#!/usr/bin/python3
# codeing = utf-8

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# Copyright (C) 2021 WindRiver Corporation

import apt
import apt_pkg
import aptly_deb_usage
import argparse
from concurrent.futures import as_completed
from concurrent.futures import ThreadPoolExecutor
import debian.deb822
import debian.debfile
import logging
import os
import requests
from requests.compat import urljoin
import shutil
from threading import Lock
import urllib.request
import utils

REPOMGR_URL = os.environ.get('REPOMGR_URL')
REPOMGR_ORIGIN = os.environ.get('REPOMGR_ORIGIN')
REPOMGR_DEPLOY_URL = os.environ.get('REPOMGR_DEPLOY_URL')

APTFETCH_JOBS = 20


class AptFetch():
    '''
    Fetch Debian packages from a set of repositories.
    '''
    def __init__(self, logger, sources_list='', workdir='/tmp/apt-fetch'):
        self.logger = logger
        self.aptcache = None
        self.aptlock = Lock()
        self.workdir = workdir
        self.sources_list = sources_list
        self.__construct_workdir(sources_list)
        self.__init_apt_cache()

    def __construct_workdir(self, sources_list):
        '''construct some directories for repo and temporary files'''
        # In case the sources_list is specified:
        #
        # ├── apt-root               # For apt cache
        # │   └── etc
        # │       └── apt
        # │           └── sources.list
        # └── downloads              # Sub directory to store downloaded packages
        #       ├── binary
        #       └── source
        #
        # In case the sources_list is ''
        # |
        # └── downloads              # Sub directory to store downloaded packages
        #       ├── binary
        #       └── source
        basedir = self.workdir
        try:
            if os.path.exists(basedir):
                shutil.rmtree(basedir)
            os.makedirs(basedir)
            if self.sources_list:
                # check to see if meta file exist
                if not os.path.exists(sources_list):
                    raise Exception('Specified sources list file %s does not exist' % sources_list)
                aptdir = os.path.join(basedir, 'apt-root/etc/apt')
                os.makedirs(aptdir)
                shutil.copyfile(sources_list, os.path.join(aptdir, 'sources.list'))
            os.makedirs(os.path.join(basedir, 'downloads', 'binary'))
            os.makedirs(os.path.join(basedir, 'downloads', 'source'))
        except Exception as e:
            self.logger.error(str(e))
            self.logger.error('Failed to construct workdir %s' % basedir)
            raise Exception('Failed to construct workdir %s' % basedir)

    def __init_apt_cache(self):
        '''Construct APT cache based on specified rootpath. Just like `apt update` on host'''
        # In case we use host's apt settings, no need to apt-upgrade.
        if not self.sources_list:
            self.aptcache = apt.Cache()
            return None
        try:
            self.aptcache = apt.Cache(rootdir=os.path.join(self.workdir, 'apt-root'))
            ret = self.aptcache.update()
            if not ret:
                raise Exception('APT cache update failed')
            self.aptcache.open()
        except Exception as e:
            self.logger.error(str(e))
            self.logger.error('apt cache init failed.')
            raise Exception('apt cache init failed.')

    # Download a binary package into downloaded folder
    def fetch_deb(self, pkg_name, pkg_version=''):
        '''Download a binary package'''
        if not pkg_name:
            raise Exception('Binary package name empty')

        destdir = os.path.join(self.workdir, 'downloads', 'binary')
        self.aptlock.acquire()
        pkg = self.aptcache.get(pkg_name)
        if not pkg:
            self.aptlock.release()
            raise Exception('Binary package "%s" was not found' % pkg_name)
        default_candidate = pkg.candidate
        if pkg_version:
            candidate = pkg.versions.get(pkg_version)
            if not candidate:
                if default_candidate:
                    epoch, ver = default_candidate.version.split(':')
                    if epoch.isdigit() and ver == pkg_version:
                        self.logger.debug('epoch %s will be skipped for %s_%s', epoch, pkg_name, ver)
                        candidate = default_candidate
                else:
                    self.aptlock.release()
                    raise Exception('Binary package "%s %s" was not found.' % (pkg_name, pkg_version))
        uri = candidate.uri
        filename = candidate.filename
        self.aptlock.release()
        try:
            res = requests.get(uri, stream=True)
            self.logger.debug('Fetching package file %s' % uri)
            with open(os.path.join(destdir, os.path.basename(filename)), 'wb') as download_file:
                for chunk in res.iter_content(chunk_size=1024 * 1024):
                    if chunk:
                        download_file.write(chunk)
        except Exception as e:
            self.logger.error(str(e))
            self.logger.error('Binary package %s %s download error' % (pkg_name, pkg_version))
            return ' '.join(['DEB-F', pkg_name, pkg_version]).strip()
        else:
            self.logger.debug('Binary package %s %s downloaded.' % (pkg_name, pkg_version))
            return ' '.join(['DEB', pkg_name, pkg_version]).strip()

