import json

def analyze_log(filepath: str) -> dict:
    result = {
        "total": 0,
        "by_level": {},
        "by_user": {},
        "last_error": None
    }
    try:
        with open(filepath, 'r', encoding='utf-8') as f:
            for line in f:
                line = line.strip()
                if not line:
                    continue
                try:
                    log_data = json.loads(line)
                except json.JSONDecodeError:
                    continue
                result["total"] += 1
                level = log_data.get("level")
                if level:
                    result["by_level"][level] = result["by_level"].get(level, 0) + 1
                user = log_data.get("user")
                if user:
                    result["by_user"][user] = result["by_user"].get(user, 0) + 1
                if level == "ERROR":
                    result["last_error"] = log_data.get("message")
    except FileNotFoundError:
        pass
    return result


if __name__ == "__main__":
    
    res = analyze_log("app.jsonl")
    print(res)
     print("成功")