partitioned_table(
    'CREATE TABLE %I'
      '(recoup_uuid BIGINT GENERATED BY DEFAULT AS IDENTITY'
      ',coin_pub BYTEA NOT NULL CHECK (LENGTH(coin_pub)=32)'
      ',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'
      ',withdraw_id INT8 NOT NULL'
    ') %s ;'
    ,table_name
    ,'PARTITION BY HASH (coin_pub);'
    ,partition_suffix
  );
  PERFORM comment_partitioned_table(
     'Information about recoups that were executed between a coin and a reserve. In this type of recoup, the amount is credited back to the reserve from which the coin originated.'
    ,table_name
    ,partition_suffix
  );
  PERFORM comment_partitioned_column(
     'Coin that is being debited in the recoup. 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(
     'Identifies the h_commitment of the recouped coin and provides the link to the credited reserve.'
    ,'withdraw_id'
    ,table_name
    ,partition_suffix
  );
  PERFORM comment_partitioned_column(
     'Signature by the coin affirming the recoup, of type TALER_SIGNATURE_WALLET_COIN_RECOUP'
    ,'coin_sig'
    ,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 withdraw operation.'
    ,'coin_blind'
    ,table_name
    ,partition_suffix
  );
END
$$;


CREATE FUNCTION constrain_table_recoup(
  IN partition_suffix TEXT
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  table_name TEXT DEFAULT 'recoup';
BEGIN
  table_name = concat_ws('_', table_name, partition_suffix);
  EXECUTE FORMAT (
    'CREATE INDEX ' || table_name || '_by_coin_pub_index '
    'ON ' || table_name || ' '
    '(coin_pub);'
  );
  EXECUTE FORMAT (
    'ALTER TABLE ' || table_name ||
    ' ADD CONSTRAINT ' || table_name || '_recoup_uuid_key'
    ' UNIQUE (recoup_uuid) '
  );
END
$$;


CREATE OR REPLACE FUNCTION foreign_table_recoup()
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  table_name TEXT DEFAULT 'recoup';
BEGIN
  EXECUTE FORMAT (
    'ALTER TABLE ' || table_name ||
    ' ADD CONSTRAINT ' || table_name || '_foreign_withdraw'
    ' FOREIGN KEY (withdraw_id) '
    ' REFERENCES withdraw (withdraw_id) ON DELETE CASCADE'
    ',ADD CONSTRAINT ' || table_name || '_foreign_coin_pub'
    ' FOREIGN KEY (coin_pub) '
    ' REFERENCES known_coins (coin_pub)'
  );
END
$$;


CREATE FUNCTION create_table_recoup_by_reserve(
  IN partition_suffix TEXT DEFAULT NULL
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  table_name TEXT DEFAULT 'recoup_by_reserve';
BEGIN
  PERFORM create_partitioned_table(
  'CREATE TABLE %I'
    '(withdraw_id INT8 NOT NULL' -- REFERENCES withdraw (withdraw_id) ON DELETE CASCADE
    ',coin_pub BYTEA CHECK (LENGTH(coin_pub)=32)' -- REFERENCES known_coins (coin_pub)
    ') %s ;'
    ,table_name
    ,'PARTITION BY HASH (withdraw_id)'
    ,partition_suffix
  );
  PERFORM comment_partitioned_table(
     'Information in this table is strictly redundant with that of recoup, but saved by a different primary key for fast lookups by withdraw_id.'
    ,table_name
    ,partition_suffix
  );
END
$$;


CREATE FUNCTION constrain_table_recoup_by_reserve(
  IN partition_suffix TEXT DEFAULT NULL
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  table_name TEXT DEFAULT 'recoup_by_reserve';
BEGIN
  table_name = concat_ws('_', table_name, partition_suffix);
  EXECUTE FORMAT (
    'CREATE INDEX ' || table_name || '_main_index '
    'ON ' || table_name || ' '
    '(withdraw_id);'
  );
END
$$;


CREATE OR REPLACE FUNCTION recoup_insert_trigger()
  RETURNS trigger
  LANGUAGE plpgsql
  AS $$
BEGIN
  INSERT INTO recoup_by_reserve
    (withdraw_id
    ,coin_pub)
  VALUES
    (NEW.withdraw_id
    ,NEW.coin_pub);
  INSERT INTO coin_history
    (coin_pub
    ,table_name
    ,serial_id)
  VALUES
    (NEW.coin_pub
    ,'recoup'
    ,NEW.recoup_uuid);
  INSERT INTO reserve_history
    (reserve_pub
    ,table_name
    ,serial_id)
  SELECT
     res.reserve_pub
    ,'recoup'
    ,NEW.recoup_uuid
  FROM withdraw wd
  JOIN reserves res
    USING (reserve_pub)
    WHERE wd.withdraw_id = NEW.withdraw_id;
  RETURN NEW;
END $$;
COMMENT ON FUNCTION recoup_insert_trigger()
  IS 'Replicates recoup inserts into recoup_by_reserve table and updates the coin_history table.';


CREATE OR REPLACE FUNCTION recoup_delete_trigger()
  RETURNS trigger
  LANGUAGE plpgsql
  AS $$
BEGIN
  DELETE FROM recoup_by_reserve
   WHERE withdraw_id = OLD.withdraw_id
     AND coin_pub = OLD.coin_pub;
  RETURN OLD;
END $$;
COMMENT ON FUNCTION recoup_delete_trigger()
  IS 'Replicate recoup deletions into recoup_by_reserve table.';


CREATE FUNCTION master_table_recoup()
RETURNS VOID
LANGUAGE plpgsql
AS $$
BEGIN
  CREATE TRIGGER recoup_on_insert
    AFTER INSERT
     ON recoup
     FOR EACH ROW EXECUTE FUNCTION recoup_insert_trigger();
  CREATE TRIGGER recoup_on_delete
    AFTER DELETE
      ON recoup
     FOR EACH ROW EXECUTE FUNCTION recoup_delete_trigger();
END
$$;


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