from django.shortcuts import render
from django.views.generic import ListView, DetailView, RedirectView
from django.views.generic.edit import UpdateView, CreateView, DeleteView, ProcessFormView, FormMixin
from django.forms.models import modelform_factory
from django.forms import CheckboxSelectMultiple
from django.core.urlresolvers import reverse_lazy
from django.contrib.auth.forms import AuthenticationForm
from django.http import HttpResponseRedirect
from django.utils import timezone
from django import forms
from django.utils.translation import ugettext_lazy as _
from django.conf import settings
from django.db import DataError, transaction

import re
from datetime import date, timedelta

from core.views import CanViewMixin, CanEditMixin, CanEditPropMixin, CanCreateMixin
from subscription.models import Subscriber
from subscription.views import get_subscriber
from counter.models import Counter, Customer, Product, Selling, Refilling, ProductType

class GetUserForm(forms.Form):
    """
    The Form class aims at providing a valid user_id field in its cleaned data, in order to pass it to some view,
    reverse function, or any other use.

    The Form implements a nice JS widget allowing the user to type a customer account id, or search the database with
    some nickname, first name, or last name (TODO)
    """
    code = forms.CharField(label="Code", max_length=10, required=False)
    id = forms.IntegerField(label="ID", required=False)
    # TODO: add a nice JS widget to search for users

    def as_p(self):
        self.fields['code'].widget.attrs['autofocus'] = True
        return super(GetUserForm, self).as_p()

    def clean(self):
        cleaned_data = super(GetUserForm, self).clean()
        cus = None
        if cleaned_data['code'] != "":
            cus = Customer.objects.filter(account_id=cleaned_data['code']).first()
        elif cleaned_data['id'] is not None:
            cus = Customer.objects.filter(user=cleaned_data['id']).first()
        sub = get_subscriber(cus.user) if cus is not None else None
        if cus is None or sub is None or (date.today() - sub.subscriptions.last().subscription_end) > timedelta(days=90):
            raise forms.ValidationError(_("User not found"))
        cleaned_data['user_id'] = cus.user.id
        cleaned_data['user'] = cus.user
        return cleaned_data

class RefillForm(forms.ModelForm):
    error_css_class = 'error'
    required_css_class = 'required'
    class Meta:
        model = Refilling
        fields = ['amount', 'payment_method', 'bank']

class CounterMain(DetailView, ProcessFormView, FormMixin):
    """
    The public (barman) view
    """
    model = Counter
    template_name = 'counter/counter_main.jinja'
    pk_url_kwarg = "counter_id"
    form_class = GetUserForm # Form to enter a client code and get the corresponding user id

    def get_context_data(self, **kwargs):
        """
        We handle here the login form for the barman
        """
        if self.request.method == 'POST':
            self.object = self.get_object()
        kwargs = super(CounterMain, self).get_context_data(**kwargs)
        kwargs['login_form'] = AuthenticationForm()
        kwargs['login_form'].fields['username'].widget.attrs['autofocus'] = True
        kwargs['form'] = self.get_form()
        if self.object.type == 'BAR':
            kwargs['barmen'] = Counter.get_barmen_list(self.object.id)
        elif self.request.user.is_authenticated():
            kwargs['barmen'] = [self.request.user]
        if 'last_basket' in self.request.session.keys():
            kwargs['last_basket'] = self.request.session.pop('last_basket')
            kwargs['last_customer'] = self.request.session.pop('last_customer')
            kwargs['last_total'] = self.request.session.pop('last_total')
            kwargs['new_customer_amount'] = self.request.session.pop('new_customer_amount')
        return kwargs

    def form_valid(self, form):
        """
        We handle here the redirection, passing the user id of the asked customer
        """
        self.kwargs['user_id'] = form.cleaned_data['user_id']
        return super(CounterMain, self).form_valid(form)

    def get_success_url(self):
        return reverse_lazy('counter:click', args=self.args, kwargs=self.kwargs)

class CounterClick(DetailView):
    """
    The click view
    This is a detail view not to have to worry about loading the counter
    Everything is made by hand in the post method
    """
    model = Counter
    template_name = 'counter/counter_click.jinja'
    pk_url_kwarg = "counter_id"

    def get(self, request, *args, **kwargs):
        """Simple get view"""
        self.customer = Customer.objects.filter(user__id=self.kwargs['user_id']).first()
        if 'basket' not in request.session.keys(): # Init the basket session entry
            request.session['basket'] = {}
            request.session['basket_total'] = 0
        request.session['not_enough'] = False
        self.refill_form = None
        ret = super(CounterClick, self).get(request, *args, **kwargs)
        if ((self.object.type != "BAR" and not request.user.is_authenticated()) or
                (self.object.type == "BAR" and
                len(Counter.get_barmen_list(self.object.id)) < 1)): # Check that at least one barman is logged in
            ret = self.cancel(request) # Otherwise, go to main view
        return ret

