from django.conf import settings
from django.db import models

from apps.catalog.models import Product
from apps.stores.models import Store
from utils.models import BaseModel


class Cart(BaseModel):
    """Pre-checkout state — one per user, may hold items from multiple stores."""

    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='cart')

    class Meta:
        verbose_name = 'سبد خرید'
        verbose_name_plural = 'سبدهای خرید'

    def __str__(self):
        return f'سبد خرید {self.user}'


class CartItem(BaseModel):
    cart = models.ForeignKey(Cart, on_delete=models.CASCADE, related_name='items')
    product = models.ForeignKey(Product, on_delete=models.CASCADE, related_name='+')
    quantity = models.PositiveIntegerField(default=1)

    class Meta:
        unique_together = ('cart', 'product')
        verbose_name = 'قلم سبد خرید'
        verbose_name_plural = 'اقلام سبد خرید'

    def __str__(self):
        return f'{self.product.name} x{self.quantity}'

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


class OrderGroup(BaseModel):
    """One checkout/payment event — fans out into one Order per store (multi-store-cart)."""

    class DeliveryType(models.TextChoices):
        EXPRESS = 'express', 'ارسال فوری'
        SCHEDULED = 'scheduled', 'زمان‌بندی شده'

    class PaymentMethod(models.TextChoices):
        WALLET = 'wallet', 'کیف پول وینسو'
        ONLINE = 'online', 'درگاه بانکی'
        CASH_ON_DELIVERY = 'cash_on_delivery', 'پرداخت در محل'

    class PaymentStatus(models.TextChoices):
        PENDING = 'pending', 'در انتظار پرداخت'
        PAID = 'paid', 'پرداخت شده'
        FAILED = 'failed', 'ناموفق'

    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name='order_groups')

    recipient_name = models.CharField(max_length=150)
    recipient_phone = models.CharField(max_length=20)
    full_address = models.TextField()

    delivery_type = models.CharField(max_length=10, choices=DeliveryType.choices, default=DeliveryType.EXPRESS)
    scheduled_at = models.DateTimeField(null=True, blank=True)

    payment_method = models.CharField(max_length=20, choices=PaymentMethod.choices)
    payment_status = models.CharField(max_length=10, choices=PaymentStatus.choices, default=PaymentStatus.PENDING)

    notes = models.TextField(blank=True)
    total_amount = models.PositiveBigIntegerField()

    class Meta:
        ordering = ['-created_at']
        verbose_name = 'گروه سفارش'
        verbose_name_plural = 'گروه‌های سفارش'

    def __str__(self):
        return f'گروه سفارش {self.uuid} - {self.user}'


class Order(BaseModel):
    class Status(models.TextChoices):
        PLACED = 'placed', 'سفارش ثبت شد'
        PREPARING = 'preparing', 'در حال آماده‌سازی'
        READY_TO_SHIP = 'ready_to_ship', 'آماده ارسال'
        HANDED_TO_COURIER = 'handed_to_courier', 'تحویل سفیر شد'
        DELIVERED = 'delivered', 'تحویل داده شد'
        CANCELLED = 'cancelled', 'لغو شده'

    CANCELLABLE_STATUSES = (Status.PLACED, Status.PREPARING)

    group = models.ForeignKey(OrderGroup, on_delete=models.PROTECT, related_name='orders')
    store = models.ForeignKey(Store, on_delete=models.PROTECT, related_name='orders')
    customer = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name='orders')

    status = models.CharField(max_length=20, choices=Status.choices, default=Status.PLACED)

    items_subtotal = models.PositiveBigIntegerField()
    delivery_fee = models.PositiveBigIntegerField(default=0)
    commission_amount = models.PositiveBigIntegerField(default=0)
    seller_payout_amount = models.PositiveBigIntegerField(default=0)

    cancel_reason = models.TextField(blank=True)
    courier_name = models.CharField(max_length=150, blank=True)
    courier_phone = models.CharField(max_length=20, blank=True)

    placed_at = models.DateTimeField(auto_now_add=True)
    delivered_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ['-created_at']
        verbose_name = 'سفارش'
        verbose_name_plural = 'سفارش‌ها'

    def __str__(self):
        return f'سفارش {self.uuid} - {self.store.name}'

    @property
    def total_amount(self):
        return self.items_subtotal + self.delivery_fee


class OrderItem(BaseModel):
    order = models.ForeignKey(Order, on_delete=models.CASCADE, related_name='items')
    product = models.ForeignKey(Product, on_delete=models.SET_NULL, null=True, related_name='+')
    product_name_snapshot = models.CharField(max_length=200)
    unit_price_snapshot = models.PositiveBigIntegerField()
    quantity = models.PositiveIntegerField()

    class Meta:
        verbose_name = 'قلم سفارش'
        verbose_name_plural = 'اقلام سفارش'

    def __str__(self):
        return f'{self.product_name_snapshot} x{self.quantity}'

    @property
    def line_total(self):
        return self.unit_price_snapshot * self.quantity


class OrderStatusLog(BaseModel):
    order = models.ForeignKey(Order, on_delete=models.CASCADE, related_name='status_logs')
    from_status = models.CharField(max_length=20, blank=True)
    to_status = models.CharField(max_length=20)
    changed_by = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.SET_NULL, null=True, blank=True, related_name='+',
    )
    note = models.TextField(blank=True)

    class Meta:
        ordering = ['created_at']
        verbose_name = 'تاریخچه وضعیت سفارش'
        verbose_name_plural = 'تاریخچه وضعیت سفارش‌ها'

    def __str__(self):
        return f'{self.order_id}: {self.from_status} -> {self.to_status}'


class Notification(BaseModel):
    class Type(models.TextChoices):
        NEW_ORDER = 'new_order', 'سفارش جدید'
        SETTLEMENT_DONE = 'settlement_done', 'تسویه حساب'
        NEW_REVIEW = 'new_review', 'نظر جدید'
        ORDER_CANCELLED = 'order_cancelled', 'لغو سفارش'

    recipient = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='notifications')
    type = models.CharField(max_length=20, choices=Type.choices)
    title = models.CharField(max_length=200)
    body = models.TextField(blank=True)
    related_order = models.ForeignKey(
        Order, on_delete=models.SET_NULL, null=True, blank=True, related_name='notifications',
    )
    is_read = models.BooleanField(default=False)

    class Meta:
        ordering = ['-created_at']
        verbose_name = 'اعلان'
        verbose_name_plural = 'اعلان‌ها'

    def __str__(self):
        return f'{self.title} - {self.recipient}'