from django import forms
from django.contrib import admin
from django.contrib.admin.widgets import FilteredSelectMultiple
from django.utils.translation import gettext_lazy as _
from modules.fleet.models import Crane
from .models import Client


class ClientAdminForm(forms.ModelForm):
    customer_cranes = forms.ModelMultipleChoiceField(
        label=_("Vozila kupca"),
        queryset=Crane.objects.filter(is_active=True, asset_type='crane').order_by('registration_number'),
        required=False,
        widget=FilteredSelectMultiple(_("Dizalice"), is_stacked=False),
        help_text=_("Odaberite postojeće dizalice koje pripadaju kupcu."),
    )

    class Meta:
        model = Client
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if self.instance.pk:
            self.fields['customer_cranes'].initial = Crane.objects.filter(client=self.instance, is_active=True, asset_type='crane')


@admin.register(Client)
class ClientAdmin(admin.ModelAdmin):
    form = ClientAdminForm
    # Polja koja se prikazuju u listi
    list_display = ('name', 'tax_id', 'city', 'client_type', 'vehicle_count', 'is_active', 'created_at')
    
    # Polja koja omogućuju klik na objekt
    list_display_links = ('name', 'tax_id')
    
    # Filteri sa strane (vrlo korisno za ERP)
    list_filter = ('client_type', 'is_active', 'created_at')
    
    # Polja po kojima admin može pretraživati
    search_fields = ('name', 'tax_id', 'email')

    readonly_fields = ('created_at', 'updated_at', 'linked_cranes_preview')

    # Grupiranje polja u formi za ljepši pregled
    fieldsets = (
        (_('Osnovni podaci'), {
            'fields': ('name', 'client_type', 'tax_id')
        }),
        (_('Kontakt podaci'), {
            'fields': ('email', 'phone', 'address', 'city', 'postal_code')
        }),
        (_('Vozila kupca'), {
            'fields': ('customer_cranes', 'linked_cranes_preview')
        }),
        (_('Sustavni podaci'), {
            'fields': ('is_active', 'created_at', 'updated_at'),
            'classes': ('collapse',)
        }),
    )

    list_per_page = 50

    @admin.display(description="Dizalice")
    def vehicle_count(self, obj):
        return obj.vehicles.filter(asset_type='crane').count()

    @admin.display(description="Povezane dizalice")
    def linked_cranes_preview(self, obj):
        if not obj.pk:
            return _("Spremite klijenta za prikaz povezanih dizalica.")
        cranes = Crane.objects.filter(client=obj, is_active=True, asset_type='crane').order_by('registration_number')
        if not cranes.exists():
            return _("Nema povezanih dizalica.")
        return ", ".join(str(crane) for crane in cranes)

    def save_related(self, request, form, formsets, change):
        super().save_related(request, form, formsets, change)
        selected_cranes = form.cleaned_data.get('customer_cranes')
        if selected_cranes is None:
            return

        selected_ids = list(selected_cranes.values_list('id', flat=True))
        Crane.objects.filter(client=form.instance, asset_type='crane').exclude(pk__in=selected_ids).update(client=None)
        if selected_ids:
            Crane.objects.filter(pk__in=selected_ids).update(client=form.instance, is_company_vehicle=False, asset_type='crane')