#!/usr/bin/env python3
"""Validate requested public web ports against an ADR-0008 reef declaration."""

from __future__ import annotations

import argparse
import json
import sys
from pathlib import Path
from typing import Any

import yaml


class GrantError(ValueError):
    pass


def validate(payload: Any, ports: list[int]) -> dict[str, Any]:
    if not isinstance(payload, dict):
        raise GrantError("reef declaration must be a YAML object")
    if any(port == 6443 for port in ports):
        raise GrantError("6443 is operator-only and cannot be publicly granted")
    if any(port not in {80, 443} for port in ports):
        raise GrantError("the public web gate accepts only ports 80 and 443")
    if not payload.get("primary_rail") and not payload.get("hosted_rails"):
        raise GrantError("provider-delegated reefs cannot publish a public listener")
    exposure = payload.get("exposure") or {}
    if exposure.get("posture") != "public":
        raise GrantError("reef exposure.posture must be public")
    grants = exposure.get("grants") or []
    for port in ports:
        matches = [grant for grant in grants if isinstance(grant, dict) and grant.get("port") in {port, str(port)}]
        if not matches:
            raise GrantError(f"reef has no substrate grant for port {port}")
        grant = matches[0]
        missing = [field for field in ("reason", "approved_on", "residual_risk_owner") if not grant.get(field)]
        if missing:
            raise GrantError(f"port {port} grant is missing {', '.join(missing)}")
    return {
        "reef_id": payload.get("reef_id"),
        "posture": "public",
        "validated_ports": sorted(set(ports)),
    }


def main() -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument("--reef-declaration", type=Path, required=True)
    parser.add_argument("--ports", required=True, help="Comma-separated ports; only 80 and 443 are grantable")
    args = parser.parse_args()
    try:
        ports = [int(value) for value in args.ports.split(",") if value]
        if not ports:
            raise GrantError("at least one requested port is required")
        payload = yaml.safe_load(args.reef_declaration.read_text(encoding="utf-8"))
        result = validate(payload, ports)
    except (OSError, yaml.YAMLError, ValueError) as exc:
        print(f"reef exposure validation failed: {exc}", file=sys.stderr)
        return 1
    print(json.dumps(result, sort_keys=True))
    return 0


if __name__ == "__main__":
    raise SystemExit(main())