#!/usr/bin/env python3
"""
Apollo USB Downlink Demo — generate and decode synthetic telemetry.

Demonstrates the full gr-apollo demod chain:
    1. Generate a synthetic USB baseband signal with known PCM frames
    2. Feed it through usb_downlink_receiver (all-in-one block)
    3. Print decoded frames as they arrive

Usage:
    uv run python examples/usb_downlink_demo.py
"""

import numpy as np
from gnuradio import blocks, gr

from apollo.constants import SAMPLE_RATE_BASEBAND
from apollo.usb_downlink_receiver import usb_downlink_receiver
from apollo.usb_signal_gen import generate_usb_baseband


def main():
    np.random.seed(42)
    known_payload = bytes(np.random.randint(0, 256, size=124, dtype=np.uint8))

    print("Generating 5-frame synthetic USB baseband signal...")
    signal, frame_bits = generate_usb_baseband(
        frames=5,
        frame_data=[known_payload] * 5,
        snr_db=30.0,  # 30 dB SNR — moderate noise
    )
    print(f"  Signal: {len(signal)} samples, {len(signal)/SAMPLE_RATE_BASEBAND:.3f}s")
    print(f"  Frames: {len(frame_bits)} x {len(frame_bits[0])} bits")

    print("\nBuilding flowgraph: usb_downlink_receiver...")
    tb = gr.top_block()

    src = blocks.vector_source_c(signal.tolist())
    receiver = usb_downlink_receiver(output_format="scaled")
    snk = blocks.message_debug()

    tb.connect(src, receiver)
    tb.msg_connect(receiver, "frames", snk, "store")

    print("Running flowgraph...")
    tb.run()

    n_frames = snk.num_messages()
    print(f"\nReceived {n_frames} frame(s) on 'frames' port")

    if n_frames > 0:
        print("\nFirst frame metadata:")
        import pmt

        msg = snk.get_message(0)
        meta = pmt.car(msg)
        fid = pmt.to_long(pmt.dict_ref(meta, pmt.intern("frame_id"), pmt.from_long(-1)))
        conf = pmt.to_long(pmt.dict_ref(meta, pmt.intern("sync_confidence"), pmt.from_long(-1)))
        print(f"  frame_id: {fid}")
        print(f"  sync_confidence: {conf}")
    else:
        print("No frames decoded (PLL may need more settling time)")


if __name__ == "__main__":
    main()