    # Download a source package into downloaded folder
    def fetch_dsc(self, pkg_name, pkg_version=''):
        '''Download a source package'''
        if not pkg_name:
            raise Exception('Source package name empty')

        destdir = os.path.join(self.workdir, 'downloads', 'source')
        self.aptlock.acquire()
        src = apt_pkg.SourceRecords()
        source_find = False
        source_lookup = src.lookup(pkg_name)
        while source_lookup:
            if pkg_name == src.package and pkg_version in ['', src.version]:
                source_find = True
                break
            source_lookup = src.lookup(pkg_name)
        if not source_find:
            self.aptlock.release()
            raise ValueError("Source package %s %s was not found" % (pkg_name, pkg_version))
        dict_files = dict()
        for src_file in src.files:
            dict_files[src_file.path] = src.index.archive_uri(src_file.path)
        self.aptlock.release()

        # Here the src.files is a list, each one points to a source file
        # Download those source files one by one with requests
        try:
            for file_path, uri in dict_files.items():
                res = requests.get(uri, stream=True)
                self.logger.debug('Fetch package file %s' % uri)
                with open(os.path.join(destdir, os.path.basename(file_path)), 'wb') as download_file:
                    for chunk in res.iter_content(chunk_size=1024 * 1024):
                        if chunk:
                            download_file.write(chunk)
        except Exception as e:
            self.logger.error(str(e))
            self.logger.error('Source package %s %s download error' % (pkg_name, pkg_version))
            return ' '.join(['DSC-F', pkg_name, pkg_version]).strip()
        else:
            self.logger.debug('Source package %s %s downloaded.' % (pkg_name, pkg_version))
            return ' '.join(['DSC', pkg_name, pkg_version]).strip()

    # Download a bundle of packages into downloaded folder
    # deb_list: binary package list file
    # dsc_list: source package list file
    def fetch_pkg_list(self, deb_set=set(), dsc_set=set()):
        '''Download a bundle of packages specified through deb_list and dsc_list.'''
        if not deb_set and not dsc_set:
            raise Exception('deb_list and dsc_list, at least one is required.')

        fetch_result = dict()
        fetch_result['deb'] = list()
        fetch_result['deb-failed'] = list()
        fetch_result['dsc'] = list()
        fetch_result['dsc-failed'] = list()
        with ThreadPoolExecutor(max_workers=APTFETCH_JOBS) as threads:
            obj_list = []
            # Download binary packages
            for pkg_ver in deb_set:
                pkg_name = pkg_ver.split()[0]
                if len(pkg_ver.split()) == 1:
                    pkg_version = ''
                else:
                    pkg_version = pkg_ver.split()[1]
                obj = threads.submit(self.fetch_deb, pkg_name, pkg_version)
                obj_list.append(obj)
            # Download source packages
            for pkg_ver in dsc_set:
                pkg_name = pkg_ver.split()[0]
                if len(pkg_ver.split()) == 1:
                    pkg_version = ''
                else:
                    pkg_version = pkg_ver.split()[1]
                obj = threads.submit(self.fetch_dsc, pkg_name, pkg_version)
                obj_list.append(obj)
            # Wait...
            for future in as_completed(obj_list):
                ret = future.result()
                if ret:
                    if ret.startswith('DEB'):
                        fetch_result['deb'].append(ret.lstrip('DEB '))
                    elif ret.startswith('DEB-F'):
                        fetch_result['deb-failed'].append(ret.lstrip('DEB-F '))
                    elif ret.startswith('DSC'):
                        fetch_result['dsc'].append(ret.lstrip('DSC '))
                    elif ret.startswith('DSC-F'):
                        fetch_result['dsc-failed'].append(ret.lstrip('DSC-F '))
        return fetch_result


class RepoMgr():
    '''
    Repository management, based on pulp or aptly, mainly used for OBS and LAT
    Two kind of repositories: local repo and remote one.
    remote repo: mirror of another repository. shouldn't insert or remove packages from it..
    local repo: a local repository, we can insert/remove packages into/from them.
    '''
    def __init__(self, repoType, repoURL, workdir, origin, logger):
        if repoType == 'aptly':
            self.repo = aptly_deb_usage.Deb_aptly(repoURL, origin, logger)
        else:
            raise Exception('Currently, only aptly repository supported')

        self.aptcache = None
        self.logger = logger
        self.workdir = workdir

    def __sync_pkg_list(self, check_list, pkg_list_file, pkg_type='binary'):
        '''Sync packages, return packages need to be downloaded'''
        if pkg_type not in ['binary', 'source']:
            self.logger.error('Parameter pkg_tye:%s error. Can only be binary or source' % pkg_type)
            raise Exception('Parameter pkg_tye:%s error. Can only be binary or source' % pkg_type)
        pkg_req = set()
        # scan the package list file
        pkg_set = self.__scan_pkg_list(pkg_list_file)
        for pkg_ver in pkg_set:
            pkg_name = pkg_ver.split()[0]
            if len(pkg_ver.split()) == 1:
                pkg_version = ''
            else:
                pkg_version = pkg_ver.split()[1]
            # Search package in check_list
            if self.repo.pkg_exist(check_list, pkg_name, pkg_type, pkg_version):
                continue
            pkg_req.add(pkg_ver)
        self.logger.info('%d %s packages need to be downloaded.' % (len(pkg_req), pkg_type))
        return pkg_req

