import filecmp
import logging
import pathlib
import shutil

from . import utils

__all__ = [
	"Organizer",
]
logger = logging.getLogger(__name__)

class Organizer:
	def __init__(self, base_dir, sync_dir):
		"""
		base_dir - the .tmp directory will be created here
		sync_dir - synced files will be moved here
		Both are expected to be concrete pathlib paths.
		"""

		self._base_dir = base_dir
		self._sync_dir = sync_dir

		self._temp_dir = pathlib.Path(self._base_dir, ".tmp")
		self._temp_nr = 0

		# check if base/sync dir exist?

		self._added_files = set()

	def clean_temp_dir(self):
		if self._temp_dir.exists():
			shutil.rmtree(self._temp_dir)
		self._temp_dir.mkdir(exist_ok=True)
		logger.debug(f"Cleaned temp dir: {self._temp_dir}")

	def temp_file(self):
		# generate the path to a new temp file in base_path/.tmp/
		# make sure no two paths are the same
		nr = self._temp_nr
		self._temp_nr += 1
		temp_file =  pathlib.Path(self._temp_dir, f"{nr:08}.tmp").resolve()
		logger.debug(f"Produced new temp file: {temp_file}")
		return temp_file

	def add_file(self, from_path, to_path):
		if not from_path.exists():
			raise utils.FileNotFoundException(f"Could not add file at {from_path}")

		# check if sync_dir/to_path is inside sync_dir?
		to_path = pathlib.Path(self._sync_dir, to_path)


		if to_path.exists():
			if filecmp.cmp(from_path, to_path, shallow=False):
				logger.info(f"Ignored {to_path}")

				# remember path for later reference
				self._added_files.add(to_path.resolve())
				logger.debug(f"Added file {to_path.resolve()}")

				# No further action needed, especially not overwriting symlinks...
				return
			else:
				logger.info(f"Different file at {to_path}")
		else:
			logger.info(f"New file at {to_path}")

		# copy the file from from_path to sync_dir/to_path
		# If the file being replaced was a symlink, the link itself is overwritten,
		# not the file the link points to.
		to_path.parent.mkdir(parents=True, exist_ok=True)
		from_path.replace(to_path)
		logger.debug(f"Moved {from_path} to {to_path}")

		# remember path for later reference, after the new file was written
		# This is necessary here because otherwise, resolve() would resolve the symlink too.
		self._added_files.add(to_path.resolve())
		logger.debug(f"Added file {to_path.resolve()}")

	def clean_sync_dir(self):
		self._clean_dir(self._sync_dir, remove_parent=False)
		logger.debug(f"Cleaned sync dir: {self._sync_dir}")

	def _clean_dir(self, path, remove_parent=True):
		for child in sorted(path.iterdir()):
			logger.debug(f"Looking at {child.resolve()}")
			if child.is_dir():
				self._clean_dir(child, remove_parent=True)
			elif child.resolve() not in self._added_files:
				if self._prompt_yes_no(f"Delete {child}?", default=False):
					child.unlink()
					logger.debug(f"Deleted {child}")

		if remove_parent:
			try:
				path.rmdir()
			except OSError: # directory not empty
				pass

	def _prompt_yes_no(self, question, default=None):
		if default is True:
			prompt = "[Y/n]"
		elif default is False:
			prompt = "[y/N]"
		else:
			prompt = "[y/n]"

		text = f"{question} {prompt} "
		WRONG_REPLY = "Please reply with 'yes'/'y' or 'no'/'n'."

		while True:
			response = input(text).strip().lower()
			if response in {"yes", "ye", "y"}:
				return True
			elif response in {"no", "n"}:
				return False
			elif response == "":
				if default is None:
					print(WRONG_REPLY)
				else:
					return default
			else:
				print(WRONG_REPLY)

# How to use:
#
# 1. Before downloading any files
# orga = Organizer("/home/user/sync/", "/home/user/sync/bookstore/")
# orga.clean_temp_dir()
#
# 2. Downloading a file
# tempfile = orga.temp_file()
# download_something_to(tempfile)
# orga.add_file(tempfile, "books/douglas_adams/hhgttg"
#
# 3. After downloading all files
# orga.clean_sync_dir()
# orga.clean_temp_dir()