import 'package:miler/Models/stop_status.dart';
import 'package:miler/data/milk_run.dart';
import 'package:miler/data/service_profile.dart';

/// ─────────────────────────────────────────────────────────────────────────
/// WHICH SCREEN OWNS AN ORDER
///
/// One rule, in one place, for the question both work screens have to answer
/// about every row of the shared day: **is this Home's or is it Deliveries'?**
///
/// ── Why it is here and not on the screens ──
///
/// It used to be answered twice. Home decided what to draw from
/// [stopStateOf] plus its own local stores; the Deliveries tab decided what to
/// list from a `where` clause inside its fetch, with a second `where` for the
/// statuses that clause was supposed to re-admit. Two expressions of one fact,
/// edited on different days, and they disagreed exactly where it hurts most:
/// **an accepted booking could be claimed by both.** It stayed on Home to be
/// collected, and it appeared on Deliveries as live work with a strip offering
/// to continue it — which opened a map, an I'VE ARRIVED and a confirmation
/// sheet for a collection the rider had not made yet.
///
/// The fix is not a third filter. It is that the classification is one function
/// on the shared data layer, above both screens, so they cannot hold different
/// opinions about where an order belongs.
///
/// ── The boundary ──
///
///     PENDING ─ accept ─▶ ACCEPTED ─ navigate ─▶ ARRIVED ─ pick up ─▶ PICKED
///     └──────────────── HOME owns all of this ──────────────┘        │
///                                                                    ▼
///                                          DELIVERIES owns from here on
///
/// **Picked up is the boundary**, and only the backend can move it. Accepting
/// an assignment is a decision about work still to be done; it is not evidence
/// that anything has been collected. Nothing in this file infers a completed
/// pickup from an acceptance.
///
/// ── The one knob ──
///
/// Where the boundary sits is a property of the rider's line, declared once as
/// [ServiceProfile.handoffAt], and read here rather than re-derived:
///
///  • **A kitchen line** ([HandoffPoint.collected]) hands over at collection.
///    The rider makes one trip to one counter for a stack of bags, so every
///    rung up to picked-up is Home's, in bulk, and Deliveries holds only what
///    is in his hands.
///  • **Logistics** ([HandoffPoint.accepted]) hands over at acceptance. There is
///    no counter and nothing to batch: he drives to one customer, raises the
///    shipment at the door and the collection *is* the job — so an accepted
///    booking is already the work tab's, which is where that flow lives.
///
/// Same rule, one declared knob. Not a line-name check, and not a per-screen
/// conditional. See [ServiceProfile.handoffAt].
/// ─────────────────────────────────────────────────────────────────────────
enum WorkDomain {
  /// Home's. Pending, accepted, on the way, arrived — everything before the
  /// backend has confirmed the load is aboard.
  pickup,

  /// The Deliveries tab's. Past the hand-over point for this line.
  delivery,

  /// Neither work screen's. Finished or withdrawn — Activity's record.
  closed,
}

/// The hand-over point between [WorkDomain.pickup] and [WorkDomain.delivery].
abstract final class WorkBoundary {
  /// True once the **backend** says the collection is done.
  ///
  /// Two sources, both authoritative, neither of them "the rider accepted it":
  ///
  ///  • The status on the row — `Picked_Up` / `Converted_To_Consignment`, or
  ///    any of the delivery rungs past them.
  ///  • The collected record, written by Home only after the pickup-complete
  ///    call has come back successful. It exists because the queue is up to one
  ///    poll behind: without it a stop the rider has just handed over jumps back
  ///    to Home for a few seconds, which reads as the confirm having failed.
  ///
  /// It deliberately does **not** consult the accepted store. That set says a
  /// decision was made, not that goods changed hands.
  static bool pickupComplete(
    Map<String, dynamic> stop, {
    Set<String> collectedIds = const <String>{},
  }) {
    final status = stopStatusOf(stop);
    if (status.isPicked || status.isDeliveryLeg) return true;
    return collectedIds.contains(MilkRun.idOf(stop));
  }

  /// True when this order is finished or withdrawn, whatever screen it was on.
  ///
  /// [StopStatus.picked] is terminal on a line that ends at the hub and is the
  /// middle of the morning on one that does not — so it is asked of the line,
  /// through the same knob everything else here reads. See
  /// [ServiceProfile.endsAtHub].
  static bool isClosed(Map<String, dynamic> stop) {
    final status = stopStatusOf(stop);
    if (status == StopStatus.delivered || status.isCancelled) return true;
    return status.isPicked && ServiceProfile.active.endsAtHub;
  }

  /// Which screen owns this order.
  ///
  /// [rejectedIds] and a server-side rejection do **not** close an order here:
  /// a declined stop stays in the pickup domain because Home is where the rider
  /// can change his mind about it. What it must never be is delivery work.
  static WorkDomain domainOf(
    Map<String, dynamic> stop, {
    Set<String> collectedIds = const <String>{},
    Set<String> acceptedIds = const <String>{},
  }) {
    if (isClosed(stop)) return WorkDomain.closed;

    final handedOver = switch (ServiceProfile.active.handoffAt) {
      HandoffPoint.collected => pickupComplete(
        stop,
        collectedIds: collectedIds,
      ),
      // On logistics the work tab takes it at acceptance — from either source,
      // because the local store leads the queue by a poll.
      HandoffPoint.accepted =>
        acceptedIds.contains(MilkRun.idOf(stop)) ||
            stopStatusOf(stop) == StopStatus.accepted ||
            stopStatusOf(stop).isActive ||
            stopStatusOf(stop) == StopStatus.arrived,
    };

    return handedOver ? WorkDomain.delivery : WorkDomain.pickup;
  }

  /// Everything the Deliveries tab is allowed to hold, out of the shared day.
  ///
  /// The tab's list, the count on Home's pill and anything else that asks "how
  /// much is waiting on the other tab?" all read this, so the two screens
  /// cannot report different numbers for the same day.
  static List<Map<String, dynamic>> deliveryQueue(
    Iterable<Map<String, dynamic>> day, {
    Set<String> collectedIds = const <String>{},
    Set<String> acceptedIds = const <String>{},
  }) => [
    for (final stop in day)
      if (domainOf(
            stop,
            collectedIds: collectedIds,
            acceptedIds: acceptedIds,
          ) ==
          WorkDomain.delivery)
        stop,
  ];

  /// Everything Home is still responsible for, out of the shared day.
  static List<Map<String, dynamic>> pickupQueue(
    Iterable<Map<String, dynamic>> day, {
    Set<String> collectedIds = const <String>{},
    Set<String> acceptedIds = const <String>{},
  }) => [
    for (final stop in day)
      if (domainOf(
            stop,
            collectedIds: collectedIds,
            acceptedIds: acceptedIds,
          ) ==
          WorkDomain.pickup)
        stop,
  ];
}