import json
import os
import shutil
import zipfile
from io import BytesIO
from pathlib import Path
from typing import Iterable


def validate_xlsx(content: bytes) -> bytes:
    """Validate that content is an XLSX-compatible ZIP containing workbook metadata."""
    try:
        with zipfile.ZipFile(BytesIO(content)) as archive:
            names = set(archive.namelist())
    except (zipfile.BadZipFile, OSError) as exc:
        raise ValueError("Checklist không phải file XLSX hợp lệ") from exc
    if "[Content_Types].xml" not in names or "xl/workbook.xml" not in names:
        raise ValueError("Checklist không phải file XLSX hợp lệ")
    return content


def normalize_json(content: bytes) -> bytes:
    """Parse and normalize an object/array JSON configuration."""
    try:
        parsed = json.loads(content.decode("utf-8-sig"))
    except (UnicodeDecodeError, json.JSONDecodeError) as exc:
        raise ValueError(f"Rule config JSON không hợp lệ: {exc}") from exc
    if not isinstance(parsed, (dict, list)):
        raise ValueError("Rule config JSON phải là object hoặc array")
    return json.dumps(parsed, ensure_ascii=False, indent=2).encode("utf-8") + b"\n"


def install_config_files(config_root: str | Path, files: Iterable[tuple[str, bytes]]) -> None:
    """Atomically replace allowlisted config files and keep one .bak copy."""
    root = Path(config_root)
    root.mkdir(parents=True, exist_ok=True)
    for target_name, content in files:
        if Path(target_name).name != target_name:
            raise ValueError("Tên file đích không hợp lệ")
        target = root / target_name
        temporary = root / f"{target_name}.tmp"
        backup = root / f"{target_name}.bak"
        with temporary.open("wb") as output:
            output.write(content)
            output.flush()
            os.fsync(output.fileno())
        if target.exists():
            shutil.copy2(target, backup)
        os.replace(temporary, target)