"""Teacher-authored feedback, independent of the generated correction data."""
from pathlib import Path

from copienator import atomic_update_json, read_json

FILENAME = "custom_remarks.json"


def copy_key(copy_id: str) -> str:
    if not copy_id.strip().isascii() or not copy_id.strip().isdecimal():
        raise ValueError("Numéro de copie invalide.")
    return str(int(copy_id))


def load_remarks(root: Path) -> dict[str, dict[str, str]]:
    data = read_json(root / FILENAME, default={})
    validate(data)
    return data


def validate(data):
    if not isinstance(data, dict) or any(
        not isinstance(key, str) or copy_key(key) != key
        or not isinstance(labels, dict)
        or any(not isinstance(label, str) or not isinstance(text, str)
               for label, text in labels.items())
        for key, labels in data.items()
    ):
        raise ValueError(f"Format invalide dans {FILENAME}.")


def remarks_for_copy(root: Path, copy_id: str) -> dict[str, str]:
    return load_remarks(root).get(copy_key(copy_id), {})


def set_remark(root: Path, copy_id: str, label: str, text: str) -> str:
    key = copy_key(copy_id)
    text = text.strip()
    previous = ""

    def update(data):
        nonlocal previous
        validate(data)
        labels = data.setdefault(key, {})
        previous = labels.get(label, "")
        if text:
            labels[label] = text
        else:
            labels.pop(label, None)
        if not labels:
            data.pop(key, None)

    atomic_update_json(root / FILENAME, update, default_factory=dict)
    return previous


def apply_custom_remarks(root: Path, copy_id: str, labels_data: dict) -> None:
    """Append after checkbox actions; replace our own entries on repeated calls."""
    remarks = remarks_for_copy(root, copy_id)
    for label, content in labels_data.items():
        result = content["result"]
        feedback = [item for item in result.get("feedback", [])
                    if not item.get("custom_remark")]
        if remarks.get(label):
            feedback.append({"text": remarks[label], "box_2d": None, "custom_remark": True})
        result["feedback"] = feedback