#!/usr/bin/python3

import argparse
import sys
import os
import termios
import tty
from select import select
import pwd
import nis
import time
import re
from shutil import copy2
from email.utils import formatdate
from enum import Enum

__version__ = '2.202101'
__dhlib__ = '/usr/share/debhelper/dh_make'
policy_version = '4.6.0'


def check_dhlib_path():
    if not os.path.isdir(__dhlib__):
        print('dh_make directory {} doesn\'t exist'.format(__dhlib__))
        exit(1)


def make_subs_func(subs_dict):
    '''
    Create a translation closure
    '''
    def prepare_key(k):
        return re.escape('#'+k+'#')

    rx = re.compile('|'.join(map(prepare_key, subs_dict)))

    def one_xlat(match):
        return subs_dict[match.group(0).replace('#', '')]

    def subs_func(text):
        return rx.sub(one_xlat, text)
    return subs_func


def process_file(args, subs_func, infile, outfile):
    '''
    Process a single file infile is the template, outfile is
    the destination. rx is a compilied regular expresssion
    '''
    outfile2 = str(outfile).rsplit('.ex', 1)[0]
    if args.overlay is None and args.addmissing and (
            os.path.isfile(outfile) or os.path.isfile(outfile2)):
        print('File {} exists, skipping\n'.format(outfile))
        return

    try:
        with open(infile, 'r') as inf, open(outfile, 'w') as outf:
            for line in inf:
                outf.write(subs_func(line))
    except OSError as e:
        print('Unable to open file {} for reading: {}'.
              format(infile, e.strerror))


def process_dhlib(args, subs_func, subdir, destdir=''):
    '''
    Recursively find all template files in the specified DHLIB directory
    and process them into our debian directory
    '''
    for f in os.listdir(os.path.join(__dhlib__, subdir)):
        file = os.path.join(__dhlib__, subdir, f)

        if os.path.isdir(file):
            process_dhlib(args, subs_func, os.path.join(subdir, f), f)
        else:
            process_file(args, subs_func, file, os.path.join(destdir, f))


def process_dir(args, subs_func, adir, destdir=''):
    '''
    Recursively find all templates in custom directory
    and process them into our debian directory
    '''
    for f in os.listdir(adir):
        file = os.path.join(adir, f)
        dest = os.path.join(destdir, f)
        if os.path.isdir(file):
            os.mkdir(dest, 0o755)
            process_dir(args, subs_func, file, dest)
        else:
            process_file(args, subs_func, file, dest)


def process_copyright(args, subs_func):
    '''
    Find the relevant copyright file and copy to our debian directory
    '''
    copyright_template = None
    if args.license == License.custom:
        copyright_template = os.path.realpath(args.copyrightfile)
    else:
        copyright_template = os.path.join(
            __dhlib__, 'licenses', args.license.name)

    if (os.path.isfile(copyright_template)):
        process_file(args, subs_func, copyright_template, 'copyright')
    else:
        print('Unable to find copyright template file {}'.
              format(copyright_template))
        exit(1)


def process_docs(python, docs_package, package_name):
    '''
    Find all documents and put the into the debian/docs
    or debian/package.docs file for dh_installdocs
    also append document stuff to control if required
    '''
    ignore_files = ('CMakeList.txt', 'CMakeLists.txt')
    docfiles = []

    if python:
        filename = 'python-{}-doc.docs'.format(package_name)
    elif docs_package:
        filename = '{}.docs'.format(package_name)
    else:
        filename = '{}-docs.docs'.format(package_name)

    if os.path.isfile(filename):
        print('debian/{} file already exists, skipping.\n'.format(filename))
        return

    file_re = re.compile(r'(^news|faq|\.md$|\.txt$|^readme|\.readme$'
                         r'|^bugs|todo|\.html$|\.pdf$)',
                         re.I)

    for docfile in os.listdir('.'):
        if file_re.search(docfile) and docfile not in ignore_files:
            docfiles.append(docfile)

    if docfiles != []:
        with open(filename, 'w') as outf:
            for docfile in docfiles:
                outf.write(docfile+'\n')

