#!/usr/bin/env python3

import rclpy
from rclpy.node import Node
from sensor_msgs.msg import Image
from cv_bridge import CvBridge
import cv2
from rclpy.qos import QoSProfile, QoSReliabilityPolicy, QoSHistoryPolicy
from qreader import QReader
from threading import Thread


class ImageSubscriber(Node):
    def __init__(self):
        super().__init__('image_subscriber')
        # 定义 QoS 配置（匹配发布者的可靠性策略）
        qos_profile = QoSProfile(
            reliability=QoSReliabilityPolicy.BEST_EFFORT,  # 或 BEST_EFFORT，取决于发布者
            history=QoSHistoryPolicy.KEEP_LAST,
            depth=10
        )

        self.subscription = self.create_subscription(
            Image,
            '/rgb_camera/image_raw',
            self.image_callback,
            qos_profile=qos_profile
        )
        self.subscription  # 防止未使用变量警告
        self.bridge = CvBridge()
        self.cv_image = None  # Store latest image

    def image_callback(self, msg):
        try:
            # 将ROS图像消息转换为OpenCV格式
            self.cv_image = self.bridge.imgmsg_to_cv2(msg, desired_encoding='bgr8')
            
        except Exception as e:
            self.get_logger().error('Failed to convert image: %s' % str(e))


class ImageProcessor:
    def __init__(self):
        self.image_subscriber = ImageSubscriber()
        self.qreader = QReader()
        self.spin_thread = None
        self.running = True
    
    def run(self):
        self.spin_thread = Thread(target=self._spin)
        self.spin_thread.start()
    
    def _spin(self):
        try:
            while self.running:
                rclpy.spin_once(self.image_subscriber, timeout_sec=0.1)
        except Exception as e:
            print(f"Spin thread error: {e}")
    
    def destroy(self):
        self.running = False
        if self.spin_thread:
            self.spin_thread.join()
        self.image_subscriber.destroy_node()

    def get_current_image(self):
        return self.image_subscriber.cv_image
    
    def decode_qrcode(self, img = None):
        if img is None:
            img = self.get_current_image()
        decoded_info = self.qreader.detect_and_decode(image=img)
        return decoded_info[0]


""" DEBUG """

def main(args=None):
    rclpy.init(args=args)
    image_subscriber = ImageSubscriber()
    
    try:
        rclpy.spin(image_subscriber)
    except KeyboardInterrupt:
        pass
    
    # 清理
    image_subscriber.destroy_node()


if __name__ == '__main__':
    main()