    def post(self, request, *args, **kwargs):
        """ Handle the many possibilities of the post request """
        self.object = self.get_object()
        self.customer = Customer.objects.filter(user__id=self.kwargs['user_id']).first()
        self.refill_form = None
        if ((self.object.type != "BAR" and not request.user.is_authenticated()) or
                (self.object.type == "BAR" and
                len(Counter.get_barmen_list(self.object.id)) < 1)): # Check that at least one barman is logged in
            return self.cancel(request)
        if 'basket' not in request.session.keys():
            request.session['basket'] = {}
            request.session['basket_total'] = 0
        request.session['not_enough'] = False
        if self.object.type != "BAR":
            self.operator = request.user
        elif self.is_barman_price():
            self.operator = self.customer.user
        else:
            self.operator = Counter.get_random_barman(self.object.id)

        if 'add_product' in request.POST['action']:
            self.add_product(request)
        elif 'del_product' in request.POST['action']:
            self.del_product(request)
        elif 'refill' in request.POST['action']:
            self.refill(request)
        elif 'code' in request.POST['action']:
            return self.parse_code(request)
        elif 'cancel' in request.POST['action']:
            return self.cancel(request)
        elif 'finish' in request.POST['action']:
            return self.finish(request)
        context = self.get_context_data(object=self.object)
        return self.render_to_response(context)

    def is_barman_price(self):
        if self.object.type == "BAR" and self.customer.user.id in [s.id for s in Counter.get_barmen_list(self.object.id)]:
            return True
        else:
            return False

    def get_price(self, pid):
        p = Product.objects.filter(pk=pid).first()
        if self.is_barman_price():
            price = p.special_selling_price
        else:
            price = p.selling_price
        return price

    def sum_basket(self, request):
        total = 0
        for pid,infos in request.session['basket'].items():
            total += infos['price'] * infos['qty']
        return total / 100

    def add_product(self, request, q = 1, p=None):
        """ Add a product to the basket """
        pid = p or request.POST['product_id']
        pid = str(pid)
        price = self.get_price(pid)
        total = self.sum_basket(request)
        if self.customer.amount < (total + q*float(price)):
            request.session['not_enough'] = True
            return False
        if pid in request.session['basket']:
            request.session['basket'][pid]['qty'] += q
        else:
            request.session['basket'][pid] = {'qty': q, 'price': int(price*100)}
        request.session['not_enough'] = False # Reset not_enough to save the session
        request.session.modified = True
        return True

    def del_product(self, request):
        """ Delete a product from the basket """
        pid = str(request.POST['product_id'])
        if pid in request.session['basket']:
            request.session['basket'][pid]['qty'] -= 1
            if request.session['basket'][pid]['qty'] <= 0:
                del request.session['basket'][pid]
        else:
            request.session['basket'][pid] = 0
        request.session.modified = True

    def parse_code(self, request):
        """Parse the string entered by the barman"""
        string = str(request.POST['code']).upper()
        if string == _("END"):
            return self.finish(request)
        elif string == _("CAN"):
            return self.cancel(request)
        regex = re.compile(r"^((?P<nb>[0-9]+)X)?(?P<code>[A-Z0-9]+)$")
        m = regex.match(string)
        if m is not None:
            nb = m.group('nb')
            code = m.group('code')
            if nb is None:
                nb = 1
            else:
                nb = int(nb)
            p = self.object.products.filter(code=code).first()
            if p is not None:
                while nb > 0 and not self.add_product(request, nb, p.id):
                    nb -= 1
        context = self.get_context_data(object=self.object)
        return self.render_to_response(context)

    def finish(self, request):
        """ Finish the click session, and validate the basket """
        with transaction.atomic():
            request.session['last_basket'] = []
            for pid,infos in request.session['basket'].items():
                # This duplicates code for DB optimization (prevent to load many times the same object)
                p = Product.objects.filter(pk=pid).first()
                if self.is_barman_price():
                    uprice = p.special_selling_price
                else:
                    uprice = p.selling_price
                if uprice * infos['qty'] > self.customer.amount:
                    raise DataError(_("You have not enough money to buy all the basket"))
                request.session['last_basket'].append("%d x %s" % (infos['qty'], p.name))
                s = Selling(label=p.name, product=p, counter=self.object, unit_price=uprice,
                       quantity=infos['qty'], seller=self.operator, customer=self.customer)
                s.save()
            request.session['last_customer'] = self.customer.user.get_display_name()
            request.session['last_total'] = "%0.2f" % self.sum_basket(request)
            request.session['new_customer_amount'] = str(self.customer.amount)
            del request.session['basket']
            request.session.modified = True
            kwargs = {
                    'counter_id': self.object.id,
                    }
            return HttpResponseRedirect(reverse_lazy('counter:details', args=self.args, kwargs=kwargs))