    # Append the document package
    if docs_package:
        with open('control', 'a')as f:
            f.write('''

Package: {0}-doc
Architecture: all
Description: documentation for {0}
 <insert long description, indented with spaces>
'''.format(package_name))


def process_infos(python, docs_package, package_name):
    '''
    Find all the info documents and put into debian/PACKAGE.info
    or debian/PACKAGE-doc.info file for dh_installinfo
    '''
    infos = []

    if python:
        filename = 'python-{}-doc.info'.format(package_name)
    elif docs_package:
        filename = '{}.info'.format(package_name)
    else:
        filename = '{}-docs.info'.format(package_name)

    if os.path.isfile(filename):
        print('debian/{} already exists, skipping.\n'.format(filename))
        return

    file_re = re.compile(r'\.info(-[0-9]+)?')
    for root, subdirs, files in os.walk('.'):
        for f in files:
            if file_re.search(f):
                infos.append(os.path.join(root, f))

    if infos != []:
        with open(filename, 'w') as outf:
            for info in infos:
                outf.write(info+'\n')


def rename_package_files(package_name):
    '''
    Any files in the /debian/ directory that are named
    package.* will be renamed with the real package name
    '''
    for oldname in os.listdir('.'):
        if oldname.startswith('package'):
            newname = oldname.replace('package', package_name)
            if os.path.isfile(newname):
                print('File {} already exists, skipping.\n'.format(newname))
            else:
                os.rename(oldname, newname)


def get_subs(args):
    '''
    Get the initial set of subsition variables
    '''
    subs = {
            'PACKAGE': '',
            'UCPACKAGE': '',
            'VERSION': '',
            'DASHLINE': '',
            'EMAIL': get_email(args.email),
            'DATE': formatdate(None, True),
            'SHORTDATE': time.strftime('%B %e %Y'),
            'YEAR': time.strftime('%Y'),
            'USERNAME': get_username(),
            'POLICY': policy_version,
            'BUILD_DEPS': ['debhelper-compat (= 13)'],
            'DH_ADDON': '',
            'SOURCE_EXTRADOCS': '',
            'RULES_START_TEXT': '',
            'RULES_END_TEXT': '',
           }
    return subs


class PackageClass(Enum):
    indep = 'i'
    library = 'l'
    single = 's'
    python = 'p'
    defaultless = 'defaultless'

    @classmethod
    def from_args(cls, args):
        """
        Return the PackageClass parsed from command line arguments
        """
        if args.defaultless:
            return cls.defaultless
        elif args.packageclass is not None:
            return cls(args.packageclass)
        elif args.indep:
            return cls.indep
        elif args.library:
            return cls.library
        elif args.python:
            return cls.python
        elif args.single:
            return cls.single
        return None


class License(Enum):
    """
    Class to hold and control the licenses
    """
    apache = 'apache'
    artistic = 'artistic'
    bsd = 'bsd'
    gpl2 = 'gpl2'
    gpl3 = 'gpl3'
    isc = 'isc'
    lgpl2 = 'lgpl2'
    lgpl3 = 'lgpl3'
    mit = 'mit'
    custom = 'c'
    blank = ''

    @classmethod
    def from_args(cls, args):
        """
        Return the right license given the command line arguments
        """
        matches = {'apache': cls.apache, 'artistic': cls.artistic,
                   'bsd': cls.bsd, 'gpl': cls.gpl2, 'gpl2': cls.gpl2,
                   'gpl3': cls.gpl3, 'isc': cls.isc, 'lgpl': cls.lgpl2,
                   'lgpl2': cls.lgpl2, 'lgpl3': cls.lgpl3, 'mit': cls.mit}
        if args.copyright == 'custom':
            if args.copyrightfile is None:
                sys.stderr.write(
                    'Copyright type "custom" requires --copyrightfile'
                    'option used.\n')
                exit(1)
            return cls.custom
        if args.copyrightfile is not None:
            sys.stderr.write('--copyrightfile only makes sense with custom'
                             'license.\n')
            exit(1)