    # Scan package list file, return required package_version in a set
    def __scan_pkg_list(self, pkg_list_file):
        pkg_set = set()
        try:
            with open(pkg_list_file, 'r') as f_list:
                lines = f_list.readlines()
        except Exception as e:
            self.logger.error(str(e))
            self.logger.error('Package list file %s read error.' % pkg_list_file)
            raise Exception('Package list file %s read error.' % pkg_list_file)
        else:
            for line in lines:
                pkg_info = line.split('#')[0].split()
                if not pkg_info:
                    continue
                if len(pkg_info) == 1:
                    pkg_set.add(pkg_info[0])
                else:
                    pkg_set.add(pkg_info[0] + ' ' + pkg_info[1])
        # If xxx_1.2.3 exist, remove xxx.
        tmp_set = pkg_set.copy()
        for pkg_ver in tmp_set:
            if pkg_ver.split()[0] in pkg_set:
                pkg_set.remove(pkg_ver.split()[0])
        return pkg_set

    # Download a bundle of packages and deployed them through repository
    # repo_name: the repository used to deploy these packages
    # no_clear: Not delete downloaded package files, for debug
    # kwarge:sources_list: Where we should fetch packages from.
    # kwarge:deb_list: file contains binary package list
    # kwarge:dsc_ist: file contains source package list
    # Output: None
    def download(self, repo_name, no_clear=False, **kwargs):
        '''Download specified packages and deploy them through a specified local repo.'''
        if 'deb_list' not in kwargs.keys():
            deb_list_file = ''
        else:
            deb_list_file = kwargs['deb_list']
        if 'dsc_list' not in kwargs.keys():
            dsc_list_file = ''
        else:
            dsc_list_file = kwargs['dsc_list']
        if not deb_list_file and not dsc_list_file:
            raise Exception('deb_list and dsc_list, at least one is required.')
        if not repo_name == '':
            # No matter if any packages can be download, create related repository firstly.
            if not self.repo.create_local(repo_name):
                raise Exception('Local repo created failed, Please double check if it already exists.')

        # Scan deb/dsc_list_file, get required packages
        deb_set = set()
        dsc_set = set()
        if deb_list_file:
            deb_set = self.__scan_pkg_list(deb_list_file)
            self.logger.info('%d binary packages will be downloaded.' % len(deb_set))
        if dsc_list_file:
            dsc_set = self.__scan_pkg_list(dsc_list_file)
            self.logger.info('%d source packages will be downloaded.' % len(dsc_set))
        # Download packages
        apt_fetch = AptFetch(self.logger, kwargs['sources_list'], self.workdir)
        fetch_result = apt_fetch.fetch_pkg_list(deb_set=deb_set, dsc_set=dsc_set)
        if fetch_result['deb'] or fetch_result['deb-failed']:
            self.logger.info('Download %d binary packages' % len(fetch_result['deb']))
            self.logger.info('%d binary packages download failed' % len(fetch_result['deb-failed']))
            for pkg_ver in fetch_result['deb']:
                self.logger.debug('Binary package %s' % pkg_ver)
            for pkg_ver in fetch_result['deb-failed']:
                self.logger.info('Failed to download binary package %s' % pkg_ver)
        if fetch_result['dsc'] or fetch_result['dsc-failed']:
            self.logger.info('Download %d source packages' % len(fetch_result['dsc']))
            self.logger.info('%d source packages download failed' % len(fetch_result['dsc-failed']))
            for pkg_ver in fetch_result['dsc']:
                self.logger.debug('Source package %s' % pkg_ver)
            for pkg_ver in fetch_result['dsc-failed']:
                self.logger.info('Failed to download source package %s' % pkg_ver)

        if repo_name == '':
            self.logger.info('All packages are downloaded to %s', self.workdir)
            return

        # Add packages into local repo
        pkg_folder = os.path.join(self.workdir, 'downloads', 'binary')
        package_files = set()
        for filename in os.listdir(pkg_folder):
            package_files.add(os.path.join(pkg_folder, filename))
        if package_files:
            self.repo.upload_pkg_local(package_files, repo_name)
        pkg_folder = os.path.join(self.workdir, 'downloads', 'source')
        for filename in os.listdir(pkg_folder):
            if filename.endswith('.dsc'):
                self.upload_pkg(repo_name, os.path.join(pkg_folder, filename))

        # Deploy local repo
        repo_str = self.repo.deploy_local(repo_name)
        if not no_clear:
            shutil.rmtree(self.workdir)
        self.logger.info('New local repo can be accessed through: %s' % repo_str)

