www/membership/members/views.py

import hashlib
import logging
import secrets
import uuid
from datetime import timedelta
from functools import wraps
from urllib.parse import urlsplit

import stripe
from authlib.integrations.django_client import OAuth
from django.conf import settings
from django.core.mail import send_mail
from django.db import transaction
from django.http import HttpResponse
from django.shortcuts import redirect, render
from django.urls import reverse
from django.utils import timezone
from django.utils.crypto import salted_hmac
from django.views.decorators.csrf import csrf_exempt
from django.views.decorators.debug import sensitive_post_parameters
from django.views.decorators.http import require_GET, require_POST, require_http_methods

from . import billing, directory
from .forms import PasswordForm, RegistrationForm
from .models import Account, ManagedGroup, RateWindow, Registration, Subscription, WebhookEvent

logger = logging.getLogger(__name__)


def page(request, **context):
    return render(request, "members.html", context)


def limited(scope, value, limit, seconds=3600):
    now = timezone.now()
    window = int(now.timestamp()) // seconds
    key = salted_hmac("membership-rate", f"{scope}:{value}:{window}").hexdigest()
    with transaction.atomic():
        entry, _ = RateWindow.objects.get_or_create(key=key, defaults={"expires_at": now + timedelta(seconds=seconds)})
        entry = RateWindow.objects.select_for_update().get(pk=entry.pk)
        entry.count += 1
        entry.save(update_fields=["count"])
        return entry.count > limit


def client_ip(request):
    if getattr(settings, "SECURE_PROXY_SSL_HEADER", None):
        return request.META.get("HTTP_X_MEMBERSHIP_CLIENT_IP", request.META.get("REMOTE_ADDR", ""))
    return request.META.get("REMOTE_ADDR", "")


def account_required(view):
    @wraps(view)
    def wrapped(request, *args, **kwargs):
        try:
            request.member = Account.objects.get(pk=request.session.get("account_id"))
        except (Account.DoesNotExist, ValueError, TypeError):
            return redirect("members:home")
        return view(request, *args, **kwargs)
    return wrapped


def remember_groups(account):
    for tier in settings.MEMBERSHIP_TIERS.values():
        ManagedGroup.objects.get_or_create(account=account, dn=tier["group_dn"])


@require_GET
def home(request):
    account = Account.objects.filter(pk=request.session.get("account_id")).first() if request.session.get("account_id") else None
    subscriptions = Subscription.objects.filter(account=account) if account else []
    return page(request, account=account, tiers=settings.MEMBERSHIP_TIERS, subscriptions=subscriptions, now=timezone.now())


@require_http_methods(["GET", "POST"])
def register(request):
    form = RegistrationForm(request.POST or None)
    if request.method == "POST" and form.is_valid():
        email = form.cleaned_data["email"]
        if limited("signup-ip", client_ip(request), 20) or limited("signup-email", email, 3):
            return HttpResponse("Please try again later.", status=429)
        token = secrets.token_urlsafe(32)
        digest = hashlib.sha256(token.encode()).hexdigest()
        Registration.objects.create(token_hash=digest, uid=form.cleaned_data["uid"], email=email, expires_at=timezone.now() + timedelta(hours=1))
        url = settings.PUBLIC_URL + reverse("members:verify", args=[token])
        try:
            send_mail("Verify your eom.dev account", f"Finish creating your account (expires in one hour):\n\n{url}\n\nIf you did not request this, ignore this message. Existing accounts are never changed by this link.", settings.DEFAULT_FROM_EMAIL, [email])
        except Exception as exc:
            Registration.objects.filter(pk=digest).delete()
            logger.error("Registration email failed kind=%s", type(exc).__name__)
            return page(request, title="Email unavailable", message="Account email could not be sent. Please try again later.")
        return page(request, title="Check your inbox", message="Use the verification link to choose a password and create your free account. If you already have an account, sign in through Dex instead.")
    return page(request, title="Create your free account", form=form, submit="Send verification email", registration=True)


@sensitive_post_parameters("password", "confirm_password")
@require_http_methods(["GET", "POST"])
def verify(request, token):
    if limited("verify-ip", client_ip(request), 60):
        return HttpResponse("Please try again later.", status=429)
    digest = hashlib.sha256(token.encode()).hexdigest()
    # Exchange the emailed bearer token for server-side session state, then
    # redirect so passwords are never posted to a URL containing that token.
    if request.method == "GET":
        if not Registration.objects.filter(pk=digest, expires_at__gt=timezone.now()).exists():
            return page(request, title="Link expired", message="Request a new verification email.")
        request.session["registration_hash"] = digest
        return redirect("members:finish_registration")
    return HttpResponse(status=405)


