"""Last exported overall marks, keyed by stable copy ID rather than student name."""
from pathlib import Path

from copienator import read_json, configuration
from copienator.return_identity import return_folders, RETURN_FOLDER_PATTERN

FINAL_SCORES_FILE = Path('.copienator') / 'final_scores.json'


def exported_scores(root: Path, repository: Path) -> dict[str, str]:
    saved = root / FINAL_SCORES_FILE
    if saved.is_file():
        data = read_json(saved)
        return {str(int(cid)): entry['score'] for cid, entry in data.get('copies', {}).items()
                if cid.isdecimal() and isinstance(entry, dict) and isinstance(entry.get('score'), str)}

    # Older exports have no machine-readable overall mark. Only use their ODS
    # when it predates the exported media; a newer sheet may contain other marks.
    output = Path(configuration.FINAL_SCORE_OUTPUT_DIR).expanduser()
    ods = Path(configuration.FINAL_SCORE_ODS_PATH).expanduser()
    output = output if output.is_absolute() else repository / output
    ods = ods if ods.is_absolute() else repository / ods
    if not ods.is_file() or not (output / root.name).is_dir():
        return {}
    candidates = {}
    for cid, folder in return_folders(root).items():
        name = RETURN_FOLDER_PATTERN.fullmatch(folder.name)['name']
        media = [p for p in (output / root.name / name).glob('*')
                 if p.suffix.lower() in ('.jpg', '.pdf') and p.is_file()]
        if media and ods.stat().st_mtime_ns <= min(p.stat().st_mtime_ns for p in media):
            candidates[str(cid)] = name
    if not candidates:
        return {}
    try:
        import pandas as pd
        from copienator.commands.add_final_score import get_rounded_score
        sheet = pd.read_excel(ods, engine='odf', header=None)
        values = dict(zip(sheet[0], sheet[1]))
        result = {}
        for cid, name in candidates.items():
            score = get_rounded_score(values.get(name))
            if score is not None:
                result[cid] = str(score)
        return result
    except (OSError, ValueError, KeyError, ImportError, OverflowError):
        return {}