from __future__ import annotations

import hashlib
import secrets
from uuid import uuid4

from govoplan_core.core.operations import OperationalCheck
from govoplan_files.backend.storage.backends import (
    StorageBackendError,
    get_storage_backend,
)


def managed_storage_roundtrip_check() -> OperationalCheck:
    """Exercise the configured managed store without retaining probe data."""

    backend = get_storage_backend()
    key = f".govoplan-health/probes/{uuid4().hex}.bin"
    payload = secrets.token_bytes(64)
    expected_digest = hashlib.sha256(payload).hexdigest()
    delete_error: Exception | None = None
    try:
        backend.put_bytes(key, payload, content_type="application/octet-stream")
        stored = backend.get_bytes(key)
        info = backend.stat(key)
        if info.size_bytes != len(payload):
            raise StorageBackendError("Managed storage returned an unexpected object size")
        if hashlib.sha256(stored).hexdigest() != expected_digest:
            raise StorageBackendError("Managed storage returned different bytes than were written")
    except Exception as exc:  # noqa: BLE001 - operational boundary reports provider failures.
        return OperationalCheck(
            id="files.managed_storage_roundtrip",
            label="Managed file storage",
            state="error",
            detail=(
                "The configured managed file store failed a bounded write/read/stat/delete "
                f"probe ({type(exc).__name__})."
            ),
            readiness_critical=True,
            metrics={"backend": backend.name, "probe_bytes": len(payload)},
        )
    finally:
        try:
            backend.delete(key)
        except Exception as exc:  # noqa: BLE001 - reported below when the data probe passed.
            delete_error = exc

    if delete_error is not None:
        return OperationalCheck(
            id="files.managed_storage_roundtrip",
            label="Managed file storage",
            state="error",
            detail=(
                "Managed file bytes round-tripped, but probe cleanup failed "
                f"({type(delete_error).__name__})."
            ),
            readiness_critical=True,
            metrics={"backend": backend.name, "probe_bytes": len(payload)},
        )
    return OperationalCheck(
        id="files.managed_storage_roundtrip",
        label="Managed file storage",
        state="ok",
        detail="The configured managed file store passed write, read, stat, integrity, and delete checks.",
        metrics={"backend": backend.name, "probe_bytes": len(payload)},
    )