"""Temporary storage of job working directories and results.

Nothing is kept longer than needed. A result lives until it is picked up or
until its TTL expires, whichever comes first.
"""

from __future__ import annotations

import logging
import shutil
from pathlib import Path

logger = logging.getLogger(__name__)

RESULT_NAME = "result.pdf"


class Storage:
    def __init__(self, root: str) -> None:
        self.root = Path(root)
        self.root.mkdir(parents=True, exist_ok=True)

    def job_dir(self, job_id: str) -> Path:
        path = self.root / job_id
        path.mkdir(parents=True, exist_ok=True)
        return path

    def result_path(self, job_id: str) -> Path:
        return self.root / job_id / RESULT_NAME

    def publish(self, job_id: str, produced: Path) -> Path:
        """Move the produced file to its final name and drop the intermediates."""
        target = self.result_path(job_id)
        if produced != target:
            produced.replace(target)

        for item in self.job_dir(job_id).iterdir():
            if item.name == RESULT_NAME:
                continue
            self._remove(item)

        return target

    def discard(self, job_id: str) -> None:
        self._remove(self.root / job_id)

    def _remove(self, path: Path) -> None:
        try:
            if path.is_dir():
                shutil.rmtree(path, ignore_errors=False)
            elif path.exists():
                path.unlink()
        except OSError as exc:
            logger.warning("Could not remove temporary path", extra={"path": str(path)}, exc_info=exc)

    def sweep_orphans(self, known_job_ids: set[str]) -> int:
        """Remove directories that belong to no known job, for example after a restart."""
        removed = 0
        for item in self.root.iterdir():
            if item.is_dir() and item.name not in known_job_ids:
                self._remove(item)
                removed += 1
        if removed:
            logger.info("Removed orphaned job directories", extra={"count": removed})
        return removed