"""
models.py
=========

This module defines the :class:`TaskCard` Pydantic model that represents a
structured representation of an informal task description.

The fields are intentionally simple but expressive enough for the unit tests
and examples in ``main.py``:

* ``title`` – short human‑readable title.
* ``subject`` – subject area or domain.
* ``deadline_hint`` – free‑form hint about when the task should be finished.
* ``deliverable_type`` – what is expected to be submitted (report, code,
  presentation, etc.).
* ``grading_hints`` – list of strings that were mentioned in the original
  text as criteria for grading.

The model uses :class:`pydantic.Field` to provide helpful descriptions and
default values.  The ``__str__`` method is overridden so that printing a
model instance gives a nicely formatted summary.
"""

from __future__ import annotations

from typing import List, Optional

from pydantic import BaseModel, Field


class TaskCard(BaseModel):
    """Pydantic model for a parsed task card.

    The fields are intentionally minimal but cover all information that the
    assignment expects to be extracted from an informal description.
    """

    title: str = Field(
        ...,
        description="Short human‑readable title of the task.",
    )
    subject: Optional[str] = Field(
        None,
        description="Subject or domain mentioned in the text (e.g. LangChain).",
    )
    deadline_hint: Optional[str] = Field(
        None,
        description="Free‑form hint about when the task should be finished.",
    )
    deliverable_type: Optional[str] = Field(
        None,
        description="What is expected to be submitted (report, code, presentation).",
    )
    grading_hints: List[str] = Field(
        default_factory=list,
        description="List of strings that were mentioned as grading criteria.",
    )

    def __str__(self) -> str:
        """Return a human‑readable summary of the card."""
        parts = [f"Title: {self.title}"]
        if self.subject:
            parts.append(f"Subject: {self.subject}")
        if self.deadline_hint:
            parts.append(f"Deadline hint: {self.deadline_hint}")
        if self.deliverable_type:
            parts.append(f"Deliverable type: {self.deliverable_type}")
        if self.grading_hints:
            parts.append(
                "Grading hints: " + ", ".join(self.grading_hints)
            )
        return "\n".join(parts)

    class Config:
        # Allow arbitrary types for future extensions.
        arbitrary_types_allowed = True

# End of models.py