--
-- 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/>
--

-- Everything in one big transaction
BEGIN;

SET search_path TO exchange;

---------------------------------------------------------------------------
--                   General procedures for DB setup
---------------------------------------------------------------------------

CREATE TABLE IF NOT EXISTS exchange_tables
  (table_serial_id BIGINT GENERATED BY DEFAULT AS IDENTITY
  ,name VARCHAR NOT NULL
  ,version VARCHAR NOT NULL
  ,action VARCHAR NOT NULL
  ,partitioned BOOL NOT NULL
  ,by_range BOOL NOT NULL
  ,finished BOOL NOT NULL DEFAULT(FALSE));
COMMENT ON TABLE exchange_tables
  IS 'Tables of the exchange and their status';
COMMENT ON COLUMN exchange_tables.name
  IS 'Base name of the table (without partition/shard)';
COMMENT ON COLUMN exchange_tables.version
  IS 'Version of the DB in which the given action happened';
COMMENT ON COLUMN exchange_tables.action
  IS 'Action to take on the table (e.g. create, alter, constrain, unconstrain, or drop)';
COMMENT ON COLUMN exchange_tables.partitioned
  IS 'TRUE if the table is partitioned';
COMMENT ON COLUMN exchange_tables.by_range
  IS 'TRUE if the table is partitioned by range';
COMMENT ON COLUMN exchange_tables.finished
  IS 'TRUE if the respective migration has been run';



CREATE OR REPLACE FUNCTION create_partitioned_table(
   IN table_definition VARCHAR
  ,IN table_name VARCHAR
  ,IN main_table_partition_str VARCHAR -- Used only when it is the main table - we do not partition shard tables
  ,IN shard_suffix VARCHAR DEFAULT NULL
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
BEGIN

  IF shard_suffix IS NOT NULL THEN
    table_name=table_name || '_' || shard_suffix;
    main_table_partition_str = '';
  END IF;

  EXECUTE FORMAT(
    table_definition,
    table_name,
    main_table_partition_str
  );

END
$$;





CREATE OR REPLACE FUNCTION create_tables(
  num_partitions INTEGER
 ,shard_domain VARCHAR
)
  RETURNS VOID
  LANGUAGE plpgsql
AS $$
DECLARE
  tc CURSOR FOR
    SELECT table_serial_id
          ,name
          ,action
          ,by_range
      FROM exchange_tables
     WHERE NOT finished
     ORDER BY table_serial_id ASC;
BEGIN
  FOR rec IN tc
  LOOP
    -- First create the master table, either
    -- completely unpartitioned, or with one
    -- master and the 'default' partition
    IF IS NULL num_partitions
    THEN
      EXECUTE FORMAT(
        'PERFORM %s_table_%s (%s)'::text
        ,rec.action
        ,rec.name
        ,NULL
      );
    ELSE
      EXECUTE FORMAT(
        'PERFORM %s_table_%s (%s)'::text
        ,rec.action
        ,rec.name
        ,0
      );
    END IF

    IF NOT NULL shard_domain
    THEN
      -- FIXME: attach shards!
      -- FIXME: how will migration work with shards!?
      FOR i IN 1..num_partitions LOOP
        EXECUTE FORMAT(
          'PERFORM %s_XXX_%s (%s)'::text
          ,rec.action
          ,rec.name
          ,i::varchar
        );
      END LOOP;
    ELSE
      FOR i IN 1..num_partitions LOOP
        EXECUTE FORMAT(
          'PERFORM %s_table_%s (%s)'::text
          ,rec.action
          ,rec.name
          ,i::varchar
        );
      END LOOP;
    END IF

    IF 0 < num_partitions
    THEN
      -- FIXME: detach default partition!
    END IF

    UPDATE exchange_tables
       SET finished=TRUE
     WHERE table_serial_id=rec.table_serial_id;
  END LOOP;
END
$$;

COMMENT ON FUNCTION create_tables
  IS 'Creates all tables for the given number of partitions that need creating.';



-- This is run last by dbinit, if partitions exist
-- or if 'force_create_partitions' is set (otherwise,
-- we are not expected to create partitions if there
-- is only 1).
CREATE OR REPLACE FUNCTION create_partitions(
  IN part_idx INTEGER
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  tc CURSOR FOR
    SELECT name
          ,action
          ,partitioned
          ,by_range
      FROM exchange_tables
     WHERE version=in_version
       AND partitioned
     ORDER BY table_seria_id ASC;
BEGIN
  FOR rec IN tc
  LOOP
    EXECUTE FORMAT(
      'PERFORM %s_table_%s (%s)'
      ,rec.action
      ,rec.name
      ,shard_idx::varchar
    );
  END LOOP;
END
$$;

