# models/api_models.py
from pydantic import BaseModel, Field, field_validator, EmailStr
from typing import Optional, List
from datetime import datetime


# User Authentication Models
class UserRegister(BaseModel):
    email: EmailStr = Field(..., description="Valid email address")
    username: str = Field(..., min_length=3, max_length=50, description="Username (3-50 characters)")
    password: str = Field(..., min_length=6, description="Password (minimum 6 characters)")

    @field_validator('username')
    @classmethod
    def validate_username(cls, v):
        if not v.isalnum():
            raise ValueError('Username must contain only alphanumeric characters')
        return v.lower().strip()

    @field_validator('password')
    @classmethod
    def validate_password(cls, v):
        if len(v) < 6:
            raise ValueError('Password must be at least 6 characters long')
        return v


class UserLogin(BaseModel):
    username: str = Field(..., description="Username")
    password: str = Field(..., description="Password")

    @field_validator('username')
    @classmethod
    def validate_username(cls, v):
        return v.strip()


class UserResponse(BaseModel):
    id: int
    email: str
    username: str
    role: str
    is_active: bool
    last_login: Optional[datetime] = None
    created_at: datetime
    updated_at: datetime

    model_config = {"from_attributes": True}


class LoginResponse(BaseModel):
    access_token: str
    token_type: str = "bearer"
    expires_in: int
    user: UserResponse


# Base Product Models
class ProductBase(BaseModel):
    product_id: Optional[str] = None
    title: Optional[str] = None
    description: Optional[str] = None
    link: Optional[str] = None
    image_link: Optional[str] = None
    availability: Optional[str] = None
    price: Optional[str] = None
    brand: Optional[str] = None
    gtin: Optional[str] = None
    mpn: Optional[str] = None
    condition: Optional[str] = None
    adult: Optional[str] = None
    multipack: Optional[int] = None
    is_bundle: Optional[str] = None
    age_group: Optional[str] = None
    color: Optional[str] = None
    gender: Optional[str] = None
    material: Optional[str] = None
    pattern: Optional[str] = None
    size: Optional[str] = None
    size_type: Optional[str] = None
    size_system: Optional[str] = None
    item_group_id: Optional[str] = None
    google_product_category: Optional[str] = None
    product_type: Optional[str] = None
    custom_label_0: Optional[str] = None
    custom_label_1: Optional[str] = None
    custom_label_2: Optional[str] = None
    custom_label_3: Optional[str] = None
    custom_label_4: Optional[str] = None
    additional_image_link: Optional[str] = None
    sale_price: Optional[str] = None
    unit_pricing_measure: Optional[str] = None
    unit_pricing_base_measure: Optional[str] = None
    identifier_exists: Optional[str] = None
    shipping: Optional[str] = None
    currency: Optional[str] = None


class ProductCreate(ProductBase):
    product_id: str = Field(..., min_length=1, description="Product ID is required")
    title: str = Field(..., min_length=1, description="Title is required")

    @field_validator('product_id', 'title')
    @classmethod
    def validate_required_fields(cls, v):
        if not v or not v.strip():
            raise ValueError('Field cannot be empty')
        return v.strip()


class ProductUpdate(ProductBase):
    pass


class ProductResponse(ProductBase):
    id: int
    created_at: datetime
    updated_at: datetime

    model_config = {"from_attributes": True}


# Stock Models
class StockBase(BaseModel):
    gtin: str = Field(..., min_length=1, description="GTIN is required")
    location: str = Field(..., min_length=1, description="Location is required")


class StockCreate(StockBase):
    quantity: int = Field(ge=0, description="Quantity must be non-negative")


class StockAdd(StockBase):
    quantity: int = Field(gt=0, description="Quantity to add must be positive")


class StockUpdate(BaseModel):
    quantity: int = Field(ge=0, description="Quantity must be non-negative")


class StockResponse(BaseModel):
    id: int
    gtin: str
    location: str
    quantity: int
    created_at: datetime
    updated_at: datetime

    model_config = {"from_attributes": True}


class StockLocationResponse(BaseModel):
    location: str
    quantity: int


class StockSummaryResponse(BaseModel):
    gtin: str
    total_quantity: int
    locations: List[StockLocationResponse]
    product_title: Optional[str] = None


# Import Models
class CSVImportRequest(BaseModel):
    url: str = Field(..., description="URL to CSV file")
    batch_size: Optional[int] = Field(1000, gt=0, le=10000, description="Batch size for processing")

    @field_validator('url')
    @classmethod
    def validate_url(cls, v):
        if not v.startswith(('http://', 'https://')):
            raise ValueError('URL must start with http:// or https://')
        return v


class ImportJobResponse(BaseModel):
    job_id: int
    status: str
    message: Optional[str] = None
    imported: Optional[int] = 0
    updated: Optional[int] = 0
    total_processed: Optional[int] = 0
    error_count: Optional[int] = 0
    error_message: Optional[str] = None
    created_at: Optional[datetime] = None
    started_at: Optional[datetime] = None
    completed_at: Optional[datetime] = None


# Response Models
class ProductListResponse(BaseModel):
    products: List[ProductResponse]
    total: int
    skip: int
    limit: int


class ProductDetailResponse(BaseModel):
    product: ProductResponse
    stock_info: Optional[StockSummaryResponse] = None


class StatsResponse(BaseModel):
    total_products: int
    unique_brands: int
    unique_categories: int
    total_stock_entries: int = 0
    total_inventory_quantity: int = 0