import base64
import datetime
import distutils.version
import logging
import json
import random
import os
import socket
import sys
import yaml

from lbrynet.conf import settings
from lbrynet.conf import AdjustableSettings
from lbrynet.core.cryptoutils import get_lbry_hash_obj


# digest_size is in bytes, and blob hashes are hex encoded
blobhash_length = get_lbry_hash_obj().digest_size * 2


log = logging.getLogger(__name__)


# defining these time functions here allows for easier overriding in testing
def now():
    return datetime.datetime.now()


def utcnow():
    return datetime.datetime.utcnow()


def isonow():
    """Return utc now in isoformat with timezone"""
    return utcnow().isoformat() + 'Z'

def today():
    return datetime.datetime.today()


def generate_id(num=None):
    h = get_lbry_hash_obj()
    if num is not None:
        h.update(str(num))
    else:
        h.update(str(random.getrandbits(512)))
    return h.digest()


def is_valid_hashcharacter(char):
    return char in "0123456789abcdef"


def is_valid_blobhash(blobhash):
    """Checks whether the blobhash is the correct length and contains only
    valid characters (0-9, a-f)

    @param blobhash: string, the blobhash to check

    @return: True/False
    """
    return len(blobhash) == blobhash_length and all(is_valid_hashcharacter(l) for l in blobhash)


def version_is_greater_than(a, b):
    """Returns True if version a is more recent than version b"""
    try:
        return distutils.version.StrictVersion(a) > distutils.version.StrictVersion(b)
    except ValueError:
        return distutils.version.LooseVersion(a) > distutils.version.LooseVersion(b)


def deobfuscate(obfustacated):
    return base64.b64decode(obfustacated.decode('rot13'))


def obfuscate(plain):
    return base64.b64encode(plain).encode('rot13')


settings_decoders = {
    '.json': json.loads,
    '.yml': yaml.load
}

settings_encoders = {
    '.json': json.dumps,
    '.yml': yaml.safe_dump
}

ADJUSTABLE_SETTINGS = AdjustableSettings().get_dict()


def load_settings(path):
    ext = os.path.splitext(path)[1]
    with open(path, 'r') as settings_file:
        data = settings_file.read()
    decoder = settings_decoders.get(ext, False)
    assert decoder is not False, "Unknown settings format .%s" % ext
    return decoder(data)


def save_settings(path):
    to_save = {k: v for k, v in settings.__dict__.iteritems() if k in ADJUSTABLE_SETTINGS}
    ext = os.path.splitext(path)[1]
    encoder = settings_encoders.get(ext, False)
    assert encoder is not False, "Unknown settings format .%s" % ext
    with open(path, 'w') as settings_file:
        settings_file.write(encoder(to_save))


def check_connection(server="www.lbry.io", port=80):
    """Attempts to open a socket to server:port and returns True if successful."""
    try:
        host = socket.gethostbyname(server)
        s = socket.create_connection((host, port), 2)
        return True
    except Exception as ex:
        log.info(
            "Failed to connect to %s:%s. Maybe the internet connection is not working",
            server, port, exc_info=True)
        return False


def setup_certs_for_windows():
    if getattr(sys, 'frozen', False) and os.name == "nt":
        cert_path = os.path.join(os.path.dirname(sys.executable), "cacert.pem")
        os.environ["REQUESTS_CA_BUNDLE"] = cert_path