import { useState, useEffect, useRef, useMemo, useCallback } from 'react';
import { fetchGroupPolygons } from '../services/vesselAnalysis';
import type { GroupPolygonDto } from '../services/vesselAnalysis';

const POLL_INTERVAL_MS = 5 * 60_000; // 5분

/** 같은 groupKey의 서브클러스터를 하나로 합산 (멤버 합산, 가장 큰 폴리곤 사용) */
function mergeByGroupKey(groups: GroupPolygonDto[]): GroupPolygonDto[] {
  const byKey = new Map<string, GroupPolygonDto[]>();
  for (const g of groups) {
    const list = byKey.get(g.groupKey) ?? [];
    list.push(g);
    byKey.set(g.groupKey, list);
  }
  const result: GroupPolygonDto[] = [];
  for (const [, items] of byKey) {
    if (items.length === 1) { result.push(items[0]); continue; }
    const seen = new Set<string>();
    const allMembers: GroupPolygonDto['members'] = [];
    for (const item of items) for (const m of item.members) {
      if (!seen.has(m.mmsi)) { seen.add(m.mmsi); allMembers.push(m); }
    }
    const biggest = items.reduce((a, b) => a.memberCount >= b.memberCount ? a : b);
    result.push({
      ...biggest,
      subClusterId: 0,
      members: allMembers,
      memberCount: allMembers.length,
    });
  }
  return result;
}

export interface UseGroupPolygonsResult {
  fleetGroups: GroupPolygonDto[];
  gearInZoneGroups: GroupPolygonDto[];
  gearOutZoneGroups: GroupPolygonDto[];
  allGroups: GroupPolygonDto[];
  isLoading: boolean;
  lastUpdated: number;
}

const EMPTY: UseGroupPolygonsResult = {
  fleetGroups: [],
  gearInZoneGroups: [],
  gearOutZoneGroups: [],
  allGroups: [],
  isLoading: false,
  lastUpdated: 0,
};

export function useGroupPolygons(enabled: boolean): UseGroupPolygonsResult {
  const [allGroups, setAllGroups] = useState<GroupPolygonDto[]>([]);
  const [isLoading, setIsLoading] = useState(false);
  const [lastUpdated, setLastUpdated] = useState(0);
  const timerRef = useRef<ReturnType<typeof setInterval>>();

  const load = useCallback(async () => {
    setIsLoading(true);
    try {
      const groups = await fetchGroupPolygons();
      setAllGroups(groups);
      setLastUpdated(Date.now());
    } catch {
      // 네트워크 오류 시 기존 데이터 유지
    } finally {
      setIsLoading(false);
    }
  }, []);

  useEffect(() => {
    if (!enabled) return;
    load();
    timerRef.current = setInterval(load, POLL_INTERVAL_MS);
    return () => clearInterval(timerRef.current);
  }, [enabled, load]);

  const fleetGroups = useMemo(
    () => mergeByGroupKey(allGroups.filter(g => g.groupType === 'FLEET')),
    [allGroups],
  );

  const gearInZoneGroups = useMemo(
    () => mergeByGroupKey(allGroups.filter(g => g.groupType === 'GEAR_IN_ZONE')),
    [allGroups],
  );

  const gearOutZoneGroups = useMemo(
    () => mergeByGroupKey(allGroups.filter(g => g.groupType === 'GEAR_OUT_ZONE')),
    [allGroups],
  );

  if (!enabled) return EMPTY;

  return { fleetGroups, gearInZoneGroups, gearOutZoneGroups, allGroups, isLoading, lastUpdated };
}