from google.cloud import storage
from concurrent.futures import ThreadPoolExecutor


class GCS:
    def __init__(self, bucket_name,project):
        self.bucket_name = bucket_name
        self.client = storage.Client(project)

    def get_file(self, filename):
        bucket = self.client.get_bucket(self.bucket_name)
        blob = storage.Blob(filename, bucket)
        return blob.download_as_text()

    def get_file_list(self, path):
        blobs = self.client.list_blobs(self.bucket_name, prefix=path)
        return [blob.name for blob in blobs]

    def file_exists(self, path):
        bucket = self.client.get_bucket(self.bucket_name)
        blob = storage.Blob(path, bucket)
        return blob.exists()
def get_files(max_thread,project,bucket_name,filelist):
    resultfiles =[]
    with ThreadPoolExecutor(max_workers=max_thread) as executor:
        # The order of the exector results is the same as the order of the input, so we can guarantee the chronological order of the returned slowlogs 
        res = executor.map(GCS.get_file, [GCS(bucket_name,project)] * len(filelist), filelist)
        for one in res:
            resultfiles.append(one)
    return resultfiles