from django.conf import settings
from django.core.validators import MinValueValidator
from django.db import models
from django.utils import timezone


class ItemTemplate(models.Model):
    name = models.CharField(max_length=120, unique=True)
    description = models.TextField(blank=True)
    category = models.CharField(max_length=80)
    # field_definitions is a list of objects describing extra fields for items of this template.
    # Example: [{"name": "rewind", "label": "Rewind?", "type": "boolean"}, {"name":"output_count","label":"Outputs","type":"number"}]
    field_definitions = models.JSONField(default=list, blank=True)
    default_purchase_price = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True)
    default_estimated_resale_price = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True)
    default_notes = models.TextField(blank=True)
    is_active = models.BooleanField(default=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    def __str__(self) -> str:
        return self.name


class Item(models.Model):
    class Status(models.TextChoices):
        IN_STOCK = "in_stock", "In stock"
        LISTED = "listed", "Listed"
        SOLD = "sold", "Sold"
        DONATED = "donated", "Donated"

    template = models.ForeignKey(ItemTemplate, null=True, blank=True, on_delete=models.SET_NULL, related_name="items")
    created_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT, related_name="items_created")
    title = models.CharField(max_length=200)
    brand = models.CharField(max_length=120, blank=True)
    category = models.CharField(max_length=80)
    condition = models.CharField(max_length=80, blank=True)
    size = models.CharField(max_length=50, blank=True)
    color = models.CharField(max_length=80, blank=True)
    purchase_price = models.DecimalField(max_digits=10, decimal_places=2, validators=[MinValueValidator(0)])
    estimated_resale_price = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True)
    sold_price = models.DecimalField(max_digits=10, decimal_places=2, null=True, blank=True)
    ebay_fee = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    shipping_cost = models.DecimalField(max_digits=10, decimal_places=2, default=0)
    status = models.CharField(max_length=20, choices=Status.choices, default=Status.IN_STOCK)
    notes = models.TextField(blank=True)
    # properties stores template-specific values keyed by field name
    properties = models.JSONField(default=dict, blank=True)
    acquisition_date = models.DateField(auto_now_add=True)
    sold_at = models.DateTimeField(null=True, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    @property
    def total_cost(self):
        return self.purchase_price + self.ebay_fee + self.shipping_cost

    @property
    def profit(self):
        if self.sold_price is None:
            return None
        return self.sold_price - self.total_cost

    @property
    def margin(self):
        if self.profit is None or self.sold_price in (None, 0):
            return None
        return self.profit / self.sold_price

    def mark_sold(self, sold_price, sold_at=None):
        self.sold_price = sold_price
        self.status = self.Status.SOLD
        self.sold_at = sold_at or timezone.now()
        self.save(update_fields=["sold_price", "status", "sold_at", "updated_at"])

    def get_absolute_url(self):
        from django.urls import reverse

        return reverse("item-detail", kwargs={"pk": self.pk})

    def __str__(self) -> str:
        return self.title


class PriceEstimate(models.Model):
    item = models.ForeignKey(Item, on_delete=models.CASCADE, related_name="price_estimates")
    source = models.CharField(max_length=80)
    source_url = models.URLField(blank=True)
    estimated_price = models.DecimalField(max_digits=10, decimal_places=2)
    notes = models.TextField(blank=True)
    retrieved_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["-retrieved_at"]


class ItemNote(models.Model):
    item = models.ForeignKey(Item, on_delete=models.CASCADE, related_name="notes_history")
    created_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT)
    body = models.TextField()
    created_at = models.DateTimeField(auto_now_add=True)


class ItemPhoto(models.Model):
    item = models.ForeignKey(Item, on_delete=models.CASCADE, related_name="photos")
    file = models.FileField(upload_to="item-photos/")
    uploaded_at = models.DateTimeField(auto_now_add=True)