from django.db import models
from django.urls import reverse
from django.contrib.auth.models import User


class Category(models.Model):
    name = models.CharField(max_length=200, db_index=True)
    slug = models.SlugField(max_length=200, db_index=True, unique=True)

    def get_absolute_url(self):
        return reverse('shop:product_list_by_category', args=[self.slug])

    class Meta:
        ordering = ('name',)
        verbose_name_plural = 'categories'

    def __str__(self):
        return self.name


class Product(models.Model):
    category = models.ForeignKey(Category, related_name='products', on_delete=models.CASCADE)
    name = models.CharField(max_length=200, db_index=True)
    slug = models.SlugField(max_length=200, db_index=True, unique=True)
    image = models.ImageField(upload_to='products/%Y/%m/%d', blank=True)
    description = models.TextField(blank=True)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    stock = models.PositiveIntegerField()
    available = models.BooleanField(default=True)
    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)

    def get_absolute_url(self):
        return reverse('shop:product_detail', args=[self.id, self.slug])

    class Meta:
        ordering = ('name',)
        indexes = [models.Index(fields=['id', 'slug'])]

    def __str__(self):
        return self.name


class ProductImage(models.Model):
    product = models.ForeignKey(Product, related_name='images', on_delete=models.CASCADE)
    image = models.ImageField(upload_to='products/additional/%Y/%m/%d')
    is_thumbnail = models.BooleanField(default=False)

    def __str__(self):
        return f"Image for {self.product.name}"


# ─── ORDERS ───────────────────────────────────────────────────────────────────

class Order(models.Model):
    STATUS_PENDING   = 'pending'
    STATUS_PAID      = 'paid'
    STATUS_FAILED    = 'failed'
    STATUS_CANCELLED = 'cancelled'
    STATUS_CHOICES = [
        (STATUS_PENDING,   'Pending Payment'),
        (STATUS_PAID,      'Paid'),
        (STATUS_FAILED,    'Payment Failed'),
        (STATUS_CANCELLED, 'Cancelled'),
    ]

    user        = models.ForeignKey(User, related_name='orders',
                                    on_delete=models.SET_NULL, null=True, blank=True)
    first_name  = models.CharField(max_length=100)
    last_name   = models.CharField(max_length=100, blank=True)
    email       = models.EmailField()
    phone       = models.CharField(max_length=30)
    address     = models.CharField(max_length=300)
    city        = models.CharField(max_length=100)
    total_price = models.DecimalField(max_digits=10, decimal_places=2)
    status      = models.CharField(max_length=20, choices=STATUS_CHOICES, default=STATUS_PENDING)
    ipay_txn_id = models.CharField(max_length=200, blank=True)
    created     = models.DateTimeField(auto_now_add=True)
    updated     = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ('-created',)

    def __str__(self):
        return f"Order #{self.id} — {self.first_name} {self.last_name}"

    def get_absolute_url(self):
        return reverse('shop:order_confirm', args=[self.id])


class OrderItem(models.Model):
    order        = models.ForeignKey(Order, related_name='items', on_delete=models.CASCADE)
    product      = models.ForeignKey(Product, related_name='order_items',
                                     on_delete=models.SET_NULL, null=True, blank=True)
    product_name = models.CharField(max_length=200)
    price        = models.DecimalField(max_digits=10, decimal_places=2)
    quantity     = models.PositiveIntegerField(default=1)

    def __str__(self):
        return f"{self.quantity}x {self.product_name}"

    @property
    def total_price(self):
        return self.price * self.quantity