#!/usr/bin/env python
import argparse
import json
import sys
from pathlib import Path

from uvicorn.importer import import_from_string


def main() -> None:
    parser = argparse.ArgumentParser(prog="gen-openapi")
    parser.add_argument(
        "app", help='App import string. Eg. "main:app"', default="main:app"
    )
    parser.add_argument("--app-dir", help="Directory containing the app", default=None)
    parser.add_argument(
        "--out", help="Output file ending in .json", default="openapi.json"
    )
    args = parser.parse_args()

    if args.app_dir is not None:
        print(f"adding {args.app_dir} to sys.path")
        sys.path.insert(0, args.app_dir)

    print(f"importing app from {args.app}")
    app = import_from_string(args.app)
    openapi = app.openapi()
    version = openapi.get("openapi", "unknown version")

    print(f"writing openapi spec v{version}")
    out = Path(args.out)
    out.parent.mkdir(parents=True, exist_ok=True)
    out.write_text(json.dumps(openapi, indent=2))


if __name__ == "__main__":
    main()