from core.admin import ReadOnlyAwareAdmin, SliceInline, TenantPrivilegeInline
from core.middleware import get_request
from core.models import TenantPrivilege, User
from django import forms
from django.contrib import admin
from django.core import serializers
from services.vpn.models import VPN_KIND, VPNService, VPNTenant
from subprocess import Popen, PIPE
from xos.exceptions import XOSValidationError


class VPNServiceForm(forms.ModelForm):

    exposed_ports = forms.CharField(required=True)

    def save(self, commit=True):
        self.instance.exposed_ports = self.cleaned_data['exposed_ports']
        return super(VPNServiceForm, self).save(commit=commit)

    def clean_exposed_ports(self):
        exposed_ports = self.cleaned_data['exposed_ports']
        port_mapping = {"udp": [], "tcp": []}
        parts = exposed_ports.split(",")
        for part in parts:
            part = part.strip()
            if "/" in part:
                (protocol, ports) = part.split("/", 1)
            elif " " in part:
                (protocol, ports) = part.split(None, 1)
            else:
                raise XOSValidationError('malformed port specifier %s, format example: "tcp 123, tcp 201:206, udp 333"' % part)

            protocol = protocol.strip()
            ports = ports.strip()

            if not (protocol in ["udp", "tcp"]):
                raise XOSValidationError('unknown protocol %s' % protocol)

            if "-" in ports:
                port_mapping[protocol].extend(self.parse_port_range(ports, "-"))
            elif ":" in ports:
                port_mapping[protocol].extend(self.parse_port_range(ports, ":"))
            else:
                port_mapping[protocol].append(int(ports))

        return port_mapping

    def parse_port_range(self, port_str, split_str):
        (first, last) = port_str.split(split_str)
        first = int(first.strip())
        last = int(last.strip())
        return list(range(first, last))

    class Meta:
        model = VPNService


class VPNServiceAdmin(ReadOnlyAwareAdmin):
    """Defines the admin for the VPNService."""
    model = VPNService
    form = VPNServiceForm
    verbose_name = "VPN Service"

    list_display = ("backend_status_icon", "name", "enabled")

    list_display_links = ('backend_status_icon', 'name', )

    fieldsets = [(None, {'fields': ['backend_status_text', 'name', 'enabled',
                                    'versionNumber', 'description', "view_url", 'exposed_ports'],
                         'classes':['suit-tab suit-tab-general']})]

    readonly_fields = ('backend_status_text', )

    inlines = [SliceInline]

    extracontext_registered_admins = True

    user_readonly_fields = ["name", "enabled", "versionNumber", "description"]

    suit_form_tabs = (('general', 'VPN Service Details'),
                      ('administration', 'Tenants'),
                      ('slices', 'Slices'),)

    suit_form_includes = (('vpnserviceadmin.html',
                           'top',
                           'administration'),)

    def queryset(self, request):
        return VPNService.get_service_objects_by_user(request.user)


class VPNTenantForm(forms.ModelForm):
    """The form used to create and edit a VPNTenant.

    Attributes:
        creator (forms.ModelChoiceField): The XOS user that created this tenant.
        client_conf (forms.CharField): The readonly configuration used on the client to connect to this Tenant.
        server_address (forms.GenericIPAddressField): The ip address on the VPN of this Tenant.
        client_address (forms.GenericIPAddressField): The ip address on the VPN of the client.
        is_persistent (forms.BooleanField): Determines if this Tenant keeps this connection alive through failures.
    """
    creator = forms.ModelChoiceField(queryset=User.objects.all())
    server_network = forms.GenericIPAddressField(
        protocol="IPv4", required=True)
    vpn_subnet = forms.GenericIPAddressField(protocol="IPv4", required=True)
    is_persistent = forms.BooleanField(required=False)
    clients_can_see_each_other = forms.BooleanField(required=False)
    failover_servers = forms.ModelMultipleChoiceField(queryset=VPNTenant.get_tenant_objects(), required=False)
    protocol = forms.ChoiceField(required=True, choices=[("udp", "udp"), ("tcp", "tcp")])

    def __init__(self, *args, **kwargs):
        super(VPNTenantForm, self).__init__(*args, **kwargs)
        self.fields['kind'].widget.attrs['readonly'] = True
        # self.fields['script_name'].widget.attrs['readonly'] = True
        self.fields[
            'provider_service'].queryset = VPNService.get_service_objects().all()

