#!/usr/bin/env python
"""Generate openapi.json from the routers in {root}/src/routers/*.

Usage (from anywhere, with the build's venv):
	python scripts/dump_openapi.py [--src SRC] [--out OUT] [--title TITLE]
"""
import argparse
import importlib
import json
import pkgutil
import sys
from pathlib import Path

from fastapi import APIRouter, FastAPI

ROOT = Path(__file__).resolve().parent.parent


def main() -> int:
	parser = argparse.ArgumentParser()
	parser.add_argument("--src", type=Path, default=ROOT / "src")
	parser.add_argument("--out", type=Path, default=ROOT / "openapi.json")
	parser.add_argument("--title", default=ROOT.name)
	args = parser.parse_args()

	src = args.src.resolve()
	routers_dir = src / "routers"
	if not routers_dir.is_dir():
		print(f"No routers directory found at {routers_dir}", file=sys.stderr)
		return 1

	# Makes `import models`, `import routers.x` and similar work
	sys.path.insert(0, str(src))

	app = FastAPI(title=args.title)
	seen = set()

	for mod_info in pkgutil.walk_packages([str(routers_dir)], prefix="routers."):
		if mod_info.ispkg:
			continue
		module = importlib.import_module(mod_info.name)
		for obj in vars(module).values():
			# Only include routers defined in this module, not ones it merely imports
			if isinstance(obj, APIRouter) and id(obj) not in seen:
				seen.add(id(obj))
				app.include_router(obj)

	# Write straight to the file so stray prints during import can't corrupt the JSON
	args.out.write_text(json.dumps(app.openapi(), indent=2), encoding="utf-8")
	print(f"Wrote {args.out} ({len(seen)} routers)")
	return 0


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