import argparse
from datetime import datetime
import logging
import os
import urllib.request
from urllib.parse import urlparse

import boto3


DEFAULT_CHUNK_SIZE = 15000

logger = logging.getLogger('main')
handler = logging.StreamHandler()
logger.addHandler(handler)
logger.setLevel(logging.INFO)

task_token = os.environ.get('SFN_TASK_TOKEN', '')


def download(url: str, s3_location: str, chunk_size: int) -> None:
    logger.info('Start downloading from {} to {}'.format(url, s3_location))

    with urllib.request.urlopen(url) as resp:
        logger.info('Response code: {}'.format(resp.getcode()))
        logger.info('Response headers: {}'.format(resp.info()))
        filename = datetime.now().strftime('%Y%m%d%H%M%S_') + extract_filename(url)
        logger.info('File name: {}'.format(filename))

        if 200 <= resp.getcode() < 300:
            s3_client = boto3.client('s3')
            s3_client.upload_fileobj(resp, s3_location, filename)
            send_success('{"status":"success"}')
        else:
            logger.error('Request failed with http code: {}', resp.getcode())
            send_failure('Unable to download', 'Http error {}'.format(resp.getcode()))

        logger.info('Upload complete')


def send_success(output: str) -> None:
    if task_token:
        sfn_client = boto3.client('stepfunctions')
        sfn_client.send_task_success(taskToken=task_token, output=output)


def send_failure(error: str, cause: str) -> None:
    if task_token:
        sfn_client = boto3.client('stepfunctions')
        sfn_client.send_task_failure(taskToken=task_token, error=error, cause=cause)


def extract_filename(url: str) -> str:
    parsed = urlparse(url)
    return os.path.basename(parsed.path)


def read_params() -> argparse.Namespace:
    """Read parameters from command line arguments"""
    parser = argparse.ArgumentParser()
    parser.add_argument("--url", type=str, help="url to download file from", required=True)
    parser.add_argument("--s3-bucket", type=str, help="source bucket", required=True)
    parser.add_argument(
        "--chunk-size",
        type=int, default=DEFAULT_CHUNK_SIZE,
        help="max size of a byte buffer used during decompression")

    args = parser.parse_args()
    return args


def log_context() -> None:
    logger.info("Env: {}".format(os.environ))