import 'package:miler/Models/stop_status.dart';
import 'package:miler/data/milk_run.dart';
import 'package:miler/data/next_leg.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;
    // Booking key as well as stop key: a multi-destination pickup is collected
    // once, before it splits into one row per door. See [MilkRun.wasCollected].
    return MilkRun.wasCollected(stop, collectedIds);
  }

  /// True when this order is finished or withdrawn, whatever screen it was on.
  ///
  /// [StopStatus.picked] is terminal for some orders and the middle of the
  /// morning for others, and **which one is a property of the order, not of the
  /// line**. It is asked of [NextLegResolver], which reads the backend's own
  /// routing answer. See the note on the picked branch below.
  ///
  /// ── Skipped closes, and why it has to close *here* ──
  ///
  /// A skip used to leave the order open, and the Deliveries tab kept it under
  /// its own heading on the argument that the rider looks for it where he left
  /// it. The cost of that was **dual ownership**: the same stop sat in the
  /// active queue *and* in Activity, so the two screens disagreed about whether
  /// the rider still owed it a visit. One order, one owner — a stop he has
  /// written off is a record, and records live on Activity.
  ///
  /// ── Why the status alone cannot answer it ──
  ///
  /// On the delivery leg the backend has no failed-attempt outcome. A
  /// successful skip leaves the consignment `Out_for_Delivery`, so
  /// `/miler/bookings` keeps returning the row as live delivery work for the
  /// rest of the day, and [stopStatusOf] reads exactly what the server sent.
  /// Asking only the payload therefore re-admits the stop on every poll and on
  /// every cold start.
  ///
  /// [closedIds] is the answer to that, and it is **not** a display flag: it is
  /// the persisted record of a mutation that already succeeded — day-stamped,
  /// scoped to this rider, tenant and line (see [WorkScope]) — written by the
  /// completed and skipped stores at the moment the rider's action came back
  /// OK. It is the same shape of evidence [pickupComplete] already takes from
  /// `collectedIds`, and it survives the process that wrote it, which is the
  /// whole point.
  ///
  /// Clearing it is what a resume does: [removeSkippedBookings] drops the id
  /// and the stop is live work again on the very next read. There is no second
  /// place holding the same opinion.
  static bool isClosed(
    Map<String, dynamic> stop, {
    Set<String> closedIds = const <String>{},

    /// `next_action` recorded at each order's pivot — see [NextLegResolver].
    Map<String, String> pivotActions = const <String, String>{},
  }) {
    if (closedIds.isNotEmpty && closedIds.contains(MilkRun.idOf(stop))) {
      return true;
    }
    final status = stopStatusOf(stop);
    if (status == StopStatus.delivered || status.isCancelled) return true;
    // Filed under its own word, never flattened into cancelled: a stop the
    // rider walked away from and one the office called off are different
    // records, and Activity slices them apart.
    if (status.isSkipped) return true;

    // ── After the pickup, ownership is a question about the ORDER ──
    //
    // This read `status.isPicked && ServiceProfile.active.endsAtHub`, and that
    // is a line-level constant deciding a per-order fact. On logistics
    // `endsAtHub` is always true, so **every collected parcel was closed at the
    // pickup** — including the hyperlocal ones the pivot had just released
    // `Out_for_Delivery` into this rider's own hands. He walked away from the
    // sender's door carrying a parcel his app had already filed as finished.
    //
    // The backend decides where a parcel goes next and always has; the app now
    // asks. [NextLeg.closed] is the only answer that retires the stop —
    // `customer` and `hub` are both journeys the rider still owes, and
    // `unknown` is a parcel in his bag whose destination has not been named,
    // which must never be silently written off. See [NextLegResolver] for the
    // precedence between the pivot, the row and the local record.
    //
    // [ServiceProfile.endsAtHub] survives as a line-level capability hint — it
    // still tells the route card whether the day ends at a depot — but it no
    // longer decides whether one order is finished.
    if (!status.isPicked && !status.isDeliveryLeg) return false;
    return NextLegResolver.resolve(
      stop,
      pivotAction: pivotActions[MilkRun.idOf(stop)] ?? '',
    ).isClosed;
  }

  /// 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>{},

    /// Orders written off today — delivered, cancelled or skipped — read back
    /// from the completed and skipped stores. See [isClosed].
    Set<String> closedIds = const <String>{},

    /// `next_action` recorded at each order's pivot — see [NextLegResolver].
    Map<String, String> pivotActions = const <String, String>{},
  }) {
    if (isClosed(stop, closedIds: closedIds, pivotActions: pivotActions)) {
      return WorkDomain.closed;
    }

    // ── A collected parcel is the work tab's, whatever the line says ──
    //
    // Below [isClosed] and above the handoff knob, deliberately. Once the
    // backend confirms the collection the parcel is physically the rider's, and
    // "in my hands, still owed a journey" is the definition of the delivery
    // domain on every line. Reading it here rather than from the per-line
    // handoff point is what lets a hyperlocal logistics parcel reach Deliveries
    // at all — its own line hands off at *acceptance*, which says nothing about
    // custody.
    //
    // ── Gated on the collection having happened ──
    //
    // [NextLegResolver] answers [NextLeg.unknown] for any row it cannot place,
    // and an uncollected booking is one of those: a pending assignment carries
    // no consignment state and no pivot record, exactly like a collected parcel
    // the server has not routed yet. Asking without this gate handed every
    // pending stop to Deliveries — the dual-ownership failure in reverse.
    //
    // "Is it in his hands?" is [pickupComplete]'s question and it has a real
    // answer: the backend's own status, or the collected record written after
    // the pivot came back OK. Only then is there a leg to resolve.
    if (pickupComplete(stop, collectedIds: collectedIds) &&
        NextLegResolver.resolve(
          stop,
          pivotAction: pivotActions[MilkRun.idOf(stop)] ?? '',
        ).isInCustody) {
      return WorkDomain.delivery;
    }

    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>{},
    Set<String> closedIds = const <String>{},
    Map<String, String> pivotActions = const <String, String>{},
  }) => [
    for (final stop in day)
      if (domainOf(
            stop,
            collectedIds: collectedIds,
            acceptedIds: acceptedIds,
            closedIds: closedIds,
            pivotActions: pivotActions,
          ) ==
          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>{},
    Set<String> closedIds = const <String>{},
    Map<String, String> pivotActions = const <String, String>{},
  }) => [
    for (final stop in day)
      if (domainOf(
            stop,
            collectedIds: collectedIds,
            acceptedIds: acceptedIds,
            closedIds: closedIds,
            pivotActions: pivotActions,
          ) ==
          WorkDomain.pickup)
        stop,
  ];
}