    # We need a bundle packages been deployed through a serials of repositories
    # We have:
    # -) a serials of atply/pulp repositories already contains some packages;
    # -) an aptly/pulp repository can be used to deploy downloaded packages
    # -) a serials of upstream Debian repository
    # -) Two text files list binary and source packages we need
    #
    # SYNC will download all packages we haven't and deployed them through
    # a local repository.
    # reponame: name of a local repository used to deploy downloaded packages
    # repo_list: String separated with space, contains serials of aptly/pulp
    #            repos can be used for OBS/LAT.
    # no_clear: do not delete downloaded packages. For debug
    # kwargs:sources_list: file contains trusted upstream repositories
    # kwargs:deb_list: file lists all needed binary packages
    # kwargs:dsc_list: file lists all needed source packages
    # Output: None
    def sync(self, repo_name, repo_list, no_clear=False, **kwargs):
        '''
        Sync a set of repositories with specified package lists, if any packages
        missed, download and deploy them through a specified local repo
        '''
        if 'deb_list' not in kwargs.keys():
            deb_list = ''
        else:
            deb_list = kwargs['deb_list']
        if 'dsc_list' not in kwargs.keys():
            dsc_list = ''
        else:
            dsc_list = kwargs['dsc_list']

        if not deb_list and not dsc_list:
            raise Exception('deb_list and dsc_list, at least one is required.')
        # construct repo list will be checked
        local_list = self.repo.list_local(quiet=True)
        remote_list = self.repo.list_remotes(quiet=True)
        # Specified local repo must exist, or failed
        if repo_name not in local_list:
            self.logger.info('Sync, local repo %s does not exist, create it.' % repo_name)
            if not self.repo.create_local(repo_name):
                raise Exception('Local repo %s created failed.' % repo_name)
        # Make sure all repos in check_list exist in aptly/pulp database.
        check_list = [repo_name]
        for repo in repo_list.split():
            if repo in local_list or repo in remote_list:
                if repo not in check_list:
                    check_list.append(repo)
            else:
                self.logger.warning('%s in the list but does not exists.' % repo)

        # Download missing packages from remote repo
        deb_set = set()
        dsc_set = set()
        if deb_list:
            deb_set = self.__sync_pkg_list(check_list, deb_list, 'binary')
        if dsc_list:
            dsc_set = self.__sync_pkg_list(check_list, dsc_list, 'source')
        # Download packages
        if deb_set or dsc_set:
            apt_fetch = AptFetch(self.logger, kwargs['sources_list'], self.workdir)
            fetch_result = apt_fetch.fetch_pkg_list(deb_set=deb_set, dsc_set=dsc_set)
            if fetch_result['deb'] or fetch_result['deb-failed']:
                self.logger.info('Download %d binary packages' % len(fetch_result['deb']))
                self.logger.info('%d binary packages download failed' % len(fetch_result['deb-failed']))
                for pkg_ver in fetch_result['deb']:
                    self.logger.debug('Binary package %s' % pkg_ver)
                for pkg_ver in fetch_result['deb-failed']:
                    self.logger.info('Failed to download binary package %s' % pkg_ver)
            if fetch_result['dsc'] or fetch_result['dsc-failed']:
                self.logger.info('Download %d source packages' % len(fetch_result['dsc']))
                self.logger.info('%d source packages download failed' % len(fetch_result['dsc-failed']))
                for pkg_ver in fetch_result['dsc']:
                    self.logger.debug('Source package %s' % pkg_ver)
                for pkg_ver in fetch_result['dsc-failed']:
                    self.logger.info('Failed to download source package %s' % pkg_ver)
            # Add packages into local repo
            pkg_folder = os.path.join(self.workdir, 'downloads', 'binary')
            package_files = set()
            for filename in os.listdir(pkg_folder):
                package_files.add(os.path.join(pkg_folder, filename))
            self.repo.upload_pkg_local(package_files, repo_name)
            pkg_folder = os.path.join(self.workdir, 'downloads', 'source')
            for filename in os.listdir(pkg_folder):
                if filename.endswith('.dsc'):
                    self.upload_pkg(repo_name, os.path.join(pkg_folder, filename))
            self.repo.upload_pkg_local(package_files, repo_name)

        # Deploy local repo
        repo_str = self.repo.deploy_local(repo_name)
        if not no_clear:
            try:
                if os.path.exists(self.workdir):
                    shutil.rmtree(self.workdir)
            except Exception as e:
                self.logger.error(str(e))
                self.logger.error('Clear work folder %s failed.' % self.workdir)
                raise Exception('Clear work folder %s failed.' % self.workdir)
        self.logger.info('local repo can be accessed through: %s ' % repo_str)

    # Merge all packages of several repositories into a new publication(aptly)
    # NOTE: aptly only. Not find similar feature in pulp...
    def merge(self, name, source_snapshots):
        '''Merge several repositories into a new aptly publication.'''
        return self.repo.merge_repos(name, source_snapshots.split(','))

    # Construct a repository mirror to an upstream Debian repository
    # kwargs:url: URL of the upstream repo (http://deb.debian.org/debian)
    # kwargs:distribution: the distribution of the repo (bullseye)
    # kwargs:component: component of the repo (main)
    # kwargs:architecture: architecture of the repo, "all" is always enabled. (amd64)
    # kwargs:with_sources: include source packages, default is False.
    # Output: None
    def mirror(self, repo_name, **kwargs):
        '''Construct a mirror based on a debian repository.'''
        url = kwargs['url']
        distribution = kwargs['distribution']
        component = kwargs['component']
        architectures = kwargs['architectures']
        if 'with_sources' not in kwargs.keys():
            with_sources = False
        else:
            with_sources = kwargs['with_sources']
        self.repo.remove_remote(repo_name)
        if with_sources:
            self.repo.create_remote(repo_name, url, distribution,
                                    components=[component],
                                    architectures=[architectures],
                                    with_sources=True)
        else:
            self.repo.create_remote(repo_name, url, distribution,
                                    components=[component],
                                    architectures=[architectures])
        repo_str = self.repo.deploy_remote(repo_name)
        if repo_str != None:
            self.logger.info('New mirror can be accessed through: %s' % repo_str)
            return True
        else:
            self.logger.error('Create mirror failed %s : %s' % (repo_name, url))
            return false

