import { useCallback, useEffect, useState } from "react";
import { useReferralWorkbenchService } from "../services/ReferralWorkbenchService";
import { patientReferrals, type PatientReferral } from "../utils/patientReferrals";

/**
 * The patient's referrals, read from their orders. Off unless `enabled`: staff work referrals from
 * the coordinator's Task instead.
 *
 * A booked mark is applied locally from the write's answer, because the search index lags a write by
 * minutes and a re-search would show the referral still open.
 */
export const usePatientReferrals = (patientId: string | undefined, enabled: boolean) => {
  const { listPatientReferrals, markReferralBooked, declineReferralInvite } = useReferralWorkbenchService();
  const [referrals, setReferrals] = useState<PatientReferral[]>([]);
  // Which patient the list answers for, and which one it failed for: an empty list alone cannot say.
  const [answeredFor, setAnsweredFor] = useState<string>();
  const [failedFor, setFailedFor] = useState<string>();

  useEffect(() => {
    if (!enabled || !patientId) {
      setReferrals([]);
      return;
    }

    let current = true;
    listPatientReferrals(patientId)
      .then((bundle) => {
        if (!current) return;
        setReferrals(patientReferrals(bundle));
        setAnsweredFor(patientId);
        setFailedFor(undefined);
      })
      .catch(() => {
        if (current) setFailedFor(patientId);
        // The task list still stands without them; the failure is not the patient's to act on.
      });

    return () => { current = false; };
  }, [enabled, patientId, listPatientReferrals]);

  const markBooked = useCallback(async (referralId: string) => {
    const { patientBookedAt } = await markReferralBooked(referralId);
    setReferrals((all) => all.map((referral) => (
      referral.id === referralId ? { ...referral, stage: "booked", bookedByPatientAt: patientBookedAt } : referral
    )));
  }, [markReferralBooked]);

  const declineInvite = useCallback(async (referralId: string) => {
    const { inviteDeclinedAt } = await declineReferralInvite(referralId);
    setReferrals((all) => all.map((referral) => (
      referral.id === referralId ? { ...referral, inviteDeclinedAt } : referral
    )));
  }, [declineReferralInvite]);

  return {
    referrals,
    markBooked,
    declineInvite,
    answered: Boolean(patientId) && answeredFor === patientId,
    failed: Boolean(patientId) && failedFor === patientId,
  };
};

export default usePatientReferrals;