"""教学用双随机帧；默认离线，--send 才在已打开的隔离通道发送。"""
import argparse
import json
import random
import subprocess
import time
from pathlib import Path


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--seed', type=int, default=2026)
    parser.add_argument('--send', action='store_true')
    parser.add_argument('--channel')
    parser.add_argument('--sequence', type=Path)
    args = parser.parse_args()
    if args.send and (not args.channel or not args.sequence):
        parser.error('--send requires --channel and a new --sequence file')
    rng = random.Random(args.seed)
    frames = [dict(index=i, id=f'0x{rng.randrange(0x600, 0x610):03X}',
                   data=' '.join(f'{rng.randrange(256):02X}' for _ in range(8)))
              for i in range(32)]
    lines = [json.dumps(frame, ensure_ascii=False) for frame in frames]
    if args.sequence:
        # 独占创建，保留已经存在的测试记录，不覆盖它们。
        with args.sequence.open('x', encoding='utf-8') as output:
            output.write('\n'.join(lines) + '\n')
    if not args.send:
        print('\n'.join(lines))
        return
    for frame in frames:
        result = subprocess.run(
            ['bmcli', 'message', 'send', f'--channel={args.channel}',
             f'--message={frame["id"]}', f'--data={frame["data"]}',
             '--count=1', '--format=json'],
            capture_output=True, text=True, encoding='utf-8', timeout=10)
        print(json.dumps(dict(index=frame['index'], returncode=result.returncode,
                              stdout=result.stdout, stderr=result.stderr),
                         ensure_ascii=False), flush=True)
        if result.returncode != 0:
            raise SystemExit(result.returncode)
        if json.loads(result.stdout).get('status') != 'ok':
            raise SystemExit('BMCLI did not return status=ok; stopped')
        # 命令调用耗时另计；这是主机侧低速激励，不承诺硬件周期精度。
        time.sleep(0.1)


if __name__ == '__main__':
    main()