"""Make backup archive and upload to S3."""

import datetime
import glob
import logging
import os
import tarfile
import time

from logging.handlers import SMTPHandler

import boto3
import botocore

import backup_config as config

backup_source = config.BACKUP_SOURCE_DIRECTORY


def check_and_remove_backup(source_file):
    """
    Sanity-check file against S3 object and remove local file.

    Args: source_file: backup file to check and remove
    """
    s3 = boto3.client('s3', config=botocore.client.Config(
        signature_version='s3v4'))
    bucket = config.S3_BUCKET
    s3_key = ''.join([config.S3_KEY, '/', source_file.rsplit('/', 1)[-1]])

    try:
        status = s3.head_object(Bucket=bucket, Key=s3_key)
        local_file_size = os.path.getsize(source_file)
        remote_file_size = status.get('ContentLength')

        # If file sizes are the same, remove local file
        if local_file_size == remote_file_size:
            os.remove(source_file)
            logging.info('Removed local file: {}'.format(source_file))

    except botocore.exceptions.ClientError as error:
        logging.error('Retrieval from S3 failed: {}'.format(error))
    return None


def make_backup_tar(source_directory):
    """
    Make tar archive of backup directory.

    Args: source_directory: backup directory path

    """
    try:
        now = time.time()
        file_name = ''.join(['/tmp/', datetime.datetime.now().strftime(
            "%Y_%m_%d_%H-%M-%S"), '.tar.gz'])
        backup_archive = tarfile.open(file_name, 'w:gz')
        for file in glob.glob(os.path.join(source_directory, '*.tar.gz')):
            # Only add files from the past 24 hours
            file_mtime = os.path.getmtime(file)
            if now - file_mtime < 86400:
                backup_archive.add(file, arcname=os.path.basename(file))
    except Exception as error:
        logging.error('Could not create archive: {}'.format(error))
    return file_name


def upload_to_s3(file_to_upload):
    """Upload backup file to S3.

    Args:
        file_to_upload (str): path to file for upload

    Return:
        object: the resulting S3 object
    """
    s3 = boto3.client('s3', config=botocore.client.Config(
        signature_version='s3v4'))
    bucket = config.S3_BUCKET
    s3_key = ''.join([config.S3_KEY, '/', file_to_upload.rsplit('/', 1)[-1]])
    kms_key_id = config.KMS_KEY_ID

    try:
        file = open(file_to_upload, 'rb')
        new_object = s3.put_object(
            ACL='private', Bucket=bucket, Key=s3_key,
            ServerSideEncryption='aws:kms', SSEKMSKeyId=kms_key_id, Body=file)
    except botocore.exceptions.ClientError as error:
        logging.error('Upload to S3 failed: {}'.format(error))

    return new_object

mail_handler = SMTPHandler(
    mailhost=config.MAIL_HOST,
    fromaddr=config.FROM_ADDR,
    toaddrs=config.TO_ADDRS,
    subject='Infoblox Backup Error'
)

logging.basicConfig(filename=config.LOGFILE_NAME, level=logging.INFO)

mail_handler.setLevel(logging.ERROR)
mail_handler.setFormatter(logging.Formatter(
    '[%(asctime)s] %(levelname)s: %(message)s'
))

logger = logging.getLogger()
logger.addHandler(mail_handler)

try:
    backup_file = make_backup_tar(backup_source)
    file = upload_to_s3(backup_file)
    logging.info('Uploaded S3 object: {}'.format(file))
    check_and_remove_backup(str(backup_file))

except Exception as error:
    logger.critical('Backup routine failed: {}'.format(error))