import os

def run_diagnostics():
    # Simulate system checks
    import random
    issues_found = random.choice([False, True])
    if issues_found:
        return "Issues detected: Fault in module X."
    else:
        return "Diagnostics complete. No issues found."


def run_diagnostics():
    import random
    import logging
    # Setup logging
    log_file = 'diagnostics_log.txt'
    if os.path.exists(log_file):
        os.remove(log_file)
    logging.basicConfig(filename=log_file, level=logging.INFO)
    
    issues = []
    # Check CPU load
    cpu_load = random.uniform(0, 100)
    logging.info('CPU load: ' + str(cpu_load))
    if cpu_load > 75:
        issues.append('High CPU load')
    # Check memory usage
    mem_usage = random.uniform(0, 100)
    logging.info('Memory usage: ' + str(mem_usage))
    if mem_usage > 80:
        issues.append('High memory usage')
    # Check disk space
    disk_space = random.uniform(0, 100)
    logging.info('Disk space: ' + str(disk_space))
    if disk_space < 20:
        issues.append('Low disk space')
    # Check network connectivity
    network_status = random.choice([True, False])
    logging.info('Network connectivity: ' + str(network_status))
    if not network_status:
        issues.append('Network connectivity issues')
    
    if issues:
        return 'Issues detected: ' + ', '.join(issues)
    else:
        return 'Diagnostics complete. No issues found.'