#!/usr/bin/env python

# Copyright 2025 WheelOS All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


import logging
import os
from typing import Dict, List, Any, Optional, Tuple

# Configure basic logging if not already configured
# In a real application, you would configure logging more elaborately
logging.basicConfig(level=logging.INFO,
                    format='%(asctime)s - %(levelname)s - %(message)s')


class SensorHealthChecker:
    """
    A class to check the health status of various sensors based on a configuration.

    It supports checking:
    1. Sensor connectivity and system detection (e.g., via /dev paths).
    2. Sensor data stream presence and basic rate/loss (requires middleware integration).
    3. Sensor internal reported health/status (requires middleware integration and sensor-specific parsing).

    Note: Data stream and internal health checks require specific libraries
    or interfaces to interact with the sensor data topics/messages, which are
    not part of the standard Python library. These checks are implemented as
    placeholders with necessary explanations.
    """

    def __init__(self, config: List[Dict[str, Any]]):
        """
        Initializes the SensorHealthChecker with a list of sensor configurations.

        Args:
            config: A list of dictionaries. Each dictionary represents a sensor
                    or a set of checks for a sensor.
                    Example config structure:
                    [
                        {
                            'name': 'FrontLiDAR',
                            'type': 'LiDAR',
                            'connectivity_checks': [
                                {'type': 'device_file', 'path': '/dev/ttyUSB0'},
                                # Add other check types if needed, e.g., network port check
                            ],
                            'data_stream_checks': {
                                'topic_name': '/sensing/lidar/front/points_raw',
                                'expected_rate_hz': 10.0,
                                'rate_tolerance_percent': 20.0, # e.g., allow rate between 8Hz and 12Hz
                                'max_packet_loss_percent': 5.0,
                                'check_duration_sec': 5.0 # Time window to measure rate/loss
                            },
                            'internal_health_checks': {
                                'status_topic': '/sensing/lidar/front/status',
                                'temp_topic': '/sensing/lidar/front/temperature',
                                'temp_threshold_c': 60.0,
                                'error_codes_to_monitor': [1001, 1005], # Specific error codes indicating failure
                                'check_duration_sec': 5.0 # Time window to monitor status messages
                            }
                        },
                        {
                            'name': 'FrontCamera',
                            'type': 'Camera',
                            'connectivity_checks': [
                                {'type': 'device_file', 'path': '/dev/video0'},
                            ],
                            'data_stream_checks': {
                                'topic_name': '/sensing/camera/front/image_raw',
                                'expected_rate_hz': 30.0,
                                'rate_tolerance_percent': 15.0,
                                'max_packet_loss_percent': 1.0,
                                'check_duration_sec': 2.0
                            },
                            'internal_health_checks': {
                                'status_topic': '/sensing/camera/front/camera_info', # Example, depends on sensor message
                                'temp_topic': '/sensing/camera/front/temperature', # Assume a separate temp topic
                                'temp_threshold_c': 70.0,
                                # Camera might not report specific error codes via topic, or need different logic
                            }
                        },
                         {
                            'name': 'VehicleGPS',
                            'type': 'GPS/GNSS',
                            'connectivity_checks': [
                                {'type': 'device_file', 'path': '/dev/gps0'}, # Example serial device
                                {'type': 'network_port', 'host': '192.168.1.10', 'port': 5000}, # Example network device
                            ],
                            'data_stream_checks': {
                                'topic_name': '/sensing/gnss/fix', # Example NavSatFix topic
                                'expected_rate_hz': 5.0,
                                'rate_tolerance_percent': 25.0,
                                'max_packet_loss_percent': 5.0,
                                'check_duration_sec': 10.0
                            },
                             'internal_health_checks': {
                                'status_topic': '/sensing/gnss/navsatfix', # NavSatFix contains status
                                'gps_check_params': {
                                    'min_satellites': 6,
                                    'max_hdop': 2.0,
                                    'required_fix_types': [2, 3] # Example: 2=3D fix, 3=3D differential fix
                                },
                                'check_duration_sec': 10.0
                            }
                        },
                        # Add other sensors like RADAR, IMU, etc.
                    ]
        """
        if not isinstance(config, list):
            logging.error("Sensor config must be a list of dictionaries.")
            self.config = []
            self.initialization_error = "Invalid configuration format."
        else:
            self.config = config
            self.initialization_error = None

