# Copyright © 2022 Aravinth Manivannan <realaravinth@batsense.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
from datetime import datetime, timedelta, timezone

from django.shortcuts import get_object_or_404, redirect, render
from django.template.response import TemplateResponse
from django.core.mail import send_mail
from django.contrib.auth.decorators import login_required
from django.http import HttpResponse
from django.template.loader import render_to_string
from django.urls import reverse
from django.db.models import Q
from django.conf import settings

from payments import get_payment_model, RedirectNeeded, PaymentStatus
from dash.models import Instance
from infrastructure.utils import create_vm_if_not_exists
from dash.utils import footer_ctx

from .utils import (
    generate_invoice as generate_invoice_util,
    GenerateInvoiceErrorCode,
    GenerateInvoiceException,
    get_invoice_link,
)


def default_ctx(title: str, username: str):
    """
    Default context for all dashboard
    """
    return {
        "title": title,
        "username": username,
        "footer": footer_ctx(),
    }


@login_required
def pending_invoices(request):
    PAGE_TITLE = "Pending Invoices"

    user = request.user
    Payment = get_payment_model()
    payments = Payment.objects.filter(~Q(status=PaymentStatus.CONFIRMED), paid_by=user)
    ctx = default_ctx(title=PAGE_TITLE, username=user.username)
    ctx["payments"] = payments
    return render(request, "billing/invoices/pending/index.html", context=ctx)


@login_required
def paid_invoices(request):
    PAGE_TITLE = "Payment Receipts"

    user = request.user
    Payment = get_payment_model()
    payments = Payment.objects.filter(status=PaymentStatus.CONFIRMED, paid_by=user)
    ctx = default_ctx(title=PAGE_TITLE, username=user.username)
    ctx["payments"] = payments
    return render(request, "billing/invoices/paid/index.html", context=ctx)


@login_required
def generate_invoice(request, instance_name: str):
    instance = get_object_or_404(Instance, name=instance_name, owned_by=request.user)

    try:
        payment = generate_invoice_util(instance=instance)
        return redirect(reverse("billing.invoice.details", args=(payment.public_ref,)))
    except GenerateInvoiceException as e:
        if e.code == GenerateInvoiceErrorCode.ALREADY_PAID:
            return HttpResponse("BAD REQUEST: Already paid", status=400)
        return redirect(reverse("dash.home"))


@login_required
def payment_details(request, payment_public_id):

    payment = get_object_or_404(
        get_payment_model(), public_ref=payment_public_id, paid_by=request.user
    )

    try:
        form = payment.get_form(data=request.POST or None)
    except RedirectNeeded as redirect_to:
        return redirect(str(redirect_to))

    PAGE_TITLE = f'Invoice for VM "{payment.instance_name}"'

    ctx = default_ctx(title=PAGE_TITLE, username=request.user.username)
    ctx["form"] = form
    ctx["payment"] = payment
    return render(request, "billing/index.html", ctx)


@login_required
def payment_success(request, payment_public_id):
    PAGE_TITLE = "Payment Success"
    ctx = default_ctx(title=PAGE_TITLE, username=request.user.username)
    payment = get_object_or_404(
        get_payment_model(), public_ref=payment_public_id, paid_by=request.user
    )

    ctx = {
        "username": request.user.username,
        "payment": payment,
        "link": get_invoice_link(payment=payment),
    }

    body = render_to_string(
        "billing/emails/payment-receipt.txt",
        context=ctx,
    )

    email = request.user.email
    sender = settings.DEFAULT_FROM_EMAIL

    send_mail(
        subject="[Gna!] Payment receipt for your Gna! VM",
        message=body,
        from_email=f"No reply Gna!<{sender}>",  # TODO read from settings.py
        recipient_list=[email],
    )

    return redirect(reverse("infra.create", args=(payment.instance_name,)))


@login_required
def payment_failure(request, payment_public_id):
    PAGE_TITLE = "Payment failure"
    payment = get_object_or_404(
        get_payment_model(), public_ref=payment_public_id, paid_by=request.user
    )
    ctx = default_ctx(title=PAGE_TITLE, username=request.user.username)
    return HttpResponse(f"{payment} failed")