from django.shortcuts import render
from django.http import HttpResponse, HttpResponseRedirect, JsonResponse
from django.views.generic import ListView
from django.db import transaction

from .models import Sale, Product, ProductCategory, Payment
from .forms import ImportProductsForm, PurchaseForm, SaleLineFormSet, ReconciliationJarForm, PurchaseSummaryForm

import csv
import io


def index(request):
    return render(request, 'don_confiao/index.html')


def buy(request):
    if request.method == "POST":
        sale_form = PurchaseForm(request.POST)
        line_formset = SaleLineFormSet(request.POST)
        sale_summary_form = PurchaseSummaryForm(request.POST)
        forms_are_valid = all([
            sale_form.is_valid(),
            line_formset.is_valid(),
            sale_summary_form.is_valid()
        ])
        if forms_are_valid:
            with transaction.atomic():
                sale = sale_form.save()
                line_formset.instance = sale
                line_formset.save()
            return HttpResponseRedirect("compras")
    else:
        sale_form = PurchaseForm()
        line_formset = SaleLineFormSet()
        sale_summary_form = PurchaseSummaryForm()
    return render(
        request,
        'don_confiao/purchase.html',
        {
            'sale_form': sale_form,
            'linea_formset': line_formset,
            'summary_form': sale_summary_form,
        }
    )


def purchases(request):
    purchases = Sale.objects.all()
    context = {
        "purchases": purchases,
    }
    return render(request, 'don_confiao/purchases.html', context)


def products(request):
    rproducts = []
    products = Product.objects.all()
    for product in products:
        rproduct = {
            "name": product.name,
            "price_list": product.price,
            "uom": product.measuring_unit,
            "categories": [c.name for c in product.categories.all()]
        }
        rproducts.append(rproduct)

    return JsonResponse(rproducts, safe=False)


def import_products(request):
    if request.method == "POST":
        form = ImportProductsForm(request.POST, request.FILES)
        if form.is_valid():
            handle_import_products_file(request.FILES["csv_file"])
            return HttpResponseRedirect("productos")
    else:
        form = ImportProductsForm()
    return render(
        request,
        "don_confiao/import_products.html",
        {'form': form}
    )


def reconciliate_jar(request):
    summary = Payment.get_reconciliation_jar_summary()
    if request.method == 'POST':
        form = ReconciliationJarForm(request.POST)
        if form.is_valid():
            reconciliation = form.save()
            reconciliation.add_payments(summary.payments)
            reconciliation.clean()
            reconciliation.save()
            return HttpResponseRedirect('cuadres')
    else:
        form = ReconciliationJarForm()
    return render(
        request,
        "don_confiao/reconciliate_jar.html",
        {'summary': summary, 'form': form}
    )


def reconciliations(request):
    return HttpResponse('<h1>Reconciliaciones</h1>')

def purchase_summary(request, id):
    purchase = Sale.objects.get(pk=id)
    return render(
        request,
        "don_confiao/purchase_summary.html",
        {
            "purchase" : purchase
        }
    )

def _categories_from_csv_string(categories_string, separator="&"):
    categories = categories_string.split(separator)
    clean_categories = [c.strip() for c in categories]
    return [_category_from_name(category) for category in clean_categories]


def _category_from_name(name):
    return ProductCategory.objects.get_or_create(name=name)[0]


def handle_import_products_file(csv_file):
    data = io.StringIO(csv_file.read().decode('utf-8'))
    reader = csv.DictReader(data, quotechar='"')
    for row in reader:
        product, created = Product.objects.update_or_create(
            name=row['producto'],
            defaults={
                'price': row['precio'],
                'measuring_unit': row['unidad']
            }
        )
        categories = _categories_from_csv_string(row["categorias"])
        product.categories.clear()
        for category in categories:
            product.categories.add(category)


class ProductListView(ListView):
    model = Product
    template_model = 'don_confiao/product_list.html'

    def get_queryset(self):
        name = self.request.GET.get('name')
        if name:
            return Product.objects.filter(name__icontains=name)
        return Product.objects.all()