#!/usr/bin/env python3
"""Read the StillShell whitespace heartbeat format without modifying it."""
import json, pathlib, sys
if len(sys.argv) != 2:
    raise SystemExit("Usage: python3 inspect-heartbeat.py heartbeat.jsonl")
p = pathlib.Path(sys.argv[1])
if p.stat().st_size > 10 * 1024 * 1024:
    raise SystemExit("Input exceeds 10 MiB; inspect a copied smaller excerpt.")
records, bad, resets = [], [], []
for number, line in enumerate(p.read_text(encoding="utf-8").splitlines(), 1):
    parts = line.split()
    if len(parts) != 2 or not all(v.isdecimal() for v in parts):
        bad.append(number)
        continue
    pid, counter = map(int, parts)
    if pid < 1 or counter < 1:
        bad.append(number)
        continue
    if records and records[-1]["pid"] == pid and counter <= records[-1]["counter"]:
        resets.append(number)
    records.append({"line": number, "pid": pid, "counter": counter})
print(json.dumps({"format": "pid counter (not JSONL)", "valid_records": len(records),
                  "first": records[0] if records else None, "last": records[-1] if records else None,
                  "pids": sorted({r["pid"] for r in records}), "counter_reset_lines": resets,
                  "malformed_lines": bad,
                  "limit": "One file snapshot does not prove a process is currently alive."}, indent=2))