Support monitor linked symbol selection

This allows for using a monitor to select the current option chain
symbol!

The deats:
- start a bg task which streams the monitor selected symbol
- dynamically repopulate expiry buttons on a newly published symbol
- move static widget creation into a chain method to avoid multiple
  quotes requests at startup
- rename a bunch of methods

piker/ui/option_chain.py

@@ -141,11 +141,7 @@ class ExpiryButton(Cell):
 
         log.info(f"Clicked {self}")
         self.click_toggle = True
-        if self.chain.sub[1] == self.key:
-            log.info(f"Clicked {self} is already selected")
-            return
-        log.info(f"Subscribing for {self.chain.sub}")
-        self.chain.start_displaying(self.chain.sub[0], self.key)
+        self.chain.start_displaying(self.chain.symbol, self.key)
 
 
 class DataFeed(object):
@@ -194,14 +190,32 @@ class DataFeed(object):
 
                 self.quote_gen = quote_gen
                 self.first_quotes = quotes
-                # self.records = records
-                # self.displayables = displayables
                 return quote_gen, quotes
             except Exception:
                 if self.quote_gen:
                     await self.quote_gen.aclose()
+                    self.quote_gen = None
                 raise
 
+    def format_quotes(self, quotes):
+        records, displayables = zip(*[
+            self.brokermod.format_option_quote(quote, {})
+            for quote in quotes.values()
+        ])
+        return records, displayables
+
+
+@asynccontextmanager
+async def find_local_monitor():
+    """Establish a portal to a local monitor for triggering
+    symbol changes.
+    """
+    async with tractor.find_actor('monitor') as portal:
+        if not portal:
+            log.warn(
+                "No monitor app could be found, no symbol link established..")
+        yield portal
+
 
 class OptionChain(object):
     """A real-time options chain UI.
@@ -210,14 +224,13 @@ class OptionChain(object):
 
     def __init__(
         self,
-        symbol: str,
-        expiry: str,
         widgets: dict,
         bidasks: Dict[str, List[str]],
         feed: DataFeed,
         rate: int,
     ):
-        self.sub = (symbol, expiry)
+        self.symbol = None
+        self.expiry = None
         self.widgets = widgets
         self.bidasks = bidasks
         self._strikes2rows = {}
@@ -230,21 +243,35 @@ class OptionChain(object):
         # right now it's only needed for the UI uupdate loop to cancel itself
         self._first_quotes = None
         self._last_expiry = None
+        # flag to determine if one-time widgets have been generated
+        self._static_widgets_initialized = False
+
+    async def _rx_symbols(self):
+        async with find_local_monitor() as portal:
+            if not portal:
+                log.warn("No local monitor could be found")
+                return
+            async for symbol in await portal.run(
+                'piker.ui.monitor',
+                'stream_symbol_selection',
+            ):
+                log.info(f"Changing symbol subscriptions to {symbol}")
+                self.start_displaying(symbol, self.expiry)
 
     @asynccontextmanager
-    async def open_update_scope(self):
+    async def open_rt_display(self, nursery, symbol, expiry=None):
         """Open an internal update task scope required to allow
         for dynamic real-time operation.
         """
-        # assign us to each expiry button
-        for key, button in (
-            self.widgets['expiry_buttons']._cell_widgets.items()
-        ):
-            button.chain = self
-
+        self._parent_nursery = nursery
         async with trio.open_nursery() as n:
             self._nursery = n
-            n.start_soon(self._start_displaying, *self.sub)
+            # fill out and start updatingn strike table
+            n.start_soon(
+                partial(self._start_displaying, symbol, expiry=expiry)
+            )
+            # listen for undlerlying symbol changes from a local monitor app
+            n.start_soon(self._rx_symbols)
             yield self
             n.cancel_scope.cancel()
 
@@ -259,9 +286,6 @@ class OptionChain(object):
         table.clear()
         self._strikes2rows.clear()
 
-    def clear_expiries(self):
-        pass
-
     def render_rows(self, records, displayables):
         """Render all strike rows in the internal table.
         """
@@ -295,7 +319,7 @@ class OptionChain(object):
 
         log.debug("Finished rendering rows!")
 
-    async def _start_displaying(self, symbol, expiry):
+    async def _start_displaying(self, symbol, expiry=None):
         """Main routine to start displaying the real time updated strike
         table.
 
