From ae001c3dd798813823b73cde72eb4310a8acfff6 Mon Sep 17 00:00:00 2001
From: Tyler Goodlet <jgbt@protonmail.com>
Date: Thu, 4 Aug 2022 15:42:31 -0400
Subject: [PATCH] Matchify the dark trigger loop

---
 piker/clearing/_ems.py | 97 ++++++++++++++++++++----------------------
 1 file changed, 46 insertions(+), 51 deletions(-)

diff --git a/piker/clearing/_ems.py b/piker/clearing/_ems.py
index 85a01c0f..4b89205c 100644
--- a/piker/clearing/_ems.py
+++ b/piker/clearing/_ems.py
@@ -174,10 +174,9 @@ async def clear_dark_triggers(
                 )
             ):
                 price = tick.get('price')
-                ttype = tick['type']
-
                 # update to keep new cmds informed
                 book.lasts[sym] = price
+                ttype = tick['type']
 
                 for oid, (
                     pred,
@@ -200,58 +199,54 @@ async def clear_dark_triggers(
                         # majority of iterations will be non-matches
                         continue
 
-                    action: str = cmd['action']
-                    symbol: str = cmd['symbol']
-                    bfqsn: str = symbol.replace(f'.{broker}', '')
+                    match cmd:
+                        # alert: nothing to do but relay a status
+                        # back to the requesting ems client
+                        case {
+                            'action': 'alert',
+                        }:
+                            resp = 'alert_triggered'
 
-                    if action == 'alert':
-                        # nothing to do but relay a status
-                        # message back to the requesting ems client
-                        resp = 'alert_triggered'
+                        # executable order submission
+                        case {
+                            'action': action,
+                            'symbol': symbol,
+                            'account': account,
+                            'size': size,
+                        }:
+                            bfqsn: str = symbol.replace(f'.{broker}', '')
+                            submit_price = price + abs_diff_away
+                            resp = 'dark_triggered'  # hidden on client-side
 
-                    else:  # executable order submission
+                            log.info(
+                                f'Dark order triggered for price {price}\n'
+                                f'Submitting order @ price {submit_price}')
 
-                        # submit_price = price + price*percent_away
-                        submit_price = price + abs_diff_away
+                            live_req = BrokerdOrder(
+                                action=action,
+                                oid=oid,
+                                account=account,
+                                time_ns=time.time_ns(),
+                                symbol=bfqsn,
+                                price=submit_price,
+                                size=size,
+                            )
+                            await brokerd_orders_stream.send(live_req)
 
-                        log.info(
-                            f'Dark order triggered for price {price}\n'
-                            f'Submitting order @ price {submit_price}')
+                            # mark this entry as having sent an order
+                            # request.  the entry will be replaced once the
+                            # target broker replies back with
+                            # a ``BrokerdOrderAck`` msg including the
+                            # allocated unique ``BrokerdOrderAck.reqid`` key
+                            # generated by the broker's own systems.
+                            book._ems_entries[oid] = live_req
 
-                        msg = BrokerdOrder(
-                            action=cmd['action'],
-                            oid=oid,
-                            account=cmd['account'],
-                            time_ns=time.time_ns(),
+                        case _:
+                            raise ValueError(f'Invalid dark book entry: {cmd}')
 
-                            # this **creates** new order request for the
-                            # underlying broker so we set a "broker
-                            # request id" (``reqid`` kwarg) to ``None``
-                            # so that the broker client knows that we
-                            # aren't trying to modify an existing
-                            # order-request and instead create a new one.
-                            reqid=None,
-
-                            symbol=bfqsn,
-                            price=submit_price,
-                            size=cmd['size'],
-                        )
-                        await brokerd_orders_stream.send(msg)
-
-                        # mark this entry as having sent an order
-                        # request.  the entry will be replaced once the
-                        # target broker replies back with
-                        # a ``BrokerdOrderAck`` msg including the
-                        # allocated unique ``BrokerdOrderAck.reqid`` key
-                        # generated by the broker's own systems.
-                        book._ems_entries[oid] = msg
-
-                        # our internal status value for client-side
-                        # triggered "dark orders"
-                        resp = 'dark_triggered'
-
-                    msg = Status(
-                        oid=oid,  # ems order id
+                    # fallthrough logic
+                    resp = Status(
+                        oid=oid,  # ems dialog id
                         time_ns=time.time_ns(),
                         resp=resp,
                         trigger_price=price,
@@ -266,13 +261,14 @@ async def clear_dark_triggers(
                             f'pred for {oid} was already removed!?'
                         )
 
+                    # send response to client-side
                     try:
-                        await ems_client_order_stream.send(msg)
+                        await ems_client_order_stream.send(resp)
                     except (
                         trio.ClosedResourceError,
                     ):
                         log.warning(
-                            f'client {ems_client_order_stream} stream is broke'
+                            f'{ems_client_order_stream} stream broke?'
                         )
                         break
 
@@ -684,7 +680,6 @@ async def translate_and_relay_brokerd_events(
                 # about.  In most default situations, with composed orders
                 # (ex.  brackets), most brokers seem to use a oca policy.
 
-
             # BrokerdStatus
             case {
                 'name': 'status',