from collections.abc import Generator

from flask import Flask
from obs import ObsClient

from extensions.storage.base_storage import BaseStorage


class HuaweiStorage(BaseStorage):
    """Implementation for huawei obs storage."""

    def __init__(self, app: Flask):
        super().__init__(app)
        app_config = self.app.config
        self.bucket_name = app_config.get("HUAWEI_OBS_BUCKET_NAME")
        self.client = ObsClient(
            access_key_id=app_config.get("HUAWEI_OBS_ACCESS_KEY"),
            secret_access_key=app_config.get("HUAWEI_OBS_SECRET_KEY"),
            server=app_config.get("HUAWEI_OBS_SERVER"),
        )

    def save(self, filename, data):
        self.client.putObject(bucketName=self.bucket_name, objectKey=filename, content=data)

    def load_once(self, filename: str) -> bytes:
        data = self.client.getObject(bucketName=self.bucket_name, objectKey=filename)["body"].response.read()
        return data

    def load_stream(self, filename: str) -> Generator:
        def generate(filename: str = filename) -> Generator:
            response = self.client.getObject(bucketName=self.bucket_name, objectKey=filename)["body"].response
            yield from response.read(4096)

        return generate()

    def download(self, filename, target_filepath):
        self.client.getObject(bucketName=self.bucket_name, objectKey=filename, downloadPath=target_filepath)

    def exists(self, filename):
        res = self._get_meta(filename)
        if res is None:
            return False
        return True

    def delete(self, filename):
        self.client.deleteObject(bucketName=self.bucket_name, objectKey=filename)

    def _get_meta(self, filename):
        res = self.client.getObjectMetadata(bucketName=self.bucket_name, objectKey=filename)
        if res.status < 300:
            return res
        else:
            return None