"""
Example 6: Multi-Sensor with Async Pipeline

Combines multiprocessing (separate CUDA contexts) with async 3-stage pipeline
(Capture → Flow → HHD) for maximum throughput.

Architecture:
    Process 1 (Sensor 0):  [Capture] → [Flow] → [HHD] → Queue
    Process 2 (Sensor 1):  [Capture] → [Flow] → [HHD] → Queue
                                                          ↓
    Main Process:         Display ← ─────────────────────┘
"""

import os
os.environ["OPENCV_VIDEOIO_MSMF_ENABLE_HW_TRANSFORMS"] = "0"

import cv2
import orisys
import multiprocessing as mp


def main():
    configs = [
        {'vid_src': './s1.mp4', 'isstitch': True, 'cuda': True, 'cal_path': './config/cal.npy'},
        {'vid_src': './s1_copy.mp4', 'isstitch': True, 'cuda': True, 'cal_path': './config/cal.npy'},
    ]
    
    # Method 1: Using async_context (recommended)
    with orisys.MultiSensor.async_context(configs) as multi:
        print("\nAsync multi-sensor started. Press 'q' to quit")
        
        for all_data in multi:
            for data in [d for d in all_data if d]:
                sid = data['sensor_id']
                print(f"Sensor {sid}: FPS={data['fps']:5.1f}, Fn={data['fnormal']:8.2f}")
                
                if data['img'] is not None and data['flow'] is not None:
                    arrows = orisys.util.draw_arrows(data['img'].copy(), data['flow'], threshold=5)
                    cv2.imshow(f"Sensor {sid}", arrows)
            
            if cv2.waitKey(1) & 0xFF == ord('q'):
                break
    
    cv2.destroyAllWindows()


def main_manual():
    """Alternative: Manual start with async flag"""
    configs = [
        {'vid_src': './s1.mp4', 'isstitch': True, 'cuda': True, 'cal_path': './config/cal.npy'},
        {'vid_src': './s1_copy.mp4', 'isstitch': True, 'cuda': True, 'cal_path': './config/cal.npy'},
    ]
    
    multi = orisys.MultiSensor(configs)
    multi.start(use_async=True)  # Enable async mode
    
    try:
        while True:
            for data in [d for d in multi.get_all() if d]:
                cv2.imshow(f"Sensor {data['sensor_id']}", data['img'])
            if cv2.waitKey(1) & 0xFF == ord('q'):
                break
    finally:
        multi.stop()
        cv2.destroyAllWindows()


if __name__ == '__main__':
    mp.freeze_support()
    main()