        # Placeholder for middleware client (e.g., ROS node, DDS participant)
        # In a real implementation, you would initialize your middleware connection here
        self._middleware_client: Optional[Any] = None
        logging.info(
            "SensorHealthChecker initialized. Middleware client is a placeholder.")
        # Example: self._middleware_client = ros.init_node("sensor_health_checker")

    def _check_device_file(self, path: str) -> Tuple[bool, str]:
        """
        Checks if a device file exists and is accessible.

        Args:
            path: The path to the device file (e.g., /dev/ttyUSB0).

        Returns:
            A tuple (success, message).
        """
        logging.debug(f"Checking device file existence: {path}")
        if os.path.exists(path):
            # Optional: Add os.stat(path) checks for permissions or device type
            # try:
            #     stat_info = os.stat(path)
            #     # Check if it's a character device (S_ISCHR) or block device (S_ISBLK)
            #     if os.stat.S_ISCHR(stat_info.st_mode) or os.stat.S_ISBLK(stat_info.st_mode):
            #          return True, f"Device file exists and is accessible: {path}"
            #     else:
            #          return False, f"Path exists but is not a device file: {path}"
            # except Exception as e:
            #     return False, f"Device file exists but could not get status ({path}): {e}"
            return True, f"Device file exists: {path}"
        else:
            return False, f"Device file not found: {path}"

    def _check_network_port(self, host: str, port: int, timeout: float = 1.0) -> Tuple[bool, str]:
        """
        Checks if a network port is open and reachable.

        Args:
            host: The hostname or IP address.
            port: The port number.
            timeout: Socket connection timeout in seconds.

        Returns:
             A tuple (success, message).
        """
        import socket  # Import socket here as it's not always needed

        logging.debug(f"Checking network port: {host}:{port}")
        try:
            # Create a TCP socket
            with socket.create_connection((host, port), timeout=timeout):
                return True, f"Network port is open: {host}:{port}"
        except ConnectionRefusedError:
            return False, f"Network port refused connection: {host}:{port}"
        except socket.timeout:
            return False, f"Network port connection timed out: {host}:{port}"
        except socket.gaierror:
            return False, f"Network port address resolution error (Unknown host): {host}"
        except Exception as e:
            return False, f"Error checking network port {host}:{port}: {e}"

    def check_connectivity(self, sensor_config: Dict[str, Any]) -> Dict[str, Any]:
        """
        Performs connectivity checks for a specific sensor based on configuration.

        Args:
            sensor_config: The dictionary for a single sensor from the main configuration.
                           Expected to have a 'connectivity_checks' key (list of dicts).

        Returns:
            A dictionary summarizing connectivity check results for the sensor.
            Example: {'status': 'PASS', 'details': [{'type': 'device_file', 'path': '/dev/ttyUSB0', 'status': 'PASS', 'message': '...'}]}
                     {'status': 'FAIL', 'details': [...], 'errors': ['...']}
        """
        sensor_name = sensor_config.get('name', 'UnknownSensor')
        logging.info(f"Checking connectivity for {sensor_name}...")
        results: Dict[str, Any] = {'status': 'PASS', 'details': []}
        errors: List[str] = []
        overall_pass = True

        connectivity_checks = sensor_config.get('connectivity_checks', [])
        if not connectivity_checks:
            results['details'].append(
                {'type': 'info', 'message': 'No connectivity checks configured.'})
            logging.info(
                f"No connectivity checks configured for {sensor_name}.")
            return results  # No checks defined, consider it passing for this stage

