LP#800478 repair logic error in acq fund transfer
authorBill Erickson <berick@esilibrary.com>
Tue, 25 Feb 2014 17:23:13 +0000 (12:23 -0500)
committerMike Rylander <mrylander@gmail.com>
Mon, 25 Aug 2014 17:39:03 +0000 (13:39 -0400)
The source data for the amount applied to each allocation and transfer
(in certain circumstances) was incorrect.

The transfer amount should not be the total amount allocated from the
source to the fund, but instead the amount of the funding source credit
in cases where we have to pull money from multiple funding source
credits.

Signed-off-by: Bill Erickson <berick@esilibrary.com>
Signed-off-by: Liam Whalen <liam.whalen@bc.libraries.coop>
Signed-off-by: Mike Rylander <mrylander@gmail.com>
Open-ILS/src/sql/Pg/200.schema.acq.sql
Open-ILS/src/sql/Pg/upgrade/XXXX.schema.acq_fund_transfer.sql [new file with mode: 0644]

index abde889..91204a4 100644 (file)
@@ -1456,7 +1456,7 @@ BEGIN
                        -- amount directly instead of applying a currency translation
                        -- and thereby inviting round-off errors.
                        --
                        -- amount directly instead of applying a currency translation
                        -- and thereby inviting round-off errors.
                        --
-                       source_deduction := - orig_allocated_amt;
+                       source_deduction := - curr_old_amt;
                ELSE 
                        source_deduction := trunc(
                                ( - curr_old_amt ) *
                ELSE 
                        source_deduction := trunc(
                                ( - curr_old_amt ) *
@@ -1513,7 +1513,7 @@ BEGIN
                                -- amount directly instead of applying a currency translation and
                                -- thereby inviting round-off errors.
                                --
                                -- amount directly instead of applying a currency translation and
                                -- thereby inviting round-off errors.
                                --
-                               source_addition := orig_allocated_amt;
+                               source_addition := curr_new_amt;
                        ELSIF source.currency_type = old_fund_currency THEN
                                --
                                -- In this case we don't need a round trip currency translation,
                        ELSIF source.currency_type = old_fund_currency THEN
                                --
                                -- In this case we don't need a round trip currency translation,
diff --git a/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.acq_fund_transfer.sql b/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.acq_fund_transfer.sql
new file mode 100644 (file)
index 0000000..66727d4
--- /dev/null
@@ -0,0 +1,361 @@
+BEGIN;
+
+CREATE OR REPLACE FUNCTION acq.transfer_fund(
+       old_fund   IN INT,
+       old_amount IN NUMERIC,     -- in currency of old fund
+       new_fund   IN INT,
+       new_amount IN NUMERIC,     -- in currency of new fund
+       user_id    IN INT,
+       xfer_note  IN TEXT         -- to be recorded in acq.fund_transfer
+       -- ,funding_source_in IN INT  -- if user wants to specify a funding source (see notes)
+) RETURNS VOID AS $$
+/* -------------------------------------------------------------------------------
+
+Function to transfer money from one fund to another.
+
+A transfer is represented as a pair of entries in acq.fund_allocation, with a
+negative amount for the old (losing) fund and a positive amount for the new
+(gaining) fund.  In some cases there may be more than one such pair of entries
+in order to pull the money from different funding sources, or more specifically
+from different funding source credits.  For each such pair there is also an
+entry in acq.fund_transfer.
+
+Since funding_source is a non-nullable column in acq.fund_allocation, we must
+choose a funding source for the transferred money to come from.  This choice
+must meet two constraints, so far as possible:
+
+1. The amount transferred from a given funding source must not exceed the
+amount allocated to the old fund by the funding source.  To that end we
+compare the amount being transferred to the amount allocated.
+
+2. We shouldn't transfer money that has already been spent or encumbered, as
+defined by the funding attribution process.  We attribute expenses to the
+oldest funding source credits first.  In order to avoid transferring that
+attributed money, we reverse the priority, transferring from the newest funding
+source credits first.  There can be no guarantee that this approach will
+avoid overcommitting a fund, but no other approach can do any better.
+
+In this context the age of a funding source credit is defined by the
+deadline_date for credits with deadline_dates, and by the effective_date for
+credits without deadline_dates, with the proviso that credits with deadline_dates
+are all considered "older" than those without.
+
+----------
+
+In the signature for this function, there is one last parameter commented out,
+named "funding_source_in".  Correspondingly, the WHERE clause for the query
+driving the main loop has an OR clause commented out, which references the
+funding_source_in parameter.
+
+If these lines are uncommented, this function will allow the user optionally to
+restrict a fund transfer to a specified funding source.  If the source
+parameter is left NULL, then there will be no such restriction.
