Refactor state extraction to use typed StateRecord and enums

- Introduced `StateRecord`, a typed NamedTuple, to replace dict-based
  state records.
- Replaced raw integer state values with proper enum names using
  `ComponentStateCode` and `ComponentErrorCode`.
- Improved internal structure by splitting `_extract_state_records()`
  and `_filter_alerts()` into cleaner, testable units.
- Added `_resolve_enum_name()` to map proto values to readable enum names.
- Updated unit tests accordingly for enum-based comparisons and removed
  deprecated test cases.

This improves downstream use of state records, such as in alert
visualisation and reporting.

Signed-off-by: cyiallou - Costas <[email protected]>

Author: cyiallou

RELEASE_NOTES.md

@@ -6,7 +6,7 @@
 
 ## Upgrading
 
-<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
+- Refactored state extraction to return `StateRecord` objects with descriptive enum names (e.g., "ACTIVE", "FAULT") instead of raw integers for `state_value`, improving clarity and downstream usability.
 
 ## New Features
 

src/frequenz/reporting/_reporting.py

@@ -2,20 +2,54 @@
 # Copyright © 2024 Frequenz Energy-as-a-Service GmbH
 
 """A highlevel interface for the reporting API."""
-
+import enum
+import logging
 from collections import namedtuple
 from datetime import datetime, timedelta
 from itertools import groupby
-from typing import Any
+from typing import NamedTuple
 
+from frequenz.client.common.enum_proto import enum_from_proto
 from frequenz.client.common.metric import Metric
+from frequenz.client.common.microgrid.components import (
+    ComponentErrorCode,
+    ComponentStateCode,
+)
 from frequenz.client.reporting import ReportingApiClient
 from frequenz.client.reporting._types import MetricSample
 
+_logger = logging.getLogger(__name__)
+
 CumulativeEnergy = namedtuple(
     "CumulativeEnergy", ["start_time", "end_time", "consumption", "production"]
 )
-"""Type for cumulative energy consumption and production over a specified time."""
+
+
+class StateRecord(NamedTuple):
+    """A record of a component state change.
+
+    A named tuple was chosen to allow safe access to the fields while keeping
+    the simplicity of a tuple. This data type can be easily used to create a
+    numpy array or a pandas DataFrame.
+    """
+
+    microgrid_id: int
+    """The ID of the microgrid."""
+
+    component_id: str
+    """The ID of the component within the microgrid."""
+
+    state_type: str
+    """The type of the state (e.g., "state", "warning", "error")."""
+
+    state_value: str
+    """The value of the state (e.g., "ON", "OFF", "ERROR" etc.)."""
+
+    start_time: datetime | None
+    """The start time of the state change."""
+
+    end_time: datetime | None
+    """The end time of the state change."""
 
 
 # pylint: disable-next=too-many-arguments
@@ -156,9 +190,9 @@ async def fetch_and_extract_state_durations(
     start_time: datetime,
     end_time: datetime,
     resampling_period: timedelta | None,
-    alert_states: list[int],
+    alert_states: list[ComponentStateCode],
     include_warnings: bool = True,
-) -> tuple[list[dict[str, Any]], list[dict[str, Any]]]:
+) -> tuple[list[StateRecord], list[StateRecord]]:
     """Fetch data using the Reporting API and extract state durations and alert records.
 
     Args:
@@ -172,14 +206,13 @@ async def fetch_and_extract_state_durations(
         end_time: The end date and time for the period.
         resampling_period: The period for resampling the data. If None, data
             will be returned in its original resolution
-        alert_states: List of component state values that should trigger an alert.
-        include_warnings: Whether to include warning state values in the alert
-            records.
+        alert_states: List of ComponentStateCode names that should trigger an alert.
+        include_warnings: Whether to include warning states in the alert records.
 
     Returns:
-        A tuple containing two lists:
-        - all_states: Contains all state records including start and end times.
-        - alert_records: Contains filtered records matching the alert criteria.
+        A tuple containing:
+            - A list of StateRecord instances representing the state changes.
+            - A list of StateRecord instances that match the alert criteria.
     """
     samples = await _fetch_component_data(
         client=client,
@@ -192,30 +225,23 @@ async def fetch_and_extract_state_durations(
         include_bounds=False,
     )
 
-    all_states, alert_records = extract_state_durations(
-        samples, alert_states, include_warnings
-    )
+    all_states = _extract_state_records(samples, include_warnings)
+    alert_records = _filter_alerts(all_states, alert_states, include_warnings)
     return all_states, alert_records
 
 
-def extract_state_durations(
+def _extract_state_records(
     samples: list[MetricSample],
-    alert_states: list[int],
-    include_warnings: bool = True,
-) -> tuple[list[dict[str, Any]], list[dict[str, Any]]]:
-    """
-    Extract state durations and alert records based on state transitions.
+    include_warnings: bool,
+) -> list[StateRecord]:
+    """Extract state records from the provided samples.
 
     Args:
         samples: List of MetricSample instances containing the reporting data.
-        alert_states: List of component state values that should trigger an alert.
-            Component error codes are reported by default.
-        include_warnings: Whether to include warning state values in the alert records.
+        include_warnings: Whether to include warning states in the alert records.
 