    def cancel(self, request):
        """ Cancel the click session """
        kwargs = {'counter_id': self.object.id}
        request.session.pop('basket', None)
        return HttpResponseRedirect(reverse_lazy('counter:details', args=self.args, kwargs=kwargs))

    def refill(self, request):
        """Refill the customer's account"""
        form = RefillForm(request.POST)
        if form.is_valid():
            form.instance.counter = self.object
            form.instance.operator = self.operator
            form.instance.customer = self.customer
            form.instance.save()
        else:
            self.refill_form = form

    def get_context_data(self, **kwargs):
        """ Add customer to the context """
        kwargs = super(CounterClick, self).get_context_data(**kwargs)
        kwargs['customer'] = self.customer
        kwargs['basket_total'] = self.sum_basket(self.request)
        kwargs['refill_form'] = self.refill_form or RefillForm()
        return kwargs

class CounterLogin(RedirectView):
    """
    Handle the login of a barman

    Logged barmen are stored in the class-wide variable 'barmen_session', in the Counter model
    """
    permanent = False
    def post(self, request, *args, **kwargs):
        """
        Register the logged user as barman for this counter
        """
        self.counter_id = kwargs['counter_id']
        form = AuthenticationForm(request, data=request.POST)
        if form.is_valid():
            user = Subscriber.objects.filter(username=form.cleaned_data['username']).first()
            if user.is_subscribed():
                Counter.add_barman(self.counter_id, user.id)
        else:
            print("Error logging the barman") # TODO handle that nicely
        return super(CounterLogin, self).post(request, *args, **kwargs)

    def get_redirect_url(self, *args, **kwargs):
        return reverse_lazy('counter:details', args=args, kwargs=kwargs)

class CounterLogout(RedirectView):
    permanent = False
    def post(self, request, *args, **kwargs):
        """
        Unregister the user from the barman
        """
        self.counter_id = kwargs['counter_id']
        Counter.del_barman(self.counter_id, request.POST['user_id'])
        return super(CounterLogout, self).post(request, *args, **kwargs)

    def get_redirect_url(self, *args, **kwargs):
        return reverse_lazy('counter:details', args=args, kwargs=kwargs)

## Counter admin views

class CounterListView(CanViewMixin, ListView):
    """
    A list view for the admins
    """
    model = Counter
    template_name = 'counter/counter_list.jinja'

class CounterEditView(CanEditPropMixin, UpdateView):
    """
    Edit a counter's main informations (for the counter's admin)
    """
    model = Counter
    form_class = modelform_factory(Counter, fields=['name', 'club', 'type', 'sellers', 'products'],
            widgets={
                'products':CheckboxSelectMultiple,
                'sellers':CheckboxSelectMultiple})
    pk_url_kwarg = "counter_id"
    template_name = 'counter/counter_edit.jinja'

class CounterCreateView(CanEditMixin, CreateView):
    """
    Create a counter (for the admins)
    """
    model = Counter
    form_class = modelform_factory(Counter, fields=['name', 'club', 'type', 'products'],
            widgets={'products':CheckboxSelectMultiple})
    template_name = 'counter/counter_edit.jinja'

class CounterDeleteView(CanEditMixin, DeleteView):
    """
    Delete a counter (for the admins)
    """
    model = Counter
    pk_url_kwarg = "counter_id"
    template_name = 'core/delete_confirm.jinja'
    success_url = reverse_lazy('counter:admin_list')

# Product management

class ProductTypeListView(CanEditPropMixin, ListView):
    """
    A list view for the admins
    """
    model = ProductType
    template_name = 'counter/producttype_list.jinja'

class ProductTypeCreateView(CanCreateMixin, CreateView):
    """
    A create view for the admins
    """
    model = ProductType
    fields = ['name', 'description', 'icon']
    template_name = 'core/create.jinja'

class ProductTypeEditView(CanEditPropMixin, UpdateView):
    """
    An edit view for the admins
    """
    model = ProductType
    template_name = 'core/edit.jinja'
    fields = ['name', 'description', 'icon']
    pk_url_kwarg = "type_id"

class ProductListView(CanEditPropMixin, ListView):
    """
    A list view for the admins
    """
    model = Product
    template_name = 'counter/product_list.jinja'

class ProductCreateView(CanCreateMixin, CreateView):
    """
    A create view for the admins
    """
    model = Product
    fields = ['name', 'description', 'product_type', 'code', 'purchase_price',
            'selling_price', 'special_selling_price', 'icon', 'club']
    template_name = 'core/create.jinja'

class ProductEditView(CanEditPropMixin, UpdateView):
    """
    An edit view for the admins
    """
    model = Product
    fields = ['name', 'description', 'product_type', 'code', 'purchase_price',
            'selling_price', 'special_selling_price', 'icon', 'club']
    pk_url_kwarg = "product_id"
    template_name = 'core/edit.jinja'
    # TODO: add management of the 'counters' ForeignKey