+
+------------------------------------------------------------------------------- */ 
+DECLARE
+       same_currency      BOOLEAN;
+       currency_ratio     NUMERIC;
+       old_fund_currency  TEXT;
+       old_remaining      NUMERIC;  -- in currency of old fund
+       new_fund_currency  TEXT;
+       new_fund_active    BOOLEAN;
+       new_remaining      NUMERIC;  -- in currency of new fund
+       curr_old_amt       NUMERIC;  -- in currency of old fund
+       curr_new_amt       NUMERIC;  -- in currency of new fund
+       source_addition    NUMERIC;  -- in currency of funding source
+       source_deduction   NUMERIC;  -- in currency of funding source
+       orig_allocated_amt NUMERIC;  -- in currency of funding source
+       allocated_amt      NUMERIC;  -- in currency of fund
+       source             RECORD;
+BEGIN
+       --
+       -- Sanity checks
+       --
+       IF old_fund IS NULL THEN
+               RAISE EXCEPTION 'acq.transfer_fund: old fund id is NULL';
+       END IF;
+       --
+       IF old_amount IS NULL THEN
+               RAISE EXCEPTION 'acq.transfer_fund: amount to transfer is NULL';
+       END IF;
+       --
+       -- The new fund and its amount must be both NULL or both not NULL.
+       --
+       IF new_fund IS NOT NULL AND new_amount IS NULL THEN
+               RAISE EXCEPTION 'acq.transfer_fund: amount to transfer to receiving fund is NULL';
+       END IF;
+       --
+       IF new_fund IS NULL AND new_amount IS NOT NULL THEN
+               RAISE EXCEPTION 'acq.transfer_fund: receiving fund is NULL, its amount is not NULL';
+       END IF;
+       --
+       IF user_id IS NULL THEN
+               RAISE EXCEPTION 'acq.transfer_fund: user id is NULL';
+       END IF;
+       --
+       -- Initialize the amounts to be transferred, each denominated
+       -- in the currency of its respective fund.  They will be
+       -- reduced on each iteration of the loop.
+       --
+       old_remaining := old_amount;
+       new_remaining := new_amount;
+       --
+       -- RAISE NOTICE 'Transferring % in fund % to % in fund %',
+       --      old_amount, old_fund, new_amount, new_fund;
+       --
+       -- Get the currency types of the old and new funds.
+       --
+       SELECT
+               currency_type
+       INTO
+               old_fund_currency
+       FROM
+               acq.fund
+       WHERE
+               id = old_fund;
+       --
+       IF old_fund_currency IS NULL THEN
+               RAISE EXCEPTION 'acq.transfer_fund: old fund id % is not defined', old_fund;
+       END IF;
+       --
+       IF new_fund IS NOT NULL THEN
+               SELECT
+                       currency_type,
+                       active
+               INTO
+                       new_fund_currency,
+                       new_fund_active
+               FROM
+                       acq.fund
+               WHERE
+                       id = new_fund;
+               --
+               IF new_fund_currency IS NULL THEN
+                       RAISE EXCEPTION 'acq.transfer_fund: new fund id % is not defined', new_fund;
+               ELSIF NOT new_fund_active THEN
+                       --
+                       -- No point in putting money into a fund from whence you can't spend it
+                       --
+                       RAISE EXCEPTION 'acq.transfer_fund: new fund id % is inactive', new_fund;
+               END IF;
+               --
+               IF new_amount = old_amount THEN
+                       same_currency := true;
+                       currency_ratio := 1;
+               ELSE
+                       --
+                       -- We'll have to translate currency between funds.  We presume that
+                       -- the calling code has already applied an appropriate exchange rate,
+                       -- so we'll apply the same conversion to each sub-transfer.
+                       --
+                       same_currency := false;
+                       currency_ratio := new_amount / old_amount;
+               END IF;
+       END IF;
+       --
+       -- Identify the funding source(s) from which we want to transfer the money.
+       -- The principle is that we want to transfer the newest money first, because
+       -- we spend the oldest money first.  The priority for spending is defined
+       -- by a sort of the view acq.ordered_funding_source_credit.
+       --
+       FOR source in
+               SELECT
+                       ofsc.id,
+                       ofsc.funding_source,
+                       ofsc.amount,
+                       ofsc.amount * acq.exchange_ratio( fs.currency_type, old_fund_currency )
+                               AS converted_amt,
+                       fs.currency_type
+               FROM
+                       acq.ordered_funding_source_credit AS ofsc,
+                       acq.funding_source fs
+               WHERE
+                       ofsc.funding_source = fs.id
+                       and ofsc.funding_source IN
+                       (
+                               SELECT funding_source
+                               FROM acq.fund_allocation
+                               WHERE fund = old_fund
+                       )
+                       -- and
+                       -- (
+                       --      ofsc.funding_source = funding_source_in
+                       --      OR funding_source_in IS NULL
+                       -- )
+               ORDER BY
+                       ofsc.sort_priority desc,
+                       ofsc.sort_date desc,
+                       ofsc.id desc
+       LOOP
+               --
+               -- Determine how much money the old fund got from this funding source,
+               -- denominated in the currency types of the source and of the fund.
+               -- This result may reflect transfers from previous iterations.
