"""MinIO client wrapper for object storage operations."""

import io
import logging
from typing import Optional

from minio import Minio
from minio.error import S3Error

from config import settings

logger = logging.getLogger(__name__)

BUCKET_NAME = "seg-media"

_minio_client: Optional[Minio] = None


def get_minio_client() -> Minio:
    """Return a singleton MinIO client instance."""
    global _minio_client
    if _minio_client is None:
        _minio_client = Minio(
            settings.minio_endpoint,
            access_key=settings.minio_access_key,
            secret_key=settings.minio_secret_key,
            secure=settings.minio_secure,
        )
    return _minio_client


def ensure_bucket_exists() -> None:
    """Create the bucket if it does not already exist."""
    client = get_minio_client()
    try:
        if not client.bucket_exists(BUCKET_NAME):
            client.make_bucket(BUCKET_NAME)
            logger.info("Created MinIO bucket: %s", BUCKET_NAME)
        else:
            logger.info("MinIO bucket %s already exists", BUCKET_NAME)
    except S3Error as exc:
        logger.error("MinIO bucket check/creation failed: %s", exc)
        raise


def upload_file(
    object_name: str,
    data: bytes,
    content_type: str = "application/octet-stream",
    length: int = -1,
) -> str:
    """Upload bytes to MinIO and return the object name.

    Args:
        object_name: Destination path inside the bucket.
        data: Raw bytes or a file-like object.
        content_type: MIME type of the object.
        length: Object size; -1 for unknown (uses chunked upload).

    Returns:
        The object name (same as input).
    """
    client = get_minio_client()
    if isinstance(data, bytes):
        data = io.BytesIO(data)
        length = len(data.getvalue())

    try:
        client.put_object(
            BUCKET_NAME,
            object_name,
            data,
            length=length,
            content_type=content_type,
        )
        logger.info("Uploaded to MinIO: %s", object_name)
        return object_name
    except S3Error as exc:
        logger.error("MinIO upload failed: %s", exc)
        raise


from datetime import timedelta

def get_presigned_url(
    object_name: str,
    expires: int = 3600,
    method: str = "GET",
) -> str:
    """Generate a presigned URL for an object.

    Args:
        object_name: Path inside the bucket.
        expires: Expiration time in seconds (default 1 hour).
        method: HTTP method (GET or PUT).

    Returns:
        Presigned URL string.
    """
    client = get_minio_client()
    try:
        url = client.get_presigned_url(method, BUCKET_NAME, object_name, expires=timedelta(seconds=expires))
        return url
    except S3Error as exc:
        logger.error("MinIO presigned URL failed: %s", exc)
        raise


def download_file(object_name: str) -> bytes:
    """Download an object from MinIO and return its bytes.

    Args:
        object_name: Path inside the bucket.

    Returns:
        Raw bytes of the object.
    """
    client = get_minio_client()
    try:
        response = client.get_object(BUCKET_NAME, object_name)
        data = response.read()
        response.close()
        response.release_conn()
        return data
    except S3Error as exc:
        logger.error("MinIO download failed: %s", exc)
        raise