import logging

from django.conf import settings
from django.contrib import messages
from django.contrib.auth.decorators import login_required
from django.http import HttpResponse, HttpResponseBadRequest
from django.shortcuts import get_object_or_404, redirect, render
from django.urls import reverse
from django.views.decorators.csrf import csrf_exempt
from django.views.decorators.http import require_http_methods, require_POST

from contacts.models import Contact
from payments.models import Invoice
from payments.services import (
    PaymentsError,
    create_checkout_session,
    mark_paid,
    next_invoice_number,
    send_invoice_email,
)

logger = logging.getLogger(__name__)


def _site_base(request) -> str:
    base = (settings.PUBLIC_SITE_URL or "").rstrip("/")
    if base:
        return base
    return request.build_absolute_uri("/").rstrip("/")


@login_required
def invoice_list(request):
    invoices = Invoice.objects.select_related("contact")[:200]
    return render(request, "payments/list.html", {"invoices": invoices})


@login_required
@require_http_methods(["GET", "POST"])
def invoice_create(request):
    contacts = Contact.objects.exclude(email="").order_by("first_name", "last_name")
    if request.method == "POST":
        contact_id = (request.POST.get("contact") or "").strip()
        description = (request.POST.get("description") or "").strip()
        amount_raw = (request.POST.get("amount") or "").strip()
        due = (request.POST.get("due_date") or "").strip()
        notes = (request.POST.get("notes") or "").strip()
        errors = []
        contact = Contact.objects.filter(pk=contact_id).first()
        if not contact:
            errors.append("Choose a contact with an email address.")
        if not description:
            errors.append("Description is required.")
        try:
            from decimal import Decimal, InvalidOperation

            amount = Decimal(amount_raw)
            if amount <= 0:
                raise InvalidOperation
        except Exception:
            amount = None
            errors.append("Enter a valid amount greater than zero.")
        if errors:
            for err in errors:
                messages.error(request, err)
        else:
            invoice = Invoice.objects.create(
                number=next_invoice_number(),
                contact=contact,
                description=description,
                amount=amount,
                currency=(settings.STRIPE_CURRENCY or "usd").lower(),
                due_date=due or None,
                notes=notes,
                created_by=request.user,
            )
            messages.success(request, f"Draft {invoice.number} created.")
            return redirect("payments:invoice_detail", pk=invoice.pk)
    return render(request, "payments/create.html", {"contacts": contacts})


@login_required
def invoice_detail(request, pk):
    invoice = get_object_or_404(Invoice.objects.select_related("contact"), pk=pk)
    return render(request, "payments/detail.html", {"invoice": invoice})


@login_required
@require_POST
def invoice_send(request, pk):
    invoice = get_object_or_404(Invoice, pk=pk)
    if invoice.status == Invoice.Status.VOID:
        messages.error(request, "Void invoices cannot be sent.")
        return redirect("payments:invoice_detail", pk=invoice.pk)
    base = _site_base(request)
    success = base + reverse("payments_public:pay_success", kwargs={"pk": invoice.pk})
    cancel = base + reverse("payments_public:pay_cancel", kwargs={"pk": invoice.pk})
    try:
        url = create_checkout_session(
            invoice, success_url=success + "?session_id={CHECKOUT_SESSION_ID}",
            cancel_url=cancel,
        )
        send_invoice_email(invoice, url or (base + reverse("payments_public:pay", kwargs={"pk": invoice.pk})))
    except PaymentsError as exc:
        messages.error(request, str(exc))
    except Exception as exc:  # noqa: BLE001
        logger.exception("invoice send failed")
        messages.error(request, f"Could not send invoice: {exc}")
    else:
        messages.success(request, f"Pay link emailed to {invoice.contact.email}.")
    return redirect("payments:invoice_detail", pk=invoice.pk)


@login_required
@require_POST
def invoice_void(request, pk):
    invoice = get_object_or_404(Invoice, pk=pk)
    invoice.status = Invoice.Status.VOID
    invoice.save(update_fields=["status", "updated_at"])
    messages.success(request, f"{invoice.number} voided.")
    return redirect("payments:invoice_detail", pk=invoice.pk)


def pay_invoice(request, pk):
    invoice = get_object_or_404(Invoice, pk=pk)
    if invoice.status == Invoice.Status.PAID:
        return redirect("payments_public:pay_success", pk=invoice.pk)
    if invoice.status == Invoice.Status.VOID:
        return render(request, "payments/pay.html", {"invoice": invoice, "closed": True})
    if invoice.hosted_invoice_url:
        return redirect(invoice.hosted_invoice_url)
    base = _site_base(request)
    success = base + reverse("payments_public:pay_success", kwargs={"pk": invoice.pk})
    cancel = base + reverse("payments_public:pay_cancel", kwargs={"pk": invoice.pk})
    try:
        url = create_checkout_session(
            invoice,
            success_url=success + "?session_id={CHECKOUT_SESSION_ID}",
            cancel_url=cancel,
        )
    except PaymentsError as exc:
        return render(
            request,
            "payments/pay.html",
            {"invoice": invoice, "error": str(exc)},
        )
    return redirect(url)


def pay_success(request, pk):
    invoice = get_object_or_404(Invoice, pk=pk)
    return render(request, "payments/success.html", {"invoice": invoice})


def pay_cancel(request, pk):
    invoice = get_object_or_404(Invoice, pk=pk)
    return render(request, "payments/cancel.html", {"invoice": invoice})


@csrf_exempt
@require_http_methods(["POST"])
def stripe_webhook(request):
    secret = (settings.STRIPE_WEBHOOK_SECRET or "").strip()
    if not secret:
        logger.error("STRIPE_WEBHOOK_SECRET unset")
        return HttpResponseBadRequest("webhook not configured")
    try:
        import stripe
    except ImportError:
        return HttpResponseBadRequest("stripe not installed")
    sig = request.headers.get("Stripe-Signature", "")
    try:
        event = stripe.Webhook.construct_event(request.body, sig, secret)
    except Exception:
        logger.exception("stripe webhook signature failed")
        return HttpResponseBadRequest("invalid signature")

    obj = event.get("data", {}).get("object", {}) or {}
    if event.get("type") in {"checkout.session.completed", "invoice.paid"}:
        invoice_id = (obj.get("metadata") or {}).get("invoice_id") or ""
        invoice = None
        if invoice_id:
            invoice = Invoice.objects.filter(pk=invoice_id).first()
        if invoice is None:
            session_id = obj.get("id") or ""
            invoice = Invoice.objects.filter(stripe_checkout_session_id=session_id).first()
        if invoice and invoice.status != Invoice.Status.PAID:
            mark_paid(invoice, stripe_id=obj.get("id") or "")
            logger.info("invoice %s marked paid via Stripe %s", invoice.number, event.get("type"))
    return HttpResponse("ok")