from typing import List, Optional, TYPE_CHECKING
if TYPE_CHECKING:
    from .inventory import Inventory  

from sqlalchemy import Identity, Integer, Unicode
from sqlalchemy.orm import Mapped, mapped_column, relationship

from . import db

class Item(db.Model):
    __tablename__ = 'Items'

    id: Mapped[int] = mapped_column("ID", Integer, Identity(start=1, increment=1), primary_key=True)
    description: Mapped[Optional[str]] = mapped_column("Description", Unicode(255), nullable=True)
    category: Mapped[Optional[str]] = mapped_column("Category", Unicode(255), nullable=True)

    inventory: Mapped[List['Inventory']] = relationship('Inventory', back_populates='item')

    def __init__(self, description: Optional[str] = None, category: Optional[str] = None):
        self.description = description
        self.category = category

    def __repr__(self):
        return f"<Item(id={self.id}, description={repr(self.description)}, category={repr(self.category)})>"
    
    def serialize(self):
        return {
            'id': self.id,
            'name': self.description,
            'category': self.category
        }
    
    @classmethod
    def sync_from_state(cls, submitted_items: list[dict]):
        """
        Syncs the Items table with the provided list of dictionaries.
        Adds new items and removes items that are not in the list.
        """
        submitted = {
            str(item.get("name", "")).strip()
            for item in submitted_items
            if isinstance(item, dict) and str(item.get("name", "")).strip()
        }
    
        existing_query = db.session.query(cls)
        existing = {item.description: item for item in existing_query.all()}
    
        existing_descriptions = set(existing.keys())
    
        print(f"Existing items: {existing_descriptions}")
        print(f"Submitted items: {submitted}")
        print(f"items to add: {submitted - existing_descriptions}")
        print(f"items to remove: {existing_descriptions - submitted}")
    
        for description in submitted - existing_descriptions:
            db.session.add(cls(description=description))
            print(f"➕ Adding item: {description}")
    
        for description in existing_descriptions - submitted:
            db.session.delete(existing[description])
            print(f"🗑️ Removing item: {description}")