/// ─────────────────────────────────────────────────────────────────────────
/// WHO THE RIDER IS RINGING
///
/// One number on a screen is not one fact. `Call` beside a kitchen's name and
/// `Call` beside a customer's name are different promises, and a rider at a
/// door who reaches the kitchen instead has lost the two minutes the control
/// existed to save him.
///
/// ── What the payload actually carries ──
///
/// Verified against production 21 Aug 2026: `GET /miler/bookings` returns
/// exactly **one** phone field, `customerphone`, which the adapter stores as
/// `pickupcontactno` — a key named after the leg it was first read on rather
/// than after whose number it is. There is no separate drop or receiver
/// contact anywhere in the contract.
///
/// So on today's data there is only one number to dial and it belongs to the
/// booking's customer: the sender on a logistics collection, the subscriber on
/// a meal delivery. Dialling it is correct on both legs. What was **not**
/// correct is the app announcing it as "Call customer" while the rider is
/// standing at a kitchen counter.
///
/// This file therefore does two things: it prefers a genuine drop contact the
/// moment the backend ships one — the precedence is written now so that day
/// needs no archaeology — and it names who is being called, per leg, so the
/// label can never drift from the number again.
/// ─────────────────────────────────────────────────────────────────────────
library;

/// A number to dial, and who answers it.
class StopContact {
  const StopContact(this.number, this.who);

  /// Empty when the stop carries no usable number. Callers omit the control
  /// rather than showing one that cannot dial.
  final String number;

  /// `the kitchen` / `the customer` — used to build the accessible label and
  /// any visible caption, so both are produced from one decision.
  final String who;

  bool get isEmpty => number.isEmpty;
  bool get isNotEmpty => number.isNotEmpty;

  /// `Call the customer`.
  String get action => 'Call $who';

  /// Resolves the contact for the leg being worked.
  ///
  /// [delivery] is the leg, not the line: a milk run's collection at a kitchen
  /// is a pickup leg even though the line delivers to customers. Ask
  /// `MilkRun.navigatesToCustomer` for it rather than deriving it here — one
  /// answer to "which leg is this", used by the map, the sheet and this.
  static StopContact forLeg(
    Map<String, dynamic> stop, {
    required bool delivery,
  }) {
    String read(List<String> keys) {
      for (final k in keys) {
        final v = (stop[k] ?? '').toString().trim();
        if (v.isNotEmpty && v != 'null' && v != '0') return v;
      }
      return '';
    }

    // Written for the contract that exists *and* the one that is coming: a
    // drop contact wins on a delivery leg the moment one is present, and until
    // then the single number the payload carries is used on both.
    const dropKeys = [
      'dropcontactno',
      'DropContactNo',
      'deliverycontactno',
      'receiverphone',
      'dropphone',
    ];
    const pickupKeys = [
      'pickupcontactno',
      'PickupContactNo',
      'contactno',
      'customerphone',
    ];

    final number = delivery
        ? read([...dropKeys, ...pickupKeys])
        : read([...pickupKeys, ...dropKeys]);

    return StopContact(number, delivery ? 'the customer' : 'the pickup');
  }
}