import base64
import io
import json
from collections.abc import Generator

from google.cloud import storage as google_cloud_storage

from configs import dify_config
from extensions.storage.base_storage import BaseStorage


class GoogleCloudStorage(BaseStorage):
    """Implementation for Google Cloud storage."""

    def __init__(self):
        super().__init__()

        self.bucket_name = dify_config.GOOGLE_STORAGE_BUCKET_NAME
        service_account_json_str = dify_config.GOOGLE_STORAGE_SERVICE_ACCOUNT_JSON_BASE64
        # if service_account_json_str is empty, use Application Default Credentials
        if service_account_json_str:
            service_account_json = base64.b64decode(service_account_json_str).decode("utf-8")
            # convert str to object
            service_account_obj = json.loads(service_account_json)
            self.client = google_cloud_storage.Client.from_service_account_info(service_account_obj)
        else:
            self.client = google_cloud_storage.Client()

    def save(self, filename, data):
        bucket = self.client.get_bucket(self.bucket_name)
        blob = bucket.blob(filename)
        with io.BytesIO(data) as stream:
            blob.upload_from_file(stream)

    def load_once(self, filename: str) -> bytes:
        bucket = self.client.get_bucket(self.bucket_name)
        blob = bucket.get_blob(filename)
        data = blob.download_as_bytes()
        return data

    def load_stream(self, filename: str) -> Generator:
        bucket = self.client.get_bucket(self.bucket_name)
        blob = bucket.get_blob(filename)
        with blob.open(mode="rb") as blob_stream:
            while chunk := blob_stream.read(4096):
                yield chunk

    def download(self, filename, target_filepath):
        bucket = self.client.get_bucket(self.bucket_name)
        blob = bucket.get_blob(filename)
        blob.download_to_filename(target_filepath)

    def exists(self, filename):
        bucket = self.client.get_bucket(self.bucket_name)
        blob = bucket.blob(filename)
        return blob.exists()

    def delete(self, filename):
        bucket = self.client.get_bucket(self.bucket_name)
        bucket.delete_blob(filename)