-implement reserve history DB logic

1 files changed, 56 insertions, 2 deletions

diff --git a/src/exchangedb/exchange-0001-part.sql b/src/exchangedb/exchange-0001-part.sql
index d8855b011..a47a2aede 100644
--- a/src/exchangedb/exchange-0001-part.sql
+++ b/src/exchangedb/exchange-0001-part.sql
@@ -3429,11 +3429,65 @@ CREATE OR REPLACE FUNCTION exchange_do_history_request(
   IN in_history_fee_val INT8,
   IN in_history_fee_frac INT4,
   OUT out_balance_ok BOOLEAN,
-  OUT out_conflict BOOLEAN)
+  OUT out_idempotent BOOLEAN)
 LANGUAGE plpgsql
 AS $$
 BEGIN
-  -- FIXME
+
+  -- Insert and check for idempotency.
+  INSERT INTO history_requests
+  (reserve_pub
+  ,request_timestamp
+  ,reserve_sig
+  ,history_fee_val
+  ,history_fee_frac)
+  VALUES
+  (in_reserve_pub
+  ,in_request_timestamp
+  ,in_reserve_sig
+  ,in_history_fee_val
+  ,in_history_fee_frac)
+  ON CONFLICT DO NOTHING;
+
+  IF NOT FOUND
+  THEN
+    out_balance_ok=TRUE;
+    out_conflict=TRUE;
+    RETURN;
+  END IF;
+
+  out_conflict=FALSE;
+
+  -- Update reserve balance.
+  UPDATE reserves
+   SET
+    current_balance_frac=current_balance_frac-in_history_fee_frac
+       + CASE
+         WHEN reserve_frac < in_history_fee_frac
+         THEN 100000000
+         ELSE 0
+         END,
+    current_balance_val=current_balance_val-in_history_fee_val
+       - CASE
+         WHEN current_balance_frac < in_history_fee_frac
+         THEN 1
+         ELSE 0
+         END
+  WHERE
+    reserve_pub=in_reserve_pub
+    AND ( (current_balance_val > in_history_fee_val) OR
+          ( (current_balance_frac >= in_history_fee_frac) AND
+            (current_balance_val >= in_history_fee_val) ) );
+
+  IF NOT FOUND
+  THEN
+    -- Either reserve does not exist, or balance insufficient.
+    -- Both we treat the same here as balance insufficient.
+    out_balance_ok=FALSE;
+    RETURN;
+  END IF;
+
+  out_balance_ok=TRUE;
 END $$;