from datetime import datetime
from flask import current_app as app

try:
    from urllib.request import pathname2url
    from urllib.request import urlparse
except ImportError:
    from urllib import pathname2url
    from urlparse import urlparse

try:
    from werkzeug.utils import secure_filename
except ImportError:
    pass


# String handling etc

def bool_short(var):
    if type(var) == bool:
        if var:
            return "Y"
        else:
            return "N"
    return var


def file_date_human(num):
    return datetime.fromtimestamp(
        num
    ).strftime(app.config['DATE_FORMAT'])


def file_size_human(num, HTML = True):
    space = ' ' if HTML else ' '
    for x in [space + 'B', 'KB', 'MB', 'GB', 'TB']:
        if num < 1024.0:
            if x == space + 'B':
                return "%d%s%s" % (num, space, x)
            return "%3.1f%s%s" % (num, space, x)
        num /= 1024.0


def file_size_MB(num):
    return "{:,.2f}".format(num/(1024*1024))


def get_or_none(key,d,none = None):
    if key in d:
        return d[key]
    else:
        return none


def is_path_safe(path):
    if path.startswith("."):
        return False
    if "/." in path:
        return False
    return True


def is_valid_url(url, qualifying = None):
    min_attributes = ('scheme', 'netloc')
    qualifying = min_attributes if qualifying is None else qualifying
    token = urlparse(url)
    return all([getattr(token, qualifying_attr)
                for qualifying_attr in qualifying])


def path2url(path):
    return pathname2url(path)


def safe_name(s):
    return safe_string(s, "-_")


def safe_path(s):
    return safe_string(s, "-_/")


def safe_string(s, valid, no_repeat = False):
    """ return a safe string, replace non alnum characters with _ . all characters in valid are considered valid. """
    safe = "".join([c if c.isalnum() or c in valid else "_" for c in s])
    if no_repeat:
        safe = re.sub(r'_+', '_', safe)
    return safe