from django.db import models
from django.contrib.auth import get_user_model
from django.core.files.base import ContentFile
from django.utils import timezone

from dateutil.relativedelta import relativedelta

from pyinvoice.models import InvoiceInfo, ServiceProviderInfo, ClientInfo, Item, Transaction, PDFInfo
from pyinvoice.templates import SimpleInvoice

from polymorphic.models import PolymorphicModel
from django_countries.fields import CountryField

from io import BytesIO

import urllib.request

from dbsettings.functions import getValue

from .functions import invoice_upload_path

from auction.models import Inquiry

class BillingAddress(models.Model):
    user = models.ForeignKey(get_user_model(), models.CASCADE)
    company = models.CharField(max_length=64, null=True, blank=True)
    vat_id = models.CharField(max_length=32, null=True, blank=True)
    first_name = models.CharField(max_length=64)
    last_name = models.CharField(max_length=64)
    street = models.CharField(max_length=128)
    city = models.CharField(max_length=64)
    zip = models.CharField(max_length=16)
    state = models.CharField(max_length=32, null=True, blank=True)
    country = CountryField()

class Invoice(models.Model):
    user = models.ForeignKey(get_user_model(), models.PROTECT)
    billing_address = models.ForeignKey(BillingAddress, models.PROTECT)
    currency = models.CharField(max_length=3)
    tax_rate = models.DecimalField(max_digits=4, decimal_places=2)
    invoice = models.FileField(null=True, blank=True, upload_to=invoice_upload_path)
    inquiry = models.OneToOneField(Inquiry, null=True, blank=True, on_delete=models.SET_NULL)

    @property
    def price_net(self):
        price = 0

        for item in self.invoiceitem_set().all():
            price += item.net_total

        return price

    @property
    def tax(self):
        return round(self.price_net * self.tax_rate / 100, 2)

    @property
    def price_gross(self):
        return self.price_net + self.tax

    @property
    def payment_instructions(self):
        return "Alle Preise in %s." % self.currency

    @property
    def url(self):
        return False

    @property
    def is_paid(self):
        paid_amount = 0

        for payment in self.invoicepayment_set().all():
            paid_amount += payment.amount

        if paid_amount >= price_gross:
            return True
        return False
    
    def generate_invoice(self):
        output = BytesIO()

        pdfinfo = PDFInfo(title='Rechnung', author='Kumi Media Ltd.', subject='Rechnung')
        doc = SimpleInvoice(output, pdfinfo)

        doc.is_paid = self.is_paid

        doc.invoice_info = InvoiceInfo("%s%i" % (getValue("billing.prefix", ""), self.id), timezone.now().date(), timezone.now().date()) 

        provider_data = { key: value for key, value in {
            "name": getValue("billing.provider.name", False),
            "street": getValue("billing.provider.street", False),
            "city": getValue("billing.provider.city", False),
            "state": getValue("billing.provider.state", False),
            "country": getValue("billing.provider.country", False),
            "post_code": getValue("billing.provider.zip", False),
            "vat_tax_number": getValue("billing.provider.vat_id", False)
        }.items() if value}

        doc.service_provider_info = ServiceProviderInfo(**provider_data)

        logo_url = getValue("billing.logo_url", False)
        if logo_url:
            try:
                logo = BytesIO(urllib.request.urlopen(logo_url).read())
                doc.logo(logo)
            except:
                pass

        profile = self.user.clientprofile if self.inquiry else self.user.partnerprofile

        client_data = { key: value for key, value in {
            "name": profile.full_name,
            "street": profile.street,
            "city": profile.city,
            "state": profile.state,
            "country": profile.country,
            "post_code": profile.zip,
            "vat_tax_number": profile.vat_id,
            "email": self.user.email,
        }.items() if value}

        doc.client_info = ClientInfo(**client_data)

        for item in self.invoiceitem_set().all():
            doc.add_item(Item(item.name, item.description, item.count, item.net_each))

        doc.set_item_tax_rate(self.tax_rate)

        for payment in self.invoicepayment_set().all():
            doc.add_transaction(Transaction(payment.gateway, payment.gateway_id, payment.timestamp, payment.amount))

        bottom_tip = (f"{ self.payment_instructions }<br /><br />" if self.payment_instructions else "") + getValue("billing.bottom_tip", "")
        bottom_tip += "<br /><br />" if bottom_tip else ""
        bottom_tip +=  "Rechnung erstellt: %s" % str(timezone.now())

        doc.set_bottom_tip(bottom_tip)

        doc.finish()

        self.invoice = ContentFile(output.getvalue(), "invoice.pdf")
        self.save()

class InvoiceItem(models.Model):
    invoice = models.ForeignKey(Invoice, models.CASCADE)
    name = models.CharField(max_length=64)
    description = models.CharField(max_length=256, null=True, blank=True)
    count = models.IntegerField()
    net_each = models.DecimalField(max_digits=11, decimal_places=2)

class InvoicePayment(PolymorphicModel):
    invoice = models.ForeignKey(Invoice, models.PROTECT)
    amount = models.DecimalField(max_digits=9, decimal_places=2)
    gateway_id = models.CharField(max_length=256)
    timestamp = models.DateTimeField(default=timezone.now)

    @property
    def gateway(self):
        raise NotImplementedError("%s does not implement gateway" % type(self))

    @classmethod
    def initiate(cls, invoice):
        raise NotImplementedError("%s does not implement initiate()" % cls.__name__)