# Copyright 2013-2021 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

import itertools
import logging
import stat

from portage import os
from portage.package.ebuild.fetch import DistfileName
from .DeletionTask import DeletionTask

class DeletionIterator:

	def __init__(self, config):
		self._config = config

	def __iter__(self):
		distdir = self._config.options.distfiles
		file_owners = self._config.file_owners
		whitelist = self._config.whitelist
		distfiles_local = self._config.options.distfiles_local
		deletion_db = self._config.deletion_db
		deletion_delay = self._config.options.deletion_delay
		start_time = self._config.start_time
		distfiles_set = set()
		distfiles_set.update(
			(
				filename
				if isinstance(filename, DistfileName)
				else DistfileName(filename)
				for filename in itertools.chain.from_iterable(
					layout.get_filenames(distdir) for layout in self._config.layouts
				)
			)
			if self._config.content_db is None
			else itertools.chain.from_iterable(
				(
					self._config.content_db.get_filenames_translate(filename)
					for filename in itertools.chain.from_iterable(
						layout.get_filenames(distdir) for layout in self._config.layouts
					)
				)
			)
		)
		for filename in distfiles_set:
			# require at least one successful stat()
			exceptions = []
			for layout in reversed(self._config.layouts):
				path = os.path.join(distdir, layout.get_path(filename))
				try:
					st = os.stat(path)
				except OSError as e:
					# is it a dangling symlink?
					try:
						if os.path.islink(path):
							os.unlink(path)
					except OSError as e:
						exceptions.append(e)
				else:
					if stat.S_ISREG(st.st_mode):
						break
			else:
				if exceptions:
					logging.error("stat failed on '%s' in distfiles: %s\n" %
						(filename, '; '.join(str(x) for x in exceptions)))
				continue

			if filename in file_owners:
				if deletion_db is not None:
					try:
						del deletion_db[filename]
					except KeyError:
						pass
			elif whitelist is not None and filename in whitelist:
				if deletion_db is not None:
					try:
						del deletion_db[filename]
					except KeyError:
						pass
			elif distfiles_local is not None and \
				os.path.exists(os.path.join(distfiles_local, filename)):
				if deletion_db is not None:
					try:
						del deletion_db[filename]
					except KeyError:
						pass
			else:
				self._config.scheduled_deletion_count += 1

				if deletion_db is None or deletion_delay is None:

					yield DeletionTask(background=True,
						distfile=filename,
						distfile_path=path,
						config=self._config)

				else:
					deletion_entry = deletion_db.get(filename)

					if deletion_entry is None:
						logging.debug("add '%s' to deletion db" % filename)
						deletion_db[filename] = start_time

					elif deletion_entry + deletion_delay <= start_time:

						yield DeletionTask(background=True,
							distfile=filename,
							distfile_path=path,
							config=self._config)

		if deletion_db is not None:
			for filename in list(deletion_db):
				if filename not in distfiles_set:
					try:
						del deletion_db[filename]
					except KeyError:
						pass
					else:
						logging.debug("drop '%s' from deletion db" %
							filename)