        if not isinstance(connectivity_checks, list):
            err_msg = f"Invalid format for connectivity_checks in {sensor_name}. Expected list."
            errors.append(err_msg)
            logging.error(err_msg)
            overall_pass = False  # Format error means checks couldn't run

        else:
            for check in connectivity_checks:
                check_type = check.get('type')
                check_pass = False
                check_message = "Check not executed or invalid type."
                check_detail: Dict[str, Any] = {'type': check_type}

                if check_type == 'device_file':
                    path = check.get('path')
                    if path:
                        check_detail['path'] = path
                        check_pass, check_message = self._check_device_file(
                            path)
                    else:
                        check_message = "Device file path is missing in config."
                        overall_pass = False  # Missing config is a failure to configure
                        errors.append(
                            f"Config error for {sensor_name} device_file check: {check_message}")
                        logging.error(errors[-1])

                elif check_type == 'network_port':
                    host = check.get('host')
                    port = check.get('port')
                    timeout = check.get('timeout', 1.0)
                    if host and isinstance(port, int):
                        check_detail['host'] = host
                        check_detail['port'] = port
                        check_pass, check_message = self._check_network_port(
                            host, port, timeout)
                    else:
                        check_message = "Network port host or port is missing/invalid in config."
                        overall_pass = False  # Missing config is a failure to configure
                        errors.append(
                            f"Config error for {sensor_name} network_port check: {check_message}")
                        logging.error(errors[-1])

                # Add other connectivity check types here (e.g., ping, specific driver status file)
                # elif check_type == 'ping': ...
                # elif check_type == 'driver_status_file': ...

                else:
                    check_message = f"Unsupported connectivity check type: {check_type}"
                    logging.warning(f"{sensor_name}: {check_message}")
                    overall_pass = False  # Unsupported type means this check fails
                    errors.append(
                        f"Config error for {sensor_name}: {check_message}")

                check_detail['status'] = 'PASS' if check_pass else 'FAIL'
                check_detail['message'] = check_message
                results['details'].append(check_detail)

                if not check_pass:
                    overall_pass = False  # If any check fails, overall status is FAIL

        results['status'] = 'PASS' if overall_pass and not errors else 'FAIL'
        if errors:
            results['errors'] = errors

        logging.info(
            f"Connectivity check for {sensor_name} finished with status: {results['status']}")
        return results

    def check_data_stream(self, sensor_config: Dict[str, Any]) -> Dict[str, Any]:
        """
        Checks sensor data stream presence, rate, and packet loss.

        *** PLACEHOLDER IMPLEMENTATION ***
        This requires integration with a specific middleware (e.g., ROS, DDS)
        and listener/subscriber logic.

        Args:
            sensor_config: The dictionary for a single sensor.
                           Expected to have a 'data_stream_checks' key (dict).

        Returns:
            A dictionary summarizing data stream check results.
            Example: {'status': 'PASS', 'details': {'topic_name': '...', 'actual_rate_hz': ..., 'packet_loss_percent': ...}}
                     {'status': 'FAIL', 'errors': ['...']}
        """
        sensor_name = sensor_config.get('name', 'UnknownSensor')
        logging.info(f"Checking data stream for {sensor_name}...")
        results: Dict[str, Any] = {
            'status': 'NOT_EXECUTED', 'details': {}, 'errors': []}

        data_stream_config = sensor_config.get('data_stream_checks')

        if not data_stream_config:
            results['status'] = 'SKIPPED'
            results['details'] = {
                'message': 'No data stream checks configured.'}
            logging.info(
                f"No data stream checks configured for {sensor_name}.")
            return results

        if not self._middleware_client:
            results['status'] = 'SKIPPED'
            error_msg = "Middleware client not initialized. Cannot check data streams."
            results['errors'].append(error_msg)
            results['details'] = {'message': error_msg}
            logging.error(f"{sensor_name}: {error_msg}")
            return results

