import os
import ssl
import sys
import logging
import os.path
import importlib.util

# Automatically detect the path to the webssh package
spec = importlib.util.find_spec('webssh')
base_dir = os.path.dirname(spec.origin) if spec else None

#font_dirs = ['static', 'css', 'fonts']
max_body_size = 1 * 1024 * 1024

#base_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
#font_dirs = ['webssh', 'static', 'css', 'fonts']

def print_version(flag):
    if flag:
        print(__version__)
        sys.exit(0)

def is_valid_encoding(encoding):
    try:
        u'test'.encode(encoding)
    except LookupError:
        return False
    except ValueError:
        return False
    return True

def check_encoding_setting(encoding):
    if encoding and not is_valid_encoding(encoding):
        raise ValueError('Unknown character encoding {!r}.'.format(encoding))

def get_server_settings(options):
    settings = dict(
        xheaders=options.xheaders,
        max_body_size=max_body_size,
        trusted_downstream=get_trusted_downstream(options.tdstream)
    )
    return settings

def get_trusted_downstream(tdstream):
    result = set()
    for ip in tdstream.split(','):
        ip = ip.strip()
        if ip:
            to_ip_address(ip)
            result.add(ip)
    return result
    
def get_origin_setting(options):
    if options.origin == '*':
        if not options.debug:
            raise ValueError(
                'Wildcard origin policy is only allowed in debug mode.'
            )
        else:
            return '*'

    origin = options.origin.lower()
    if origin in ['same', 'primary']:
        return origin

    origins = set()
    for url in origin.split(','):
        orig = parse_origin_from_url(url)
        if orig:
            origins.add(orig)

    if not origins:
        raise ValueError('Empty origin list')

    return origins

    
def get_ssl_context(options):
    if not options.certfile and not options.keyfile:
        return None
    elif not options.certfile:
        raise ValueError('certfile is not provided')
    elif not options.keyfile:
        raise ValueError('keyfile is not provided')
    elif not os.path.isfile(options.certfile):
        raise ValueError('File {!r} does not exist'.format(options.certfile))
    elif not os.path.isfile(options.keyfile):
        raise ValueError('File {!r} does not exist'.format(options.keyfile))
    else:
        ssl_ctx = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
        ssl_ctx.load_cert_chain(options.certfile, options.keyfile)
        return ssl_ctx