add chart for grid buy and sell prices

sample2.py

@@ -31,6 +31,8 @@ class SystemState(BaseModel):
     load_forecast: LoadForecast = LoadForecast()
     pv_forecast: PvForecast = PvForecast()
     now: datetime = datetime.now()
+    sell_prices: list[float] = []
+    buy_prices: list[float] = []
     output: Output | None = None
 
 state: SystemState = panel.rx(lambda s: SystemState.model_validate(s) if s else SystemState())(w42_state)
@@ -100,6 +102,41 @@ def load_fc_chart(state: SystemState) -> dict:
 
 load_fc_chart_rx = panel.rx(load_fc_chart)(state)
 
+def prices_chart(state: SystemState) -> dict:
+    return {
+        'title': {
+            'text': 'Electricity Prices'
+        },
+        'legend': {
+            'data': ['Sell Prices', 'Buy Prices']
+        },
+        'tooltip': {
+            'trigger': 'axis'
+        },
+        'xAxis': {
+            'type': 'category',
+            'data': [get_label(state.now, i) for i in range(len(state.sell_prices))]
+        },
+        'yAxis': {
+            'type': 'value'
+        },
+        'series': [
+            {
+                'name': 'Sell Prices',
+                'data': state.sell_prices,
+                'type': 'line',
+                'color': 'green'
+            }, {
+                'name': 'Buy Prices',
+                'data': state.buy_prices,
+                'type': 'line',
+                'color': 'red'
+            }
+        ]
+    }
+
+prices_chart_rx = panel.rx(prices_chart)(state)
+
 datetime_fmt = "%Y-%m-%d %H:%M:%S"
 
 value = w42_state.rx.value
@@ -114,6 +151,11 @@ _ = panel.template.FastListTemplate(
             sizing_mode='stretch_width',
             height=400
         ),
+        panel.pane.ECharts(
+            prices_chart_rx,
+            sizing_mode='stretch_width',
+            height=300
+        ),
         w42_state,
         panel.pane.Markdown(panel.bind(lambda s: f"State at {s.now.strftime(datetime_fmt)}, Load Forecast Time: {s.load_forecast.at}", state), sizing_mode='stretch_width'),
     ],