        # --- ACTUAL IMPLEMENTATION WOULD GO HERE ---
        # This would involve:
        # 1. Getting parameters from data_stream_config (topic_name, expected_rate_hz, etc.)
        topic_name = data_stream_config.get('topic_name')
        expected_rate_hz = data_stream_config.get('expected_rate_hz')
        rate_tolerance_percent = data_stream_config.get(
            'rate_tolerance_percent', 10.0)
        max_packet_loss_percent = data_stream_config.get(
            'max_packet_loss_percent', 0.0)
        check_duration_sec = data_stream_config.get('check_duration_sec', 5.0)

        if not topic_name:
            results['status'] = 'FAIL'
            error_msg = "Data stream check configured but 'topic_name' is missing."
            results['errors'].append(error_msg)
            logging.error(f"{sensor_name}: {error_msg}")
            return results

        results['details']['topic_name'] = topic_name
        results['details']['expected_rate_hz'] = expected_rate_hz
        results['details']['check_duration_sec'] = check_duration_sec

        logging.warning(
            f"Data stream check for {sensor_name} on topic '{topic_name}' is a placeholder.")
        # Example logic outline:
        # subscriber = self._middleware_client.create_subscription(topic_name, ...)
        # messages_received = 0
        # start_time = time.time()
        # last_seq_num = None # To check packet loss if messages have sequence numbers

        # while time.time() - start_time < check_duration_sec:
        #     # Wait for messages with a timeout
        #     message = subscriber.wait_for_message(timeout=...)
        #     if message:
        #         messages_received += 1
        #         # If message has sequence number (e.g., ROS Header):
        #         # current_seq_num = message.header.seq if hasattr(message, 'header') else None
        #         # if last_seq_num is not None and current_seq_num is not None and current_seq_num > last_seq_num + 1:
        #         #     lost_count += (current_seq_num - last_seq_num - 1)
        #         # last_seq_num = current_seq_num
        #     # else: timeout occurred, no message received

        # # Calculate actual rate
        # actual_rate_hz = messages_received / check_duration_sec if check_duration_sec > 0 else 0.0

        # # Calculate packet loss (requires sequence numbers)
        # # total_expected_messages = ... based on first/last sequence numbers or expected rate
        # # packet_loss_count = ...
        # # packet_loss_percent = (packet_loss_count / total_expected_messages) * 100 if total_expected_messages > 0 else 0.0
        # # For placeholder, assume 0 loss
        # packet_loss_percent = 0.0 # Placeholder

        # # Compare results against thresholds
        # rate_pass = True
        # if expected_rate_hz is not None:
        #     lower_bound = expected_rate_hz * (1 - rate_tolerance_percent / 100.0)
        #     upper_bound = expected_rate_hz * (1 + rate_tolerance_percent / 100.0)
        #     rate_pass = lower_bound <= actual_rate_hz <= upper_bound
        #     results['details']['actual_rate_hz'] = actual_rate_hz
        #     results['details']['rate_pass'] = rate_pass
        # else:
        #      results['details']['message'] = "No expected rate configured, only checking for presence."
        #      rate_pass = actual_rate_hz > 0 # Just check if any messages were received

        # loss_pass = packet_loss_percent <= max_packet_loss_percent
        # results['details']['packet_loss_percent'] = packet_loss_percent
        # results['details']['loss_pass'] = loss_pass

        # results['status'] = 'PASS' if rate_pass and loss_pass else 'FAIL'

        # --- End of placeholder implementation ---
        results['status'] = 'SKIPPED'  # Placeholder status
        results['details'][
            'message'] = "Data stream check requires middleware integration (placeholder)."
        logging.info(
            f"Data stream check for {sensor_name} skipped (placeholder).")

        return results

    def check_internal_health(self, sensor_config: Dict[str, Any]) -> Dict[str, Any]:
        """
        Checks sensor internal health status, errors, temperature, etc.

        *** PLACEHOLDER IMPLEMENTATION ***
        This requires integration with a specific middleware and knowledge
        of sensor-specific status message formats.

