# Copyright 2013 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

import logging
import stat

from portage import os
from .DeletionTask import DeletionTask

class DeletionIterator(object):

	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(os.listdir(self._config.options.distfiles))
		for filename in distfiles_set:
			try:
				st = os.stat(os.path.join(distdir, filename))
			except OSError as e:
				logging.error("stat failed on '%s' in distfiles: %s\n" %
					(filename, e))
				continue
			if not stat.S_ISREG(st.st_mode):
				continue
			elif 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,
						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,
							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)