# SPDX-License-Identifier: AGPL-3.0-or-later
"""
Views for WireGuard application.
"""

from io import BytesIO
import urllib.parse

from django.contrib import messages
from django.contrib.messages.views import SuccessMessageMixin
from django.http import Http404, HttpResponse
from django.shortcuts import redirect
from django.urls import reverse_lazy
from django.utils.translation import gettext as _
from django.views.generic import FormView, TemplateView, View

from plinth import network
from plinth.modules.names.components import DomainName
from plinth.views import AppView

from . import forms, utils


class WireguardView(AppView):
    """Serve configuration page."""
    app_id = 'wireguard'
    diagnostics_module_name = 'wireguard'
    template_name = 'wireguard.html'

    def get_context_data(self, **kwargs):
        """Return additional context for rendering the template."""
        context = super().get_context_data(**kwargs)
        info = utils.get_info()
        server_info = info['my_server']
        context['server'] = server_info
        context['client_peers'] = info['my_client']['servers']
        context['server_endpoints'] = []

        if server_info:
            domains = DomainName.list_names(filter_for_service='wireguard')
            listen_port = server_info.get('listen_port')
            context['server_endpoints'] = [
                f'{domain}:{listen_port}' for domain in domains
                if not domain.endswith('.local')
            ]

        return context


class AddClientView(SuccessMessageMixin, FormView):
    """View to add a client."""
    form_class = forms.AddClientForm
    template_name = 'wireguard_add_client.html'
    success_url = reverse_lazy('wireguard:index')
    success_message = _('Added new client.')

    def get_context_data(self, **kwargs):
        """Return additional context for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Add Allowed Client')

        # Show next available IP.
        try:
            connection = utils._server_connection()
            setting_name = utils.nm.SETTING_WIREGUARD_SETTING_NAME
            settings = connection.get_setting_by_name(setting_name)
            context['next_ip'] = utils._get_next_available_ip_address(settings)
        except Exception:
            context['next_ip'] = None

        return context

    def form_valid(self, form):
        """Add the client."""
        public_key = form.cleaned_data.get('public_key')
        try:
            utils.add_client(public_key)
        except ValueError:
            messages.warning(self.request,
                             _('Client with public key already exists'))
            return redirect('wireguard:index')

        return super().form_valid(form)


class SessionClientDataMixin:
    """Shared session data loading for auto-client views."""

    def get_session_client_data(self, request):
        """Extract client data from session."""
        next_ip = request.session.get('next_ip')
        pubkey = request.session.get('client_pubkey')
        privkey = request.session.get('client_privkey')
        endpoint = request.session.get('endpoint')

        if not all([next_ip, privkey, pubkey, endpoint]):
            raise Http404("Session expired")

        return {
            'next_ip': next_ip,
            'privkey': privkey,
            'pubkey': pubkey,
            'endpoint': endpoint
        }

    def get_client_config(self, request):
        """Rebuild client config from session."""
        data = self.get_session_client_data(request)

        return utils.build_client_config(data['next_ip'], data['privkey'],
                                         data['pubkey'], data['endpoint'])


class ClientActionsView(SessionClientDataMixin, View):
    action = None

    def get(self, request):
        import segno

        config = self.get_client_config(request)
        if self.action == 'download':
            response = HttpResponse(config, content_type='text/plain')
            response['Content-Disposition'] = \
                'attachment; filename="wg-client.conf"'
            return response
        elif self.action == 'qr':
            qrcode = segno.make(config)
            buffer = BytesIO()
            qrcode.save(buffer, kind='svg', scale=5)

            return HttpResponse(buffer.getvalue(),
                                content_type='image/svg+xml')

        raise Http404("Invalid action")


class AutoAddClientView(SuccessMessageMixin, FormView):
    """View to add a client with keypair generation."""
    form_class = forms.AutoAddClientForm
    template_name = 'wireguard_auto_add_client.html'
    success_url = reverse_lazy('wireguard:index')
    success_message = _('Added new client.')

    def get_context_data(self, **kwargs):
        """Return additional context for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Add Allowed Client')

        context['domains'] = []
        info = utils.get_info()
        server_info = info['my_server']

        if server_info:
            domains = DomainName.list_names(filter_for_service='wireguard')
            filtered_domains = [
                domain for domain in domains if not domain.endswith('.local')
            ]
            port = server_info.get('listen_port', 51820)
            endpoint = f"{filtered_domains[0]}:{port}"

        try:
            client_privkey, client_pubkey = utils.generate_client_keypair()

            # Get next IP
            connection = utils._server_connection()
            setting_name = utils.nm.SETTING_WIREGUARD_SETTING_NAME
            settings = connection.get_setting_by_name(setting_name)
            next_ip = utils._get_next_available_ip_address(settings)

            data = {
                'next_ip': next_ip,
                'client_privkey': client_privkey,
                'client_pubkey': client_pubkey,
                'endpoint': endpoint
            }