        license = matches.get(args.copyright)
        if license is None:
            if args.native:
                license = cls.gpl3
            else:
                license = cls.blank
        return license


version_string = '''
dh_make version {}

Copyright (C) 1998-2020 Craig Small <csmall@debian.org>
Based on deb-make by Christoph Lameter <clameter@debian.org>.
Custom template support by Bruce Sass <bmsass@shaw.ca>.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
'''.format(__version__)
copyright_choices = ('apache', 'artistic', 'bsd', 'gpl', 'gpl2', 'gpl3',
                     'isc', 'lgpl', 'lgpl2', 'lgpl3', 'mit', 'custom')
parser = argparse.ArgumentParser(
        prog="dh_make",
        formatter_class=argparse.RawTextHelpFormatter,
        description="prepare Debian packaging from an original source archive")
parser.add_argument('-a', '--addmissing', action='store_true',
                    help='reprocess package and add missing files')
parser.add_argument('-c', '--copyright', metavar='<type>',
                    choices=copyright_choices,
                    help='use <type> of license in copyright file '
                    '(apache|artistic|bsd|gpl|gpl2|gpl3|isc|lgpl|lgpl2|'
                    'lgpl3|mit|custom)')

parser.add_argument('--copyrightfile', metavar='<file>',
                    help='Template to use for custom copyright')
parser.add_argument('-d', '--defaultless', action='store_true',
                    help='skip the default Debian and package class templates')
parser.add_argument('--docs', action='store_true',
                    help='create a separate docs package')
parser.add_argument('-e', '--email', metavar='<address>',
                    help='use <address> as the maintainer e-mail address')
parser.add_argument('-f', '--file', metavar='<file>',
                    help='use <file> as the original source archive')
parser.add_argument('-n', '--native', action='store_true',
                    help='the program is Debian native, don\'t generate .orig')
parser.add_argument('-o', '--overlay', metavar='<dir>',
                    help='reprocess package using templates in <dir>')
parser.add_argument('-p', '--packagename', metavar='<name>',
                    help='force package name to be <name>')
parser.add_argument('-t', '--templates', metavar='<dir>',
                    help='apply customizing templates from <dir>')
parser.add_argument('-y', '--yes', action='store_true',
                    help='automatic yes to prompts and run non-interactively')
parser.add_argument('--createorig', action='store_true',
                    help='create orig.tar.xz file')
parser.add_argument('--with-emacs', action='store_true',
                    help='add files for emacsen')
pcgroup = parser.add_mutually_exclusive_group()
pcgroup.add_argument('-C', '--packageclass', metavar='<cls>',
                     choices=('s', 'i', 'l', 'p'),
                     help='set package class (s|i|l|p)')
pcgroup.add_argument('-s', '--single', action='store_true',
                     help='set package class to single')
pcgroup.add_argument('-i', '--indep', action='store_true',
                     help='set package class to arch-independent')
pcgroup.add_argument('-l', '--library', action='store_true',
                     help='set package class to library')
pcgroup.add_argument('--python', action='store_true',
                     help='set package class to python')

parser.add_argument('-v', '--version', action='version',
                    version=version_string)


def getch():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(sys.stdin.fileno())
        [i, o, e] = select([sys.stdin.fileno()], [], [], 5)
        if i:
            ch = sys.stdin.read(1)
        else:
            ch = ''
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    return ch


def get_logname():
    """
    Return current users login name
    """
    if 'LOGNAME' in os.environ:
        return os.environ['LOGNAME']
    elif 'USER' in os.environ:
        return os.environ['USER']
    else:
        sys.stderr.write('Cannot get username; neither LOGNAME nor USER is set'
                         'in the environment!\n')
        exit(1)


def get_username():

    username = os.environ.get('DEBFULLNAME')
    if username:
        return username

    logname = get_logname()
    if logname:
        username = pwd.getpwnam(logname).pw_gecos.rsplit(',')[0]
        if username:
            return username

    # NIS/ypmatch
    try:
        username = nis.match(logname, 'passwd.byname').split(':')[4]
        if username:
            return username
    except nis.error:
        pass

