sample2, show grid cost

sample2.py

@@ -14,7 +14,7 @@ API_TOKEN = "d0vA6CsrY69N3JAOGtuZMEb9QpbJWPcoxhxRyBXZn8SIisB3weLKjMZwQRo8c2k9BRD
 w42_state = panel.rx(None)
 
 # TODO: must pass token, otherwise subscription should fail
-attach_w42_state(rx_var=w42_state, system_id=SYSTEM_ID)
+attach_w42_state(rx_var=w42_state, system_id=SYSTEM_ID, token=API_TOKEN)
 
 state_as_text = panel.bind(lambda s: f"W42 State:\n\n```\n{json.dumps(s, indent=2)}\n```\n\nReplace this with some awesome visuals", w42_state)
 
@@ -39,6 +39,9 @@ class Configuration(BaseModel):
     location_lat: float = 0.0
     location_lon: float = 0.0
 
+class Stats(BaseModel):
+    grid_cost_total: float = 0.0
+
 class SystemState(BaseModel):
     load_forecast: LoadForecast = LoadForecast()
     pv_forecast: PvForecast = PvForecast()
@@ -47,6 +50,7 @@ class SystemState(BaseModel):
     buy_prices: list[float] = []
     output: Output | None = None
     config: Configuration = Configuration()
+    stats: Stats = Stats()
 
 state: SystemState = panel.rx(lambda s: SystemState.model_validate(s) if s else SystemState())(w42_state)
 
@@ -178,11 +182,16 @@ async def process_config_change(_btn):
 config_submit = panel.widgets.Button(name="Update Configuration", button_type="primary", width=200)
 config_submit.on_click(process_config_change)
 
+def summary(state: SystemState) -> str:
+    total_cost = state.stats.grid_cost_total
+    return f"## Summary\n\nGrid {'cost' if total_cost > 0 else 'income'} total: {abs(state.stats.grid_cost_total):.2f} ZAR"
+
 _ = panel.template.FastListTemplate(
     title="Sample W42 App",
     sidebar=[panel.pane.Markdown("This is a sample sidebar.")],
     main=[
         # panel.pane.Markdown(state_as_text, sizing_mode='stretch_width'),
+        panel.pane.Markdown(panel.rx(summary)(state), sizing_mode='stretch_width'),
         panel.pane.ECharts(
             load_fc_chart_rx,
             sizing_mode='stretch_width',