@sensitive_post_parameters("password", "confirm_password")
@require_http_methods(["GET", "POST"])
def finish_registration(request):
    digest = request.session.get("registration_hash")
    if not digest or not Registration.objects.filter(pk=digest, expires_at__gt=timezone.now()).exists():
        return page(request, title="Link expired", message="Request a new verification email.")
    form = PasswordForm(request.POST or None)
    if request.method == "POST" and form.is_valid():
        if limited("provision-ip", client_ip(request), 10):
            return HttpResponse("Please try again later.", status=429)
        try:
            with transaction.atomic():
                registration = Registration.objects.select_for_update().get(pk=digest, expires_at__gt=timezone.now())
                identity = directory.create_account(registration.uid, registration.email, form.cleaned_data["password"])
                account = Account.objects.create(**identity)
                remember_groups(account)
                Registration.objects.filter(uid=registration.uid).delete()
            request.session.pop("registration_hash", None)
            return page(request, title="Account created", message="Your free account is now in OpenLDAP. Sign in through Dex to manage membership.")
        except ValueError:
            form.add_error(None, "An account with those details may already exist. Sign in through Dex or contact the administrator.")
        except Exception as exc:
            logger.error("Account provisioning failed kind=%s", type(exc).__name__)
            form.add_error(None, "Account creation could not finish. Try Dex sign-in first, or contact the administrator before retrying.")
    return page(request, title="Choose your password", form=form, submit="Create free account")


def dex():
    oauth = OAuth()
    remote = oauth.register("dex", client_id=settings.DEX_CLIENT_ID, client_secret=settings.DEX_CLIENT_SECRET, server_metadata_url=settings.DEX_ISSUER + "/.well-known/openid-configuration", client_kwargs={"scope": "openid email profile groups federated:id", "code_challenge_method": "S256", "timeout": 10})
    metadata = remote.load_server_metadata()
    if metadata.get("issuer") != settings.DEX_ISSUER:
        raise ValueError("Dex discovery issuer mismatch.")
    metadata["id_token_signing_alg_values_supported"] = ["RS256"]
    for endpoint in ("authorization_endpoint", "token_endpoint", "jwks_uri"):
        url = urlsplit(metadata.get(endpoint, ""))
        if url.scheme != "https" or url.netloc != urlsplit(settings.DEX_ISSUER).netloc or url.username:
            raise ValueError("Dex endpoints must be HTTPS URLs on the configured issuer origin.")
    return remote


@require_POST
def login(request):
    if limited("login-ip", client_ip(request), 60):
        return HttpResponse(status=429)
    try:
        return dex().authorize_redirect(request, settings.PUBLIC_URL + reverse("members:callback"), nonce=secrets.token_urlsafe(32), connector_id=settings.DEX_CONNECTOR_ID)
    except Exception as exc:
        logger.error("Dex login unavailable kind=%s", type(exc).__name__)
        return page(request, title="Sign-in unavailable", message="Please try again later.")


def link_identity(claims):
    if claims.get("iss") != settings.DEX_ISSUER or claims.get("email_verified") is not True or not isinstance(claims.get("sub"), str) or not claims["sub"] or len(claims["sub"]) > 512:
        raise ValueError("A verified Dex identity is required.")
    identity = directory.identity_for_login(claims.get("preferred_username"))
    federated = claims.get("federated_claims") or {}
    if federated.get("connector_id") != settings.DEX_CONNECTOR_ID or federated.get("user_id") != identity["ldap_uuid"]:
        raise ValueError("Dex must authenticate the configured LDAP connector with entryUUID as idAttr.")
    if identity["email"].casefold() != str(claims.get("email", "")).casefold():
        raise ValueError("Dex and LDAP email disagree.")
    # Link using the signed LDAP uid plus immutable entryUUID, NEVER by email.
    with transaction.atomic():
        account, _ = Account.objects.get_or_create(ldap_uuid=identity["ldap_uuid"], defaults=identity)
        account = Account.objects.select_for_update().get(pk=account.pk)
        if account.oidc_sub and account.oidc_sub != claims["sub"]:
            raise ValueError("Identity is already linked to another Dex subject.")
        account.oidc_sub = claims["sub"]
        account.email = identity["email"]
        account.ldap_dn = identity["ldap_dn"]
        account.save(update_fields=["oidc_sub", "email", "ldap_dn"])
        remember_groups(account)
        return account


@require_GET
def callback(request):
    try:
        token = dex().authorize_access_token(request, claims_options={"iss": {"essential": True, "value": settings.DEX_ISSUER}}, leeway=30)
        if not token.get("id_token"):
            raise ValueError("ID token is required.")
        account = link_identity(token.get("userinfo") or {})
    except Exception as exc:
        logger.error("Dex callback rejected kind=%s", type(exc).__name__)
        return page(request, title="Sign-in could not be verified", message="Try signing in again, or contact the administrator.")
    # Do not persist access/refresh/ID tokens or stale group claims in sessions.
    request.session.flush()
    request.session["account_id"] = str(account.pk)
    return redirect("members:home")


