#!/usr/bin/env python3
"""
Pick N random scenario JSONs from a pool and inject them into the mock server.

Usage:
    ./inject_random.py                      # 5 random from scenarios/pool/
    ./inject_random.py --count 3
    ./inject_random.py --dir scenarios/pool --count 5 --host 127.0.0.1 --port 8888

Each injected task is tagged with a sequential `_tag` field (if present) so
you can match the `postTaskResult` responses back to which pool entry ran.
"""
import argparse
import json
import random
import sys
import urllib.request
from pathlib import Path


def main() -> int:
    here = Path(__file__).parent
    parser = argparse.ArgumentParser()
    parser.add_argument("--dir", default=str(here / "scenarios" / "pool"),
                        help="Directory with scenario JSON files")
    parser.add_argument("--count", type=int, default=5,
                        help="How many scenarios to pick randomly")
    parser.add_argument("--host", default="127.0.0.1")
    parser.add_argument("--port", type=int, default=8888)
    parser.add_argument("--seed", type=int, default=None,
                        help="Optional RNG seed for reproducibility")
    args = parser.parse_args()

    pool_dir = Path(args.dir)
    files = sorted(pool_dir.glob("*.json"))
    if not files:
        print(f"no scenarios in {pool_dir}", file=sys.stderr)
        return 1
    if args.count > len(files):
        print(f"asked for {args.count} but pool has only {len(files)}",
              file=sys.stderr)
        return 1

    if args.seed is not None:
        random.seed(args.seed)
    picked = random.sample(files, args.count)

    tasks = []
    for p in picked:
        with p.open() as f:
            tasks.append(json.load(f))
        print(f"  picked: {p.name}")

    url = f"http://{args.host}:{args.port}/_admin/inject"
    req = urllib.request.Request(
        url,
        data=json.dumps(tasks).encode(),
        headers={"Content-Type": "application/json"},
        method="POST",
    )
    with urllib.request.urlopen(req, timeout=5) as resp:
        print(f"injected {len(tasks)} tasks -> {resp.status} {resp.read().decode()}")
    return 0


if __name__ == "__main__":
    sys.exit(main())