"""
Views for Google Calendar integration management.
"""

import logging

from django.contrib.auth.decorators import login_required
from django.http import HttpResponse
from django.shortcuts import redirect, render
from django.views.decorators.csrf import csrf_exempt

from .google_sync import (
    check_if_google_callback_is_valid,
    sync_from_google_to_local,
    sync_from_local_to_google,
)
from .models import UserGCalCoupling

logger = logging.getLogger(__name__)


@login_required
def run_sync(request):
    """Manually trigger a sync from local to Google Calendar."""
    sync_from_local_to_google()
    return redirect("/")


@login_required
def manage(request):
    """
    View for managing Google Calendar integration settings.

    Allows users to enable/disable GCal sync and configure their email.
    """
    if request.method == "POST":
        activate = request.POST.get("activate", "0")

        if activate == "1":
            # Enable GCal coupling
            email = request.POST.get("email", "")
            if email:
                UserGCalCoupling.objects.filter(user=request.user).delete()
                coupling = UserGCalCoupling(user=request.user, email=email)
                coupling.save()
                sync_from_local_to_google()
        else:
            # Disable GCal coupling
            UserGCalCoupling.objects.filter(user=request.user).delete()
            sync_from_local_to_google()

    context = {}
    user_coupling = UserGCalCoupling.objects.filter(user=request.user)
    context["enabled"] = user_coupling.exists()

    if user_coupling.count() > 1:
        logger.warning(
            f"User {request.user.username} has multiple GCal couplings. "
            "This should not happen."
        )

    if user_coupling.exists():
        context["mail"] = user_coupling.first().email

    return render(request, "eventplanner_gcal/management.html", context)


@csrf_exempt
def gcal_api_callback(request):
    """
    Callback endpoint for Google Calendar push notifications.

    This is called by Google when calendar events are updated.
    """
    token = request.META.get("HTTP_X_GOOG_CHANNEL_TOKEN", "")
    channel_id = request.META.get("HTTP_X_GOOG_CHANNEL_ID", "")
    resource_id = request.META.get("HTTP_X_GOOG_RESOURCE_ID", "")

    valid = check_if_google_callback_is_valid(token, channel_id, resource_id)

    if not valid:
        logger.warning(
            f"Received invalid GCal callback: token={token}, "
            f"channel_id={channel_id}, resource_id={resource_id}"
        )
        return HttpResponse("<h1>Old Channel - no update triggered</h1>")

    logger.info(
        f"Received Google Callback with headers - "
        f"Token: {token}, ID: {channel_id}, ResID: {resource_id}"
    )

    result = sync_from_google_to_local()

    logger.info(
        f"Finished processing callback from GCal - New Information present: {result}"
    )

    return HttpResponse("<h1>Callback successful</h1>")


# Backwards compatibility aliases
runSync = run_sync
gcalApiCallback = gcal_api_callback