#!/usr/bin/env python3
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"""Temporary directory helper for caching intermediate command artifacts."""

import hashlib
import tempfile
from pathlib import Path

from .dirs import CACHE_DIR


class TmpHandler:
    """Create and reuse a temporary working directory."""

    def __init__(
        self,
        tmp_dir_parent: Path = CACHE_DIR,
        tmp_directory_prefix: str = "temp_data_fox_cli_",
    ) -> None:
        """Initialize the temporary directory handler.

        Args:
            tmp_dir_parent: Parent directory used to create or find temp dirs.
            tmp_directory_prefix: Prefix used for managed temp directories.
        """
        self._tmp_dir_parent = tmp_dir_parent.resolve()
        self._tmp_directory_prefix = tmp_directory_prefix
        current_tmp_dir = self._check_for_tmp_directory()
        if current_tmp_dir is None:
            self.tmp_dir = self._create_tmp_directory()
        else:
            self.tmp_dir = current_tmp_dir

    def check_for_tmp_file(self, file_path: Path, file_extension: str) -> Path | None:
        """Return a cached temporary file path if one already exists.

        Args:
            file_path: Source file path used for deterministic cache naming.
            file_extension: Extension to use for the cached file.

        Returns:
            Cached file path if present, otherwise ``None``.
        """
        file_name = TmpHandler.get_hash_name(file_path, file_extension)
        file_path = self.tmp_dir / file_name
        if file_path.exists():
            return file_path
        return None

    def _check_for_tmp_directory(self) -> Path | None:
        """Return an existing managed temporary directory if available.

        Returns:
            Existing managed directory path, otherwise ``None``.
        """
        dirs = [d for d in self._tmp_dir_parent.iterdir() if d.is_dir()]
        for d in dirs:
            if self._tmp_directory_prefix in d.name:
                return d.resolve()
        return None

    def _create_tmp_directory(self) -> Path:
        """Create and return a new managed temporary directory.

        Returns:
            Path to the newly created temporary directory.
        """
        return Path(
            tempfile.mkdtemp(
                prefix=self._tmp_directory_prefix, dir=self._tmp_dir_parent
            )
        )

    @staticmethod
    def get_hash_name(file_path: Path, file_extension: str) -> Path:
        """Generate a deterministic cache filename from an absolute file path.

        Args:
            file_path: Source file path used as hash input.
            file_extension: Extension to append to the generated name.

        Returns:
            Generated cache filename.
        """
        file_path_hash = hashlib.sha256(
            str(file_path.resolve()).encode("utf-8")
        ).hexdigest()
        file_name = f"{file_path_hash}_{file_path.stem}"
        return Path(f"{file_name}.{file_extension}")