from decimal import Decimal, InvalidOperation
from pathlib import Path
from copienator import atomic_update_json, read_json

def read_scores(path: Path) -> dict:
    scores = read_json(annotation_score_for_return(path))
    if not isinstance(scores, dict):
        raise ValueError(f"score.json doit contenir un objet JSON : {path}")
    return scores


def set_score(path: Path, label: str, value: str) -> str:
    try:
        number = Decimal(value.strip().replace(",", "."))
    except InvalidOperation:
        raise ValueError("Le score doit être un nombre.") from None
    if not number.is_finite() or number < 0:
        raise ValueError("Le score doit être un nombre positif ou nul.")
    previous = ""

    def update(scores):
        nonlocal previous
        if not isinstance(scores, dict) or label not in scores:
            raise ValueError(f"Label absent de score.json : {label}")
        previous = str(scores[label])
        scores[label] = str(number)

    # A Rendre/score.json is often a symlink to the annotation score file.
    # Resolve it before atomic replacement so the link continues to work.
    atomic_update_json(annotation_score_for_return(path).resolve(strict=True), update, default_factory=dict)
    return previous



def annotation_score_for_return(path: Path) -> Path:
    """Resolve fallback return copies as well as symlinks to their source scores."""
    if path.is_symlink() or path.parent.parent.name != 'A Rendre':
        return path.resolve()
    from copienator.return_identity import RETURN_FOLDER_PATTERN
    match = RETURN_FOLDER_PATTERN.fullmatch(path.parent.name)
    if not match:
        return path
    root = path.parent.parent.parent
    cid = match['copy_id']
    sources = read_json(root / '.copienator' / 'return_sources.json', default={})
    mode = sources.get(str(int(cid)))
    modes = (mode,) if mode in ('Bnot', 'BGnot', 'Anot') else ('Bnot', 'BGnot', 'Anot')
    candidates = [p for m in modes for p in (root / m).glob('Copie*/score.json')
                  if p.parent.name[5:].isdigit() and int(p.parent.name[5:]) == int(cid)]
    if len(candidates) > 1:
        raise ValueError('Source des scores ambiguë : relancez la préparation de A Rendre dans le mode souhaité.')
    return candidates[0] if candidates else path


def remember_return_source(root: Path, copy_id: str, source: Path):
    path = root / '.copienator' / 'return_sources.json'
    path.parent.mkdir(exist_ok=True)
    atomic_update_json(path, lambda data: data.update({str(int(copy_id)): source.parent.name}), default_factory=dict)