import calendar
import datetime
from django.db import models
from django.db.models import Sum
from django.urls import reverse
from django.utils import timezone


class LuxSource(models.Model):
    name = models.CharField(max_length=200)
    date_recorded = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.name


class LuxSpendingCategory(models.Model):
    name = models.CharField(max_length=200)
    date_recorded = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.name


class LuxPaymentMethod(models.Model):
    name = models.CharField(max_length=200)
    
    def __str__(self):
        return self.name


class LuxFixedMonthly(models.Model):
    name = models.CharField(max_length=200)
    amount = models.DecimalField(max_digits=6, decimal_places=2)
    source = models.ForeignKey(LuxSource, on_delete=models.CASCADE)
    category = models.ForeignKey(LuxSpendingCategory, on_delete=models.CASCADE)
    payment_method = models.ForeignKey(LuxPaymentMethod, null=True, on_delete=models.CASCADE)
    date_recorded = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.name


class LuxPurchaseStatsManager(models.Manager):

    def get_monthly_spending(self, month=timezone.now().month):
        last_day = calendar.monthrange(timezone.now().year, month)[1]
        start_date = datetime.date(timezone.now().year, month, 1)
        end_date = datetime.date(timezone.now().year, month, last_day)
        return self.filter(date_recorded__range=(start_date, end_date)).aggregate(Sum('amount'))

    def get_monthly_spending_by_category(self, cat, number_of_months=1):
        cat = LuxSpendingCategory.objects.get(name=cat)
        today = timezone.now() 
        month = today.replace(day=1).month
        start_month = month - number_of_months + 1
        start_date = datetime.date(timezone.now().year, start_month, 1)
        last_day = calendar.monthrange(timezone.now().year, month)[1]
        end_date = datetime.date(timezone.now().year, month, last_day)
        return self.filter(date_recorded__range=(start_date, end_date)).filter(category=cat).aggregate(Sum('amount'))


class LuxPurchase(models.Model):
    amount = models.DecimalField(max_digits=6, decimal_places=2)
    source = models.ForeignKey(LuxSource, on_delete=models.CASCADE)
    category = models.ForeignKey(LuxSpendingCategory, null=True, on_delete=models.CASCADE)
    date_recorded = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ('-date_recorded',)
    
    def __str__(self):
        return "%s - %s" %(self.amount, self.source.name)

    def get_absolute_url(self):
        return reverse("luxbudget:detail", kwargs={"pk": self.pk})

    objects = models.Manager()  # The default manager.
    stats = LuxPurchaseStatsManager()