        Args:
            sensor_config: The dictionary for a single sensor.
                           Expected to have an 'internal_health_checks' key (dict).

        Returns:
            A dictionary summarizing internal health check results.
            Example: {'status': 'PASS', 'details': {'temperature_c': ..., 'temp_pass': True, 'errors_detected': []}}
                     {'status': 'FAIL', 'errors': ['...']}
        """
        sensor_name = sensor_config.get('name', 'UnknownSensor')
        logging.info(f"Checking internal health for {sensor_name}...")
        results: Dict[str, Any] = {
            'status': 'NOT_EXECUTED', 'details': {}, 'errors': []}

        health_config = sensor_config.get('internal_health_checks')

        if not health_config:
            results['status'] = 'SKIPPED'
            results['details'] = {
                'message': 'No internal health checks configured.'}
            logging.info(
                f"No internal health checks configured for {sensor_name}.")
            return results

        if not self._middleware_client:
            results['status'] = 'SKIPPED'
            error_msg = "Middleware client not initialized. Cannot check internal health."
            results['errors'].append(error_msg)
            results['details'] = {'message': error_msg}
            logging.error(f"{sensor_name}: {error_msg}")
            return results

        # --- ACTUAL IMPLEMENTATION WOULD GO HERE ---
        logging.warning(
            f"Internal health check for {sensor_name} is a placeholder.")
        # This would involve:
        # 1. Getting parameters from health_config (status_topic, temp_topic, etc.)
        # 2. Subscribing to relevant topics.
        # 3. Monitoring messages over a check_duration_sec window.
        # 4. Parsing sensor-specific fields from messages (e.g., temperature, error codes, GPS status).
        # 5. Comparing parsed values against configured thresholds (temp_threshold_c, error_codes_to_monitor, min_satellites, max_hdop, etc.).

        # Example logic outline for temperature check:
        # temp_topic = health_config.get('temp_topic')
        # temp_threshold_c = health_config.get('temp_threshold_c')
        # if temp_topic and temp_threshold_c is not None:
        #    # Subscribe to temp_topic, get latest temp message within duration
        #    latest_temp = ... # Parse temp from message
        #    results['details']['temperature_c'] = latest_temp
        #    results['details']['temp_pass'] = latest_temp <= temp_threshold_c
        #    if not results['details']['temp_pass']:
        #        results['errors'].append(f"Temperature {latest_temp}°C exceeds threshold {temp_threshold_c}°C")

        # Example logic outline for error code check:
        # status_topic = health_config.get('status_topic')
        # error_codes_to_monitor = health_config.get('error_codes_to_monitor', [])
        # if status_topic and error_codes_to_monitor:
        #    # Subscribe to status_topic, monitor messages within duration
        #    # Check if any message contains a monitored error code
        #    detected_errors = []
        #    # ... logic to check messages ...
        #    results['details']['errors_detected'] = detected_errors
        #    if detected_errors:
        #        results['errors'].append(f"Monitored error codes detected: {detected_errors}")

        # Example logic outline for GPS check:
        # gps_check_params = health_config.get('gps_check_params')
        # gps_topic = health_config.get('status_topic') # Assuming status_topic is NavSatFix
        # if gps_topic and gps_check_params:
        #     # Subscribe to gps_topic, get latest message
        #     latest_fix = ... # Parse NavSatFix
        #     sats = latest_fix.satellites_visible if hasattr(latest_fix, 'satellites_visible') else None # Example field
        #     hdop = latest_fix.position_covariance[0] if hasattr(latest_fix, 'position_covariance') and len(latest_fix.position_covariance) > 0 else None # Example HDOP source
        #     fix_type = latest_fix.status.status # Example fix type field
        #     results['details']['gps_status'] = {'satellites': sats, 'hdop': hdop, 'fix_type': fix_type}

