from pydantic import BaseModel, Field
from typing import Optional, List
from datetime import datetime

# Base schemas
class GroceryBase(BaseModel):
    name: str
    category: str
    organic: bool = False
    weight: Optional[float] = None
    weight_unit: str = "g"

class GroceryCreate(GroceryBase):
    pass

class GroceryUpdate(BaseModel):
    name: Optional[str] = None
    category: Optional[str] = None
    organic: Optional[bool] = None
    weight: Optional[float] = None
    weight_unit: Optional[str] = None

class Grocery(GroceryBase):
    id: int
    created_at: datetime
    updated_at: Optional[datetime] = None
    
    class Config:
        from_attributes = True

# Shop schemas
class ShopBase(BaseModel):
    name: str
    city: str
    address: Optional[str] = None

class ShopCreate(ShopBase):
    pass

class ShopUpdate(BaseModel):
    name: Optional[str] = None
    city: Optional[str] = None
    address: Optional[str] = None

class Shop(ShopBase):
    id: int
    created_at: datetime
    updated_at: Optional[datetime] = None
    
    class Config:
        from_attributes = True

# Shopping Event schemas
class GroceryInEvent(BaseModel):
    grocery_id: int
    amount: float = Field(..., gt=0)
    price: float = Field(..., ge=0)  # Price at the time of this shopping event (allow free items)

class GroceryWithEventData(BaseModel):
    id: int
    name: str
    category: str
    organic: bool
    weight: Optional[float] = None
    weight_unit: str
    amount: float  # Amount purchased in this event
    price: float   # Price at the time of this event
    
    class Config:
        from_attributes = True

class ShoppingEventBase(BaseModel):
    shop_id: int
    date: Optional[datetime] = None
    total_amount: Optional[float] = Field(None, ge=0)
    notes: Optional[str] = None

class ShoppingEventCreate(ShoppingEventBase):
    groceries: List[GroceryInEvent] = []

class ShoppingEventUpdate(BaseModel):
    shop_id: Optional[int] = None
    date: Optional[datetime] = None
    total_amount: Optional[float] = Field(None, ge=0)
    notes: Optional[str] = None
    groceries: Optional[List[GroceryInEvent]] = None

class ShoppingEventResponse(ShoppingEventBase):
    id: int
    created_at: datetime
    updated_at: Optional[datetime] = None
    shop: Shop
    groceries: List[GroceryWithEventData] = []
    
    class Config:
        from_attributes = True

# Statistics schemas
class CategoryStats(BaseModel):
    category: str
    total_spent: float
    item_count: int
    avg_price: float

class ShopStats(BaseModel):
    shop_name: str
    total_spent: float
    visit_count: int
    avg_per_visit: float