import os.path
import boto3
from botocore.config import Config
from concurrent.futures import ThreadPoolExecutor

class S3:
    def __init__(self, bucket_name,instance=None):
        self.bucket_name = bucket_name
        if instance is None:
            endpoint = None
            if "AWS_ENDPOINT_S3" in os.environ:
                s3_config = Config(
                    s3={'addressing_style': 'virtual'}
                )
                endpoint = os.environ["AWS_ENDPOINT_S3"]
                self.s3 = boto3.resource('s3', endpoint_url=endpoint, config=s3_config)
            else:
                self.s3 = boto3.resource('s3')
        else:
            self.s3 = instance

    def get_file(self, filename):
        key = filename
        print('\nget object:', filename)
        return self.s3.Object(self.bucket_name, key).get()['Body'].read()
    
    def get_file_list(self, path):
        bucket = self.s3.Bucket(self.bucket_name)
        prefix = path
        return [obj.key for obj in bucket.objects.filter(Prefix=prefix)]

    def file_exists(self, path):
        bucket = self.s3.Bucket(self.bucket_name)
        prefix = path
        return any([obj.key == path for obj in bucket.objects.filter(Prefix=prefix)])
def get_files(max_thread,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(S3.get_file, [S3(bucket_name,boto3.session.Session().resource('s3'))] * len(filelist), filelist)
        for one in res:
            resultfiles.append(one)
    return resultfiles