        #     gps_pass = True
        #     if sats is not None and sats < gps_check_params.get('min_satellites', 0):
        #          results['errors'].append(f"GPS satellites {sats} below minimum {gps_check_params['min_satellites']}")
        #          gps_pass = False
        #     if hdop is not None and hdop > gps_check_params.get('max_hdop', float('inf')):
        #          results['errors'].append(f"GPS HDOP {hdop} above maximum {gps_check_params['max_hdop']}")
        #          gps_pass = False
        #     required_fixes = gps_check_params.get('required_fix_types')
        #     if required_fixes is not None and fix_type not in required_fixes:
        #          results['errors'].append(f"GPS fix type {fix_type} not among required types {required_fixes}")
        #          gps_pass = False

        #     results['details']['gps_pass'] = gps_pass

        # # Determine overall status based on individual checks and collected errors
        # overall_pass = not results['errors'] # Simple: pass if no errors were added
        # results['status'] = 'PASS' if overall_pass else 'FAIL'

        # --- End of placeholder implementation ---
        results['status'] = 'SKIPPED'  # Placeholder status
        results['details'][
            'message'] = "Internal health check requires middleware integration and message parsing (placeholder)."
        logging.info(
            f"Internal health check for {sensor_name} skipped (placeholder).")

        return results

    def run_checks(self) -> Dict[str, Any]:
        """
        Runs all configured checks for all sensors.

        Returns:
            A dictionary containing the results for each sensor and aggregated errors.
            Example Structure:
            {
                'report_status': 'PASS' or 'FAIL',
                'sensor_results': [
                    {
                        'name': 'FrontLiDAR',
                        'type': 'LiDAR',
                        'connectivity_check': {'status': 'PASS', ...},
                        'data_stream_check': {'status': 'SKIPPED', ...}, # or PASS/FAIL
                        'internal_health_check': {'status': 'SKIPPED', ...}, # or PASS/FAIL
                        'report_status': 'PASS' or 'FAIL', # Overall for this sensor
                        'errors': [...] # Errors specific to this sensor
                    },
                    ...
                ],
                'aggregated_errors': [...] # All errors from all checks
            }
        """
        if self.initialization_error:
            return {
                'report_status': 'FAIL',
                'initialization_error': self.initialization_error,
                'aggregated_errors': [self.initialization_error]
            }

        logging.info("Starting sensor health checks...")
        all_sensor_results: List[Dict[str, Any]] = []
        aggregated_errors: List[str] = []
        report_status = 'PASS'

        for sensor_config in self.config:
            sensor_name = sensor_config.get('name', 'UnknownSensor')
            sensor_type = sensor_config.get('type', 'UnknownType')
            logging.info(
                f"--- Checking sensor: {sensor_name} ({sensor_type}) ---")

            sensor_result: Dict[str, Any] = {
                'name': sensor_name,
                'type': sensor_type,
                'report_status': 'PASS',  # Assume pass unless a check fails
                'errors': []
            }

            # Run connectivity checks
            conn_check_result = self.check_connectivity(sensor_config)
            sensor_result['connectivity_check'] = conn_check_result
            if conn_check_result['status'] == 'FAIL':
                sensor_result['report_status'] = 'FAIL'
                sensor_result['errors'].extend(
                    conn_check_result.get('errors', []))
                aggregated_errors.extend(
                    [f"{sensor_name} Connectivity: {err}" for err in conn_check_result.get('errors', [])])
                if 'details' in conn_check_result:
                    for detail in conn_check_result['details']:
                        if detail.get('status') == 'FAIL':
                            sensor_result['errors'].append(
                                f"Connectivity check failed: {detail.get('type')} - {detail.get('message')}")

            # Run data stream checks (placeholder)
            # In a real implementation, you'd need to ensure the middleware
            # client is connected/ready before calling this.
            data_stream_check_result = self.check_data_stream(sensor_config)
            sensor_result['data_stream_check'] = data_stream_check_result
            if data_stream_check_result['status'] == 'FAIL':
                sensor_result['report_status'] = 'FAIL'
                sensor_result['errors'].extend(
                    data_stream_check_result.get('errors', []))
                aggregated_errors.extend(
                    [f"{sensor_name} Data Stream: {err}" for err in data_stream_check_result.get('errors', [])])

