exchange/src/exchangedb/exchange_do_deposit.sql

--
-- This file is part of TALER
-- Copyright (C) 2014--2022 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 OR REPLACE FUNCTION exchange_do_deposit(
  IN in_amount_with_fee_val INT8,
  IN in_amount_with_fee_frac INT4,
  IN in_h_contract_terms BYTEA,
  IN in_wire_salt BYTEA,
  IN in_wallet_timestamp INT8,
  IN in_exchange_timestamp INT8,
  IN in_refund_deadline INT8,
  IN in_wire_deadline INT8,
  IN in_merchant_pub BYTEA,
  IN in_receiver_wire_account VARCHAR,
  IN in_h_payto BYTEA,
  IN in_known_coin_id INT8,
  IN in_coin_pub BYTEA,
  IN in_coin_sig BYTEA,
  IN in_shard INT8,
  IN in_policy_blocked BOOLEAN,
  IN in_policy_details_serial_id INT8,
  OUT out_exchange_timestamp INT8,
  OUT out_balance_ok BOOLEAN,
  OUT out_conflict BOOLEAN)
LANGUAGE plpgsql
AS $$
DECLARE
  wtsi INT8; -- wire target serial id
BEGIN
-- Shards: INSERT policy_details (by policy_details_serial_id)
--         INSERT wire_targets (by h_payto), on CONFLICT DO NOTHING;
--         INSERT deposits (by coin_pub, shard), ON CONFLICT DO NOTHING;
--         UPDATE known_coins (by coin_pub)

INSERT INTO exchange.wire_targets
  (wire_target_h_payto
  ,payto_uri)
  VALUES
  (in_h_payto
  ,in_receiver_wire_account)
ON CONFLICT DO NOTHING -- for CONFLICT ON (wire_target_h_payto)
  RETURNING wire_target_serial_id INTO wtsi;

IF NOT FOUND
THEN
  SELECT wire_target_serial_id
  INTO wtsi
  FROM exchange.wire_targets
  WHERE wire_target_h_payto=in_h_payto;
END IF;


INSERT INTO exchange.deposits
  (shard
  ,coin_pub
  ,known_coin_id
  ,amount_with_fee_val
  ,amount_with_fee_frac
  ,wallet_timestamp
  ,exchange_timestamp
  ,refund_deadline
  ,wire_deadline
  ,merchant_pub
  ,h_contract_terms
  ,coin_sig
  ,wire_salt
  ,wire_target_h_payto
  ,policy_blocked
  ,policy_details_serial_id
  )
  VALUES
  (in_shard
  ,in_coin_pub
  ,in_known_coin_id
  ,in_amount_with_fee_val
  ,in_amount_with_fee_frac
  ,in_wallet_timestamp
  ,in_exchange_timestamp
  ,in_refund_deadline
  ,in_wire_deadline
  ,in_merchant_pub
  ,in_h_contract_terms
  ,in_coin_sig
  ,in_wire_salt
  ,in_h_payto
  ,in_policy_blocked
  ,in_policy_details_serial_id)
  ON CONFLICT DO NOTHING;

IF NOT FOUND
THEN
  -- Idempotency check: see if an identical record exists.
  -- Note that by checking 'coin_sig', we implicitly check
  -- identity over everything that the signature covers.
  -- We do select over merchant_pub and wire_target_h_payto
  -- primarily here to maximally use the existing index.
  SELECT
     exchange_timestamp
   INTO
     out_exchange_timestamp
   FROM exchange.deposits
   WHERE shard=in_shard
     AND merchant_pub=in_merchant_pub
     AND wire_target_h_payto=in_h_payto
     AND coin_pub=in_coin_pub
     AND coin_sig=in_coin_sig;
     -- AND policy_details_serial_id=in_policy_details_serial_id; -- FIXME: is this required for idempotency?

  IF NOT FOUND
  THEN
    -- Deposit exists, but with differences. Not allowed.
    out_balance_ok=FALSE;
    out_conflict=TRUE;
    RETURN;
  END IF;

  -- Idempotent request known, return success.
  out_balance_ok=TRUE;
  out_conflict=FALSE;

  RETURN;
END IF;


out_exchange_timestamp=in_exchange_timestamp;

-- Check and update balance of the coin.
UPDATE known_coins
  SET
    remaining_frac=remaining_frac-in_amount_with_fee_frac
       + CASE
         WHEN remaining_frac < in_amount_with_fee_frac
         THEN 100000000
         ELSE 0
         END,
    remaining_val=remaining_val-in_amount_with_fee_val
       - CASE
         WHEN remaining_frac < in_amount_with_fee_frac
         THEN 1
         ELSE 0
         END
  WHERE coin_pub=in_coin_pub
    AND ( (remaining_val > in_amount_with_fee_val) OR
          ( (remaining_frac >= in_amount_with_fee_frac) AND
            (remaining_val >= in_amount_with_fee_val) ) );

IF NOT FOUND
THEN
  -- Insufficient balance.
  out_balance_ok=FALSE;
  out_conflict=FALSE;
  RETURN;
END IF;

-- Everything fine, return success!
out_balance_ok=TRUE;
out_conflict=FALSE;

END $$;