@@ -303,10 +327,34 @@ class OptionChain(object):
         (eg. when clicking a new expiry button) spin up a new subscription,
         populate the table and start updating it.
         """
-        # set window title
-        self.widgets['window'].set_title(
-            self._title.format(symbol=symbol)
-        )
+        # redraw any symbol specific UI components
+        if self.symbol != symbol or expiry is None:
+            # set window title
+            self.widgets['window'].set_title(
+                self._title.format(symbol=symbol)
+            )
+
+            # retreive all contracts to populate expiry row
+            all_contracts = await contracts(self.feed.brokermod, symbol)
+            # start streaming soonest contract by default if not provided
+            expiry = next(iter(all_contracts)).expiry if not expiry else expiry
+
+            # TODO: figure out how to compact these buttons
+            expiries = {
+                key.expiry: key.expiry[:key.expiry.find('T')]
+                for key in all_contracts
+            }
+            expiry_row = self.widgets['expiry_row']
+            expiry_row.clear_widgets()
+
+            for expiry, justdate in expiries.items():
+                button = ExpiryButton(text=str(justdate), key=expiry)
+                # assign us to each expiry button
+                button.chain = self
+                expiry_row.add_widget(button)
+
+        if self.widgets.get('table'):
+            self.clear_strikes()
 
         if self._update_cs:
             log.warn("Cancelling existing update task")
@@ -316,24 +364,23 @@ class OptionChain(object):
         if self._quote_gen:
             await self._quote_gen.aclose()
 
-        self.clear_strikes()
-
         if self._nursery is None:
             raise RuntimeError(
                 "You must call open this chain's update scope first!")
 
-        n = self._nursery
         log.debug(f"Waiting on first_quotes for {symbol}:{expiry}")
         self._quote_gen, first_quotes = await self.feed.open_stream(
             [(symbol, expiry)]
         )
         log.debug(f"Got first_quotes for {symbol}:{expiry}")
+        records, displayables = self.feed.format_quotes(first_quotes)
 
-        # redraw the UI
-        records, displayables = zip(*[
-            self.feed.brokermod.format_option_quote(quote, {})
-            for quote in first_quotes.values()
-        ])
+        # draw static widgets only once
+        if self._static_widgets_initialized is False:
+            self._init_static_widgets(displayables)
+            self._static_widgets_initialized = True
+
+        n = self._nursery
         self.render_rows(records, displayables)
 
         with trio.open_cancel_scope() as cs:
@@ -349,10 +396,78 @@ class OptionChain(object):
                     first_quotes=first_quotes,
                 )
             )
+        self.symbol, self.expiry = symbol, expiry
 
     def start_displaying(self, symbol, expiry):
-        self.sub = (symbol, expiry)
-        self._nursery.start_soon(self._start_displaying, symbol, expiry)
+        if self.symbol == symbol and self.expiry == expiry:
+            log.info(f"Clicked {symbol}:{expiry} is already selected")
+            return
+
+        log.info(f"Subscribing for {symbol}:{expiry}")
+        self._nursery.start_soon(
+            partial(self._start_displaying, symbol, expiry=expiry)
+        )
+
+    def _init_static_widgets(self, displayables):
+        assert self._static_widgets_initialized is False
+        container = self.widgets['container']
+
+        # calls / puts header
+        type_header = BoxLayout(
+            orientation='horizontal',
+            size_hint=(1, 1/30.),
+        )
+        calls = Label(text='calls', font_size='20')
+        puts = Label(text='puts', font_size='20')
+        type_header.add_widget(calls)
+        type_header.add_widget(puts)
+        container.add_widget(type_header)
+
+        # figure out header fields for each table based on quote keys
+        headers = displayables[0].keys()
+        header_row = StrikeRow(strike='strike', size_hint=(1, None))
+        header_record = {key: key for key in headers}
+        header_record['contract_type'] = 'put'
+        header_row.append_sub_row(
+            header_record,
+            header_record,
+            headers=headers,
+            bidasks=self.bidasks,
+            is_header=True,
+            size_hint=(1, None),
+        )
+        header_record['contract_type'] = 'call'
+        header_row.append_sub_row(
+            header_record,
+            header_record,
+            headers=headers,
+            bidasks=self.bidasks,
+            is_header=True,
+            size_hint=(1, None),
+        )
+        container.add_widget(header_row)
+
+        # build out chain tables
+        table = TickerTable(
+            sort_key='strike',
+            cols=1,
+            size_hint=(1, None),
+        )
+        header_row.table = table
+        table.bind(minimum_height=table.setter('height'))
+        pager = PagerView(
+            container=container,
+            contained=table,
+            nursery=self._nursery
+        )
+        container.add_widget(pager)
+
+        self.widgets.update({
+            'table': table,
+            'type_header': type_header,
+            'table': table,
+            'pager': pager,
+        })
 
