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

"""
Collect the scanline_126007 dataset.

See the README file for more information.

Author: Gertjan 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 os
import numpy as np
import json

from PIL import Image
from functools import wraps
from urllib.request import urlretrieve

IMG_URL = "https://web.archive.org/web/20070611200633im_/http://www.eecs.berkeley.edu/Research/Projects/CS/vision/grouping/segbench/BSDS300/html/images/plain/normal/gray/126007.jpg"

MD5_IMG = "0ca6db4848b6d319d94a37e697930fb4"
MD5_JSON = "057d5741b623308af00c42e2c8e525c3"

NAME_IMG = "126007.jpg"
NAME_JSON = "scanline_126007.json"


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


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_IMG)
def download_img(target_path=None):
    urlretrieve(IMG_URL, target_path)


@validate(MD5_JSON)
def write_json(img_path, target_path=None):
    name = "scanline_126007"
    longname = "Scanline 126007"
    index = 200

    im = Image.open(img_path)
    arr = np.array(im)
    line = list(map(int, list(arr[index, :])))

    series = [{"label": "Line %s" % index, "type": "int", "raw": line}]

    data = {
        "name": name,
        "longname": longname,
        "n_obs": len(line),
        "n_dim": len(series),
        "time": {"index": list(range(len(line)))},
        "series": series,
    }

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


def collect(output_dir="."):
    img_path = os.path.join(output_dir, NAME_IMG)
    json_path = os.path.join(output_dir, NAME_JSON)

    download_img(target_path=img_path)
    write_json(img_path, target_path=json_path)


def clean(output_dir="."):
    img_path = os.path.join(output_dir, NAME_IMG)
    json_path = os.path.join(output_dir, NAME_JSON)

    if os.path.exists(img_path):
        os.unlink(img_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()