from django.contrib import admin
from django.contrib.admin import ModelAdmin
from django.utils.html import format_html
from .models import (
    Crane,
    Vehicle,
    WorkOrder,
    WorkOrderInvoice,
    VehicleServiceRecord,
    VehicleServicePhoto,
    VehicleServiceAttachment,
)


class ServicePhotoInline(admin.TabularInline):
    model = VehicleServicePhoto
    extra = 0
    fields = ('thumbnail_preview', 'image', 'description', 'uploaded_by', 'created_at')
    readonly_fields = ('thumbnail_preview', 'created_at')
    show_change_link = True

    @admin.display(description="Pregled")
    def thumbnail_preview(self, obj):
        if obj.image:
            return format_html(
                '<a href="{}" target="_blank">'
                '<img src="{}" style="height:64px;width:auto;border-radius:4px;object-fit:cover;" />'
                '</a>',
                obj.image.url,
                obj.image.url,
            )
        return "—"

class ServiceAttachmentInline(admin.TabularInline):
    model = VehicleServiceAttachment
    extra = 0
    fields = ('file', 'description', 'uploaded_by', 'created_at')
    readonly_fields = ('created_at',)
    show_change_link = True


class WorkOrderInline(admin.TabularInline):
    model = WorkOrder
    extra = 0
    fields = ('creator', 'date', 'start_mileage', 'end_mileage', 'location', 'travel_start_at', 'travel_end_at', 'purpose', 'status')
    readonly_fields = ('date',)


class ServiceRecordInline(admin.TabularInline):
    model = VehicleServiceRecord
    extra = 0
    fields = ('task', 'performed_by', 'service_date', 'mileage', 'next_service_due_at', 'cost')
    readonly_fields = ('service_date', 'next_service_due_at')


class WorkOrderInvoiceInline(admin.TabularInline):
    model = WorkOrderInvoice
    extra = 0
    fields = ('naziv_racuna', 'lokacija', 'datum', 'opis', 'image', 'created_by', 'created_at', 'is_active')
    readonly_fields = ('created_at',)


@admin.register(Vehicle)
class VehicleAdmin(admin.ModelAdmin):
    list_display = (
        'registration_number',
        'crane_serial_number',
        'superstructure_working_hours',
        'chassis_working_hours',
        'make',
        'model',
        'year',
        'current_mileage',
        'service_interval_km',
        'next_service_at_display',
        'is_company_vehicle',
        'client',
        'assigned_servicer',
        'is_active',
    )
    list_filter = ('is_active', 'is_company_vehicle', 'make', 'service_interval_km')
    search_fields = ('registration_number', 'vin', 'make', 'model', 'assigned_servicer__username', 'client__name')
    readonly_fields = ()
    inlines = (WorkOrderInline, ServiceRecordInline)
    ordering = ('registration_number',)
    fieldsets = (
        (None, {
            'fields': ('asset_type', 'registration_number', 'vin', 'make', 'model', 'year'),
        }),
        ('Vlasništvo', {
            'fields': ('is_company_vehicle', 'client', 'assigned_servicer'),
        }),
        ('Servis', {
            'fields': ('current_mileage', 'service_interval_km', 'superstructure_working_hours', 'chassis_working_hours', 'is_active'),
        }),
    )

    def next_service_at_display(self, obj):
        try:
            return obj.next_service_at()
        except Exception:
            return None
    next_service_at_display.short_description = "Sljedeći servis @ (km)"
    next_service_at_display.admin_order_field = 'current_mileage'

    def get_queryset(self, request):
        queryset = super().get_queryset(request)
        return queryset.filter(asset_type='vehicle')

    def save_model(self, request, obj, form, change):
        obj.asset_type = 'vehicle'
        super().save_model(request, obj, form, change)


@admin.register(Crane)
class CraneAdmin(VehicleAdmin):
    list_display = (
        'registration_number',
        'crane_serial_number',
        'superstructure_working_hours',
        'chassis_working_hours',
        'make',
        'model',
        'year',
        'current_mileage',
        'service_interval_km',
        'next_service_at_display',
        'client',
        'assigned_servicer',
        'is_active',
    )
    list_filter = ('is_active', 'client', 'make', 'service_interval_km', 'crane_serial_number')
    search_fields = ('registration_number', 'crane_serial_number', 'vin', 'make', 'model', 'assigned_servicer__username', 'client__name')
    fieldsets = (
        (None, {
            'fields': ('asset_type', 'registration_number', 'crane_serial_number', 'vin', 'make', 'model', 'year'),
        }),
        ('Povezivanje', {
            'fields': ('client', 'assigned_servicer', 'is_company_vehicle'),
        }),
        ('Servis', {
            'fields': ('current_mileage', 'service_interval_km', 'superstructure_working_hours', 'chassis_working_hours', 'is_active'),
        }),
    )

    def get_queryset(self, request):
        queryset = ModelAdmin.get_queryset(self, request)
        return queryset.filter(asset_type='crane')

    def save_model(self, request, obj, form, change):
        obj.asset_type = 'crane'
        ModelAdmin.save_model(self, request, obj, form, change)


@admin.register(WorkOrder)
class WorkOrderAdmin(admin.ModelAdmin):
    list_display = ('id', 'vehicle', 'creator', 'date', 'location', 'travel_start_at', 'travel_end_at', 'start_mileage', 'end_mileage', 'distance_display', 'status')
    list_filter = ('status', 'date', 'vehicle')
    search_fields = ('vehicle__registration_number', 'creator__username', 'purpose')
    readonly_fields = ('date',)
    ordering = ('-date',)
    inlines = (WorkOrderInvoiceInline,)

    def distance_display(self, obj):
        return obj.distance
    distance_display.short_description = "Prijeđeno (km)"


@admin.register(WorkOrderInvoice)
class WorkOrderInvoiceAdmin(admin.ModelAdmin):
    list_display = ('id', 'work_order', 'naziv_racuna', 'lokacija', 'datum', 'created_by', 'is_active')
    list_filter = ('datum', 'is_active', 'work_order')
    search_fields = ('naziv_racuna', 'lokacija', 'opis', 'work_order__id')
    ordering = ('-datum', '-created_at')

@admin.register(VehicleServiceRecord)
class VehicleServiceRecordAdmin(admin.ModelAdmin):
    list_display = ('id', 'service_title', 'task', 'vehicle', 'performed_by', 'service_date', 'mileage', 'next_service_due_at', 'cost', 'short_description')
    list_filter = ('service_date', 'performed_by', 'vehicle')
    search_fields = ('service_title', 'vehicle__registration_number', 'performed_by__username', 'description', 'parts')
    readonly_fields = ('id', 'service_date', 'next_service_due_at')
    ordering = ('-service_date',)
    inlines = (ServicePhotoInline, ServiceAttachmentInline)
    fieldsets = (
        (None, {
            'fields': ('id', 'service_title', 'task', 'vehicle', 'performed_by', 'service_date'),
        }),
        ('Detalji servisa', {
            'fields': ('description', 'parts', 'mileage', 'cost', 'next_service_due_at'),
        }),
    )

    @admin.display(description="Opis")
    def short_description(self, obj):
        if obj.description:
            return obj.description[:60] + ('…' if len(obj.description) > 60 else '')
        return "—"