import decimal
from django.db import models
from decimal import Decimal
from django.core.validators import MinValueValidator, MaxValueValidator

# Create your models here.

class SiteConfiguration(models.Model):
    name = models.CharField(max_length=100, default="Shop name", unique=True)

    logo = models.ImageField(upload_to='shop_logos/', blank=True, null=True)
    favicon = models.ImageField(upload_to='shop_favicons/', blank=True, null=True)

    contact_email = models.EmailField(max_length=254, blank=True, null=True)
    contact_phone = models.CharField(max_length=20, blank=True, null=True)
    contact_address = models.TextField(blank=True, null=True)
    opening_hours = models.JSONField(blank=True, null=True) #FIXME: vytvoř JSON tvar pro otvírací dobu, přes validátory

    #Social
    facebook_url = models.URLField(max_length=200, blank=True, null=True)
    instagram_url = models.URLField(max_length=200, blank=True, null=True)
    youtube_url = models.URLField(max_length=200, blank=True, null=True)
    tiktok_url = models.URLField(max_length=200, blank=True, null=True)
    whatsapp_number = models.CharField(max_length=20, blank=True, null=True)

    #zasilkovna settings
    zasilkovna_shipping_price = models.DecimalField(max_digits=10, decimal_places=2, default=decimal.Decimal("50.00"))
    #FIXME: není implementováno ↓↓↓
    zasilkovna_api_key = models.CharField(max_length=255, blank=True, null=True, help_text="API klíč pro přístup k Zásilkovna API (zatím není využito)")
    #FIXME: není implementováno ↓↓↓
    zasilkovna_api_password = models.CharField(max_length=255, blank=True, null=True, help_text="API heslo pro přístup k Zásilkovna API (zatím není využito)")
    #FIXME: není implementováno ↓↓↓
    free_shipping_over = models.DecimalField(max_digits=10, decimal_places=2, default=decimal.Decimal("2000.00"))

    # Deutsche Post settings
    deutschepost_api_url = models.URLField(max_length=255, default="https://gw.sandbox.deutschepost.com", help_text="Deutsche Post API URL (sandbox/production)")
    deutschepost_client_id = models.CharField(max_length=255, blank=True, null=True, help_text="Deutsche Post OAuth Client ID")
    deutschepost_client_secret = models.CharField(max_length=255, blank=True, null=True, help_text="Deutsche Post OAuth Client Secret")
    deutschepost_customer_ekp = models.CharField(max_length=20, blank=True, null=True, help_text="Deutsche Post Customer EKP number")
    deutschepost_shipping_price = models.DecimalField(max_digits=10, decimal_places=2, default=decimal.Decimal("6.00"), help_text="Default Deutsche Post shipping price in EUR")

    #coupon settings
    multiplying_coupons = models.BooleanField(default=True, help_text="Násobení kupónů v objednávce (ano/ne), pokud ne tak se použije pouze nejvyšší slevový kupón")
    addition_of_coupons_amount = models.BooleanField(default=False, help_text="Sčítání slevových kupónů v objednávce (ano/ne), pokud ne tak se použije pouze nejvyšší slevový kupón")

    class CURRENCY(models.TextChoices):
        EUR = "EUR", "Euro"
        CZK = "CZK", "Czech Koruna" 
        USD = "USD", "US Dollar"
        GBP = "GBP", "British Pound"
        PLN = "PLN", "Polish Zloty"
        HUF = "HUF", "Hungarian Forint"
        SEK = "SEK", "Swedish Krona"
        DKK = "DKK", "Danish Krone"
        NOK = "NOK", "Norwegian Krone"
        CHF = "CHF", "Swiss Franc"
    currency = models.CharField(max_length=10, default=CURRENCY.EUR, choices=CURRENCY.choices)

    class Meta:
        verbose_name = "Shop Configuration"
        verbose_name_plural = "Shop Configuration"

    def save(self, *args, **kwargs):
        # zajištění singletonu
        self.pk = 1
        super().save(*args, **kwargs)

    @classmethod
    def get_solo(cls):
        obj, _ = cls.objects.get_or_create(pk=1)
        return obj


class VATRate(models.Model):
    """Business owner configurable VAT rates"""
    name = models.CharField(
        max_length=100, 
        help_text="E.g. 'German Standard', 'German Reduced', 'Czech Standard'"
    )
    description = models.TextField(
        blank=True,
        help_text="Optional description: 'Standard rate for most products', 'Books and food', etc."
    )

    rate = models.DecimalField(
        max_digits=6,
        decimal_places=4,  # Allows rates like 19.5000%
        validators=[MinValueValidator(Decimal('0')), MaxValueValidator(Decimal('100'))],
        help_text="VAT rate as percentage (e.g. 19.00 for 19%)"
    )

    

    is_default = models.BooleanField(
        default=False,
        help_text="Default rate for new products"
    )
    is_active = models.BooleanField(
        default=True,
        help_text="Whether this VAT rate is active and available for use"
    )
    created_at = models.DateTimeField(auto_now_add=True)
    
    class Meta:
        verbose_name = "VAT Rate"
        verbose_name_plural = "VAT Rates"
        ordering = ['-is_default', 'rate', 'name']
    
    def __str__(self):
        return f"{self.name} ({self.rate}%)"
    
    def save(self, *args, **kwargs):
        # Ensure only one default rate
        if self.is_default:
            VATRate.objects.filter(is_default=True).update(is_default=False)
        super().save(*args, **kwargs)
        
        # If no default exists, make first active one default
        if not VATRate.objects.filter(is_default=True).exists():
            first_active = VATRate.objects.filter(is_active=True).first()
            if first_active:
                first_active.is_default = True
                first_active.save()

    @property
    def rate_decimal(self):
        """Returns rate as decimal for calculations (19.00% -> 0.19)"""
        return self.rate / Decimal('100')
    
    @classmethod
    def get_default(cls):
        """Get the default VAT rate"""
        return cls.objects.filter(is_default=True, is_active=True).first()