import logging
import urllib
from http import cookies
from os import environ
from urllib.parse import urlparse

from decouple import config
from fastapi import Request, HTTPException
from starlette.datastructures import FormData

if config("ENABLE_SSO", cast=bool, default=True):
    from onelogin.saml2.auth import OneLogin_Saml2_Auth

if config("LOCAL_DEV", default=False, cast=bool):
    API_PREFIX = ""
else:
    API_PREFIX = "/api"

SAML2 = {
    "strict": config("saml_strict", cast=bool, default=True),
    "debug": config("saml_debug", cast=bool, default=True),
    "sp": {
        "entityId": config("SITE_URL") + API_PREFIX + "/sso/saml2/metadata/",
        "assertionConsumerService": {
            "url": config("SITE_URL") + API_PREFIX + "/sso/saml2/acs/",
            "binding": "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
        },
        "singleLogoutService": {
            "url": config("SITE_URL") + API_PREFIX + "/sso/saml2/sls/",
            "binding": "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
        },
        "NameIDFormat": "urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress",
        "x509cert": config("sp_crt", default=""),
        "privateKey": config("sp_key", default=""),
    },
    "security": {
        "requestedAuthnContext": False
    },
    "idp": None
}

# in case tenantKey is included in the URL
sp_acs = config("idp_tenantKey", default="")
if sp_acs is not None and len(sp_acs) > 0:
    SAML2["sp"]["assertionConsumerService"]["url"] += sp_acs + "/"

idp = None
# SAML2 config handler
if config("SAML2_MD_URL", default=None) is not None and len(config("SAML2_MD_URL")) > 0:
    print("SAML2_MD_URL provided, getting IdP metadata config")
    from onelogin.saml2.idp_metadata_parser import OneLogin_Saml2_IdPMetadataParser

    idp_data = OneLogin_Saml2_IdPMetadataParser.parse_remote(config("SAML2_MD_URL", default=None))
    idp = idp_data.get("idp")

if SAML2["idp"] is None:
    if len(config("idp_entityId", default="")) > 0 \
            and len(config("idp_sso_url", default="")) > 0 \
            and len(config("idp_x509cert", default="")) > 0:
        idp = {
            "entityId": config("idp_entityId"),
            "singleSignOnService": {
                "url": config("idp_sso_url"),
                "binding": "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
            },
            "x509cert": config("idp_x509cert")
        }
        if len(config("idp_sls_url", default="")) > 0:
            idp["singleLogoutService"] = {
                "url": config("idp_sls_url"),
                "binding": "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect"
            }

if idp is None:
    logging.info("No SAML2 IdP configuration found")
else:
    SAML2["idp"] = idp


def init_saml_auth(req):
    if idp is None:
        raise Exception("No SAML2 config provided")
    return OneLogin_Saml2_Auth(req, old_settings=SAML2)


async def prepare_request(request: Request):
    if not is_saml2_available():
        raise HTTPException(status_code=401, detail="SSO configuration not available.")
    request.args = dict(request.query_params).copy() if request.query_params else {}
    form: FormData = await request.form()
    request.form = dict(form)
    cookie_str = request.headers.get("cookie", "")
    if "session" in cookie_str:
        cookie = cookies.SimpleCookie()
        cookie.load(cookie_str)
        # Even though SimpleCookie is dictionary-like, it internally uses a Morsel object
        # which is incompatible with requests. Manually construct a dictionary instead.
        extracted_cookies = {}
        for key, morsel in cookie.items():
            extracted_cookies[key] = morsel.value
        if "session" not in extracted_cookies:
            logging.info("!!! session not found in extracted_cookies")
            logging.info(extracted_cookies)
        session = extracted_cookies.get("session", {})
    else:
        session = {}
    # If server is behind proxys or balancers use the HTTP_X_FORWARDED fields
    headers = request.headers
    proto = headers.get('x-forwarded-proto', 'http')
    url_data = urlparse('%s://%s' % (proto, headers['host']))
    path = request.url.path
    site_url = urlparse(config("SITE_URL"))
    # to support custom port without changing IDP config
    host_suffix = ""
    if site_url.port is not None and request.url.port is None:
        host_suffix = f":{site_url.port}"

    # add / to /acs
    if not path.endswith("/"):
        path = path + '/'
    if len(API_PREFIX) > 0 and not path.startswith(API_PREFIX):
        path = API_PREFIX + path

    return {
        'https': 'on' if proto == 'https' else 'off',
        'http_host': request.headers['host'] + host_suffix,
        'server_port': url_data.port,
        'script_name': path,
        'get_data': request.args.copy(),
        # Uncomment if using ADFS as IdP, https://github.com/onelogin/python-saml/pull/144
        # 'lowercase_urlencoding': True,
        'post_data': request.form.copy(),
        'cookie': {"session": session},
        'request': request
    }


def is_saml2_available():
    return idp is not None


def get_saml2_provider():
    return config("idp_name", default="saml2") if is_saml2_available() and len(
        config("idp_name", default="saml2")) > 0 else None


def get_landing_URL(query_params: dict = None, redirect_to_link2=False):
    if query_params is not None and len(query_params.keys()) > 0:
        query_params = "?" + urllib.parse.urlencode(query_params)
    else:
        query_params = ""

    if redirect_to_link2:
        if len(config("sso_landing_override", default="")) == 0:
            logging.warning("SSO trying to redirect to custom URL, but sso_landing_override env var is empty")
        else:
            return config("sso_landing_override") + query_params

    return config("SITE_URL") + config("sso_landing", default="/login") + query_params


environ["hastSAML2"] = str(is_saml2_available())