import os
import zipfile
import tempfile
import shutil
from pathlib import Path
from errors import get_logger

log = get_logger("mega_sync")

DB_PATH = "./database"
MEGA_FILENAME = "generai_db.zip"


def _zip_db(out_path: str) -> bool:
    db = Path(DB_PATH)
    if not db.exists():
        return False
    with zipfile.ZipFile(out_path, 'w', zipfile.ZIP_DEFLATED) as zf:
        for f in db.rglob('*'):
            if f.is_file():
                zf.write(f, f.relative_to(db.parent))
    return True


def _unzip_db(zip_path: str):
    db = Path(DB_PATH)
    if db.exists():
        shutil.rmtree(db)
    with zipfile.ZipFile(zip_path, 'r') as zf:
        zf.extractall('.')


def download_db(email: str, password: str) -> bool:
    try:
        from mega import Mega
        m = Mega().login(email, password)
        node = m.find(MEGA_FILENAME)
        if not node:
            log.info("Nessun DB su MEGA — si parte da zero.")
            return False
        tmp_dir = tempfile.mkdtemp()
        try:
            m.download(node, tmp_dir)
            # cerca il file scaricato nella dir temporanea
            files = list(Path(tmp_dir).iterdir())
            if not files:
                log.warning("Download MEGA: nessun file ricevuto.")
                return False
            _unzip_db(str(files[0]))
            log.info("DB scaricato da MEGA con successo.")
            return True
        finally:
            shutil.rmtree(tmp_dir, ignore_errors=True)
    except Exception as e:
        log.warning("Download MEGA fallito: %s", e)
        return False


def upload_db(email: str, password: str) -> bool:
    try:
        from mega import Mega
        m = Mega().login(email, password)
        tmp = tempfile.NamedTemporaryFile(suffix='.zip', delete=False)
        tmp.close()
        try:
            if not _zip_db(tmp.name):
                log.info("DB vuoto — niente da caricare su MEGA.")
                return False
            old = m.find(MEGA_FILENAME)
            if old:
                m.delete(old)
            m.upload(tmp.name, dest_filename=MEGA_FILENAME)
            log.info("DB caricato su MEGA con successo.")
            return True
        finally:
            os.unlink(tmp.name)
    except Exception as e:
        log.warning("Upload MEGA fallito: %s", e)
        return False