Core generation walk: assignees x windows fan-out with presence (Feature 07, task 1) (#75)

custom_components/nestquest/materialize.py

@@ -0,0 +1,167 @@
+"""The materialization walk (Feature 07 core).
+
+:func:`materialize` turns the schedule rules + custody presence of the
+active quest definitions into concrete ``quest_instances`` rows over a
+date range.  It is the pure walk over definitions x dates x assignees x
+windows; HA scheduling (day-rollover triggers) and skip-completed
+generation are separate later tasks and live elsewhere.
+
+The walk is deterministic and idempotent:
+
+- All inputs — the active definitions with their rules, assignees and
+  windows, AND the assignee children's presence schedules and scoped
+  overrides — are read inside ONE locked transaction (see
+  :func:`~.dao_rules.load_materialization_input`), so the walk sees a
+  single coherent snapshot rather than a definition state from one
+  instant and a presence state from another.
+- Presence is snapshotted into an immutable
+  :class:`~.presence.PresenceEngine` from that same coherent read.
+- For each date in the range, each definition whose decoded rule
+  :func:`~.recurrence.occurs_on` on that date, each assignee who is
+  ``is_present`` on that date and each declared window, one instance is
+  written through :class:`~.dao_instances.QuestInstancesDao.upsert_if_valid`
+  with a ``generated_at`` stamp shared by the whole batch (one coherent
+  time per run).
+
+A config change that lands AFTER the snapshot is read but BEFORE a
+tuple's write (an assignment removed, a definition or child deactivated,
+a window removed) makes that tuple SKIP rather than abort the batch:
+:meth:`~.dao_instances.QuestInstancesDao.upsert_if_valid` re-validates
+every materialization precondition (active definition, active child,
+live assignment, declared window, and its CURRENT ``due_time``) inside
+the SAME transaction as the INSERT, so the check and the write cannot be
+split by a racing config edit.
+
+The upsert is idempotent on (definition_id, child_id, due_date, window),
+so re-running the materialization over the same range never duplicates a
+row; skipped-completed handling is deliberately NOT done here.
+"""
+from __future__ import annotations
+
+import datetime
+
+from .dao_instances import QuestInstancesDao
+from .dao_rules import (
+    _validate_date,
+    load_materialization_input,
+    schedule_rule_from_storage,
+    schedule_rule_storage_from_record,
+)
+from .db import NestQuestDatabase
+from .presence import PresenceEngine, PresenceOverride, PresenceSchedule
+from .recurrence import ScheduleRule, occurs_on
+
+
+def _now_stamp() -> str:
+    """Return the batch's shared UTC second-precision generation stamp."""
+    return datetime.datetime.now(datetime.timezone.utc).isoformat(
+        timespec="seconds"
+    )
+
+
+def _decode_rule(snapshot) -> ScheduleRule:
+    """Decode a snapshot's rule record back into a ScheduleRule.
+
+    The record carried by the snapshot is the one the definition
+    referenced at read time, so decoding it here (rather than re-reading
+    through ``ScheduleRulesDao``) preserves the coherence the snapshot
+    guarantees.
+    """
+    return schedule_rule_from_storage(
+        schedule_rule_storage_from_record(snapshot.rule)
+    )
+
+
+def _build_engine(
+    schedules_records,
+    overrides_records,
+) -> PresenceEngine:
+    """Convert raw presence records into an immutable PresenceEngine."""
+    schedules: dict[int, PresenceSchedule] = {}
+    for child_id, record in schedules_records.items():
+        schedules[child_id] = PresenceSchedule.decode(
+            child_id, record.anchor_date, record.pattern
+        )
+    overrides: dict[int, list[PresenceOverride]] = {}
+    for child_id, records in overrides_records.items():
+        overrides[child_id] = [
+            PresenceOverride(
+                record.child_id,
+                record.start_date,
+                record.end_date,
+                record.is_present,
+                record.note,
+            )
+            for record in records
+        ]
+    return PresenceEngine(schedules, overrides)
+
+
+async def materialize(
+    database: NestQuestDatabase,
+    start_date: str,
+    end_date: str,
+) -> int:
+    """Generate quest instances for the closed range [start_date, end_date].
+
+    ``start_date`` and ``end_date`` must be strict ISO calendar dates
+    (YYYY-MM-DD) with ``end_date`` on or after ``start_date``; anything
+    else raises ValueError naming the offending field.  Returns the number
+    of instances upserted for the range (idempotent — a re-run refreshes
+    the same rows, never duplicates them).
+
+    All inputs are read in ONE locked transaction; each tuple's write then
+    goes through the atomic :meth:`~.dao_instances.QuestInstancesDao.upsert_if_valid`,
+    which re-validates the tuple and its current ``due_time`` in the same
+    transaction as the INSERT, so a config change that arrives mid-batch
+    skips the affected tuples rather than aborting the batch or leaving a
+    partial result.
+    """
+    _validate_date(start_date, "start_date")
+    _validate_date(end_date, "end_date")
+    if end_date < start_date:
+        raise ValueError(
+            f"end_date must be on or after start_date, got "
+            f"{end_date!r} < {start_date!r}"
+        )
+
+    snapshots, schedules_records, overrides_records = await (
+        load_materialization_input(database, start_date, end_date)
+    )
+    engine = _build_engine(schedules_records, overrides_records)
+
+    definitions = [
+        (snapshot.definition.id, _decode_rule(snapshot),
+         snapshot.assignees, snapshot.windows)
+        for snapshot in snapshots
+    ]
+
+    generated_at = _now_stamp()
+    instances = QuestInstancesDao(database)
+
+    start = datetime.datetime.strptime(start_date, "%Y-%m-%d").date()
+    end = datetime.datetime.strptime(end_date, "%Y-%m-%d").date()
+
+    count = 0
+    cursor = start
+    while cursor <= end:
+        iso = cursor.isoformat()
+        for definition_id, rule, assignees, windows in definitions:
+            if not occurs_on(rule, cursor):
+                continue
+            for child in assignees:
+                if not engine.is_present(child.id, cursor):
+                    continue
+                for window in windows:
+                    written = await instances.upsert_if_valid(
+                        definition_id,
+                        child.id,
+                        iso,
+                        generated_at,
+                        window=window.window,
+                        due_time=window.due_time,
+                    )
+                    if written is not None:
+                        count += 1
+        cursor += datetime.timedelta(days=1)
+    return count