"""Heatbeat utils."""

import fcntl
import json
import time

from notifications_delivery import config


def send(workers):
    """Send heartbeat data."""
    heartbeat_data = {
        'timestamp': time.time(),
        'workers': []
    }
    for worker in workers:
        heartbeat_data['workers'].append({
            'name': worker.name,
            'is_alive': worker.is_alive(),
        })
    with open(config.HEARTBEAT_FILE, 'w') as f:
        fcntl.flock(f, fcntl.LOCK_EX)
        try:
            json.dump(heartbeat_data, f)
        finally:
            fcntl.flock(f, fcntl.LOCK_UN)


def validate():
    """Validate heartbeat data."""
    try:
        with open(config.HEARTBEAT_FILE, 'r') as f:
            fcntl.flock(f, fcntl.LOCK_SH)
            try:
                data = json.load(f)

                if time.time() - data['timestamp'] > config.HEARTBEAT_TIMEOUT:
                    print('Heartbeat data is stale')
                    return False

                dead_workers = [
                    worker['name'] for worker in data['workers'] if not worker['is_alive']
                ]
                if dead_workers:
                    print(f'Dead workers: {", ".join(dead_workers)}')
                    return False

            except (json.decoder.JSONDecodeError, KeyError, ValueError):
                print('Invalid heartbeat data')
                return False

            finally:
                fcntl.flock(f, fcntl.LOCK_UN)

    except FileNotFoundError:
        print("Can't read heartbeat data")
        return False

    return True