    # List all repositories
    # Output: None
    def list(self):
        '''List all repos.'''
        self.repo.list_remotes()
        self.repo.list_local()

    # Clean all packages and repositories
    def clean(self):
        '''Clear all meta files. Construct a clean environment'''
        self.repo.clean_all()

    # Copy specified packages from one repository to another
    def copy_pkgs(self, source, dest, pkg_names, pkg_type='binary', deploy=True, overwrite=True):
        '''Copy specified packages from source repository to destination repository.'''
        if pkg_type != 'binary' and pkg_type != 'source':
            self.logger.error('The package type must be binary or source')
            return False
        if source == dest:
            self.logger.error('%s and %s are the same repository.' % (source, dest))
            return False
        if pkg_type != 'binary' and pkg_type != 'source':
            self.logger.error('The package type must be binary or source')
            return False
        pkg_list = list()
        for pkg in pkg_names.split(','):
            pkg_list.append(pkg.strip())
        ret = self.repo.copy_pkgs(source, dest, pkg_list, pkg_type)
        if not ret:
            self.logger.error('Copy %s packages from %s to %s failed' % (pkg_type, source, dest))
            return False
        elif deploy:
            self.repo.deploy_local(dest)
            return True

    # list a repository
    # repo_name: the name of the repo been listed.
    # Output: True is all works in order
    def list_pkgs(self, repo_name, quiet=False):
        '''List a specified repository.'''
        local_list = self.repo.list_local(quiet=True)
        remote_list = self.repo.list_remotes(quiet=True)
        pkg_list = []
        for repo in local_list:
            if repo == repo_name:
                self.logger.info('List a local repo')
                pkgs = self.repo.pkg_list([repo])
                pkg_list.extend(pkgs)
                if not quiet:
                    self.logger.info("Local repo %s:" % repo_name)
                    for pkg in sorted(pkgs):
                        self.logger.info("  %s" % pkg)
        for repo in remote_list:
            if repo == repo_name:
                self.logger.info('List a remote mirror')
                pkgs = self.repo.pkg_list([repo])
                pkg_list.extend(pkgs)
                if not quiet:
                    self.logger.info("Remote repo %s:" % repo_name)
                    for pkg in sorted(pkgs):
                        self.logger.info("  %s" % pkg)
        return pkg_list

    # delete a repository
    # repo_name: the name of the repo been deleted.
    # Output: True is all works in order
    def remove_repo(self, repo_name):
        '''Remove a specified repository.'''
        local_list = self.repo.list_local(quiet=True)
        remote_list = self.repo.list_remotes(quiet=True)
        for repo in local_list:
            if repo == repo_name:
                self.logger.info('Remove a local repo')
                self.repo.remove_local(repo)
                return True
        for repo in remote_list:
            if repo == repo_name:
                self.logger.info('Remove a remote mirror')
                self.repo.remove_remote(repo)
                return True
        self.logger.warning("Remove repo failed: repo '%s' not found" % repo_name)
        return False

    # Before uploading a source package into a local repo, scan all repos,
    # find all duplicate files with different size.
    # dsc: Dsc data of the source package. <class 'debian.deb822.Dsc'>
    # Return a dictionary: {repo_1: {file_a, ...}, ...}
    #   Input dsc contains file_a, while repo_1 also contains such a file
    #   with different size.
    def __check_orig_files(self, dsc):
        different_files = {}
        repo_list = self.repo.list_local(quiet=True)
        repo_list += self.repo.list_remotes(quiet=True)
        for repo in repo_list:
            for meta_file in dsc['Files']:
                if meta_file['name'].find('.orig.'):
                    new_file_size = meta_file['size']
                    if dsc['Source'].startswith('lib'):
                        prefix_dir = dsc['Source'][:4] + '/' + dsc['Source']
                    else:
                        prefix_dir = dsc['Source'][0] + '/' + dsc['Source']
                    target_path = repo + '/pool/main/' + prefix_dir + '/' + meta_file['name']
                    target_url = urljoin(REPOMGR_DEPLOY_URL, target_path)
                    try:
                        orig_file = urllib.request.urlopen(target_url)
                    except Exception:
                        # no such file in repo, that is good
                        self.logger.debug('%s does not contain %s' % (repo, meta_file['name']))
                        continue
                    if orig_file.length != int(new_file_size):
                        self.logger.debug('File %s is not same as the one in %s.' %
                                          (meta_file['name'], repo))
                        if repo not in different_files.keys():
                            different_files[repo] = {meta_file['name']}
                        else:
                            different_files[repo].add(meta_file['name'])
        return different_files

