// ==============================|| Routing decision, in words ||============================== //
//
// `GET /admin/bookings/:id` returns a `routing` block: the decision the backend
// took about where a parcel goes, and the inputs it took it from. This turns
// that into the sentences the order drawer shows.
//
// It exists so support can answer "why does the rider's screen say hand over at
// a base instead of deliver to the customer?" as a lookup instead of
// reconstructing a pincode rule by hand on the phone.
//
// TWO RULES THIS FILE EXISTS TO HOLD:
//
//   1. A PROJECTION IS NOT A DECISION. Before pickup, nothing has been decided —
//      `routing.decided` is false and what is shown is what WILL happen. Saying
//      "this went via a base" about a parcel nobody has collected yet is a
//      wrong answer delivered confidently, which is worse than no answer.
//
//   2. THE WIRE SAYS HUB, PEOPLE SAY BASE. The translation happens here, at the
//      edge, and never travels back up: every value sent to the backend keeps
//      its wire spelling.

/** What the rider does next with the parcel. Keys are the backend's wire
 *  values; an unrecognised one is shown as itself rather than swallowed —
 *  the backend may add actions, and a blank row is worse than a raw word. */
export const NEXT_ACTION_LABEL = Object.freeze({
  pickup: 'Collect from the pickup point',
  inward_at_hub: 'Carry to a base and hand over',
  start_delivery: 'Start the delivery run',
  deliver: 'Deliver to the receiver',
  handed_to_hub: 'Handed over at the base',
  none: 'Nothing further for the rider'
});

export const nextActionLabel = (action) => NEXT_ACTION_LABEL[action] || action || '—';

/** Why the parcel is going the way it is, in one sentence an operator can read
 *  to a rider over the phone. */
export const routingReason = (routing) => {
  if (!routing) return '';
  return routing.is_hyperlocal
    ? 'Same postal area — the collecting rider carries it straight to the receiver.'
    : 'Different postal area — it goes through a base rather than direct to the receiver.';
};

/** The from → to line, with the honesty caveat when nothing has been decided
 *  yet. A booking not yet collected has no routing FACT, only a forecast. */
export const routingRoute = (routing) => {
  if (!routing) return '';
  const from = routing.from_pincode || '—';
  const to = routing.destination_pincode || '—';
  const line = `${from} → ${to}`;
  return routing.decided ? line : `${line} · not yet collected, so this is what will happen, not what has`;
};

/** The base a parcel is routed to, as one readable line. Null when no base is
 *  involved — which is the correct answer for a hyperlocal parcel, not a gap. */
export const baseLine = (base) => {
  if (!base || !base.name) return null;
  return base.pincode ? `${base.name} · ${base.pincode}` : base.name;
};

/**
 * Everything the drawer renders, in one call, so the component holds no
 * decisions of its own.
 */
export const summariseRouting = (routing) => {
  if (!routing) return null;
  return {
    decided: Boolean(routing.decided),
    reason: routingReason(routing),
    route: routingRoute(routing),
    nextAction: nextActionLabel(routing.next_action),
    base: baseLine(routing.next_hub),
    baseAddress: routing.next_hub?.address || null,
    consignmentState: routing.consignment_state || '—',
    inwardedAt: routing.inwardedat || null
  };
};