"""Procedures that operate on files/ directories"""
import hashlib
import json
import os
import random
import string
import tarfile
import pathlib

from functools import partial
from typing import Dict
from typing import List
from werkzeug.utils import secure_filename

import ipfshttpclient


def get_hash_of_files(files: List[str]) -> str:
    """Given a list of valid of FILES, return their hash as a string"""
    md5hash = hashlib.md5()
    for file_path in sorted(files):
        if not os.path.exists(file_path):
            raise FileNotFoundError
        with open(file_path, "rb") as file_:
            for buf in iter(partial(file_.read, 4096), b''):
                md5hash.update(bytearray(
                    hashlib.md5(buf).hexdigest(), "utf-8"))
    return md5hash.hexdigest()


def get_dir_hash(directory: str) -> str:
    """Return the hash of a DIRECTORY"""
    if not os.path.exists(directory):
        raise FileNotFoundError
    all_files = [
        os.path.join(root, names) for root, _, files in os.walk(directory)
        for names in sorted(files)
    ]
    return get_hash_of_files(all_files)


def jsonfile_to_dict(json_file: str) -> Dict:
    """Give a JSON_FILE, return a python dict"""
    with open(json_file, encoding="utf-8") as _file:
        data = json.load(_file)
        return data
    raise FileNotFoundError


def generate_random_n_string(n_length: int) -> str:
    """Generate a random string that is N chars long"""
    return ''.join(
        random.choice(string.ascii_uppercase + string.digits)
        for _ in range(n_length))


def extract_uploaded_file(gzipped_file,
                          target_dir: str,
                          token: str = "") -> Dict:
    """Get the (directory) hash of extracted contents of GZIPPED_FILE; and move
contents to TARGET_DIR/<dir-hash>.

    """
    if not token:
        token = (f"{generate_random_n_string(6)}-"
                 f"{generate_random_n_string(6)}")
    tar_target_loc = os.path.join(target_dir, token,
                                  secure_filename(gzipped_file.filename))
    try:
        if not os.path.exists(os.path.join(target_dir, token)):
            os.mkdir(os.path.join(target_dir, token))
        gzipped_file.save(tar_target_loc)
        # Extract to "tar_target_loc/token"
        tar = tarfile.open(tar_target_loc)
        tar.extractall(path=os.path.join(target_dir, token))
        tar.close()
    # pylint: disable=W0703
    except Exception:
        return {"status": 128, "error": "gzip failed to unpack file"}
    return {"status": 0, "token": token}


def cache_ipfs_file(ipfs_file: str,
                    cache_dir: str,
                    ipfs_addr: str = "/ip4/127.0.0.1/tcp/5001") -> str:
    """Check if a file exists in cache; if it doesn't, cache it.  Return the
    cached file location

    """
    file_loc = os.path.join(cache_dir, ipfs_file.split("ipfs/")[-1])
    if not os.path.exists(file_loc):
        client = ipfshttpclient.connect(ipfs_addr)
        client.get(ipfs_file,
                   target=str(
                       pathlib.Path
                       (os.path.join(cache_dir,
                                     ipfs_file.split("ipfs/")[-1])).parent))
    return file_loc