            # Run internal health checks (placeholder)
            # Need middleware client and potential sensor-specific parsers initialized.
            internal_health_check_result = self.check_internal_health(
                sensor_config)
            sensor_result['internal_health_check'] = internal_health_check_result
            if internal_health_check_result['status'] == 'FAIL':
                sensor_result['report_status'] = 'FAIL'
                sensor_result['errors'].extend(
                    internal_health_check_result.get('errors', []))
                aggregated_errors.extend(
                    [f"{sensor_name} Internal Health: {err}" for err in internal_health_check_result.get('errors', [])])

            # If any check for this sensor failed, update overall status
            if sensor_result['report_status'] == 'FAIL':
                report_status = 'FAIL'

            all_sensor_results.append(sensor_result)
            logging.info(
                f"--- Sensor {sensor_name} finished with overall status: {sensor_result['report_status']} ---")

        logging.info("Finished all sensor health checks.")

        return {
            'report_status': report_status,
            'sensor_results': all_sensor_results,
            'aggregated_errors': aggregated_errors
        }

    # Example method to connect to middleware (implement based on your actual middleware)
    # def connect_middleware(self, middleware_type: str, **kwargs):
    #     """
    #     Connects to the specified middleware.
    #     This method needs actual implementation based on ROS, DDS, etc.
    #     """
    #     logging.info(f"Connecting to middleware type: {middleware_type}")
    #     try:
    #         if middleware_type == 'ros':
    #             # Example for ROS 1 (rospy)
    #             # import rospy
    #             # rospy.init_node('sensor_health_checker_node', anonymous=True)
    #             # self._middleware_client = rospy
    #             pass # Replace with real ROS init

    #         elif middleware_type == 'dds':
    #             # Example for DDS (using a hypothetical library)
    #             # import my_dds_library
    #             # self._middleware_client = my_dds_library.Participant(**kwargs)
    #              pass # Replace with real DDS init
    #         else:
    #             raise ValueError(f"Unsupported middleware type: {middleware_type}")

    #         logging.info(f"Successfully initialized placeholder middleware client for {middleware_type}.")
    #         self._middleware_client = True # Set to True or actual client object on success
    #     except Exception as e:
    #         logging.error(f"Failed to connect to middleware {middleware_type}: {e}")
    #         self._middleware_client = None # Ensure it's None on failure
    #         self.initialization_error = f"Failed to connect to middleware: {e}"


