Batman

app/services.py

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+from __future__ import annotations
+
+import sqlite3
+from dataclasses import dataclass
+
+from . import db
+from .config import get_settings
+
+
+@dataclass
+class ServiceDue:
+    """Service-due snapshot for one bike.
+
+    status:
+      "no-data"  -> cannot compute (missing current mileage or last service,
+                    or no interval set)
+      "ok"       -> still under the interval
+      "due-soon" -> within a short lead time of the interval - book it soon
+      "overdue"  -> past the interval - book a service now
+    """
+
+    current_mileage: int | None
+    last_service: db.BikeEvent | None
+    miles_since: int | None
+    miles_until_due: int | None  # negative when overdue
+    status: str
+
+
+def compute_service_due(conn: sqlite3.Connection, bike: db.Bike) -> ServiceDue:
+    # 'current_mileage' is derived from the most recent event that recorded a
+    # mileage, i.e. the bike's latest known odometer reading.
+    current_evt = db.latest_event_with_mileage(conn, bike.id)
+    current_mileage = current_evt.mileage if current_evt else None
+
+    # The 'last service' is the most recent event typed 'service' that ALSO has
+    # a mileage recorded, so we can compute a delta.
+    last_service = db.latest_event_of_type(conn, bike.id, "service")
+    if last_service is not None and last_service.mileage is None:
+        last_service = None
+
+    no_data = ServiceDue(current_mileage, last_service, None, None, "no-data")
+    if current_mileage is None or last_service is None or bike.service_interval_miles is None:
+        return no_data
+
+    miles_since = current_mileage - last_service.mileage
+    interval = bike.service_interval_miles
+    miles_until_due = interval - miles_since
+    if miles_since > interval:
+        status = "overdue"
+    elif miles_until_due <= get_settings().service_due_soon_miles:
+        status = "due-soon"
+    else:
+        status = "ok"
+
+    return ServiceDue(
+        current_mileage=current_mileage,
+        last_service=last_service,
+        miles_since=miles_since,
+        miles_until_due=miles_until_due,
+        status=status,
+    )
+
+
+@dataclass
+class BikeSummary:
+    bike: db.Bike
+    due: ServiceDue
+    event_count: int
+    total_cost: int
+
+
+def summarize_bike(conn: sqlite3.Connection, bike: db.Bike) -> BikeSummary:
+    return BikeSummary(
+        bike=bike,
+        due=compute_service_due(conn, bike),
+        event_count=db.count_events(conn, bike.id),
+        total_cost=db.sum_cost(conn, bike.id),
+    )
+
+
+def all_summaries(conn: sqlite3.Connection) -> list[BikeSummary]:
+    """All bikes with summaries; bikes needing attention first."""
+    summaries = [summarize_bike(conn, b) for b in db.list_bikes(conn)]
+    rank = {"overdue": 0, "due-soon": 1, "ok": 2, "no-data": 3}
+    summaries.sort(key=lambda s: (rank.get(s.due.status, 4), s.bike.name))
+    return summaries
+
+
+def action_needed(conn: sqlite3.Connection) -> list[BikeSummary]:
+    """Bikes past their service interval - book it now."""
+    return [s for s in all_summaries(conn) if s.due.status == "overdue"]
+
+
+def due_soon(conn: sqlite3.Connection) -> list[BikeSummary]:
+    """Bikes within the lead time of the interval - book it soon."""
+    return [s for s in all_summaries(conn) if s.due.status == "due-soon"]
+
+
+def status_class(due: ServiceDue) -> str:
+    return {
+        "overdue": "badge-overdue",
+        "due-soon": "badge-due-soon",
+        "ok": "badge-ok",
+        "no-data": "badge-muted",
+    }[due.status]
+
+
+def status_text(due: ServiceDue) -> str:
+    if due.status == "no-data":
+        return "no service logged"
+    if due.status == "due-soon":
+        return f"book soon - {due.miles_until_due:,} mi left"
+    if due.status == "ok":
+        return f"due in {due.miles_until_due:,} mi"
+    return f"overdue by {abs(due.miles_until_due):,} mi"