    # upload a Debian package and deploy it
    # repo_name: the name of the repository used to contain and deploy the package
    # package: pathname of the package(xxx.deb or xxx.dsc) to be uploaded
    # deploy: If True, deploy the repository after "binary" package been uploaded.
    # Output: True if all works.
    def upload_pkg(self, repo_name, package, deploy=True):
        '''Upload a Debian package into a specified repository.'''
        local_list = self.repo.list_local(quiet=True)
        if repo_name not in local_list:
            self.logger.info('upload_pkg: repository %s does not exist, creating it.' % repo_name)
            self.repo.create_local(repo_name)

        if not package and deploy:
            # No repo found, no package specified, just create & deploy the repo and return
            self.repo.deploy_local(repo_name)
            return True

        self.logger.debug('upload_pkg: upload package %s into %s' % (package, repo_name))
        if '.deb' == os.path.splitext(package)[-1]:
            pkg_type = 'binary'
            try:
                deb = debian.debfile.DebFile(package, 'r').debcontrol()
            except Exception as e:
                self.logger.error('Error: %s' % e)
                self.logger.error('Binary package %s read error.' % package)
                raise Exception('Binary package error.')
            pkg_version = deb['Version']
            pkg_name = deb['Package']
            self.repo.upload_pkg_local({package}, repo_name)
        elif '.dsc' == os.path.splitext(package)[-1]:
            pkg_type = 'source'
            try:
                dsc = debian.deb822.Dsc(open(package, 'r'))
            except Exception as e:
                self.logger.error('Error: %s' % e)
                self.logger.error('Source package %s read error.' % package)
                raise Exception('Source package error.')
            pkg_name = dsc['Source']
            pkg_version = dsc['Version']

            # In case there is already an *.orig.* file with different size in any repos,
            # refuse to upload it.
            different_files = self.__check_orig_files(dsc)
            if different_files:
                for repo, meta_files in different_files.items():
                    self.logger.error('%s contains different file: %s' % (repo, str(meta_files)))
                    self.logger.error('Package %s upload failed.  Repo %s already contains '
                                      'file %s with different content.' %
                                      (package, repo, str(meta_files)))
                return False

            pkg_files = set()
            pkg_files.add(package)
            for meta_file in dsc['Files']:
                pkg_files.add(os.path.join(os.path.dirname(package), meta_file['name']))
            self.repo.upload_pkg_local(pkg_files, repo_name)
        else:
            self.logger.warning('Only Debian style files, like deb and dsc, are supported.')
            return False
        self.logger.debug('upload_pkg: package %s been uploaded into %s' % (package, repo_name))
        # deploy = False only effect on binary package.
        if 'binary' == pkg_type and not deploy:
            return True

        self.repo.deploy_local(repo_name)
        # Double check if the package been uploaded successfully
        if not self.search_pkg(repo_name, pkg_name, pkg_version, pkg_type == 'binary'):
            self.logger.error('upload_pkg: verify failed, no %s package %s %s in %s'
                              % (pkg_type, pkg_name, pkg_version, repo_name))
            return False
        return True

    # search a package from a repository
    # repo_name: name of the repository to search the package in
    # pkg_name: name of the Debian package to be searched
    # pkg_version: version number of the package to be searched
    # binary: binary package or source one?
    # Output: True if find, or False
    def search_pkg(self, repo_name, pkg_name, pkg_version=None, binary=True):
        '''Find a package from a specified repo.'''
        repo_find = False
        repo = None
        r_list = self.repo.list_local(quiet=True)
        for repo in r_list:
            if repo == repo_name:
                repo_find = True
        r_list = self.repo.list_remotes(quiet=True)
        for repo in r_list:
            if repo == repo_name:
                repo_find = True
        if not repo_find:
            self.logger.error('Search package, repository does not exist.')
            return False

        if binary:
            pkg_type = 'binary'
        else:
            pkg_type = 'source'
        if not self.repo.pkg_exist([repo_name], pkg_name, pkg_type, pkg_version):
            self.logger.info('Search %s package %s, not found.' % (pkg_type, pkg_name))
            return False
        return True

    # Deploy a local repository
    def deploy_repo(self, repo_name, suffix=''):
        '''Deploy a local repository manually.'''
        local_list = self.repo.list_local(quiet=True)
        if repo_name not in local_list:
            self.logger.error('Local repository deploy failed, %s does not exist.' % repo_name)
            return
        return self.repo.deploy_local(repo_name, suffix)