+               --
+               SELECT
+                       COALESCE( sum( amount ), 0 ),
+                       COALESCE( sum( amount )
+                               * acq.exchange_ratio( source.currency_type, old_fund_currency ), 0 )
+               INTO
+                       orig_allocated_amt,     -- in currency of the source
+                       allocated_amt           -- in currency of the old fund
+               FROM
+                       acq.fund_allocation
+               WHERE
+                       fund = old_fund
+                       and funding_source = source.funding_source;
+               --      
+               -- Determine how much to transfer from this credit, in the currency
+               -- of the fund.   Begin with the amount remaining to be attributed:
+               --
+               curr_old_amt := old_remaining;
+               --
+               -- Can't attribute more than was allocated from the fund:
+               --
+               IF curr_old_amt > allocated_amt THEN
+                       curr_old_amt := allocated_amt;
+               END IF;
+               --
+               -- Can't attribute more than the amount of the current credit:
+               --
+               IF curr_old_amt > source.converted_amt THEN
+                       curr_old_amt := source.converted_amt;
+               END IF;
+               --
+               curr_old_amt := trunc( curr_old_amt, 2 );
+               --
+               old_remaining := old_remaining - curr_old_amt;
+               --
+               -- Determine the amount to be deducted, if any,
+               -- from the old allocation.
+               --
+               IF old_remaining > 0 THEN
+                       --
+                       -- In this case we're using the whole allocation, so use that
+                       -- amount directly instead of applying a currency translation
+                       -- and thereby inviting round-off errors.
+                       --
+                       source_deduction := - curr_old_amt;
+               ELSE 
+                       source_deduction := trunc(
+                               ( - curr_old_amt ) *
+                                       acq.exchange_ratio( old_fund_currency, source.currency_type ),
+                               2 );
+               END IF;
+               --
+               IF source_deduction <> 0 THEN
+                       --
+                       -- Insert negative allocation for old fund in fund_allocation,
+                       -- converted into the currency of the funding source
+                       --
+                       INSERT INTO acq.fund_allocation (
+                               funding_source,
+                               fund,
+                               amount,
+                               allocator,
+                               note
+                       ) VALUES (
+                               source.funding_source,
+                               old_fund,
+                               source_deduction,
+                               user_id,
+                               'Transfer to fund ' || new_fund
+                       );
+               END IF;
+               --
+               IF new_fund IS NOT NULL THEN
+                       --
+                       -- Determine how much to add to the new fund, in
+                       -- its currency, and how much remains to be added:
+                       --
+                       IF same_currency THEN
+                               curr_new_amt := curr_old_amt;
+                       ELSE
+                               IF old_remaining = 0 THEN
+                                       --
+                                       -- This is the last iteration, so nothing should be left
+                                       --
+                                       curr_new_amt := new_remaining;
+                                       new_remaining := 0;
+                               ELSE
+                                       curr_new_amt := trunc( curr_old_amt * currency_ratio, 2 );
+                                       new_remaining := new_remaining - curr_new_amt;
+                               END IF;
+                       END IF;
+                       --
+                       -- Determine how much to add, if any,
+                       -- to the new fund's allocation.
+                       --
+                       IF old_remaining > 0 THEN
+                               --
+                               -- In this case we're using the whole allocation, so use that amount
+                               -- amount directly instead of applying a currency translation and
+                               -- thereby inviting round-off errors.
+                               --
+                               source_addition := curr_new_amt;
+                       ELSIF source.currency_type = old_fund_currency THEN
+                               --
+                               -- In this case we don't need a round trip currency translation,
+                               -- thereby inviting round-off errors:
+                               --
+                               source_addition := curr_old_amt;
+                       ELSE 
+                               source_addition := trunc(
+                                       curr_new_amt *
+                                               acq.exchange_ratio( new_fund_currency, source.currency_type ),
+                                       2 );
+                       END IF;
+                       --
+                       IF source_addition <> 0 THEN
+                               --
+                               -- Insert positive allocation for new fund in fund_allocation,
+                               -- converted to the currency of the founding source
+                               --
+                               INSERT INTO acq.fund_allocation (
+                                       funding_source,
+                                       fund,
+                                       amount,
+                                       allocator,
+                                       note
+                               ) VALUES (
+                                       source.funding_source,
+                                       new_fund,
+                                       source_addition,
+                                       user_id,
+                                       'Transfer from fund ' || old_fund
+                               );
+                       END IF;
+               END IF;
+               --
+               IF trunc( curr_old_amt, 2 ) <> 0
+               OR trunc( curr_new_amt, 2 ) <> 0 THEN
+                       --
+                       -- Insert row in fund_transfer, using amounts in the currency of the funds
+                       --
+                       INSERT INTO acq.fund_transfer (
+                               src_fund,
+                               src_amount,
+                               dest_fund,
+                               dest_amount,
+                               transfer_user,
+                               note,
+                               funding_source_credit
+                       ) VALUES (
+                               old_fund,
+                               trunc( curr_old_amt, 2 ),
+                               new_fund,
+                               trunc( curr_new_amt, 2 ),
+                               user_id,
+                               xfer_note,
+                               source.id
+                       );
+               END IF;
+               --
+               if old_remaining <= 0 THEN
+                       EXIT;                   -- Nothing more to be transferred
+               END IF;
+       END LOOP;
+END;
+$$ LANGUAGE plpgsql;
+
+COMMIT;