"""
Models for API responses common to all routers in the application.
"""

from typing import Generic, TypeVar

from pydantic import BaseModel, Field, model_serializer

T = TypeVar("T")


class BaseCollectionResponse(BaseModel, Generic[T]):
    """Base model for collection responses.

    Collections are typically lists of items found in the database. When
    no items are found, the `data` field will be an empty list.
    """

    data: list[T] = Field(..., description="List of data items.")
    more: bool = Field(
        ..., description="Indicates if more items are available beyond this response."
    )

    @property
    def count(self) -> int:
        return len(self.data)

    @model_serializer(mode="plain")
    def add_count(self):
        d = self.__dict__.copy()
        d["count"] = self.count
        return d

    class Config:
        json_schema_extra = {
            "example": {
                "data": [{"id": 1, "name": "Item 1"}],
                "more": False,
                "count": 1,
            }
        }


class BaseErrorResponse(BaseModel):
    """Base model for generic error responses."""

    detail: str = Field(..., description="A detailed error message.")

    class Config:
        json_schema_extra = {"example": {"detail": "Not found."}}