from django import forms
from django.utils.translation import ugettext as _
from django.contrib import admin

from .models import (
    AdditionalGroup,
    Group,
    Shadow,
    User,
)

PASSWORD_MISMATCH_ERROR = _("Passwords don't match")


class AdditionalGroupInline(admin.TabularInline):
    model = AdditionalGroup


class ShadowInline(admin.TabularInline):
    model = Shadow
    readonly_fields = ['passwd']
    can_delete = False


class UserCreationForm(forms.ModelForm):
    """
    A form for creating system users.

    """
    password1 = forms.CharField(label=_('Password'),
                                widget=forms.PasswordInput)
    password2 = forms.CharField(label=_('Password (again)'),
                                widget=forms.PasswordInput)

    class Meta:
        model = User
        fields = []

    def clean_password2(self):
        """
        Check that the two password entries match.

        """
        password1 = self.cleaned_data.get('password1')
        password2 = self.cleaned_data.get('password2')
        if password1 and password2 and password1 != password2:
            raise forms.ValidationError(PASSWORD_MISMATCH_ERROR)
        return password2

    def save(self, commit=True):
        """
        Save the provided password in hashed format.

        """
        user = User.objects.create_user(
            password=self.cleaned_data['password1'], commit=commit)
        return user

    def save_m2m(self):
        """
        No additional groups are created when this form is saved, so this
        method just does nothing.
        """


class UserAdmin(admin.ModelAdmin):
    actions = ['perform_delete_selected']
    readonly_fields = ['uid']
    add_form = UserCreationForm
    inlines = [AdditionalGroupInline, ShadowInline]

    add_fieldsets = (
        (None, {
            'classes': ('wide',),
            'fields': ('password1', 'password2')}),
    )

    def get_form(self, request, obj=None, **kwargs):
        """
        Use special form during user creation.

        """
        defaults = {}
        if obj is None:
            defaults.update({
                'form': self.add_form,
                'fields': admin.options.flatten_fieldsets(self.add_fieldsets),
            })
        defaults.update(kwargs)
        return super(UserAdmin, self).get_form(request, obj, **defaults)

    def get_readonly_fields(self, request, obj=None):
        if obj:
            return ['uid']
        return []

    def perform_delete_selected(self, request, queryset):
        for user in queryset.all():
            user.delete()
    perform_delete_selected.short_description = _('Delete selected users')

    def get_actions(self, request):
        actions = super(UserAdmin, self).get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions


class GroupAdmin(admin.ModelAdmin):
    actions = ['perform_delete_selected']

    def get_inline_instances(self, request, obj=None):
        if obj is None:
            return []
        return super(GroupAdmin, self).get_inline_instances(request, obj)

    def perform_delete_selected(self, request, queryset):
        for group in queryset.all():
            group.delete()
    perform_delete_selected.short_description = _('Delete selected groups')

    def get_actions(self, request):
        actions = super(GroupAdmin, self).get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions


admin.site.register(Group, GroupAdmin)
admin.site.register(User, UserAdmin)