"""Snapshot file storage and retention management."""

from __future__ import annotations

import logging
from datetime import datetime
from pathlib import Path

logger = logging.getLogger(__name__)


class SnapshotStore:
    """Manages screenshot storage and cleanup."""

    def __init__(self, base_directory: str, retention_count: int = 50) -> None:
        self.base_directory = Path(base_directory)
        self.retention_count = retention_count
        self.base_directory.mkdir(parents=True, exist_ok=True)

    def _website_directory(self, website_id: str) -> Path:
        directory = self.base_directory / website_id
        directory.mkdir(parents=True, exist_ok=True)
        return directory

    def _timestamp_filename(self, timestamp: datetime) -> str:
        return timestamp.strftime("%Y-%m-%dT%H-%M-%S") + ".png"

    def save_screenshot(
        self,
        website_id: str,
        timestamp: datetime,
        image_bytes: bytes,
    ) -> str:
        """Save a screenshot and enforce retention limits."""
        directory = self._website_directory(website_id)
        filename = self._timestamp_filename(timestamp)
        filepath = directory / filename
        filepath.write_bytes(image_bytes)
        logger.debug("Screenshot saved: %s", filepath)

        self._cleanup_old_snapshots(directory)
        return str(filepath)

    def _cleanup_old_snapshots(self, directory: Path) -> None:
        """Remove oldest snapshots beyond retention_count."""
        screenshots = sorted(directory.glob("*.png"), key=lambda p: p.stat().st_mtime)
        excess = len(screenshots) - self.retention_count
        if excess <= 0:
            return

        for old_file in screenshots[:excess]:
            try:
                old_file.unlink()
                logger.debug("Removed old snapshot: %s", old_file)
            except OSError as exc:
                logger.warning("Failed to remove snapshot %s: %s", old_file, exc)