            # Add properties to template context
            context['domains'] = filtered_domains
            context.update(data)

            # Store info on instance for reuse
            self.request.session.update(data)

        except Exception as e:
            messages.warning(f"Client key generation failed: {e}")
        pass

        return context

    def form_valid(self, form):
        """Add client using generated public key."""
        try:
            client_pubkey = self.request.session.pop('client_pubkey')
            utils.add_client(client_pubkey)
        except KeyError:
            messages.warning(self.request,
                             _('Session expired. Please try again.'))
            return redirect('wireguard:auto-add-client')
        except ValueError:
            messages.warning(self.request, _('Client already exists'))
            return redirect('wireguard:index')

        return super().form_valid(form)


class ShowClientView(SuccessMessageMixin, TemplateView):
    """View to show a client's details."""
    template_name = 'wireguard_show_client.html'

    def get_context_data(self, **kwargs) -> dict[str, object]:
        """Return additional context data for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Allowed Client')

        public_key = urllib.parse.unquote(self.kwargs['public_key'])
        server_info = utils.get_info()['my_server']
        if not server_info or public_key not in server_info['peers']:
            raise Http404

        domains = DomainName.list_names(filter_for_service='wireguard')
        context['server'] = server_info
        context['client'] = server_info['peers'][public_key]
        context['endpoints'] = [
            domain + ':' + str(server_info['listen_port'])
            for domain in domains if not domain.endswith('.local')
        ]
        return context


class EditClientView(SuccessMessageMixin, FormView):
    """View to modify a client."""
    form_class = forms.AddClientForm
    template_name = 'wireguard_edit_client.html'
    success_url = reverse_lazy('wireguard:index')
    success_message = _('Updated client.')

    def get_context_data(self, **kwargs):
        """Return additional context for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Modify Client')
        return context

    def get_initial(self):
        """Get initial form data."""
        initial = super().get_initial()
        initial['public_key'] = urllib.parse.unquote(self.kwargs['public_key'])
        return initial

    def form_valid(self, form):
        """Update the client."""
        old_public_key = form.initial['public_key']
        public_key = form.cleaned_data.get('public_key')

        if old_public_key != public_key:
            try:
                utils.add_client(public_key)
            except ValueError:
                messages.warning(self.request,
                                 _('Client with public key already exists'))

            utils.remove_client(old_public_key)

        return super().form_valid(form)


class DeleteClientView(SuccessMessageMixin, TemplateView):
    """View to delete a client."""
    template_name = 'wireguard_delete_client.html'

    def get_context_data(self, **kwargs):
        """Return additional context data for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Delete Allowed Client')
        context['public_key'] = urllib.parse.unquote(self.kwargs['public_key'])
        return context

    def post(self, request, public_key):
        """Delete the client."""
        public_key = urllib.parse.unquote(public_key)
        try:
            utils.remove_client(public_key)
            messages.success(request, _('Client deleted.'))
        except KeyError:
            messages.error(request, _('Client not found'))

        return redirect('wireguard:index')


class AddServerView(SuccessMessageMixin, FormView):
    """View to add a server."""
    form_class = forms.AddServerForm
    template_name = 'wireguard_add_server.html'
    success_url = reverse_lazy('wireguard:index')
    success_message = _('Added new server.')

    def get_context_data(self, **kwargs):
        """Return additional context for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Add Connection to Server')
        return context

    def form_valid(self, form):
        """Add the server."""
        utils.add_server(form.get_settings())
        return super().form_valid(form)


class ShowServerView(SuccessMessageMixin, TemplateView):
    """View to show a server's details."""
    template_name = 'wireguard_show_server.html'

    def get_context_data(self, **kwargs):
        """Return additional context data for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Connection to Server')

        interface = self.kwargs['interface']
        info = utils.get_info()
        server = info['my_client']['servers'].get(interface)
        if not server:
            raise Http404

        context['interface'] = interface
        context['server'] = server
        return context


class EditServerView(SuccessMessageMixin, FormView):
    """View to modify a server."""
    form_class = forms.AddServerForm
    template_name = 'wireguard_edit_server.html'
    success_url = reverse_lazy('wireguard:index')
    success_message = _('Updated server.')

    def get_context_data(self, **kwargs):
        """Return additional context for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Modify Connection to Server')
        return context

    def get_initial(self):
        """Get initial form data."""
        initial = super().get_initial()
        interface = self.kwargs['interface']
        info = utils.get_nm_info()
        server = info.get(interface)
        if not server:
            raise Http404

        initial['ip_address_and_network'] = server.get(
            'ip_address_and_network')
        if server['peers']:
            peer = next(peer for peer in server['peers'].values())
            initial['peer_endpoint'] = peer['endpoint']
            initial['peer_public_key'] = peer['public_key']
            initial['private_key'] = server['private_key']
            initial['preshared_key'] = peer['preshared_key']
            initial['default_route'] = server['default_route']

        return initial

    def form_valid(self, form):
        """Update the server."""
        interface = self.kwargs['interface']
        utils.edit_server(interface, form.get_settings())
        return super().form_valid(form)


class DeleteServerView(SuccessMessageMixin, TemplateView):
    """View to delete a server."""
    template_name = 'wireguard_delete_server.html'

    def get_context_data(self, **kwargs):
        """Return additional context data for rendering the template."""
        context = super().get_context_data(**kwargs)
        context['title'] = _('Delete Connection to Server')

        interface = self.kwargs['interface']
        info = utils.get_nm_info()
        server = info.get(interface)
        if not server:
            raise Http404

        context['interface'] = interface
        if server['peers']:
            peer = next(peer for peer in server['peers'].values())
            context['peer_endpoint'] = peer['endpoint']
            context['peer_public_key'] = peer['public_key']

        return context

    def post(self, request, interface):
        """Delete the server."""
        connection = network.get_connection_by_interface_name(interface)
        network.delete_connection(connection.get_uuid())
        messages.success(request, _('Server deleted.'))
        return redirect('wireguard:index')


class EnableServerView(SuccessMessageMixin, View):
    """View to enable the WireGuard server."""

    def post(self, request):
        """Create server interface."""
        try:
            utils.setup_server()
            messages.success(request,
                             _('WireGuard server started successfully.'))
        except Exception as error:
            messages.error(
                request,
                _('Failed to start WireGuard server: {}').format(error))
        return redirect('wireguard:index')