COMMENT ON FUNCTION create_partitions
  IS 'Creates all partitions that need creating.';




CREATE OR REPLACE FUNCTION drop_default_partitions_NG()
  RETURNS VOID
  LANGUAGE plpgsql
AS $$
DECLARE
  tc CURSOR FOR
    SELECT name
      FROM exchange_tables
     WHERE partitioned
       AND NOT by_range;
BEGIN
  RAISE NOTICE 'Dropping default tables of partitioned tables';
  FOR rec IN tc
  LOOP
    EXECUTE FORMAT (
      'DROP TABLE IF EXISTS %s_default ;'::text,
    rec.name;
END
$$;

COMMENT ON FUNCTION drop_default_partitions
  IS 'Drop all default partitions once other partitions are attached.
      Might be needed in sharding too.';


CREATE OR REPLACE FUNCTION detach_default_partitions_NG()
  RETURNS VOID
  LANGUAGE plpgsql
AS $$
DECLARE
  tc CURSOR FOR
    SELECT name
      FROM exchange_tables
     WHERE partitioned
       AND NOT by_range;
BEGIN
  RAISE NOTICE 'Detaching all default table partitions';
  FOR rec IN tc
  LOOP
    EXECUTE FORMAT (
      'ALTER TABLE IF EXISTS %s DETACH PARTITION %s_default;'::text,
      rec.name,
      rec.name
    );
  END LOOP;
END
$$;

COMMENT ON FUNCTION detach_default_partitions
  IS 'We need to drop default and create new one before deleting the default partitions
      otherwise constraints get lost too. Might be needed in sharding too';


CREATE OR REPLACE FUNCTION create_hash_partition_NG(
    source_table_name VARCHAR
    ,modulus INTEGER
    ,partition_num INTEGER
  )
  RETURNS VOID
  LANGUAGE plpgsql
AS $$
BEGIN

  RAISE NOTICE 'Creating partition %_%', source_table_name, partition_num;

  EXECUTE FORMAT(
    'CREATE TABLE IF NOT EXISTS %I '
      'PARTITION OF %I '
      'FOR VALUES WITH (MODULUS %s, REMAINDER %s)'
    ,source_table_name || '_' || partition_num
    ,source_table_name
    ,modulus
    ,partition_num-1
  );

END
$$;


CREATE OR REPLACE FUNCTION create_partitions_NG(
  num_partitions INTEGER
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  tc CURSOR FOR
    SELECT name
      FROM exchange_tables
     WHERE partitioned
       AND NOT by_range;
DECLARE
  i INTEGER;
BEGIN
  PERFORM detach_default_partitions();
  FOR rec IN tc
  LOOP
    i := num_partitions
    LOOP

    PERFORM create_hash_partition(
       quote_literal (rec.name)
      ,num_partitions
      ,i
    );

    i=i-1;
    EXIT WHEN i=0;
    END LOOP; -- i = num_partitions ... 0
  END LOOP; -- for all partitioned tables

  PERFORM drop_default_partitions();

END
$$;


-- OLD LOGIC:
-------------------------------------------------------------------
------------------------- Partitions ------------------------------
-------------------------------------------------------------------


CREATE OR REPLACE FUNCTION create_range_partition(
  source_table_name VARCHAR
  ,partition_num INTEGER
)
  RETURNS void
  LANGUAGE plpgsql
AS $$
BEGIN
  RAISE NOTICE 'TODO';
END
$$;

CREATE OR REPLACE FUNCTION detach_default_partitions()
  RETURNS VOID
  LANGUAGE plpgsql
AS $$
BEGIN

  RAISE NOTICE 'Detaching all default table partitions';

  ALTER TABLE IF EXISTS wire_targets
    DETACH PARTITION wire_targets_default;

  ALTER TABLE IF EXISTS reserves
    DETACH PARTITION reserves_default;

  ALTER TABLE IF EXISTS reserves_in
    DETACH PARTITION reserves_in_default;

  ALTER TABLE IF EXISTS reserves_close
    DETACH PARTITION reserves_close_default;

  ALTER TABLE IF EXISTS history_requests
    DETACH partition history_requests_default;

  ALTER TABLE IF EXISTS close_requests
    DETACH partition close_requests_default;

  ALTER TABLE IF EXISTS reserves_open_requests
    DETACH partition reserves_open_requests_default;

  ALTER TABLE IF EXISTS reserves_out
    DETACH PARTITION reserves_out_default;

  ALTER TABLE IF EXISTS reserves_out_by_reserve
    DETACH PARTITION reserves_out_by_reserve_default;

  ALTER TABLE IF EXISTS known_coins
    DETACH PARTITION known_coins_default;

