import boto3
import botocore
import itertools
import datetime
import pytz


S3_BUCKET = 'prod-orcdbucket'
S3_DIR = 'feed-drop/AmazonUnlimited'

REPORT_TYPES = ['Activity', 'Playlist', 'User']
COUNTRIES = ['US', 'AT', 'GB', 'DE', 'IT', 'FR', 'AU', 'ES']
ORGS = ['ORCA', 'ORED']

MISSING_FILES_MANIFEST = 'missing_files.txt'
FILE_MANIFEST = 'manifest.txt'
STALE_MANIFEST = 'stale_manifest.txt'

DATE_RANGES = [
    { 'start_date': 20180101, 'end_date': 20180131 }
    # { 'start_date': 20181201, 'end_date': 20181204  }
    # { 'start_date': 20190201, 'end_date': 20190228 },
    # { 'start_date': 20190301, 'end_date': 20190331 }
]

DATE_THRESHOLD = datetime.datetime(2019, 3, 20, tzinfo=pytz.timezone('US/Eastern'))


def main():
    s3_resource = boto3.resource('s3')

    for date_range in DATE_RANGES:
        for date in range(date_range['start_date'], date_range['end_date'] + 1):
            print('processing {date}'.format(date=date))
            check_files_for_date(s3_resource, date)


def check_files_for_date(s3_resource, date):
    s3_keys = get_s3_keys_for_date(date)

    for s3_key in s3_keys:
        check_for_file_existance(s3_resource, s3_key)


def get_s3_keys_for_date(date):
    def build_s3_key(org, country, report_type):
        filename = _get_filename(org, country, date, report_type)
        return '{dir}/{report_filename}'.format(
            dir=S3_DIR, report_filename=filename)

    return _create_s3_key_iterable(build_s3_key)


def check_for_file_existance(s3, file_key):
    s3_object = s3.Object(S3_BUCKET, file_key)

    # import pdb; pdb.set_trace()
    try:
        s3_object.content_length

        if s3_object.last_modified.astimezone(pytz.timezone('US/Eastern')) < DATE_THRESHOLD:
            # old files
            add_file_to_manifest(file_key, STALE_MANIFEST)
        else:
            # good files
            add_file_to_manifest(file_key, FILE_MANIFEST)
    except botocore.exceptions.ClientError:
        add_file_to_manifest(file_key, MISSING_FILES_MANIFEST)


def add_file_to_manifest(file_key, manifest):
    file_name = file_key.split('/')[-1]

    with open(manifest, "a") as manifest:
        manifest.write(file_name)
        manifest.write("\n")


def _get_filename(org, country, date, report_type):
    return '{org}_{country}_{date}_Daily_{report_type}_Report.txt.zip'.format(
        org=org, country=country, date=date, report_type=report_type)


def _create_s3_key_iterable(builder):
    combos = itertools.product(ORGS,
                               COUNTRIES,
                               REPORT_TYPES)
    return itertools.starmap(builder, combos)


if __name__ == '__main__':
    main()