import { useCallback, useEffect, useRef, useState } from "react";
import type { EventGpsCoordinate } from "./event-location-coordinate";

export type EventLocationAddressResolver = (coordinate: EventGpsCoordinate, signal: AbortSignal) => Promise<string>;

export type EventLocationAddressLookup = {
  pending: boolean;
  error: string | null;
  changeLocation: (value: string) => void;
  retry: () => void;
};

export function useEventLocationAddress({ active = true, coordinate, resolveAddress, onChange }: {
  active?: boolean;
  coordinate: EventGpsCoordinate | null;
  resolveAddress: EventLocationAddressResolver;
  onChange: (value: string) => void;
}): EventLocationAddressLookup {
  const [pending, setPending] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [retryGeneration, setRetryGeneration] = useState(0);
  const requestRef = useRef<AbortController | null>(null);
  const longitude = coordinate?.[0];
  const latitude = coordinate?.[1];

  useEffect(() => {
    setError(null);
    if (!active || longitude === undefined || latitude === undefined) {
      setPending(false);
      return;
    }
    const controller = new AbortController();
    requestRef.current = controller;
    setPending(true);
    onChange("");
    // Coalesce keyboard adjustments. GPS stays immediate while only the final
    // point is reverse-geocoded; a former point's address must never be reused.
    const timer = window.setTimeout(async () => {
      if (controller.signal.aborted) return;
      try {
        const address = await resolveAddress([longitude, latitude], controller.signal);
        if (!controller.signal.aborted) onChange(address);
      } catch (failure) {
        if (!controller.signal.aborted) {
          setError(failure instanceof Error ? failure.message : "地址查询失败，请重试或手动填写");
        }
      } finally {
        if (!controller.signal.aborted) setPending(false);
      }
    }, 250);
    return () => {
      window.clearTimeout(timer);
      controller.abort();
      if (requestRef.current === controller) requestRef.current = null;
    };
  }, [active, longitude, latitude, resolveAddress, onChange, retryGeneration]);

  const changeLocation = useCallback((value: string) => {
    requestRef.current?.abort();
    setPending(false);
    setError(null);
    onChange(value);
  }, [onChange]);

  return { pending, error, changeLocation, retry: () => setRetryGeneration((current) => current + 1) };
}