import logging
from dataclasses import dataclass, field
from datetime import datetime
from pathlib import Path
from typing import Dict, List

logger = logging.getLogger(__name__)


@dataclass
class DirectoryMonitor:
    dir: Path
    glob: str = '*'
    times: Dict[Path, datetime] = field(default_factory=dict, repr=False)
    changed: List[Path] = field(init=False, repr=False)
    new: List[Path] = field(init=False, repr=False)
    deleted: List[Path] = field(init=False, repr=False)
    last_checked: datetime = field(default_factory=datetime.now)

    def __post_init__(self):
        self.update()

    def update(self):
        self.last_checked = datetime.now()
        self.new, self.changed, self.deleted = [], [], []

        # iterate through the directory and update the stored times
        for file in self.dir.rglob(self.glob):
            if file.is_dir():
                logger.debug(f'Skipping directory: {file}')
                continue

            modified_time = datetime.fromtimestamp(file.stat().st_mtime)
            if file in self.times:
                if modified_time > self.times[file]:
                    logger.info(f'Updated file: {file}')
                    self.changed.append(file)
            else:
                logger.debug(f'New file: {file}')
                self.new.append(file)

            self.times[file] = modified_time

        # remove any entries for files that no longer exist
        for file in list(self.times.keys()):
            if not file.exists():
                logger.warning(f'Detected deleted file: {file}')
                del self.times[file]
                self.deleted.append(file)