"""
Views для управления единицами измерения (Unit of Measure)
"""
from django.contrib.auth.decorators import login_required
from django.contrib import messages
from django.shortcuts import render, redirect, get_object_or_404
from django.db.models import Q, Count
from django.core.paginator import Paginator
from django.urls import reverse

from products.models import UnitOfMeasure, ProductSalesUnit
from products.forms import ProductSalesUnitForm


@login_required
def unit_of_measure_list(request):
    """
    Список всех единиц измерения с возможностью фильтрации и поиска
    """
    # Получаем параметры фильтрации
    search_query = request.GET.get('q', '').strip()
    is_active_filter = request.GET.get('is_active', '')

    # Базовый queryset
    units = UnitOfMeasure.objects.all()

    # Аннотируем количество использований
    units = units.annotate(
        usage_count=Count('productsalesunit')
    )

    # Применяем фильтры
    if search_query:
        units = units.filter(
            Q(code__icontains=search_query) |
            Q(name__icontains=search_query) |
            Q(short_name__icontains=search_query)
        )

    if is_active_filter:
        units = units.filter(is_active=(is_active_filter == 'true'))

    # Сортировка
    units = units.order_by('position', 'code')

    # Пагинация
    paginator = Paginator(units, 50)
    page_number = request.GET.get('page')
    page_obj = paginator.get_page(page_number)

    context = {
        'page_obj': page_obj,
        'search_query': search_query,
        'is_active_filter': is_active_filter,
        'total_units': units.count(),
    }

    return render(request, 'products/uom/unit_list.html', context)


@login_required
def product_sales_unit_list(request):
    """
    Список всех единиц продажи товаров с возможностью фильтрации
    """
    # Получаем параметры фильтрации
    search_query = request.GET.get('q', '').strip()
    unit_filter = request.GET.get('unit', '')
    is_active_filter = request.GET.get('is_active', '')
    is_default_filter = request.GET.get('is_default', '')

    # Базовый queryset
    sales_units = ProductSalesUnit.objects.select_related(
        'product', 'unit'
    ).all()

    # Применяем фильтры
    if search_query:
        sales_units = sales_units.filter(
            Q(product__name__icontains=search_query) |
            Q(product__sku__icontains=search_query) |
            Q(name__icontains=search_query)
        )

    if unit_filter:
        sales_units = sales_units.filter(unit_id=unit_filter)

    if is_active_filter:
        sales_units = sales_units.filter(is_active=(is_active_filter == 'true'))

    if is_default_filter:
        sales_units = sales_units.filter(is_default=(is_default_filter == 'true'))

    # Сортировка
    sales_units = sales_units.order_by('product__name', 'position')

    # Пагинация
    paginator = Paginator(sales_units, 50)
    page_number = request.GET.get('page')
    page_obj = paginator.get_page(page_number)

    # Для фильтра единиц
    all_units = UnitOfMeasure.objects.filter(is_active=True).order_by('position', 'code')

    context = {
        'page_obj': page_obj,
        'search_query': search_query,
        'unit_filter': unit_filter,
        'is_active_filter': is_active_filter,
        'is_default_filter': is_default_filter,
        'all_units': all_units,
        'total_sales_units': sales_units.count(),
    }

    return render(request, 'products/uom/sales_unit_list.html', context)


@login_required
def product_sales_unit_create(request):
    """
    Создание новой единицы продажи
    """
    if request.method == 'POST':
        form = ProductSalesUnitForm(request.POST)
        if form.is_valid():
            sales_unit = form.save()
            messages.success(
                request,
                f'Единица продажи "{sales_unit.name}" для товара "{sales_unit.product.name}" успешно создана!'
            )
            return redirect('products:sales-unit-list')
    else:
        # Предзаполнение товара если передан в параметрах
        initial = {}
        product_id = request.GET.get('product')
        if product_id:
            initial['product'] = product_id

        form = ProductSalesUnitForm(initial=initial)

    context = {
        'form': form,
        'title': 'Создание единицы продажи',
        'submit_text': 'Создать'
    }
    return render(request, 'products/uom/sales_unit_form.html', context)


@login_required
def product_sales_unit_update(request, pk):
    """
    Редактирование единицы продажи
    """
    sales_unit = get_object_or_404(ProductSalesUnit, pk=pk)

    if request.method == 'POST':
        form = ProductSalesUnitForm(request.POST, instance=sales_unit)
        if form.is_valid():
            sales_unit = form.save()
            messages.success(
                request,
                f'Единица продажи "{sales_unit.name}" успешно обновлена!'
            )
            return redirect('products:sales-unit-list')
    else:
        form = ProductSalesUnitForm(instance=sales_unit)

    context = {
        'form': form,
        'sales_unit': sales_unit,
        'title': f'Редактирование: {sales_unit.name}',
        'submit_text': 'Сохранить'
    }
    return render(request, 'products/uom/sales_unit_form.html', context)


@login_required
def product_sales_unit_delete(request, pk):
    """
    Удаление единицы продажи
    """
    sales_unit = get_object_or_404(ProductSalesUnit, pk=pk)

    if request.method == 'POST':
        product_name = sales_unit.product.name
        unit_name = sales_unit.name
        sales_unit.delete()
        messages.success(
            request,
            f'Единица продажи "{unit_name}" для товара "{product_name}" успешно удалена!'
        )
        return redirect('products:sales-unit-list')

    context = {
        'sales_unit': sales_unit,
    }
    return render(request, 'products/uom/sales_unit_delete.html', context)