import copy
from urllib.parse import urlparse

from django.conf import settings
from saml2.config import SPConfig
from saml2 import BINDING_HTTP_POST, BINDING_HTTP_REDIRECT

def is_relative(url):
    absolute = bool(urlparse(url).netloc)
    return not absolute

def absolutize(path, default_base):
    if is_absolute(path):
        return path
    else:
        return default_base + path

SAML_CONFIG = settings.SAML_CONFIG

_idp_configs = {}
_relative_paths = []

def relative_config_loader(request=None):
    host = request.get_host()
    if host in _idp_configs:
        return _idp_configs[host]

    base = request.scheme + "://" + request.get_host()

    config = copy.deepcopy(settings.SAML_CONFIG)
    endpoints = config['service']['sp']['endpoints']

    if not _relative_paths:
        if is_relative(config['entityid']):
            _relative_paths.append('entityid')
        if is_relative(endpoints['assertion_consumer_service'][0]):
            _relative_paths.append('assertion_consumer_service')
        if is_relative(endpoints['single_logout_service'][0][0]):
            _relative_paths.append('single_logout_service')

    if 'single_logout_service' in _relative_paths:
        absolute_rdir = base + endpoints['single_logout_service'][0][0]
        absolute_post = base + endpoints['single_logout_service'][1][0]
        sls_endpoint = [
            (absolute_rdir, BINDING_HTTP_REDIRECT),
            (absolute_post, BINDING_HTTP_POST)
        ]
        config['service']['sp']['endpoints']['single_logout_service'] = sls_endpoint
    if 'assertion_consumer_service' in _relative_paths:
        acs = base + endpoints['assertion_consumer_service'][0]
        config['service']['sp']['endpoints']['assertion_consumer_service'][0] = acs
        
    if 'entityid' in _relative_paths:
        config['entityid'] = base + config['entityid']

    conf = SPConfig()
    conf.load(config)
    
    _idp_configs[host] = conf

    return conf