# 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

logger = logging.getLogger(__name__)


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:
                    logger.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:
                        logger.debug(f"add '{filename}' to deletion db")
                        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:
                        logger.debug(f"drop '{filename}' from deletion db")
