// composables/usePersianTimeAgo.ts
import { formatDistance } from "date-fns-jalali";
import { faIR } from "date-fns-jalali/locale";
import { Jalali } from "jalali-ts";

const toGregorianDate = (input: Date | string): Date | null => {
    if (input instanceof Date) {
        return isNaN(input.getTime()) ? null : input;
    }
    if (typeof input !== "string" || !input) return null;

    const yearStr = input.slice(0, 4);
    const year = Number(yearStr);

    // jDateTimeField from django_jalali serializes with the Jalali year
    // (typically 13XX or 14XX). Anything below ~1700 is treated as Jalali
    // and converted to the equivalent Gregorian moment via jalali-ts.
    // date-fns-jalali's parseISO can't be used here — it parses the year
    // numerically without calendar conversion.
    if (!Number.isNaN(year) && year < 1700) {
        try {
            return Jalali.parse(input).date;
        } catch {
            return null;
        }
    }

    const native = new Date(input);
    return isNaN(native.getTime()) ? null : native;
};

export function usePersianTimeAgo(date: Date | string) {
    const timeAgo = ref("");

    const updateTimeAgo = () => {
        const parsed = toGregorianDate(date);
        if (!parsed) {
            timeAgo.value = "";
            return;
        }
        timeAgo.value = formatDistance(parsed, new Date(), {
            addSuffix: true,
            locale: faIR,
        });
    };

    onMounted(() => {
        updateTimeAgo();

        const interval = setInterval(updateTimeAgo, 60000);

        onUnmounted(() => clearInterval(interval));
    });

    return timeAgo;
}