from datetime import datetime

from pydantic import BaseModel, Field


class WeatherDataIn(BaseModel):
    """Payload accepted by POST /stations/{station_name}/observations.

    station_name is taken from the URL path, not the request body.
    """

    temperature: float | None = Field(None, description="Temperature in Celsius")
    pressure: float | None = Field(None, description="Atmospheric pressure in hPa")
    relative_humidity: float | None = Field(
        None, description="Relative humidity in percent (0-100)"
    )


class WeatherRecordOut(BaseModel):
    """A single observation record (includes server-assigned fields)."""

    id: int
    station_name: str
    temperature: float | None
    pressure: float | None
    relative_humidity: float | None
    received_at: datetime


class ObservationListResponse(BaseModel):
    """Response for GET /stations/{station_name}/observations."""

    station_name: str
    count: int
    records: list[WeatherRecordOut]


class StationInfo(BaseModel):
    """Summary of a known weather station."""

    name: str
    observation_count: int
    latest_observation_at: datetime | None


class StationListResponse(BaseModel):
    """Response for GET /stations."""

    stations: list[StationInfo]
    count: int