"""Shared Pydantic field helpers for workplan / workstream compatibility."""
from __future__ import annotations

import uuid
from typing import Any

from pydantic import AliasChoices, Field, computed_field, model_validator


def workplan_id_field(*, default: uuid.UUID | None = None) -> uuid.UUID | None:
    return Field(
        default=default,
        validation_alias=AliasChoices("workplan_id", "workstream_id"),
    )


class LegacyWorkstreamIdBodyMixin:
    """Detect POST/PUT bodies that used legacy ``workstream_id`` without ``workplan_id``."""

    used_legacy_workstream_id: bool = Field(default=False, exclude=True)

    @model_validator(mode="before")
    @classmethod
    def _detect_legacy_workstream_id(cls, data: Any) -> Any:
        if isinstance(data, dict):
            if data.get("workstream_id") is not None and data.get("workplan_id") is None:
                return {**data, "used_legacy_workstream_id": True}
        return data


class WorkplanIdCompatMixin:
    """Accept ``workplan_id`` or legacy ``workstream_id`` on input; emit both on output."""

    workplan_id: uuid.UUID = workplan_id_field()

    @computed_field  # type: ignore[prop-decorator]
    @property
    def workstream_id(self) -> uuid.UUID:
        return self.workplan_id


class WorkplanIdCreateMixin(LegacyWorkstreamIdBodyMixin):
    workplan_id: uuid.UUID | None = workplan_id_field(default=None)

    @model_validator(mode="after")
    def _require_workplan_id(self):
        if self.workplan_id is None:
            raise ValueError("workplan_id is required")
        return self


class OptionalWorkplanIdCompatMixin:
    workplan_id: uuid.UUID | None = workplan_id_field(default=None)

    @computed_field  # type: ignore[prop-decorator]
    @property
    def workstream_id(self) -> uuid.UUID | None:
        return self.workplan_id