def wg_events(file, filter_client, filter_type, limit, collapse='1',
              since='', filter_event='', endpoint_cache_file=''):
    """
    Format WireGuard events with dedup, counts, gap and endpoint resolution.
    Output per line: ts|client|endpoint|event|count|gap_seconds
    """
    from datetime import datetime
    from collections import defaultdict
    do_collapse = str(collapse) != '0'
    limit       = int(limit) if limit else 50
    since_dt    = parse_since(since) if since else None

    # Load endpoint cache once
    endpoint_cache = {}
    if endpoint_cache_file and os.path.exists(endpoint_cache_file):
        try:
            with open(endpoint_cache_file) as f:
                endpoint_cache = json.load(f)
        except Exception:
            pass

    events = []
    try:
        with open(file) as f:
            for line in f:
                try:
                    e = json.loads(line.strip())
                    client = e.get('client', '')
                    if not client:
                        continue
                    if filter_client and client != filter_client:
                        continue
                    if filter_type and not client.startswith(filter_type + '-'):
                        continue
                    if filter_event and e.get('event', '') != filter_event:
                        continue
                    if since_dt:
                        ts_str = e.get('timestamp', '')
                        try:
                            from datetime import timezone