        self.fields['kind'].initial = VPN_KIND

        if self.instance:
            self.fields['creator'].initial = self.instance.creator
            self.fields['vpn_subnet'].initial = self.instance.vpn_subnet
            self.fields[
                'server_network'].initial = self.instance.server_network
            self.fields[
                'clients_can_see_each_other'].initial = self.instance.clients_can_see_each_other
            self.fields['is_persistent'].initial = self.instance.is_persistent
            self.fields['protocol'].initial = self.instance.protocol
            if (self.instance.failover_servers):
                self.initial['failover_servers'] = [model.pk for model in list(serializers.deserialize('json', self.instance.failover_servers))]

        if (not self.instance) or (not self.instance.pk):
            self.fields['creator'].initial = get_request().user
            self.fields['vpn_subnet'].initial = "255.255.255.0"
            self.fields['server_network'].initial = "10.66.77.0"
            self.fields['clients_can_see_each_other'].initial = True
            self.fields['is_persistent'].initial = True
            if VPNService.get_service_objects().exists():
                self.fields["provider_service"].initial = VPNService.get_service_objects().all()[
                    0]

    def save(self, commit=True):
        self.instance.creator = self.cleaned_data.get("creator")
        self.instance.is_persistent = self.cleaned_data.get('is_persistent')
        self.instance.vpn_subnet = self.cleaned_data.get("vpn_subnet")
        self.instance.server_network = self.cleaned_data.get('server_network')
        self.instance.clients_can_see_each_other = self.cleaned_data.get(
            'clients_can_see_each_other')
        self.instance.failover_servers = serializers.serialize("json", self.cleaned_data.get('failover_servers'))

        self.instance.port_number = self.instance.provider_service.get_next_available_port(self.instance.protocol)
        self.instance.protocol = self.cleaned_data.get("protocol")

        if (not self.instance.ca_crt):
            self.instance.ca_crt = self.generate_ca_crt()

        return super(VPNTenantForm, self).save(commit=commit)

    def generate_ca_crt(self):
        """str: Generates the ca cert by reading from the ca file"""
        with open("/opt/openvpn/easyrsa3/pki/ca.crt") as crt:
            return crt.readlines()

    class Meta:
        model = VPNTenant


class VPNTenantAdmin(ReadOnlyAwareAdmin):
    verbose_name = "VPN Tenant Admin"
    list_display = ('id', 'backend_status_icon', 'instance',
                    'server_network', 'vpn_subnet')
    list_display_links = ('id', 'backend_status_icon',
                          'instance', 'server_network', 'vpn_subnet')
    fieldsets = [(None, {'fields': ['backend_status_text', 'kind',
                                    'provider_service', 'instance', 'creator',
                                    'server_network', 'vpn_subnet', 'is_persistent',
                                    'clients_can_see_each_other', 'failover_servers', "protocol"],
                         'classes': ['suit-tab suit-tab-general']})]
    readonly_fields = ('backend_status_text', 'instance')
    form = VPNTenantForm
    inlines = [TenantPrivilegeInline]

    suit_form_tabs = (('general', 'Details'), ('tenantprivileges', 'Privileges'))

    def queryset(self, request):
        return VPNTenant.get_tenant_objects_by_user(request.user)

    def certificate_name(self, tenant_privilege):
        return str(tenant_privilege.user.email) + "-" + str(tenant_privilege.tenant.id)

    def save_formset(self, request, form, formset, change):
        super(VPNTenantAdmin, self).save_formset(request, form, formset, change)
        for obj in formset.deleted_objects:
            # If anything deleated was a TenantPrivilege then revoke the certificate
            if type(obj) is TenantPrivilege:
                certificate = self.certificate_name(obj)
                Popen("/opt/openvpn/easyrsa3/easyrsa --batch revoke " + certificate, shell=True, stdout=PIPE).communicate()
            # TODO(jermowery): determine if this is necessary.
            # if type(obj) is VPNTenant:
                # if the tenant was deleted revoke all certs assoicated
                # pass

        for obj in formset.new_objects:
            # If there were any new TenantPrivlege objects then create certs
            if type(obj) is TenantPrivilege:
                certificate = self.certificate_name(obj)
                Popen("/opt/openvpn/easyrsa3/easyrsa --batch build-client-full " + certificate + " nopass", shell=True, stdout=PIPE).communicate()


# Associate the admin forms with the models.
admin.site.register(VPNService, VPNServiceAdmin)
admin.site.register(VPNTenant, VPNTenantAdmin)