#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
Retrieve the bitcoin dataset.

See the README file for more information.

Author: G.J.J. van den Burg
License: This file is part of TCPD, see the top-level LICENSE file.
Copyright: 2019, The Alan Turing Institute

"""

import argparse
import hashlib
import json
import os
import clevercsv

from functools import wraps
from urllib.request import urlretrieve

CSV_URL = "https://web.archive.org/web/20191114131838if_/https://api.blockchain.info/charts/market-price?timespan=all&format=csv"

MD5_CSV = "9bd4f7b06d78347415f6aafe1d9eb680"
MD5_JSON = "f90ff14ed1fc0c3d47d4394d25cbce93"

NAME_CSV = "market-price.csv"
NAME_JSON = "bitcoin.json"


class ValidationError(Exception):
    def __init__(self, filename):
        message = (
            "Validating the file '%s' failed. \n"
            "Please raise an issue on the GitHub page for this project "
            "if the error persists." % filename
        )
        super().__init__(message)


def check_md5sum(filename, checksum):
    with open(filename, "rb") as fp:
        data = fp.read()
    h = hashlib.md5(data).hexdigest()
    return h == checksum


def validate(checksum):
    """Decorator that validates the target file."""

    def validate_decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            target = kwargs.get("target_path", None)
            if os.path.exists(target) and check_md5sum(target, checksum):
                return
            out = func(*args, **kwargs)
            if not os.path.exists(target):
                raise FileNotFoundError("Target file expected at: %s" % target)
            if not check_md5sum(target, checksum):
                raise ValidationError(target)
            return out

        return wrapper

    return validate_decorator


@validate(MD5_CSV)
def get_market_price(target_path=None):
    urlretrieve(CSV_URL, target_path)


@validate(MD5_JSON)
def write_json(csv_path, target_path=None):
    rows = clevercsv.read_table(csv_path)

    rows = rows[500:]
    last_idx = next(
        (i for i, r in enumerate(rows) if r[0] == "2019-06-19 00:00:00"), None
    )
    rows = rows[: (last_idx + 1)]

    name = "bitcoin"
    longname = "Bitcoin Price"
    values = [float(r[1]) for r in rows]
    time = [r[0].split(" ")[0] for r in rows]
    time_fmt = "%Y-%m-%d"
    series = [{"label": "USD/Bitcoin", "type": "float", "raw": values}]

    data = {
        "name": name,
        "longname": longname,
        "n_obs": len(time),
        "n_dim": len(series),
        "time": {
            "type": "string",
            "format": time_fmt,
            "index": list(range(0, len(time))),
            "raw": time,
        },
        "series": series,
    }

    with open(target_path, "w") as fp:
        json.dump(data, fp, indent="\t")


def collect(output_dir="."):
    csv_path = os.path.join(output_dir, NAME_CSV)
    json_path = os.path.join(output_dir, NAME_JSON)

    get_market_price(target_path=csv_path)
    write_json(csv_path, target_path=json_path)


def clean(output_dir="."):
    csv_path = os.path.join(output_dir, NAME_CSV)
    json_path = os.path.join(output_dir, NAME_JSON)

    if os.path.exists(csv_path):
        os.unlink(csv_path)
    if os.path.exists(json_path):
        os.unlink(json_path)


def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "-o", "--output-dir", help="output directory to use", default="."
    )
    parser.add_argument(
        "action",
        choices=["collect", "clean"],
        help="Action to perform",
        default="collect",
        nargs="?",
    )
    return parser.parse_args()


def main(output_dir="."):
    args = parse_args()
    if args.action == "collect":
        collect(output_dir=args.output_dir)
    elif args.action == "clean":
        clean(output_dir=args.output_dir)


if __name__ == "__main__":
    main()