@require_POST
def logout(request):
    request.session.flush()
    return redirect("members:home")


def stripe_redirect(url, host):
    parsed = urlsplit(url or "")
    if parsed.scheme != "https" or parsed.hostname != host or parsed.username:
        raise ValueError("Unexpected Stripe redirect host.")
    return redirect(url)


@require_POST
@account_required
def checkout(request, tier):
    config = settings.MEMBERSHIP_TIERS.get(tier)
    if not config:
        return HttpResponse(status=404)
    if limited("checkout", str(request.member.pk), 20):
        return HttpResponse(status=429)
    try:
        with transaction.atomic():
            account = Account.objects.select_for_update().get(pk=request.member.pk)
            api = billing.client()
            if not account.stripe_customer:
                customer = api.customers.create({"email": account.email, "metadata": {"membership_account": str(account.pk)}}, options={"idempotency_key": f"member-customer-{account.pk}"})
                account.stripe_customer = customer["id"]
                account.save(update_fields=["stripe_customer"])
            # Canonical check prevents duplicate subscriptions even before sync.
            existing = api.subscriptions.list({"customer": account.stripe_customer, "status": "all", "limit": 100})
            if any(sub.get("status") not in {"canceled", "incomplete_expired"} for sub in existing.auto_paging_iter()):
                return page(request, title="You already have a subscription", message="Use Manage billing to change your plan or payment details.")
            if account.checkout_id:
                session = api.checkout.sessions.retrieve(account.checkout_id)
                if session.get("status") == "open":
                    return stripe_redirect(session["url"], "checkout.stripe.com")
                account.checkout_key = uuid.uuid4()
            session = api.checkout.sessions.create({
                "mode": "subscription", "customer": account.stripe_customer,
                "line_items": [{"price": config["price_id"], "quantity": 1}],
                "client_reference_id": str(account.pk),
                "subscription_data": {"metadata": {"membership_account": str(account.pk)}},
                "success_url": settings.PUBLIC_URL + reverse("members:home") + "?checkout=complete",
                "cancel_url": settings.PUBLIC_URL + reverse("members:home"),
            }, options={"idempotency_key": f"member-checkout-{account.pk}-{account.checkout_key}"})
            account.checkout_id = session["id"]
            account.save(update_fields=["checkout_id", "checkout_key"])
        return stripe_redirect(session["url"], "checkout.stripe.com")
    except Exception as exc:
        logger.error("Checkout failed account=%s kind=%s", request.member.pk, type(exc).__name__)
        return page(request, title="Checkout unavailable", message="Please try again later. Membership is only granted after Stripe confirms payment.")


@require_POST
@account_required
def portal(request):
    if not request.member.stripe_customer or not settings.STRIPE_PORTAL_CONFIGURATION:
        return page(request, title="Billing unavailable", message="No billing account or billing portal configuration is available.")
    if limited("portal", str(request.member.pk), 30):
        return HttpResponse(status=429)
    try:
        session = billing.client().billing_portal.sessions.create({"customer": request.member.stripe_customer, "configuration": settings.STRIPE_PORTAL_CONFIGURATION, "return_url": settings.PUBLIC_URL + reverse("members:home")})
        return stripe_redirect(session["url"], "billing.stripe.com")
    except Exception as exc:
        logger.error("Billing portal failed kind=%s", type(exc).__name__)
        return page(request, title="Billing unavailable", message="Please try again later.")


@csrf_exempt
@require_POST
def webhook(request):
    if not settings.STRIPE_WEBHOOK_SECRET:
        return HttpResponse(status=503)
    try:
        event = stripe.Webhook.construct_event(request.body, request.headers.get("Stripe-Signature", ""), settings.STRIPE_WEBHOOK_SECRET, tolerance=300)
        if event.get("livemode") != settings.STRIPE_LIVE_MODE or event.get("account"):
            return HttpResponse(status=400)
        obj = event["data"]["object"]
        customer = billing._id(obj.get("customer"))
        account = Account.objects.filter(stripe_customer=customer).first() if customer else None
        # Store no raw payload/PII. The worker rereads canonical Stripe state;
        # duplicate, delayed and reordered events can never restore expired time.
        WebhookEvent.objects.get_or_create(stripe_id=event["id"], defaults={"account": account, "processed_at": None if account else timezone.now()})
    except (ValueError, KeyError, TypeError, stripe.SignatureVerificationError):
        return HttpResponse(status=400)
    return HttpResponse(status=200)