import os
from io import BytesIO

from minio import Minio
from minio.error import S3Error


STORAGE_BASE = os.getenv("LOCAL_STORAGE_PATH", "./data/files")
MINIO_ENDPOINT = os.getenv("MINIO_ENDPOINT", "localhost:9000")
MINIO_ACCESS_KEY = os.getenv("MINIO_ACCESS_KEY", "minioadmin")
MINIO_SECRET_KEY = os.getenv("MINIO_SECRET_KEY", "minioadmin")
MINIO_SECURE = os.getenv("MINIO_SECURE", "false").lower() == "true"


def _local_path(bucket: str, file_path: str) -> str:
    return os.path.join(STORAGE_BASE, bucket, file_path)


def _save_local(bucket: str, file_path: str, content: bytes) -> str:
    full_path = _local_path(bucket, file_path)
    os.makedirs(os.path.dirname(full_path), exist_ok=True)
    with open(full_path, "wb") as f:
        f.write(content)
    return full_path


def _read_local(bucket: str, file_path: str) -> bytes:
    with open(_local_path(bucket, file_path), "rb") as f:
        return f.read()


def get_minio_client() -> Minio:
    return Minio(
        MINIO_ENDPOINT,
        access_key=MINIO_ACCESS_KEY,
        secret_key=MINIO_SECRET_KEY,
        secure=MINIO_SECURE,
    )


def ensure_bucket(bucket_name: str) -> bool:
    """确保 bucket 存在；MinIO 不可用时返回 False 表示使用本地降级。"""
    try:
        client = get_minio_client()
        if not client.bucket_exists(bucket_name):
            client.make_bucket(bucket_name)
        return True
    except S3Error:
        return False
    except Exception:
        return False


def upload_file(bucket: str, file_path: str, content: bytes) -> str:
    """上传文件到 MinIO；连接失败时降级保存到本地文件系统。"""
    if ensure_bucket(bucket):
        try:
            client = get_minio_client()
            client.put_object(
                bucket,
                file_path,
                BytesIO(content),
                length=len(content),
                content_type="application/vnd.openxmlformats-officedocument.wordprocessingml.document",
            )
            return f"minio://{bucket}/{file_path}"
        except S3Error:
            pass
        except Exception:
            pass

    return _save_local(bucket, file_path, content)


def download_file(bucket: str, file_path: str) -> bytes:
    """从 MinIO 下载文件；读取失败时尝试本地降级路径。"""
    if ensure_bucket(bucket):
        try:
            client = get_minio_client()
            response = client.get_object(bucket, file_path)
            try:
                return response.read()
            finally:
                response.close()
                response.release_conn()
        except S3Error:
            pass
        except Exception:
            pass

    return _read_local(bucket, file_path)


def save_file(content: bytes, file_path: str) -> str:
    """兼容旧调用：保存到默认 templates bucket。"""
    return upload_file("templates", file_path, content)


def read_file(file_path: str) -> bytes:
    """兼容旧调用：从默认 templates bucket 读取。"""
    return download_file("templates", file_path)


def delete_file(file_path: str):
    """删除本地降级文件。MinIO 对象删除后续按接口需要再补充。"""
    full_path = _local_path("templates", file_path)
    if os.path.exists(full_path):
        os.remove(full_path)