 
 async def new_chain_ui(
@@ -364,33 +479,6 @@ async def new_chain_ui(
 ) -> None:
     """Create and return a new option chain UI.
     """
-    # retreive all contracts just because we need a default when the
-    # UI starts up
-    all_contracts = await contracts(brokermod, symbol)
-    # start streaming soonest contract by default
-    expiry = next(iter(all_contracts)).expiry
-
-    widgets = {}
-
-    # define bid-ask "stacked" cells
-    # (TODO: needs some rethinking and renaming for sure)
-    bidasks = brokermod._option_bidasks
-
-    feed = DataFeed(portal, brokermod)
-    chain = OptionChain(
-        symbol,
-        expiry,
-        widgets,
-        bidasks,
-        feed,
-        rate=rate,
-    )
-    quote_gen, first_quotes = await chain.feed.open_stream([chain.sub])
-    records, displayables = zip(*[
-        brokermod.format_option_quote(quote, {})
-        for quote in first_quotes.values()
-    ])
-
     # use `monitor` styling for now
     from .monitor import _kv
     Builder.load_string(_kv)
@@ -398,78 +486,30 @@ async def new_chain_ui(
     # the master container
     container = BoxLayout(orientation='vertical', spacing=0)
 
-    # TODO: figure out how to compact these buttons
-    expiries = {
-        key.expiry: key.expiry[:key.expiry.find('T')]
-        for key in all_contracts
-    }
-    expiry_buttons = Row(
-        record=expiries,
-        headers=expiries,
-        is_header=True,
-        size_hint=(1, None),
-        cell_type=ExpiryButton,
-    )
-    # top row of expiry buttons
-    container.add_widget(expiry_buttons)
-
-    # denote calls vs. puts side of table
-    type_header = BoxLayout(
+    # expiry buttons row (populated later once contracts are retreived)
+    expiry_row = BoxLayout(
         orientation='horizontal',
-        size_hint=(1, 1/28.),
+        size_hint=(1, None),
     )
-    calls = Label(text='calls', font_size='20')
-    puts = Label(text='puts', font_size='20')
-    type_header.add_widget(calls)
-    type_header.add_widget(puts)
-    container.add_widget(type_header)
+    container.add_widget(expiry_row)
 
-    # figure out header fields for each table based on quote keys
-    headers = displayables[0].keys()
-    header_row = StrikeRow(strike='strike', size_hint=(1, None))
-    header_record = {key: key for key in headers}
-    header_record['contract_type'] = 'put'
-    header_row.append_sub_row(
-        header_record,
-        header_record,
-        headers=headers,
-        bidasks=bidasks,
-        is_header=True,
-        size_hint=(1, None),
-    )
-    header_record['contract_type'] = 'call'
-    header_row.append_sub_row(
-        header_record,
-        header_record,
-        headers=headers,
-        bidasks=bidasks,
-        is_header=True,
-        size_hint=(1, None),
-    )
-    container.add_widget(header_row)
-
-    # build out chain tables
-    table = TickerTable(
-        sort_key='strike',
-        cols=1,
-        size_hint=(1, None),
-    )
-    header_row.table = table
-    table.bind(minimum_height=table.setter('height'))
-    pager = PagerView(
-        container=container,
-        contained=table,
-        nursery=nursery
-    )
-    container.add_widget(pager)
-    widgets.update({
+    widgets = {
         'window': Window,
         'root': container,
         'container': container,
-        'table': table,
-        'expiry_buttons': expiry_buttons,
-        'pager': pager,
-    })
+        'expiry_row': expiry_row,
+    }
+    # define bid-ask "stacked" cells
+    # (TODO: needs some rethinking and renaming for sure)
+    bidasks = brokermod._option_bidasks
+
+    feed = DataFeed(portal, brokermod)
+    chain = OptionChain(
+        widgets,
+        bidasks,
+        feed,
+        rate=rate,
+    )
     return chain
 
 
@@ -493,9 +533,9 @@ async def _async_main(
             nursery,
             rate=rate,
         )
-        async with chain.open_update_scope():
+        async with chain.open_rt_display(nursery, symbol):
             try:
-                # Trio-kivy entry point.
+                # trio-kivy entry point.
                 await async_runTouchApp(chain.widgets['root'])  # run kivy
             finally:
                 # cancel GUI update task