from __future__ import annotations

import os
from typing import Mapping


_SUPPORTED_ENV_KEYS = (
    "DREAM_WEAVER_GATEWAY_API_KEY",
    "DREAM_WEAVER_API_KEY",
)


def load_gateway_api_key(env: Mapping[str, str] | None = None) -> str | None:
    values = env if env is not None else os.environ
    for key in _SUPPORTED_ENV_KEYS:
        raw = values.get(key)
        if raw is None:
            continue
        trimmed = raw.strip()
        if trimmed:
            return trimmed
    return None


def extract_gateway_api_key(headers: Mapping[str, str]) -> str | None:
    for header_name in ("x-dream-weaver-api-key", "x-api-key"):
        value = headers.get(header_name)
        if value:
            trimmed = value.strip()
            if trimmed:
                return trimmed

    authorization = headers.get("authorization", "")
    if authorization.lower().startswith("bearer "):
        token = authorization[7:].strip()
        if token:
            return token

    return None


def is_gateway_request_authorized(
    headers: Mapping[str, str],
    required_api_key: str | None,
) -> bool:
    if required_api_key is None:
        return True
    presented = extract_gateway_api_key(headers)
    return presented == required_api_key