import { useEffect, useState } from "react";

import { api } from "../api/client";
import type { TodayPlan } from "../api/types";
import { useDialog } from "../dialog/DialogContext";
import { useSession } from "../session/SessionContext";

/** The patient's plan for today; refreshed whenever the dialog moves (a dose answered, a check-in done). */
export function useToday(): { plan: TodayPlan | null; failed: boolean } {
  const { session } = useSession();
  const { pending } = useDialog();
  const [plan, setPlan] = useState<TodayPlan | null>(null);
  const [failed, setFailed] = useState(false);

  useEffect(() => {
    if (!session) return;
    let alive = true;
    api
      .today(session.token)
      .then((p) => {
        if (!alive) return;
        setPlan(p);
        setFailed(false);
      })
      .catch(() => alive && setFailed(true));
    return () => {
      alive = false;
    };
  }, [session, pending]);

  return { plan, failed };
}

const MONTHS = ["января", "февраля", "марта", "апреля", "мая", "июня", "июля", "августа", "сентября", "октября", "ноября", "декабря"];
const WEEKDAYS = ["воскресенье", "понедельник", "вторник", "среда", "четверг", "пятница", "суббота"];

/** "12 марта, вторник" — from an ISO date, no timezone shift. */
export function humanDate(iso: string): string {
  const [y, m, d] = iso.split("-").map(Number);
  const wd = new Date(Date.UTC(y, m - 1, d)).getUTCDay();
  return `${d} ${MONTHS[m - 1]}, ${WEEKDAYS[wd]}`;
}

/** "4 октября" — from an ISO date. */
export function dayMonth(iso: string): string {
  const [, m, d] = iso.split("-").map(Number);
  return `${d} ${MONTHS[m - 1]}`;
}