"""Vendor Product model - independent copy pattern.

This model represents a vendor's product. Products can be:
1. Created from a marketplace import (has marketplace_product_id)
2. Created directly by the vendor (no marketplace_product_id)

When created from marketplace, the marketplace_product_id FK provides
"view original source" comparison feature.

Money values are stored as integer cents (e.g., €105.91 = 10591).
See docs/architecture/money-handling.md for details.
"""

from sqlalchemy import (
    Boolean,
    Column,
    ForeignKey,
    Index,
    Integer,
    String,
    UniqueConstraint,
)
from sqlalchemy.dialects.sqlite import JSON
from sqlalchemy.orm import relationship

from app.core.database import Base
from app.utils.money import cents_to_euros, euros_to_cents
from models.database.base import TimestampMixin


class Product(Base, TimestampMixin):
    """Vendor-specific product.

    Products can be created from marketplace imports or directly by vendors.
    When from marketplace, marketplace_product_id provides source comparison.

    Price fields use integer cents for precision (€19.99 = 1999 cents).
    """

    __tablename__ = "products"

    id = Column(Integer, primary_key=True, index=True)
    vendor_id = Column(Integer, ForeignKey("vendors.id"), nullable=False)
    marketplace_product_id = Column(
        Integer, ForeignKey("marketplace_products.id"), nullable=True
    )

    # === VENDOR REFERENCE ===
    vendor_sku = Column(String, index=True)  # Vendor's internal SKU

    # === PRODUCT IDENTIFIERS ===
    # GTIN (Global Trade Item Number) - barcode for EAN matching with orders
    # Populated from MarketplaceProduct.gtin during product import
    gtin = Column(String(50), index=True)  # EAN/UPC barcode number
    gtin_type = Column(String(20))  # Format: gtin13, gtin14, gtin12, gtin8, isbn13, isbn10

    # === PRODUCT FIELDS (copied from marketplace at creation) ===
    # Pricing - stored as integer cents (€19.99 = 1999)
    price_cents = Column(Integer)  # Price in cents
    sale_price_cents = Column(Integer)  # Sale price in cents
    currency = Column(String(3), default="EUR")

    # Product Info
    brand = Column(String)
    condition = Column(String)
    availability = Column(String)

    # Media
    primary_image_url = Column(String)
    additional_images = Column(JSON)

    # Digital Product Fields
    download_url = Column(String)
    license_type = Column(String(50))

    # === TAX / VAT ===
    # Luxembourg VAT rates: 0 (exempt), 3 (super-reduced), 8 (reduced), 14 (intermediate), 17 (standard)
    # Prices are stored as gross (VAT-inclusive). Tax rate is used for profit calculation.
    tax_rate_percent = Column(Integer, default=17, nullable=False)

    # === SUPPLIER TRACKING & COST ===
    supplier = Column(String(50))  # 'codeswholesale', 'internal', etc.
    supplier_product_id = Column(String)  # Supplier's product reference
    cost_cents = Column(Integer)  # What vendor pays to acquire (in cents) - for profit calculation
    margin_percent_x100 = Column(Integer)  # Markup percentage * 100 (e.g., 25.5% = 2550)

    # === PRODUCT TYPE ===
    is_digital = Column(Boolean, default=False, index=True)
    product_type = Column(String(20), default="physical")  # physical, digital, service, subscription

    # === VENDOR-SPECIFIC ===
    is_featured = Column(Boolean, default=False)
    is_active = Column(Boolean, default=True)
    display_order = Column(Integer, default=0)

    # Inventory Settings
    min_quantity = Column(Integer, default=1)
    max_quantity = Column(Integer)

    # Digital Fulfillment
    fulfillment_email_template = Column(String)  # Template name for digital delivery

    # === RELATIONSHIPS ===
    vendor = relationship("Vendor", back_populates="products")
    marketplace_product = relationship(
        "MarketplaceProduct", back_populates="vendor_products"
    )
    translations = relationship(
        "ProductTranslation",
        back_populates="product",
        cascade="all, delete-orphan",
    )
    inventory_entries = relationship(
        "Inventory", back_populates="product", cascade="all, delete-orphan"
    )

    # === CONSTRAINTS & INDEXES ===
    __table_args__ = (
        UniqueConstraint(
            "vendor_id", "marketplace_product_id", name="uq_vendor_marketplace_product"
        ),
        Index("idx_product_vendor_active", "vendor_id", "is_active"),
        Index("idx_product_vendor_featured", "vendor_id", "is_featured"),
        Index("idx_product_vendor_sku", "vendor_id", "vendor_sku"),
        Index("idx_product_supplier", "supplier", "supplier_product_id"),
    )

    def __repr__(self):
        return (
            f"<Product(id={self.id}, vendor_id={self.vendor_id}, "
            f"vendor_sku='{self.vendor_sku}')>"
        )

    # === PRICE PROPERTIES (Euro convenience accessors) ===

    @property
    def price(self) -> float | None:
        """Get price in euros (for API/display)."""
        if self.price_cents is not None:
            return cents_to_euros(self.price_cents)
        return None

    @price.setter
    def price(self, value: float | None):
        """Set price from euros."""
        self.price_cents = euros_to_cents(value) if value is not None else None

    @property
    def sale_price(self) -> float | None:
        """Get sale price in euros (for API/display)."""
        if self.sale_price_cents is not None:
            return cents_to_euros(self.sale_price_cents)
        return None

    @sale_price.setter
    def sale_price(self, value: float | None):
        """Set sale price from euros."""
        self.sale_price_cents = euros_to_cents(value) if value is not None else None

