from django.db import models
from django.utils.translation import gettext_lazy as _

class Category(models.Model):
    name_en = models.CharField(_("Name (English)"), max_length=100)
    name_ar = models.CharField(_("Name (Arabic)"), max_length=100)
    slug = models.SlugField(unique=True)

    class Meta:
        verbose_name_plural = _("Categories")

    def __str__(self):
        return f"{self.name_en} / {self.name_ar}"

class Product(models.Model):
    category = models.ForeignKey(Category, on_delete=models.CASCADE, related_name="products")
    name_en = models.CharField(_("Name (English)"), max_length=200)
    name_ar = models.CharField(_("Name (Arabic)"), max_length=200)
    sku = models.CharField(_("SKU"), max_length=50, unique=True)
    description = models.TextField(_("Description"), blank=True)
    price = models.DecimalField(_("Price"), max_digits=10, decimal_places=2)
    stock_quantity = models.PositiveIntegerField(_("Stock Quantity"), default=0)
    image = models.URLField(_("Product Image"), blank=True, null=True)
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f"{self.name_en} ({self.sku})"

class Customer(models.Model):
    name = models.CharField(_("Name"), max_length=200)
    phone = models.CharField(_("Phone"), max_length=20, blank=True)
    email = models.EmailField(_("Email"), blank=True)
    address = models.TextField(_("Address"), blank=True)

    def __str__(self):
        return self.name

class Supplier(models.Model):
    name = models.CharField(_("Name"), max_length=200)
    contact_person = models.CharField(_("Contact Person"), max_length=200, blank=True)
    phone = models.CharField(_("Phone"), max_length=20, blank=True)

    def __str__(self):
        return self.name

class Sale(models.Model):
    customer = models.ForeignKey(Customer, on_delete=models.SET_NULL, null=True, blank=True)
    total_amount = models.DecimalField(max_digits=12, decimal_places=2)
    discount = models.DecimalField(max_digits=12, decimal_places=2, default=0)
    created_at = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f"Sale #{self.id} - {self.total_amount}"

class SaleItem(models.Model):
    sale = models.ForeignKey(Sale, on_delete=models.CASCADE, related_name="items")
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    quantity = models.PositiveIntegerField()
    unit_price = models.DecimalField(max_digits=10, decimal_places=2)
    line_total = models.DecimalField(max_digits=12, decimal_places=2)

class Purchase(models.Model):
    supplier = models.ForeignKey(Supplier, on_delete=models.SET_NULL, null=True)
    total_amount = models.DecimalField(max_digits=12, decimal_places=2)
    created_at = models.DateTimeField(auto_now_add=True)

class SystemSetting(models.Model):
    business_name = models.CharField(_("Business Name"), max_length=200, default="Meezan Accounting")
    address = models.TextField(_("Address"), blank=True)
    phone = models.CharField(_("Phone"), max_length=20, blank=True)
    email = models.EmailField(_("Email"), blank=True)
    currency_symbol = models.CharField(_("Currency Symbol"), max_length=10, default="$")
    tax_rate = models.DecimalField(_("Tax Rate (%)"), max_digits=5, decimal_places=2, default=0)
    logo_url = models.URLField(_("Logo URL"), blank=True, null=True)

    def __str__(self):
        return self.business_name