from __future__ import annotations

import re
import sys
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
BACKEND = ROOT / "backend"
DOCS = ROOT / "docs" / "API_CONTRACTS.md"  # docs/API_CONTRACTS.md

ALLOWED_NON_ENVELOPE_ENDPOINTS = {
    ("GET", "/health"),
    ("GET", "/api/v1/exports/{export_id}/download"),
}

IGNORED_OPENAPI_PATHS = {
    "/openapi.json",
    "/docs",
    "/docs/oauth2-redirect",
    "/redoc",
}


def _load_app_routes() -> set[tuple[str, str]]:
    sys.path.insert(0, str(BACKEND))
    from app.main import create_app

    app = create_app()
    routes: set[tuple[str, str]] = set()
    for route in app.routes:
        path = getattr(route, "path", None)
        methods = getattr(route, "methods", set())
        if not path or path in IGNORED_OPENAPI_PATHS:
            continue
        for method in sorted(methods - {"HEAD", "OPTIONS"}):
            routes.add((method, path))
    return routes


def _load_documented_routes() -> set[tuple[str, str]]:
    docs = DOCS.read_text(encoding="utf-8")
    return set(re.findall(r"###\s+(GET|POST|PATCH|DELETE)\s+`([^`]+)`", docs))


def main() -> None:
    implemented_routes = _load_app_routes()
    documented_routes = _load_documented_routes()

    missing_docs = sorted(implemented_routes - documented_routes)
    stale_docs = sorted(documented_routes - implemented_routes)
    missing_non_envelope = sorted(ALLOWED_NON_ENVELOPE_ENDPOINTS - implemented_routes)

    errors: list[str] = []
    for method, path in missing_docs:
        errors.append(f"Missing documented API route: {method} {path}")
    for method, path in stale_docs:
        errors.append(f"Documented API route is not implemented: {method} {path}")
    for method, path in missing_non_envelope:
        errors.append(f"Allowed non-envelope endpoint is not implemented: {method} {path}")

    if errors:
        raise SystemExit("\n".join(errors))

    print(
        "API contract audit OK: "
        f"{len(implemented_routes)} implemented routes match docs; "
        f"{len(ALLOWED_NON_ENVELOPE_ENDPOINTS)} explicit non-envelope endpoints tracked."
    )


if __name__ == "__main__":
    main()