# backend/modules/invoicing/admin.py

from django.contrib import admin
from .models import InvoiceTransaction

@admin.register(InvoiceTransaction)
class InvoiceTransactionEntryAdmin(admin.ModelAdmin):
    """
    Konfiguracija prikaza financijskih zapisa u Admin panelu.
    """
    # Prikaz stupaca u listi
    list_display = ('invoice_number', 'work_order_ref', 'amount', 'created_at', 'is_active')
    
    # Omogućuje brzo filtriranje
    list_filter = ('created_at', 'is_active', 'work_order')
    list_select_related = ('work_order__vehicle',)
    
    # Omogućuje pretragu
    search_fields = ('invoice_number', 'work_order__id', 'work_order__vehicle__registration_number')
    
    # Polja koja se ne smiju mijenjati u adminu
    readonly_fields = ('id', 'created_at', 'updated_at')

    # Grupiranje polja za lakši pregled
    fieldsets = (
        (None, {
            'fields': ('invoice_number', 'work_order', 'amount', 'payment_date', 'is_active')
        }),
        ('Sustavni podaci', {
            'fields': ('id', 'created_at', 'updated_at'),
            'classes': ('collapse',)
        }),
    )

    @admin.display(description="Povezani putni nalog")
    def work_order_ref(self, obj):
        if not obj.work_order_id:
            return "—"
        short_id = str(obj.work_order_id).split('-')[0].upper()
        registration = getattr(obj.work_order.vehicle, 'registration_number', '')
        if registration:
            return f"WO-{short_id} ({registration})"
        return f"WO-{short_id}"