  ALTER TABLE IF EXISTS refresh_commitments
    DETACH PARTITION refresh_commitments_default;

  ALTER TABLE IF EXISTS refresh_revealed_coins
    DETACH PARTITION refresh_revealed_coins_default;

  ALTER TABLE IF EXISTS refresh_transfer_keys
    DETACH PARTITION refresh_transfer_keys_default;

  ALTER TABLE IF EXISTS deposits
    DETACH PARTITION deposits_default;

--- TODO range partitioning
--  ALTER TABLE IF EXISTS deposits_by_ready
--    DETACH PARTITION deposits_by_ready_default;
--
--  ALTER TABLE IF EXISTS deposits_for_matching
--    DETACH PARTITION deposits_default_for_matching_default;

  ALTER TABLE IF EXISTS refunds
    DETACH PARTITION refunds_default;

  ALTER TABLE IF EXISTS wire_out
    DETACH PARTITION wire_out_default;

  ALTER TABLE IF EXISTS aggregation_transient
    DETACH PARTITION aggregation_transient_default;

  ALTER TABLE IF EXISTS aggregation_tracking
    DETACH PARTITION aggregation_tracking_default;

  ALTER TABLE IF EXISTS recoup
    DETACH PARTITION recoup_default;

  ALTER TABLE IF EXISTS recoup_by_reserve
    DETACH PARTITION recoup_by_reserve_default;

  ALTER TABLE IF EXISTS recoup_refresh
    DETACH PARTITION recoup_refresh_default;

  ALTER TABLE IF EXISTS prewire
    DETACH PARTITION prewire_default;

  ALTER TABLE IF EXISTS cs_nonce_locks
    DETACH partition cs_nonce_locks_default;

  ALTER TABLE IF EXISTS purse_requests
    DETACH partition purse_requests_default;

  ALTER TABLE IF EXISTS purse_decision
    DETACH partition purse_decision_default;

  ALTER TABLE IF EXISTS purse_merges
    DETACH partition purse_merges_default;

  ALTER TABLE IF EXISTS account_merges
    DETACH partition account_merges_default;

  ALTER TABLE IF EXISTS contracts
    DETACH partition contracts_default;

  ALTER TABLE IF EXISTS purse_deposits
    DETACH partition purse_deposits_default;

  ALTER TABLE IF EXISTS wad_out_entries
    DETACH partition wad_out_entries_default;

  ALTER TABLE IF EXISTS wads_in
    DETACH partition wads_in_default;

  ALTER TABLE IF EXISTS wad_in_entries
    DETACH partition wad_in_entries_default;
END
$$;

COMMENT ON FUNCTION detach_default_partitions
  IS 'We need to drop default and create new one before deleting the default partitions
      otherwise constraints get lost too. Might be needed in sharding too';


CREATE OR REPLACE FUNCTION drop_default_partitions()
  RETURNS VOID
  LANGUAGE plpgsql
AS $$
BEGIN

  RAISE NOTICE 'Dropping default table partitions';

  DROP TABLE IF EXISTS wire_targets_default;
  DROP TABLE IF EXISTS reserves_default;
  DROP TABLE IF EXISTS reserves_in_default;
  DROP TABLE IF EXISTS reserves_close_default;
  DROP TABLE IF EXISTS reserves_open_requests_default;
  DROP TABLE IF EXISTS history_requests_default;
  DROP TABLE IF EXISTS close_requests_default;

  DROP TABLE IF EXISTS reserves_out_default;
  DROP TABLE IF EXISTS reserves_out_by_reserve_default;
  DROP TABLE IF EXISTS known_coins_default;
  DROP TABLE IF EXISTS refresh_commitments_default;
  DROP TABLE IF EXISTS refresh_revealed_coins_default;
  DROP TABLE IF EXISTS refresh_transfer_keys_default;
  DROP TABLE IF EXISTS deposits_default;
--DROP TABLE IF EXISTS deposits_by_ready_default;
--DROP TABLE IF EXISTS deposits_for_matching_default;
  DROP TABLE IF EXISTS refunds_default;
  DROP TABLE IF EXISTS wire_out_default;
  DROP TABLE IF EXISTS aggregation_transient_default;
  DROP TABLE IF EXISTS aggregation_tracking_default;
  DROP TABLE IF EXISTS recoup_default;
  DROP TABLE IF EXISTS recoup_by_reserve_default;
  DROP TABLE IF EXISTS recoup_refresh_default;
  DROP TABLE IF EXISTS prewire_default;
  DROP TABLE IF EXISTS cs_nonce_locks_default;

  DROP TABLE IF EXISTS purse_requests_default;
  DROP TABLE IF EXISTS purse_decision_default;
  DROP TABLE IF EXISTS purse_merges_default;
  DROP TABLE IF EXISTS account_merges_default;
  DROP TABLE IF EXISTS purse_deposits_default;
  DROP TABLE IF EXISTS contracts_default;

