"""
MIT License

Copyright (c) 2025 Hopsenn

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""

import hashlib
import base64
import secrets
import requests

from . import settings
from urllib.parse import urlencode
from django.contrib.auth import get_user_model


def get_hopid_logout_url():
    next_url = settings.HOPID_CLIENT_LOGOUT_URI or settings.HOPID_CLIENT_URI
    query = urlencode({"next": next_url})
    return f"{settings.HOPID_URL}/users/logout/?{query}"


def get_user_from_token(access_token):
    userinfo_url = f"{settings.HOPID_URL}/users/userinfo/"
    headers = {'Authorization': f'Bearer {access_token}'}

    try:
        userinfo_response = requests.get(userinfo_url, headers=headers, timeout=5)
    except requests.RequestException:
        return None

    if userinfo_response.status_code != 200:
        return None

    userinfo = userinfo_response.json()
    email = userinfo.get('email')
    username = userinfo.get('username')

    if not email or not username:
        return None

    profile, _ = get_user_model().objects.get_or_create(email=email, defaults={'username': username.lower()})
    return profile


def get_jwt_tokens(code, code_verifier):
    token_url = f"{settings.HOPID_URL}/o/token/"
    token_data = {
        'grant_type': 'authorization_code',
        'code': code,
        'redirect_uri': settings.HOPID_CLIENT_CALLBACK_URI or settings.HOPID_CLIENT_URI + '/id/callback/',
        'client_id': settings.HOPID_CLIENT_ID,
        'client_secret': settings.HOPID_CLIENT_SECRET,
        'code_verifier': code_verifier,
    }

    try:
        token_response = requests.post(token_url, data=token_data, timeout=5)
    except requests.RequestException:
        return {"error": "Token request failed"}

    if token_response.status_code != 200:
        return {"error": "Token exchange failed"}

    tokens = token_response.json()
    return tokens


def generate_pkce_pair():
    verifier = secrets.token_urlsafe(64)
    challenge = base64.urlsafe_b64encode(
        hashlib.sha256(verifier.encode()).digest()
    ).rstrip(b'=').decode()
    return verifier, challenge


def get_hopid_login_url(request, method=None):
    nonce = secrets.token_urlsafe(32)
    verifier, challenge = generate_pkce_pair()

    request.session['pkce_verifier'] = verifier
    request.session['oidc_nonce'] = nonce

    base = f"{settings.HOPID_URL}/o/authorize/"

    params = {
        "client_id": settings.HOPID_CLIENT_ID,
        "response_type": "code",
        "scope": "openid profile email",
        "redirect_uri": settings.HOPID_CLIENT_CALLBACK_URI or settings.HOPID_CLIENT_URI + '/id/callback/',
        "nonce": nonce,
        "code_challenge": challenge,
        "code_challenge_method": "S256"
    }

    if method:
        params.update({'method': method.lower()})

    return f"{base}?{urlencode(params)}"