    # Delete a Debian package from a local repository
    # repo_name: name of the LOCAL repository to delete the package from
    # pkg_name: name of the binary package to be deleted
    # pkg_type: 'source' or 'binary'
    # pkg_version: version number of the package to be deleted
    # Output: True if find and delete, or False
    def delete_pkg(self, repo_name, pkg_name, pkg_type, pkg_version='', deploy=True):
        '''Find and delete a binary package from a specified local repo.'''
        repo_find = False
        repo = None
        if pkg_type not in {'binary', 'source'}:
            self.logger.error('Delete package, pkg_type must be one of '
                              'either "binary" or "source".')
            return False
        if not repo_name.startswith(aptly_deb_usage.PREFIX_LOCAL):
            self.logger.error('Delete package, only local repositories support this operation.')
            return False
        local_list = self.repo.list_local(quiet=True)
        for repo in local_list:
            if repo == repo_name:
                repo_find = True
        if not repo_find:
            self.logger.error('Delete package, repository does not exist.')
            return False

        if not self.repo.pkg_exist([repo_name], pkg_name, pkg_type, pkg_version):
            self.logger.info('Delete package, package not found.')
            return False

        self.repo.delete_pkg_local(repo_name, pkg_name, pkg_type, pkg_version)
        # deploy = False only effect on binary packages
        if 'binary' == pkg_type and not deploy:
            return True
        self.repo.deploy_local(repo_name)
        return True


# Simple example on using this class.
applogger = logging.getLogger('repomgr')
utils.set_logger(applogger)


def _handleDownload(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, args.basedir, REPOMGR_ORIGIN, applogger)
    kwargs = {'sources_list': args.sources_list, 'deb_list': args.deb_list,
              'dsc_list': args.dsc_list}
    repomgr.download(args.repository, **kwargs, no_clear=args.no_clear)


def _handleSync(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, args.basedir, REPOMGR_ORIGIN, applogger)
    kwargs = {'sources_list': args.sources_list, 'deb_list': args.deb_list,
              'dsc_list': args.dsc_list}
    repomgr.sync(args.repository, args.repo_list, **kwargs, no_clear=args.no_clear)


def _handleMirror(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    kwargs = {'url': args.url, 'distribution': args.distribution, 'component': args.component,
              'architectures': args.architectures, 'with_sources': args.with_sources}
    repomgr.mirror(args.repository, **kwargs)


def _handleMerge(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    repomgr.merge(args.name, args.repo_list)


def _handleCopyPkg(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    repomgr.copy_pkgs(args.source, args.destination, args.package_name, deploy=True, pkg_type=args.package_type)


def _handleUploadPkg(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    repomgr.upload_pkg(args.repository, args.package)


def _handleDeletePkg(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    repomgr.delete_pkg(args.repository, args.package_name, args.package_type,
                       pkg_version=args.package_version)


def _handleSearchPkg(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    if args.package_type == 'binary':
        repomgr.search_pkg(args.repository, args.package_name, pkg_version=args.package_version,
                           binary=True)
    else:
        repomgr.search_pkg(args.repository, args.package_name, pkg_version=args.package_version,
                           binary=False)


def _handleRemoveRope(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    repomgr.remove_repo(args.repository)


def _handleList(_args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    repomgr.list()


def _handleListPkgs(args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    repomgr.list_pkgs(args.repository)


def _handleClean(_args):
    repomgr = RepoMgr('aptly', REPOMGR_URL, '/tmp', REPOMGR_ORIGIN, applogger)
    repomgr.clean()


def subcmd_download(subparsers):
    download_parser = subparsers.add_parser('download',
                                            help='Download specified packages and deploy them '
                                                 'through a new build repository.\n\n')
    download_parser.add_argument('--repository', '-r', help='Name of the local repository', required=False,
                                 default='deb-local-down')
    download_parser.add_argument('--deb_list', help='Binary package list file', required=False, default='')
    download_parser.add_argument('--dsc_list', help='Source package list file', required=False, default='')
    download_parser.add_argument('--basedir', help='Temporary folder to store packages', required=False,
                                 default='/tmp/repomgr')
    download_parser.add_argument('--sources_list', help='Upstream sources list file.', required=False,
                                 default='')
    download_parser.add_argument('--no-clear', help='Not remove temporary files', action='store_true')
    download_parser.set_defaults(handle=_handleDownload)


def subcmd_sync(subparsers):
    sync_parser = subparsers.add_parser('sync',
                                        help='Sync a set of repositories with specified package'
                                             'lists.\n\n')
    sync_parser.add_argument('--repository', '-r', help='Name of the local repository', required=False,
                             default='deb-local-sync')
    sync_parser.add_argument('--repo_list', '-l', help='a set of local repos', required=False,
                             default='')
    sync_parser.add_argument('--deb_list', help='Binary package list file', required=False,
                             default='')
    sync_parser.add_argument('--dsc_list', help='Source package list file', required=False,
                             default='')
    sync_parser.add_argument('--basedir', help='Temporary folder to store packages', required=False,
                             default='/tmp/repomgr')
    sync_parser.add_argument('--sources_list', help='Upstream sources list file', required=False,
                             default='')
    sync_parser.add_argument('--no-clear', help='Not remove temporary files', action='store_true')
    sync_parser.set_defaults(handle=_handleSync)