    @property
    def cost(self) -> float | None:
        """Get cost in euros (what vendor pays to acquire)."""
        if self.cost_cents is not None:
            return cents_to_euros(self.cost_cents)
        return None

    @cost.setter
    def cost(self, value: float | None):
        """Set cost from euros."""
        self.cost_cents = euros_to_cents(value) if value is not None else None

    @property
    def margin_percent(self) -> float | None:
        """Get margin percent (e.g., 25.5)."""
        if self.margin_percent_x100 is not None:
            return self.margin_percent_x100 / 100.0
        return None

    @margin_percent.setter
    def margin_percent(self, value: float | None):
        """Set margin percent."""
        self.margin_percent_x100 = int(value * 100) if value is not None else None

    # === TAX / PROFIT CALCULATION PROPERTIES ===

    @property
    def net_price_cents(self) -> int | None:
        """Calculate net price (excluding VAT) from gross price.

        Formula: Net = Gross / (1 + rate/100)
        Example: €119 gross at 17% VAT = €119 / 1.17 = €101.71 net
        """
        if self.price_cents is None:
            return None
        # Use integer math to avoid floating point issues
        # Net = Gross * 100 / (100 + rate)
        return int(self.price_cents * 100 / (100 + self.tax_rate_percent))

    @property
    def net_price(self) -> float | None:
        """Get net price in euros."""
        cents = self.net_price_cents
        return cents_to_euros(cents) if cents is not None else None

    @property
    def vat_amount_cents(self) -> int | None:
        """Calculate VAT amount in cents.

        Formula: VAT = Gross - Net
        """
        if self.price_cents is None:
            return None
        net = self.net_price_cents
        if net is None:
            return None
        return self.price_cents - net

    @property
    def vat_amount(self) -> float | None:
        """Get VAT amount in euros."""
        cents = self.vat_amount_cents
        return cents_to_euros(cents) if cents is not None else None

    @property
    def profit_cents(self) -> int | None:
        """Calculate profit in cents.

        Formula: Profit = Net Revenue - Cost
        Returns None if cost is not set.
        """
        net = self.net_price_cents
        if net is None or self.cost_cents is None:
            return None
        return net - self.cost_cents

    @property
    def profit(self) -> float | None:
        """Get profit in euros."""
        cents = self.profit_cents
        return cents_to_euros(cents) if cents is not None else None

    @property
    def profit_margin_percent(self) -> float | None:
        """Calculate profit margin as percentage of net revenue.

        Formula: Margin% = (Profit / Net) * 100
        Example: €41.71 profit on €101.71 net = 41.0% margin
        """
        net = self.net_price_cents
        profit = self.profit_cents
        if net is None or profit is None or net == 0:
            return None
        return round((profit / net) * 100, 2)

    # === INVENTORY PROPERTIES ===

    # Constant for unlimited inventory (digital products)
    UNLIMITED_INVENTORY = 999999

    @property
    def has_unlimited_inventory(self) -> bool:
        """Check if product has unlimited inventory.

        Digital products have unlimited inventory by default.
        They don't require physical stock tracking.
        """
        return self.is_digital

    @property
    def total_inventory(self) -> int:
        """Calculate total inventory across all locations.

        Digital products return unlimited inventory.
        """
        if self.has_unlimited_inventory:
            return self.UNLIMITED_INVENTORY
        return sum(inv.quantity for inv in self.inventory_entries)

    @property
    def available_inventory(self) -> int:
        """Calculate available inventory (total - reserved).

        Digital products return unlimited inventory since they
        don't have physical stock constraints.
        """
        if self.has_unlimited_inventory:
            return self.UNLIMITED_INVENTORY
        return sum(inv.available_quantity for inv in self.inventory_entries)

    # === SOURCE COMPARISON METHOD ===

    def get_source_comparison_info(self) -> dict:
        """Get current values with source values for comparison.

        Returns a dict with current field values and original source values
        from the marketplace product. Used for "view original source" feature.
        Only populated when product was created from a marketplace source.
        """
        mp = self.marketplace_product
        return {
            # Price
            "price": self.price,
            "price_cents": self.price_cents,
            "price_source": cents_to_euros(mp.price_cents) if mp and mp.price_cents else None,
            # Sale Price
            "sale_price": self.sale_price,
            "sale_price_cents": self.sale_price_cents,
            "sale_price_source": cents_to_euros(mp.sale_price_cents) if mp and mp.sale_price_cents else None,
            # Currency
            "currency": self.currency,
            "currency_source": mp.currency if mp else None,
            # Brand
            "brand": self.brand,
            "brand_source": mp.brand if mp else None,
            # Condition
            "condition": self.condition,
            "condition_source": mp.condition if mp else None,
            # Availability
            "availability": self.availability,
            "availability_source": mp.availability if mp else None,
            # Images
            "primary_image_url": self.primary_image_url,
            "primary_image_url_source": mp.image_link if mp else None,
            # Product type (independent fields, no source comparison)
            "is_digital": self.is_digital,
            "product_type": self.product_type,
        }

    # === TRANSLATION HELPERS ===

    def get_translation(self, language: str) -> "ProductTranslation | None":
        """Get translation for a specific language."""
        for t in self.translations:
            if t.language == language:
                return t
        return None

    def get_title(self, language: str = "en") -> str | None:
        """Get title for a specific language."""
        translation = self.get_translation(language)
        return translation.title if translation else None

    def get_description(self, language: str = "en") -> str | None:
        """Get description for a specific language."""
        translation = self.get_translation(language)
        return translation.description if translation else None