commerce logika

backend/commerce/models.py

@@ -1,16 +1,58 @@
 from django.db import models
+from django.conf import settings
+from django.utils import timezone
+from django.utils.translation import gettext_lazy as _
+from decimal import Decimal
+
+
+class Category(models.Model):
+    name = models.CharField(max_length=100)
+
+    #adresa kategorie např: /category/elektronika/mobily/
+    url = models.SlugField(unique=True)
+
+    #kategorie se můžou skládat pod sebe
+    parent = models.ForeignKey(
+        'self', null=True, blank=True, on_delete=models.CASCADE, related_name='subcategories'
+    )
+
+    description = models.TextField(blank=True)
+
+    #ikona
+    image = models.ImageField(upload_to='categories/', blank=True) 
+
+    class Meta:
+        verbose_name_plural = "Categories"
+
+    def __str__(self):
+        return self.name
+    
+
 
 class Product(models.Model):
     name = models.CharField(max_length=200)
     description = models.TextField(blank=True)
+    code = models.CharField(max_length=100, unique=True, blank=True, null=True)
+
+    category = models.ForeignKey(Category, related_name='products', on_delete=models.PROTECT)
+
     price = models.DecimalField(max_digits=10, decimal_places=2)
     currency = models.CharField(max_length=10, default="czk")
+
+    url = models.SlugField(unique=True)
+
     stock = models.PositiveIntegerField(default=0)
     is_active = models.BooleanField(default=True)
+
+    #limitka
+    limited_to = models.DateTimeField(null=True, blank=True)
+
     default_carrier = models.ForeignKey(
         "Carrier", on_delete=models.SET_NULL, null=True, blank=True, related_name="default_for_products"
     )
+
     created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
 
     @property
     def available(self):
@@ -18,11 +60,21 @@ class Product(models.Model):
 
     def __str__(self):
         return f"{self.name} ({self.price} {self.currency.upper()})"
+    
+#obrázek pro produkty
+class ProductImage(models.Model):
+    product = models.ForeignKey(Product, related_name='images', on_delete=models.CASCADE)
+
+    image = models.ImageField(upload_to='products/')
+
+    alt_text = models.CharField(max_length=150, blank=True)
+    is_main = models.BooleanField(default=False)
+
+    def __str__(self):
+        return f"{self.product.name} image"
 
 
 # Dopravci a způsoby dopravy
-from django.db import models
-
 class Carrier(models.Model):
     name = models.CharField(max_length=100)  # název dopravce (Zásilkovna, Česká pošta…)
     base_price = models.DecimalField(max_digits=10, decimal_places=2, default=0)  # základní cena dopravy
@@ -38,3 +90,126 @@ class Carrier(models.Model):
     def __str__(self):
         return f"{self.name} ({self.base_price} Kč)"
 
+
+
+class DiscountCode(models.Model):
+    code = models.CharField(max_length=50, unique=True)
+    description = models.CharField(max_length=255, blank=True)
+    
+    # sleva v procentech (0–100)
+    percent = models.DecimalField(max_digits=5, decimal_places=2, help_text="Např. 10.00 = 10% sleva")
+    
+    # nebo fixní částka
+    amount = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True, help_text="Fixní sleva v CZK")
+
+    valid_from = models.DateTimeField(default=timezone.now)
+    valid_to = models.DateTimeField(null=True, blank=True)
+    active = models.BooleanField(default=True)
+
+    usage_limit = models.PositiveIntegerField(null=True, blank=True)
+    used_count = models.PositiveIntegerField(default=0)
+
+    specific_products = models.ManyToManyField(
+        Product, blank=True, related_name="discount_codes"
+    )
+    specific_categories = models.ManyToManyField(
+        Category, blank=True, related_name="discount_codes"
+    )
+
+    def is_valid(self):
+        now = timezone.now()
+        if not self.active:
+            return False
+        if self.valid_to and self.valid_to < now:
+            return False
+        if self.usage_limit and self.used_count >= self.usage_limit:
+            return False
+        return True
+
+    def __str__(self):
+        return f"{self.code} ({self.percent}% or {self.amount} CZK)"
+
+
+class Order(models.Model):
+    class Status(models.TextChoices):
+        PENDING = "pending", _("Čeká na platbu")
+        PAID = "paid", _("Zaplaceno")
+        CANCELLED = "cancelled", _("Zrušeno")
+        SHIPPED = "shipped", _("Odesláno")
+        COMPLETED = "completed", _("Dokončeno")
+
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL, related_name="orders", on_delete=models.CASCADE
+    )
+
+    status = models.CharField(
+        max_length=20, choices=Status.choices, default=Status.PENDING
+    )
+
+    # Stored order grand total; recalculated on save
+    total_price = models.DecimalField(max_digits=10, decimal_places=2, default=0)
+    currency = models.CharField(max_length=10, default="CZK")
+
+    # fakturační údaje (zkopírované z user profilu při objednávce)
+    first_name = models.CharField(max_length=100)
+    last_name = models.CharField(max_length=100)
+    email = models.EmailField()
+    phone = models.CharField(max_length=20, blank=True)
+    address = models.CharField(max_length=255)
+    city = models.CharField(max_length=100)
+    postal_code = models.CharField(max_length=20)
+    country = models.CharField(max_length=100, default="Czech Republic")
+
+    note = models.TextField(blank=True)
+
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    discount = models.ManyToOneRel("DiscountCode", null=True, blank=True, on_delete=models.PROTECT)
+
+    def __str__(self):
+        return f"Order #{self.id} - {self.user.email} ({self.status})"
+    
+    def calculate_total_price(self):
+        for discount in self.discount.all():
+            total = Decimal('0.0')
+
+            # getting all prices from order items (with discount applied if valid)
+            for item in self.items.all():
+                total = total + item.get_total_price(discount)
+
+            return total
+
+
+    def save(self, *args, **kwargs):
+
+        # Keep total_price always in sync with items and discount
+        self.total_price = self.calculate_total_price()
+        
+        super().save(*args, **kwargs)
+    
+
+class OrderItem(models.Model):
+    order = models.ForeignKey(Order, related_name="items", on_delete=models.CASCADE)
+    product = models.ForeignKey("products.Product", on_delete=models.PROTECT)
+    quantity = models.PositiveIntegerField(default=1)
+
+    def get_total_price(self, discount_object:DiscountCode):
+        """Calculate total price for this item, applying discount if valid."""
+
+        if discount_object and discount_object.is_valid():
+
+            if (self.product in discount_object.specific_products.all() or self.product.category in discount_object.specific_categories.all()):
+                if discount_object.percent:
+                    return (self.quantity * self.product.price) * (Decimal('1.0') - discount_object.percent / Decimal('100'))
+                
+                elif discount_object.amount:
+                    return (self.quantity * self.product.price) - discount_object.amount
+                
+                else:
+                    raise ValueError("Discount code must have either percent or amount defined.")
+        else:
+            return ValueError("Invalid discount code.")
+
+    def __str__(self):
+        return f"{self.product.name} x{self.quantity}"