"""Traitlets-based configuration for the snapshot server extension."""

import os

from traitlets.config.configurable import Configurable
from traitlets.traitlets import Bool, Unicode, default


class SnapshotConfig(Configurable):
    """Configuration options for the notebook snapshot extension."""

    storage_type = Unicode(
        "local",
        config=True,
        help='Storage backend type. Either "local" or "s3" (covers AWS S3, MinIO, etc.).',
    )
    local_root = Unicode(
        "",
        config=True,
        help="Directory for local snapshot storage. Empty means <server root_dir>/.notebook_versions.",
    )

    s3_endpoint = Unicode(
        "",
        config=True,
        help="S3 endpoint host (without scheme), e.g. localhost:9000 for MinIO or s3.us-east-1.amazonaws.com for AWS S3.",
    )

    @default("s3_endpoint")
    def _default_s3_endpoint(self):
        """Default to the ``S3_ENDPOINT`` environment variable."""
        return os.environ.get("S3_ENDPOINT", "")

    s3_access_key = Unicode(
        "",
        config=True,
        help="S3 access key ID.",
    )

    @default("s3_access_key")
    def _default_s3_access_key(self):
        """Default to the ``S3_ACCESS_KEY`` environment variable."""
        return os.environ.get("S3_ACCESS_KEY", "")

    s3_secret_key = Unicode(
        "",
        config=True,
        help="S3 secret access key.",
    )

    @default("s3_secret_key")
    def _default_s3_secret_key(self):
        """Default to the ``S3_SECRET_KEY`` environment variable."""
        return os.environ.get("S3_SECRET_KEY", "")

    s3_bucket = Unicode(
        "notebook-snapshot",
        config=True,
        help="S3 bucket name. Created automatically if it does not exist.",
    )

    s3_secure = Bool(
        False,
        config=True,
        help="Use HTTPS for the S3 connection.",
    )

    s3_prefix = Unicode(
        "",
        config=True,
        help="Optional prefix prepended to all object keys in the S3 bucket.",
    )