  DROP TABLE IF EXISTS wad_out_entries_default;
  DROP TABLE IF EXISTS wads_in_default;
  DROP TABLE IF EXISTS wad_in_entries_default;

END
$$;

COMMENT ON FUNCTION drop_default_partitions
  IS 'Drop all default partitions once other partitions are attached.
      Might be needed in sharding too.';

CREATE OR REPLACE FUNCTION create_partitions(
    num_partitions INTEGER
)
RETURNS VOID
LANGUAGE plpgsql
AS $$
DECLARE
  modulus INTEGER;
BEGIN

  modulus := num_partitions;

  PERFORM detach_default_partitions();

  LOOP

    PERFORM create_hash_partition(
      'wire_targets'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_wire_targets_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'reserves'
      ,modulus
      ,num_partitions
    );

    PERFORM create_hash_partition(
      'reserves_in'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_reserves_in_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'reserves_close'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_reserves_close_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'reserves_out'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_reserves_out_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'reserves_out_by_reserve'
      ,modulus
      ,num_partitions
    );

    PERFORM create_hash_partition(
      'known_coins'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_known_coins_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'refresh_commitments'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_refresh_commitments_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'refresh_revealed_coins'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_refresh_revealed_coins_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'refresh_transfer_keys'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_refresh_transfer_keys_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'deposits'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_deposits_partition(num_partitions::varchar);

-- TODO: dynamically (!) creating/deleting deposits partitions:
--    create new partitions 'as needed', drop old ones once the aggregator has made
--    them empty; as 'new' deposits will always have deadlines in the future, this
--    would basically guarantee no conflict between aggregator and exchange service!
-- SEE also: https://www.cybertec-postgresql.com/en/automatic-partition-creation-in-postgresql/
-- (article is slightly wrong, as this works:)
--CREATE TABLE tab (
--  id bigint GENERATED ALWAYS AS IDENTITY,
--  ts timestamp NOT NULL,
--  data text
-- PARTITION BY LIST ((ts::date));
-- CREATE TABLE tab_def PARTITION OF tab DEFAULT;
-- BEGIN
-- CREATE TABLE tab_part2 (LIKE tab);
-- insert into tab_part2 (id,ts, data) values (5,'2022-03-21', 'foo');
-- alter table tab attach partition tab_part2 for values in ('2022-03-21');
-- commit;
-- Naturally, to ensure this is actually 100% conflict-free, we'd
-- need to create tables at the granularity of the wire/refund deadlines;
-- that is right now configurable via AGGREGATOR_SHIFT option.

-- FIXME: range partitioning
--    PERFORM create_range_partition(
--      'deposits_by_ready'
--      ,modulus
--      ,num_partitions
--    );
--
--    PERFORM create_range_partition(
--      'deposits_for_matching'
--      ,modulus
--      ,num_partitions
--    );

    PERFORM create_hash_partition(
      'refunds'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_refunds_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'wire_out'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_wire_out_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'aggregation_transient'
      ,modulus
      ,num_partitions
    );

    PERFORM create_hash_partition(
      'aggregation_tracking'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_aggregation_tracking_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'recoup'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_recoup_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'recoup_by_reserve'
      ,modulus
      ,num_partitions
    );

    PERFORM create_hash_partition(
      'recoup_refresh'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_recoup_refresh_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'prewire'
      ,modulus
      ,num_partitions
    );

    PERFORM create_hash_partition(
      'cs_nonce_locks'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_cs_nonce_locks_partition(num_partitions::varchar);


    PERFORM create_hash_partition(
      'close_requests'
      ,modulus
      ,num_partitions
    );

    PERFORM create_hash_partition(
      'reserves_open_requests'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_reserves_open_request_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'history_requests'
      ,modulus
      ,num_partitions
    );


    ---------------- P2P ----------------------

    PERFORM create_hash_partition(
      'purse_requests'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_purse_requests_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'purse_decision'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_purse_decision_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'purse_merges'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_purse_merges_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'account_merges'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_account_merges_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'contracts'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_contracts_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'purse_deposits'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_purse_deposits_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'wad_out_entries'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_wad_out_entries_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'wads_in'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_wads_in_partition(num_partitions::varchar);

    PERFORM create_hash_partition(
      'wad_in_entries'
      ,modulus
      ,num_partitions
    );
    PERFORM add_constraints_to_wad_in_entries_partition(num_partitions::varchar);

    num_partitions=num_partitions-1;
    EXIT WHEN num_partitions=0;

  END LOOP;

  PERFORM drop_default_partitions();

END
$$;