     Returns:
-        A tuple containing two lists:
-        - all_states: Contains all state records including start and end times.
-        - alert_records: Contains filtered records matching the alert criteria.
+        A list of StateRecord instances representing the state changes.
     """
     alert_metrics = ["warning", "error"] if include_warnings else ["error"]
     state_metrics = ["state"] + alert_metrics
@@ -225,96 +251,122 @@ def extract_state_durations(
     )
 
     if not filtered_samples:
-        return [], []
+        return []
 
     # Group samples by (microgrid_id, component_id, metric)
     all_states = []
     for key, group in groupby(
         filtered_samples, key=lambda s: (s.microgrid_id, s.component_id, s.metric)
     ):
-        states = _process_group_samples(key, list(group))
-        all_states.extend(states)
+        all_states.extend(_process_sample_group(key, list(group)))
 
-    all_states.sort(
-        key=lambda x: (x["microgrid_id"], x["component_id"], x["start_time"])
-    )
-
-    alert_records = _filter_alerts(all_states, alert_states, alert_metrics)
-    return all_states, alert_records
+    all_states.sort(key=lambda x: (x.microgrid_id, x.component_id, x.start_time))
+    return all_states
 
 
-def _process_group_samples(
-    key: tuple[int, int, str],
-    group_samples: list["MetricSample"],
-) -> list[dict[str, Any]]:
+def _process_sample_group(
+    key: tuple[int, str, str],
+    group_samples: list[MetricSample],
+) -> list[StateRecord]:
     """Process samples for a single group to extract state durations.
 
     Args:
         key: Tuple containing microgrid ID, component ID, and metric.
         group_samples: List of samples for the group.
 
     Returns:
-        List of state records.
+        A list of StateRecord instances representing the state changes.
     """
     mid, cid, metric = key
+    if not group_samples:
+        return []
+
     state_records = []
-    current_state_value = None
-    start_time = None
+    current_state_value: float | None = None
+    start_time: datetime | None = None
+    enum_class = ComponentStateCode if metric == "state" else ComponentErrorCode
 
     for sample in group_samples:
         if current_state_value != sample.value:
             # Close previous state run
             if current_state_value is not None:
                 state_records.append(
-                    {
-                        "microgrid_id": mid,
-                        "component_id": cid,
-                        "state_type": metric,
-                        "state_value": current_state_value,
-                        "start_time": start_time,
-                        "end_time": sample.timestamp,
-                    }
+                    StateRecord(
+                        microgrid_id=mid,
+                        component_id=cid,
+                        state_type=metric,
+                        state_value=_resolve_enum_name(current_state_value, enum_class),
+                        start_time=start_time,
+                        end_time=sample.timestamp,
+                    )
                 )
             # Start new state run
             current_state_value = sample.value
             start_time = sample.timestamp
 
     # Close the last state run
     state_records.append(
-        {
-            "microgrid_id": mid,
-            "component_id": cid,
-            "state_type": metric,
-            "state_value": current_state_value,
-            "start_time": start_time,
-            "end_time": None,
-        }
+        StateRecord(
+            microgrid_id=mid,
+            component_id=cid,
+            state_type=metric,
+            state_value=(
+                _resolve_enum_name(current_state_value, enum_class)
+                if current_state_value is not None
+                else ""
+            ),
+            start_time=start_time,
+            end_time=None,
+        )
     )
 
     return state_records
 
 
+def _resolve_enum_name(value: float, enum_class: type[enum.Enum]) -> str:
+    """Resolve the name of an enum member from its integer value.
+
+    Args:
+        value: The integer value of the enum.
+        enum_class: The enum class to convert the value to.
+
+    Returns:
+        The name of the enum member if it exists, otherwise the value as a string.
+    """
+    result = enum_from_proto(int(value), enum_class)
+    if isinstance(result, int):
+        _logger.warning(
+            "Unknown enum value %s for %s, returning the integer value as a string.",
+            value,
+            enum_class.__name__,
+        )
+        return str(result)
+    return result.name
+
+
 def _filter_alerts(
-    all_states: list[dict[str, Any]],
-    alert_states: list[int],
-    alert_metrics: list[str],
-) -> list[dict[str, Any]]:
+    all_states: list[StateRecord],
+    alert_states: list[ComponentStateCode],
+    include_warnings: bool,
+) -> list[StateRecord]:
     """Identify alert records from all states.
 
     Args:
         all_states: List of all state records.
-        alert_states: List of component state values that should trigger an alert.
-        alert_metrics: List of metric names that should trigger an alert.
+        alert_states: List of ComponentStateCode names that should trigger an alert.
+        include_warnings: Whether to include warning states in the alert records.
 
     Returns:
-        List of alert records.
+        A list of StateRecord instances that match the alert criteria.
     """
+    alert_metrics = ["warning", "error"] if include_warnings else ["error"]
+    _alert_state_names = {state.name for state in alert_states}
     return [
         state
         for state in all_states
         if (
-            (state["state_type"] == "state" and state["state_value"] in alert_states)
-            or (state["state_type"] in alert_metrics)
+            (state.state_type == "state" and state.state_value in _alert_state_names)
+            or (state.state_type in alert_metrics)
         )
     ]