"""Core mint + revoke logic.

Bridges the source-adapter layer (:mod:`app.adapters`) to the DB
layer (:mod:`app.models`), reusing the desktop app's signing /
encoding primitives from ``datatools_license.crypto`` so blobs minted
here verify against the same embedded pubkey on the buyer's machine.
"""

from __future__ import annotations

import os
import uuid
from datetime import datetime, timezone
from typing import Optional

from sqlalchemy import select
from sqlalchemy.orm import Session

from app.adapters.base import SaleEvent
from app.config import get_settings
from app.models import License


def _init_key_env() -> None:
    """Resolve secret-file pointers into env vars before importing crypto.

    ``datatools_license.crypto`` looks for ``DATATOOLS_LICENSE_PRIVKEY``
    / ``DATATOOLS_LICENSE_PUBKEY`` in ``os.environ``. When those come
    from secret files (``*_FILE`` env vars), we read them once at
    module import and stash so crypto can pick them up without
    changes.
    """
    settings = get_settings()
    priv = settings.resolve_license_privkey()
    if priv:
        os.environ.setdefault("DATATOOLS_LICENSE_PRIVKEY", priv)
    pub = settings.license_pubkey_hex
    if pub:
        os.environ.setdefault("DATATOOLS_LICENSE_PUBKEY", pub)


_init_key_env()

# Imported after env init so the crypto module reads the correct key.
from datatools_license.crypto import encode_blob, sign  # noqa: E402
from datatools_license.features import all_features_for_tier  # noqa: E402
from datatools_license.schema import (  # noqa: E402
    License as LicenseDataclass,
    Tier,
    _utcnow_iso,
    default_expiry_iso,
)


def _generate_license_key(tier: str) -> str:
    rid = uuid.uuid4().hex
    return f"DT1-{tier.upper()}-{rid[:8]}-{rid[8:16]}"


def _iso_to_dt(iso: str) -> datetime:
    return datetime.fromisoformat(iso.replace("Z", "+00:00"))


def mint_from_sale(session: Session, sale: SaleEvent) -> License:
    """Idempotently mint a license for *sale*.

    If a row with the same ``(source, source_order_id)`` already
    exists, return it untouched — Gumroad retrying a webhook does not
    produce a second blob with a different signature. Manual mints
    (``source_order_id is None``) skip the dedup check and always
    produce a new row.
    """
    if sale.source_order_id is not None:
        existing = session.execute(
            select(License).where(
                License.source == sale.source,
                License.source_order_id == sale.source_order_id,
            )
        ).scalar_one_or_none()
        if existing is not None:
            return existing

    tier_enum = Tier(sale.tier)
    license_key = _generate_license_key(sale.tier)
    issued_iso = _utcnow_iso()
    expires_iso = default_expiry_iso(years=sale.years)

    unsigned = LicenseDataclass(
        name=sale.buyer_name,
        email=sale.buyer_email,
        license_key=license_key,
        tier=tier_enum,
        features=all_features_for_tier(tier_enum),
        issued_at=issued_iso,
        expires_at=expires_iso,
        signature="",
    )
    signature = sign(unsigned.to_canonical_dict())
    payload = unsigned.to_canonical_dict()
    payload["signature"] = signature
    blob = encode_blob(payload)

    row = License(
        license_key=license_key,
        name=sale.buyer_name,
        email=sale.buyer_email,
        tier=sale.tier,
        issued_at=_iso_to_dt(issued_iso),
        expires_at=_iso_to_dt(expires_iso),
        blob=blob,
        source=sale.source,
        source_order_id=sale.source_order_id,
        promotion=sale.promotion,
        amount_paid=sale.amount_paid,
        currency=sale.currency,
        notes=sale.notes,
    )
    session.add(row)
    session.flush()
    return row


def revoke_license(
    session: Session,
    *,
    license_key: str,
    reason: Optional[str] = None,
) -> Optional[License]:
    row = session.get(License, license_key)
    if row is None:
        return None
    row.revoked_at = datetime.now(timezone.utc)
    if reason:
        suffix = f"\nRevoked: {reason}"
        row.notes = ((row.notes or "") + suffix).strip()
    return row