"""
Pagination schemas for standardized paginated responses.
"""
from typing import TypeVar, Generic, List, Optional
from pydantic import BaseModel, Field

T = TypeVar('T')


class PaginationParams(BaseModel):
    """Pagination query parameters."""
    page: int = Field(default=1, ge=1, description="Page number (1-indexed)")
    page_size: int = Field(default=10, ge=1, le=100, description="Items per page")

    @property
    def skip(self) -> int:
        """Calculate the number of items to skip."""
        return (self.page - 1) * self.page_size


class PaginatedResponse(BaseModel, Generic[T]):
    """Generic paginated response wrapper."""
    items: List[T]
    total: int = Field(description="Total number of items")
    page: int = Field(description="Current page number")
    page_size: int = Field(description="Items per page")
    total_pages: int = Field(description="Total number of pages")

    @classmethod
    def create(
        cls,
        items: List[T],
        total: int,
        page: int,
        page_size: int
    ) -> "PaginatedResponse[T]":
        """Factory method to create a paginated response."""
        total_pages = max(1, (total + page_size - 1) // page_size)
        return cls(
            items=items,
            total=total,
            page=page,
            page_size=page_size,
            total_pages=total_pages
        )