#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import os
import sys
import time
import tarfile
import logging
import argparse
import requests
import tempfile


DEFAULT_URL = "https://clickhouse-datasets.s3.amazonaws.com"

AVAILABLE_DATASETS = {
    "hits": "hits_v1.tar",
    "visits": "visits_v1.tar",
}

RETRIES_COUNT = 5


def _get_temp_file_name():
    return os.path.join(
        tempfile._get_default_tempdir(), next(tempfile._get_candidate_names())
    )


def build_url(base_url, dataset):
    return os.path.join(base_url, dataset, "partitions", AVAILABLE_DATASETS[dataset])


def download_with_progress(url, path):
    logging.info("Downloading from %s to temp path %s", url, path)
    for i in range(RETRIES_COUNT):
        try:
            with open(path, "wb") as f:
                response = requests.get(url, stream=True)
                response.raise_for_status()
                total_length = response.headers.get("content-length")
                if total_length is None or int(total_length) == 0:
                    logging.info(
                        "No content-length, will download file without progress"
                    )
                    f.write(response.content)
                else:
                    dl = 0
                    total_length = int(total_length)
                    logging.info("Content length is %ld bytes", total_length)
                    for data in response.iter_content(chunk_size=4096):
                        dl += len(data)
                        f.write(data)
                        if sys.stdout.isatty():
                            done = int(50 * dl / total_length)
                            percent = int(100 * float(dl) / total_length)
                            sys.stdout.write(
                                "\r[{}{}] {}%".format(
                                    "=" * done, " " * (50 - done), percent
                                )
                            )
                            sys.stdout.flush()
            break
        except Exception as ex:
            sys.stdout.write("\n")
            time.sleep(3)
            logging.info("Exception while downloading %s, retry %s", ex, i + 1)
            if os.path.exists(path):
                os.remove(path)
    else:
        raise Exception(
            "Cannot download dataset from {}, all retries exceeded".format(url)
        )

    sys.stdout.write("\n")
    logging.info("Downloading finished")


def unpack_to_clickhouse_directory(tar_path, clickhouse_path):
    logging.info(
        "Will unpack data from temp path %s to clickhouse db %s",
        tar_path,
        clickhouse_path,
    )
    with tarfile.open(tar_path, "r") as comp_file:
        comp_file.extractall(path=clickhouse_path)
    logging.info("Unpack finished")


if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO)

    parser = argparse.ArgumentParser(
        description="Simple tool for dowloading datasets for clickhouse from S3"
    )

    parser.add_argument(
        "--dataset-names",
        required=True,
        nargs="+",
        choices=list(AVAILABLE_DATASETS.keys()),
    )
    parser.add_argument("--url-prefix", default=DEFAULT_URL)
    parser.add_argument("--clickhouse-data-path", default="/var/lib/clickhouse/")

    args = parser.parse_args()
    datasets = args.dataset_names
    logging.info("Will fetch following datasets: %s", ", ".join(datasets))
    for dataset in datasets:
        logging.info("Processing %s", dataset)
        temp_archive_path = _get_temp_file_name()
        try:
            download_url_for_dataset = build_url(args.url_prefix, dataset)
            download_with_progress(download_url_for_dataset, temp_archive_path)
            unpack_to_clickhouse_directory(temp_archive_path, args.clickhouse_data_path)
        except Exception as ex:
            logging.info("Some exception occured %s", str(ex))
            raise
        finally:
            logging.info(
                "Will remove downloaded file %s from filesystem if it exists",
                temp_archive_path,
            )
            if os.path.exists(temp_archive_path):
                os.remove(temp_archive_path)
        logging.info("Processing of %s finished", dataset)
    logging.info("Fetch finished, enjoy your tables!")