def subcmd_mirror(subparsers):
    mirror_parser = subparsers.add_parser('mirror',
                                          help='Construct a mirror based on a remote'
                                               'repository.\n\n')
    mirror_parser.add_argument('--repository', '-r', help='Name of the remote repository', required=False,
                               default='deb-remote-tmp')
    mirror_parser.add_argument('--url', help='URL of remote repository', required=False,
                               default='http://nginx.org/packages/debian/')
    mirror_parser.add_argument('--distribution', '-d', help='distribution name', required=False,
                               default='buster')
    mirror_parser.add_argument('--component', '-c', help='component name', required=False,
                               default='nginx')
    mirror_parser.add_argument('--architectures', '-a', help='architectures', required=False,
                               default='amd64')
    mirror_parser.add_argument('--with-sources', '-s', help='include source packages',
                               action='store_true')
    mirror_parser.set_defaults(handle=_handleMirror)


def subcmd_merge(subparsers):
    merge_parser = subparsers.add_parser('merge',
                                         help='Merge several repositories into a new publication.\n\n')
    merge_parser.add_argument('--name', '-n', help='Name of the new merged publication', required=True)
    merge_parser.add_argument('--repo_list', '-l', help='a set of repos, seperate by comma', required=True)
    merge_parser.set_defaults(handle=_handleMerge)

def subcmd_copy_pkg(subparsers):
    copy_pkg_parser = subparsers.add_parser('copy_pkg',
                                         help='Copy specified packages from source repository into destination one.\n\n')
    copy_pkg_parser.add_argument('--source', '-s', help='Name of the source repository', required=True)
    copy_pkg_parser.add_argument('--destination', '-d', help='Name of the destination repository, must be a local repo', required=True)
    copy_pkg_parser.add_argument('--package_name', '-p', help='Name of the package(s) to be copied, separate by comma', required=True)
    copy_pkg_parser.add_argument('--package_type', '-t', help='Package type, "binary" or "source"', required=False, default='binary')
    copy_pkg_parser.set_defaults(handle=_handleCopyPkg)

def main():
    # command line arguments
    parser = argparse.ArgumentParser(add_help=True,
                                     description='Repository management Tool',
                                     epilog='''Tips: Use %(prog)s --help to get help for all of '
                                            'parameters\n\n''')
    subparsers = parser.add_subparsers(title='Repo control Commands:',
                                       help='sub-command for repo-ctl\n\n')

    # Three functions for three sub commands: pylint checking(too-many-statements)
    subcmd_download(subparsers)
    subcmd_sync(subparsers)
    subcmd_mirror(subparsers)
    subcmd_merge(subparsers)
    subcmd_copy_pkg(subparsers)

    clean_parser = subparsers.add_parser('clean', help='Clear all aptly repos.\n\n')
    clean_parser.set_defaults(handle=_handleClean)

    remove_repo_parser = subparsers.add_parser('remove_repo',
                                               help='Remove a specific repository.\n\n')
    remove_repo_parser.add_argument('--repository', '-r',
                                    help='Name of the repo to be removed')
    remove_repo_parser.set_defaults(handle=_handleRemoveRope)

    upload_pkg_parser = subparsers.add_parser('upload_pkg',
                                              help='Upload a Debian package into a specific '
                                                   'repository.\n\n')
    upload_pkg_parser.add_argument('--package', '-p',
                                   help='Debian package to be uploaded.', required=False)
    upload_pkg_parser.add_argument('--repository', '-r',
                                   help='Repository used to deploy this package.')
    upload_pkg_parser.set_defaults(handle=_handleUploadPkg)

    delete_pkg_parser = subparsers.add_parser('delete_pkg',
                                              help='Delete a specified Debian package from a '
                                                   'specified repository.\n\n')
    delete_pkg_parser.add_argument('--package_name', '-p', help='Package name to be deleted.')
    delete_pkg_parser.add_argument('--package_type', '-t',
                                   help='Package type to be deleted, "binary" or "source".')
    delete_pkg_parser.add_argument('--package_version', '-v',
                                   help='Version number of the package.', required=False)
    delete_pkg_parser.add_argument('--repository', '-r', help='Local Repository to delete the '
                                   'package from.')
    delete_pkg_parser.set_defaults(handle=_handleDeletePkg)

    search_pkg_parser = subparsers.add_parser('search_pkg',
                                              help='Search a specified package from a specified '
                                                   'repository.\n\n')
    search_pkg_parser.add_argument('--package_name', '-p', help='package to be looking for.')
    search_pkg_parser.add_argument('--package_version', '-v', help='The version of the package.',
                                   required=False)
    search_pkg_parser.add_argument('--repository', '-r',
                                   help='The Repository to search the package in.')
    search_pkg_parser.add_argument('--package_type', '-t', help='binary or source',
                                   required=False)
    search_pkg_parser.set_defaults(handle=_handleSearchPkg)

    list_parser = subparsers.add_parser('list',
                                        help='List all aptly repos, including local repo and '
                                             'remote mirror.\n\n')
    list_parser.set_defaults(handle=_handleList)

    list_pkgs_parser = subparsers.add_parser('list_pkgs',
                                        help='List contents of a specific repo.\n\n')
    list_pkgs_parser.add_argument('--repository', '-r',
                                  help='Name of the repo to be listed')
    list_pkgs_parser.set_defaults(handle=_handleListPkgs)

    args = parser.parse_args()

    if hasattr(args, 'handle'):
        args.handle(args)
    else:
        parser.print_help()


if __name__ == '__main__':
    main()