# Example Usage (replace with your actual sensor config)
if __name__ == "__main__":
    # This is a sample configuration. Replace with your actual sensor setup.
    SAMPLE_SENSOR_CONFIG = [
        {
            'name': 'SampleLiDAR',
            'type': 'LiDAR',
            'connectivity_checks': [
                {'type': 'device_file', 'path': '/dev/ttyUSB_LIDAR'},  # Example path
                # {'type': 'device_file', 'path': '/dev/nonexistent_device'}, # Example fail
            ],
            'data_stream_checks': {
                'topic_name': '/sample/lidar/points',
                'expected_rate_hz': 10.0,
                'rate_tolerance_percent': 20.0,
                'max_packet_loss_percent': 5.0,
                'check_duration_sec': 3.0
            },
            'internal_health_checks': {
                'status_topic': '/sample/lidar/status',
                'temp_topic': '/sample/lidar/temperature',
                'temp_threshold_c': 65.0,
                'error_codes_to_monitor': [1001, 1005],
                'check_duration_sec': 3.0
            }
        },
        {
            'name': 'SampleCamera',
            'type': 'Camera',
            'connectivity_checks': [
                {'type': 'device_file', 'path': '/dev/video0'},  # Example path
                {'type': 'network_port', 'host': '192.168.1.100',
                    'port': 8080, 'timeout': 0.5},  # Example network check
            ],
            'data_stream_checks': {
                'topic_name': '/sample/camera/image',
                'expected_rate_hz': 30.0,
                'rate_tolerance_percent': 15.0,
                'max_packet_loss_percent': 1.0,
                'check_duration_sec': 2.0
            },
            'internal_health_checks': {
                'status_topic': '/sample/camera/info',
                'check_duration_sec': 2.0
                # No temp or specific error codes configured for this example
            }
        },
        {
            'name': 'SampleGPS',
            'type': 'GPS/GNSS',
            'connectivity_checks': [
                {'type': 'device_file', 'path': '/dev/ttyACM0'},  # Example path
            ],
            'data_stream_checks': {
                'topic_name': '/sample/gnss/fix',  # Example NavSatFix topic
                'expected_rate_hz': 5.0,
                'rate_tolerance_percent': 25.0,
                'max_packet_loss_percent': 5.0,
                'check_duration_sec': 5.0
            },
            'internal_health_checks': {
                'status_topic': '/sample/gnss/navsatfix',  # Assuming NavSatFix contains status
                'gps_check_params': {
                    'min_satellites': 5,
                    'max_hdop': 1.8,
                    # Example: 2D/3D fix indicators
                    'required_fix_types': [2, 3]
                },
                'check_duration_sec': 5.0
            }
        },
        {
            'name': 'SensorWithNoChecks',
            'type': 'Dummy',
            # No connectivity, data stream, or internal health checks configured
        }
    ]

    # In a real application, you would load this config from a file (e.g., YAML, JSON)
    # Example:
    # import yaml
    # with open('sensor_config.yaml', 'r') as f:
    #     sensor_config = yaml.safe_load(f)
    # checker = SensorHealthChecker(sensor_config)

    checker = SensorHealthChecker(SAMPLE_SENSOR_CONFIG)

    # In a real application, you would call this to connect to your middleware
    # checker.connect_middleware('ros') # Or 'dds' or your custom type

    print("\nRunning sensor health checks...")
    health_report = checker.run_checks()

    import json
    print("\n--- Sensor Health Report (JSON Output) ---")
    print(json.dumps(health_report, indent=4))

    # Example of processing the report
    print("\n--- Report Summary ---")
    print(f"Overall Status: {health_report.get('report_status')}")

    if health_report.get('sensor_results'):
        print("\nSensor Details:")
        for sensor_result in health_report['sensor_results']:
            name = sensor_result.get('name', 'N/A')
            status = sensor_result.get('report_status', 'N/A')
            print(f"  {name}: {status}")
            # Optionally print details for failed checks
            if status == 'FAIL':
                print(f"    Errors: {sensor_result.get('errors', ['None'])}")
                # Print specific check failures
                conn_status = sensor_result.get(
                    'connectivity_check', {}).get('status')
                if conn_status == 'FAIL':
                    print(f"    Connectivity Status: {conn_status}")
                    for det in sensor_result['connectivity_check'].get('details', []):
                        if det.get('status') == 'FAIL':
                            print(
                                f"      - {det.get('type')}: {det.get('message')}")

                data_status = sensor_result.get(
                    'data_stream_check', {}).get('status')
                if data_status == 'FAIL':
                    print(f"    Data Stream Status: {data_status}")
                    print(
                        f"      Details: {sensor_result['data_stream_check'].get('details', {})}")

                internal_status = sensor_result.get(
                    'internal_health_check', {}).get('status')
                if internal_status == 'FAIL':
                    print(f"    Internal Health Status: {internal_status}")
                    print(
                        f"      Details: {sensor_result['internal_health_check'].get('details', {})}")

    if health_report.get('aggregated_errors'):
        print("\nAggregated Errors:")
        for error in health_report['aggregated_errors']:
            print(f"- {error}")

    if health_report.get('initialization_error'):
        print(
            f"\nInitialization Error: {health_report['initialization_error']}")
