fix(output): the plan's first row shows its rates from now

The first row of the plan covers now to the end of its plan interval: its time
and its car, PV and load kWh all start at minute_start. Its Import and Export
rates were read at the aligned interval start instead, a minute already in the
past. A rate that changed earlier in the interval was then shown for the whole
row. For example, a cancelled Intelligent dispatch still showed its 6.90p
discount after the plan had moved the rest of the half hour to the day rate.

The rate cells, a merged row's min-max range, and the replicated-rate symbol
now all read from minute_start. Every later row starts on its interval
boundary, so only the first row can change. The JSON slot_minute stays the
aligned start, which the override system keys on.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: CI

apps/predbat/output.py

@@ -1181,8 +1181,11 @@ def import_rate_color(rate):
             minute_timestamp = self.midnight_utc + timedelta(minutes=(minute_relative_start + self.minutes_now))
 
             rate_start = minute_timestamp
-            rate_value_import = dp2(self.rate_import.get(minute, 0))
-            rate_value_export = dp2(self.rate_export.get(minute, 0))
+            # From minute_start, not the aligned interval start: the first row covers now to the end of its
+            # interval, like its times and kWh, and a rate that changed earlier in the interval (a cancelled
+            # Intelligent dispatch, say) no longer applies to it. Every later row starts on its interval anyway.
+            rate_value_import = dp2(self.rate_import.get(minute_start, 0))
+            rate_value_export = dp2(self.rate_export.get(minute_start, 0))
             # Default to a single value; overridden to a "{min}-{max}" range below when this row
             # turns out to be the first of a merged/rowspan cell whose minutes span more than one
             # distinct rate - only the first row of a span is ever actually rendered as a tooltip.
@@ -1231,7 +1234,7 @@ def import_rate_color(rate):
                     in_span = True
                     start_span = True
                     minute_relative_end = self.charge_window_best[charge_window_n]["end"] - minute_now_align
-                    rate_text_import = self.rate_range_text(self.rate_import, minute, charge_end_minute, rate_value_import)
+                    rate_text_import = self.rate_range_text(self.rate_import, minute_start, charge_end_minute, rate_value_import)
                 else:
                     rowspan = 0
 
@@ -1243,7 +1246,7 @@ def import_rate_color(rate):
                     in_span = True
                     start_span = True
                     minute_relative_end = self.export_window_best[export_window_n]["end"] - minute_now_align
-                    rate_text_export = self.rate_range_text(self.rate_export, minute, export_end_minute, rate_value_export)
+                    rate_text_export = self.rate_range_text(self.rate_export, minute_start, export_end_minute, rate_value_export)
                 else:
                     rowspan = 0
 
@@ -1553,7 +1556,7 @@ def import_rate_color(rate):
                 soc_sym = "⬇ " + soc_sym
 
             # Import and export rates -> to string
-            adjust_type = self.rate_import_replicated.get(minute, None)
+            adjust_type = self.rate_import_replicated.get(minute_start, None)
             adjust_symbol = self.adjust_symbol(adjust_type)
             if adjust_symbol:
                 rate_str_import = "<i>%02.02f %s</i>" % (rate_value_import, adjust_symbol)
@@ -1566,7 +1569,7 @@ def import_rate_color(rate):
             if charge_window_n >= 0:
                 rate_str_import = "<b>" + rate_str_import + "</b>"
 
-            adjust_type = self.rate_export_replicated.get(minute, None)
+            adjust_type = self.rate_export_replicated.get(minute_start, None)
             adjust_symbol = self.adjust_symbol(adjust_type)
             if adjust_symbol:
                 rate_str_export = "<i>%02.02f %s</i>" % (rate_value_export, adjust_symbol)

apps/predbat/tests/test_plan_json_rate_adjust.py

@@ -239,6 +239,34 @@ def run_test_plan_json_rate_adjust(my_predbat):
     my_predbat.car_charging_slots[1] = []
     my_predbat.num_cars = saved_num_cars
 
+    # The first row covers now to the end of its plan interval - its kWh and times already start at now, so
+    # its rates must too. Reading the rate at the aligned interval start showed a price the plan no longer
+    # uses, e.g. a cancelled Intelligent dispatch still at 6.90 after the minutes from now went to 30.26.
+    print("Test the first plan row shows the rate from now, not from the start of its half hour")
+    saved_minutes_now = my_predbat.minutes_now
+    saved_rate_import = my_predbat.rate_import
+    saved_rate_export = my_predbat.rate_export
+    saved_car_slots = my_predbat.car_charging_slots[0]
+    try:
+        aligned = (saved_minutes_now // my_predbat.plan_interval_minutes) * my_predbat.plan_interval_minutes
+        my_predbat.minutes_now = aligned + 10
+        my_predbat.car_charging_slots[0] = []
+        my_predbat.rate_import = {minute: (6.9 if minute < aligned + 10 else 30.26) for minute in range(aligned - 60, aligned + 48 * 60)}
+        my_predbat.rate_export = {minute: (5.0 if minute < aligned + 10 else 12.0) for minute in range(aligned - 60, aligned + 48 * 60)}
+        html_plan, raw_plan = my_predbat.publish_html_plan(pv_step, pv_step, load_step, load_step, my_predbat.end_record, publish=False)
+        first = raw_plan["rows"][0] if raw_plan.get("rows") else {}
+        if first.get("import_rate") != 30.26 or first.get("export_rate") != 12.0:
+            print("ERROR: Expected the first row's rates from now (30.26 / 12.0), got {} / {}".format(first.get("import_rate"), first.get("export_rate")))
+            failed = True
+        if first.get("slot_minute") != aligned:
+            print("ERROR: slot_minute must stay the aligned interval start {} for the override system, got {}".format(aligned, first.get("slot_minute")))
+            failed = True
+    finally:
+        my_predbat.minutes_now = saved_minutes_now
+        my_predbat.rate_import = saved_rate_import
+        my_predbat.rate_export = saved_rate_export
+        my_predbat.car_charging_slots[0] = saved_car_slots
+
     # Clean up
     my_predbat.num_cars = 0
     my_predbat.car_charging_slots[0] = []