import Parse from '../db/parse-client.js';

export interface AggregateCountsResult {
  memberCountByRoom: Map<string, number>;
  todayMsgCountByRoom: Map<string, number>;
  totalMsgCountByRoom: Map<string, number>;
  groupCountByCommunity: Map<string, number>;
}

/** 按 roomId 字段分组计数 */
function countByRoomId(rows: any[], roomIdField = 'roomId'): Map<string, number> {
  const map = new Map<string, number>();
  for (const r of rows) {
    const rid = typeof r.get === 'function' ? (r.get(roomIdField) as string) : (r[roomIdField] as string);
    if (rid) map.set(rid, (map.get(rid) || 0) + 1);
  }
  return map;
}

export async function fetchAggregateCounts(): Promise<AggregateCountsResult> {
  const todayStart = new Date();
  todayStart.setHours(0, 0, 0, 0);

  const [memberCounts, todayMsgCounts, totalMsgCounts, groupCounts] = await Promise.all([
    // 1. 活跃成员数 — select 只取 roomId
    (async () => {
      const q = new Parse.Query('GroupMember');
      q.equalTo('status', 'active');
      q.select('roomId');
      q.limit(100000);
      const rows = await q.find({ useMasterKey: true });
      return countByRoomId(rows);
    })(),

    // 2. 今日消息数 — select 只取 roomId
    (async () => {
      const q = new Parse.Query('Message');
      q.containedIn('msgType', [0, 2]);
      q.notEqualTo('content', '');
      q.greaterThanOrEqualTo('timestamp', todayStart);
      q.select('roomId');
      q.limit(100000);
      const rows = await q.find({ useMasterKey: true });
      return countByRoomId(rows);
    })(),

    // 3. 总消息数 — select 只取 roomId
    (async () => {
      const q = new Parse.Query('Message');
      q.select('roomId');
      q.limit(200000);
      const rows = await q.find({ useMasterKey: true });
      return countByRoomId(rows);
    })(),

    // 4. 群数按小区 — select 只取 community 指针
    (async () => {
      const q = new Parse.Query('GroupChat');
      q.select('community');
      q.limit(5000);
      const rows = await q.find({ useMasterKey: true });
      const map = new Map<string, number>();
      for (const r of rows) {
        const community = r.get('community');
        const cid = community?.id || '_null';
        map.set(cid, (map.get(cid) || 0) + 1);
      }
      return map;
    })(),
  ]);

  return {
    memberCountByRoom: memberCounts,
    todayMsgCountByRoom: todayMsgCounts,
    totalMsgCountByRoom: totalMsgCounts,
    groupCountByCommunity: groupCounts,
  };
}