munch-ease-backend/common.py

from typing import Any, Dict, Generic, List, Optional, TypeVar

from pydantic import BaseModel, ConfigDict, Field, model_validator


def to_camel(s: str) -> str:
    parts = s.split("_")
    return parts[0] + "".join(p.title() for p in parts[1:])


class ApiModel(BaseModel):
    model_config = ConfigDict(
        alias_generator=to_camel,
        populate_by_name=True,
        ser_json_inf_nan="null",
        arbitrary_types_allowed=True,
    )


class BaseLinkedModel(ApiModel):
    @model_validator(mode="before")
    @classmethod
    def auto_populate_ids(cls, data: dict[str, Any]) -> dict[str, Any]:
        if isinstance(data, dict):
            for key, value in data.copy().items():
                if not key.endswith("_id") and hasattr(value, "id") and value is not None:
                    id_key = key + "_id"

                    if id_key in data:
                        # If the id_key already exists, ensure it matches the value's id
                        if data[id_key] != value.id:
                            raise ValueError(
                                f"ID mismatch for {key}: {data[id_key]} != {value.id}"
                            )
                    else:
                        # If the id_key does not exist, set it to the value's id
                        data[id_key] = value.id

        return data


class ProblemDetails(ApiModel):
    type: str = Field(default="about:blank")
    title: str
    status: int
    detail: Optional[str] = None
    instance: Optional[str] = None
    errors: Optional[Dict[str, Any]] = None


T = TypeVar("T")


class Page(ApiModel, Generic[T]):
    items: List[T]
    next_cursor: Optional[str] = Field(default=None, alias="nextCursor")
    prev_cursor: Optional[str] = Field(default=None, alias="prevCursor")
    total: Optional[int] = Field(default=None, description="Optional total count")