import type { UserLoginActivity } from "../../types/api";

export type DisplayLoginActivity = UserLoginActivity & { grouped_count: number };

type ActivityStatus = NonNullable<UserLoginActivity["activity_status"]>;

const activityTime = (value: string) => new Date(value).getTime();

export const activitySourceKey = (item: UserLoginActivity) => {
  if (!item.login_ip) return `session:${item.id}`;
  return [item.client_type, item.login_ip].join("|");
};

export const groupLoginActivitiesBySource = (
  activities: UserLoginActivity[],
  resolveStatus: (item: UserLoginActivity) => ActivityStatus,
): DisplayLoginActivity[] => {
  const grouped = new Map<
    string,
    { row: DisplayLoginActivity; firstLoginAt: string; hasOnlineSession: boolean }
  >();

  activities.forEach((item) => {
    const key = activitySourceKey(item);
    const status = resolveStatus(item);
    const existing = grouped.get(key);
    if (!existing) {
      grouped.set(key, {
        row: { ...item, activity_status: status, grouped_count: 1 },
        firstLoginAt: item.login_at,
        hasOnlineSession: status === "ONLINE",
      });
      return;
    }

    existing.row.grouped_count += 1;
    existing.hasOnlineSession ||= status === "ONLINE";
    if (activityTime(item.login_at) < activityTime(existing.firstLoginAt)) {
      existing.firstLoginAt = item.login_at;
    }
    if (activityTime(item.last_seen_at) > activityTime(existing.row.last_seen_at)) {
      const groupedCount = existing.row.grouped_count;
      existing.row = { ...item, activity_status: status, grouped_count: groupedCount };
    }
  });

  return Array.from(grouped.values())
    .map(({ row, firstLoginAt, hasOnlineSession }) => ({
      ...row,
      login_at: firstLoginAt,
      activity_status: hasOnlineSession ? "ONLINE" : row.activity_status,
      ended_at: hasOnlineSession ? null : row.ended_at,
      end_reason: hasOnlineSession ? null : row.end_reason,
    }))
    .sort((left, right) => activityTime(right.last_seen_at) - activityTime(left.last_seen_at));
};