From de77c7d209a68ac1677757a9cde911225e7fd0eb Mon Sep 17 00:00:00 2001
From: Tyler Goodlet <jgbt@protonmail.com>
Date: Sat, 11 Jun 2022 16:18:05 -0400
Subject: [PATCH] Better doc strings and detailed comments

---
 piker/brokers/ib/broker.py | 23 +++++++++++++++++++++-
 piker/pp.py                | 40 ++++++++++++++++++++++++++------------
 2 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/piker/brokers/ib/broker.py b/piker/brokers/ib/broker.py
index 263e9868..c032870f 100644
--- a/piker/brokers/ib/broker.py
+++ b/piker/brokers/ib/broker.py
@@ -312,9 +312,14 @@ async def trades_dialogue(
             accounts.add(account)
 
         pp_msgs = {}
+
+        # process pp value reported from ib's system. we only use these
+        # to cross-check sizing since average pricing on their end uses
+        # the so called (bs) "FIFO" style which more or less results in
+        # a price that's not useful for traders who want to not lose
+        # money.. xb
         for client in aioclients.values():
             for pos in client.positions():
-
                 msg = pack_position(pos)
                 msg.account = accounts_def.inverse[msg.account]
                 pp_msgs[msg.symbol] = msg
@@ -322,8 +327,14 @@ async def trades_dialogue(
                 assert msg.account in accounts, (
                     f'Position for unknown account: {msg.account}')
 
+        # built-out piker pps from trade ledger, underneath using
+        # LIFO style breakeven pricing calcs.
         trades_by_account: dict = {}
         conf = get_config()
+
+        # retreive new trade executions from the last session
+        # and/or day's worth of trading and convert into trade
+        # records suitable for a local ledger file.
         for proxy in proxies.values():
             trade_entries = await proxy.trades()
             records = trades_to_records(
@@ -332,18 +343,27 @@ async def trades_dialogue(
             )
             trades_by_account.update(records)
 
+        # write recent session's trades to the user's (local) ledger
+        # file.
         for acctid, trades_by_id in trades_by_account.items():
             with config.open_trade_ledger('ib', acctid) as ledger:
                 ledger.update(trades_by_id)
 
+            # (incrementally) update the user's pps in mem and
+            # in the `pps.toml`.
             records = norm_trade_records(trades_by_id)
             active = update_pps_conf('ib', acctid, records)
+
+            # relay re-formatted pps as msgs to the ems.
             for fqsn, pp in active.items():
 
                 ibppmsg = pp_msgs[fqsn.rstrip('.ib')]
                 msg = BrokerdPosition(
                     broker='ib',
                     # account=acctid + '.ib',
+                    # XXX: ok so this is annoying, we're relaying
+                    # an account name with the backend suffix prefixed
+                    # but when reading accounts from ledgers 
                     account=ibppmsg.account,
                     # XXX: the `.ib` is stripped..?
                     symbol=ibppmsg.symbol,
@@ -614,6 +634,7 @@ def norm_trade_records(
 
 
 def trades_to_records(
+
     accounts: bidict,
     trade_entries: list[object],
     source_type: str = 'api',
diff --git a/piker/pp.py b/piker/pp.py
index b300e7d8..784192c8 100644
--- a/piker/pp.py
+++ b/piker/pp.py
@@ -21,7 +21,6 @@ that doesn't try to cuk most humans who prefer to not lose their moneys..
 
 '''
 from typing import (
-    Any,
     Optional,
     Union,
 )
@@ -153,14 +152,15 @@ def update_pps(
     Compile a set of positions from a trades ledger.
 
     '''
-
     pps: dict[str, Position] = pps or {}
 
     # lifo update all pps from records
     for r in records:
-        key = r.fqsn or r.symkey
+
         pp = pps.setdefault(
-            key,
+            r.fqsn or r.symkey,
+
+            # if no existing pp, allocate fresh one.
             Position(
                 Symbol.from_fqsn(
                     r.fqsn,
@@ -173,6 +173,11 @@ def update_pps(
         # don't do updates for ledger records we already have
         # included in the current pps state.
         if r.tid in pp.fills:
+            # NOTE: likely you'll see repeats of the same
+            # ``TradeRecord`` passed in here if/when you are restarting
+            # a ``brokerd.ib`` where the API will re-report trades from
+            # the current session, so we need to make sure we don't
+            # "double count" these in pp calculations.
             continue
 
         # lifo style average price calc
@@ -187,7 +192,16 @@ def _split_active(
     pps: dict[str, Position],
 
 ) -> tuple[dict, dict]:
+    '''
+    Split pps into those that are "active" (non-zero size) and "closed"
+    (zero size) and return in 2 dicts.
 
+    Returning the "closed" set is important for updating the pps state
+    in any ``pps.toml`` such that we remove entries which are no longer
+    part of any "VaR" set (well presumably, except of course your liquidity
+    asset could be full of "risk" XD ).
+
+    '''
     active = {}
     closed = {}
 
@@ -207,8 +221,14 @@ def load_pps_from_ledger(
     brokername: str,
     acctname: str,
 
-) -> dict[str, Any]:
+) -> tuple[dict, dict]:
+    '''
+    Open a ledger file by broker name and account and read in and
+    process any trade records into our normalized ``TradeRecord``
+    form and then pass these into the position processing routine
+    and deliver the two dict-sets of the active and closed pps.
 
+    '''
     with config.open_trade_ledger(
         brokername,
         acctname,
@@ -217,10 +237,8 @@ def load_pps_from_ledger(
 
     brokermod = get_brokermod(brokername)
     records = brokermod.norm_trade_records(ledger)
-    pps = update_pps(
-        brokername,
-        records,
-    )
+    pps = update_pps(brokername, records)
+
     return _split_active(pps)
 
 
@@ -282,14 +300,12 @@ def update_pps_conf(
     config.write(
         conf,
         'pps',
+        # TODO: make nested tables and/or inline tables work?
         # encoder=config.toml.Encoder(preserve=True),
     )
 
     return active
 
-    # from pprint import pprint
-    # pprint(conf)
-
 
 if __name__ == '__main__':
     update_pps_conf('ib', 'algopaper')