# app/tiers.py — tier gates for Sparrow
#
# BYOK does not apply to Sparrow — "bring your own" means bring your own
# hardware (self-hosting). is_self_hosted() checks the cf-orch URL target.
from __future__ import annotations

import os
from fastapi import HTTPException


def is_self_hosted() -> bool:
    """
    True when cf-orch is on localhost or a LAN address.

    Self-hosted users get unrestricted access equivalent to Paid tier.
    Cloud users are gated by the standard tier model.
    """
    orch_url = os.environ.get("CF_ORCH_URL", "")
    if not orch_url:
        return True  # no orch = local dev mode = self-hosted
    host = orch_url.split("//")[-1].split(":")[0].split("/")[0]
    return host in ("localhost", "127.0.0.1") or host.startswith("10.") or \
           host.startswith("192.168.") or host.startswith("172.")


def require_tier(feature: str, tier: str | None = None) -> None:
    """
    Gate a feature by tier. Raises 402 if the caller does not qualify.

    For self-hosted instances all features are unlocked.
    tier=None means the request carries no tier — treat as Free.
    """
    if is_self_hosted():
        return

    _TIER_RANK = {"free": 0, "paid": 1, "premium": 2}
    _FEATURE_MIN: dict[str, str] = {
        "stems": "paid",
        "parallel_branch": "paid",
        "session_allocation": "premium",
        "priority_queue": "premium",
    }

    min_tier = _FEATURE_MIN.get(feature, "free")
    caller_rank = _TIER_RANK.get(tier or "free", 0)
    required_rank = _TIER_RANK[min_tier]

    if caller_rank < required_rank:
        raise HTTPException(
            status_code=402,
            detail=f"Feature '{feature}' requires {min_tier} tier.",
        )