    # TODO ldap?

    # all failed
    return 'unknown'


def get_email(args_email):
    """
    Attempt to get user's email from various methods
    """
    if args_email is not None:
        return args_email
    elif 'DEBEMAIL' in os.environ:
        return os.environ['DEBEMAIL']
    elif 'EMAIL' in os.environ:
        return os.environ['EMAIL']

    # TODO ldapsearch

    logname = get_logname()

    try:
        with open('/etc/mailname', 'r') as f:
            mailhost = f.read().rstrip()
    except IOError:
        mailhost = 'unknown'
    return '{}@{}'.format(logname, mailhost)


def get_package(args, subs):
    """
    Determine the package name and versions
    """
    package_name = None
    package_version = None
    cwd = os.getcwd()

    # Split out the version and name
    if args.packagename is not None:
        match = re.match(r'(.*)_([0-9][0-9a-zA-Z+.~-]*)$',
                         args.packagename)
        if match is not None:
            package_name = match.group(1)
            package_version = match.group(2)
        else:
            match = re.match(r'(.*)_(.*)', args.packagename)
            if match is not None:
                print('''
The directory name you have specified is invalid!
It seems the <packagename>_<version> format was attempted,
since underscores are illegal in both package-name and version.
Make sure that the version starts with a digit and contains only
digits, lower and uppercase letters, dashes, or the signs plus, dot, tilde.

Your current directory is:
{}
Perhaps you could try going to directory where the sources are?

Please note that this change is necessary ONLY during the initial
Debianization with dh_make.  When building the package, dpkg-source
will gracefully handle almost any upstream tarball.
'''.format(cwd))
                exit(1)
            else:
                package_name = args.packagename

    cwd_match = re.match(r'.*/(.*)-([0-9][0-9a-zA-Z+.~-]*)$', cwd)
    if cwd_match is not None:
        if package_name is None:
            package_name = cwd_match.group(1)
        if package_version is None:
            package_version = cwd_match.group(2)

    # Validate names
    if package_name is not None:
        match = re.match(r'^[a-z0-9+.-]+$', package_name)
        if match is None:
            print('''
Package name "{}" is not in a valid format.
Debian policy manual states:
   "Package names must only consist of lower case letters, digits (0-9),
    plus (+) or minus (-) signs, and periods (.)"
'''.format(package_name))
            exit(1)

        match = re.match(r'^[a-z0-9+.-]$', package_name)
        if match is not None:
            print('''
Package name "{}" is not in a valid format.
You cannot create single-letter package names.
'''.format(package_name))
            exit(1)

    if package_name is not None and package_version is not None:
        subs['PACKAGE'] = package_name
        subs['UCPACKAGE'] = package_name.capitalize()
        subs['VERSION'] = package_version
        subs['DASHLINE'] = '-' * len(package_name + 'for Debian')
        return

    print('''
For dh_make to find the package name and version, the current directory
needs to be in the format of <package>-<version>.  Alternatively use the
-p flag using the format <name>_<version> to override it.
The directory name you have specified is invalid!

Your current directory is:
{}
Perhaps you could try going to directory where the sources are?

Please note that this change is necessary ONLY during the initial
Debianization with dh_make.  When building the package, dpkg-source
will gracefully handle almost any upstream tarball.
            '''.format(cwd))
    exit(1)


def confirm_fields(args, subs):
    """
    Print the fields we will be using and get confirmation
    from the user this is correct
    """
    vals = {'Maintainer Name': subs['USERNAME'],
            'Email-Address': subs['EMAIL'],
            'Date': subs['DATE'],
            'Package Name': subs['PACKAGE'],
            'Version': subs['VERSION'],
            'License': args.license.name,
            'Package Type': args.package_class.name,
            }
    valid = {
        '\r': True, '\n': True,
        'y': True, 'yes': True,
        'n': False, 'no': False
    }
    for f, v in vals.items():
        print("{0:<20}: {1}".format(f, v))

    if args.yes:
        return True
    print('Are the details correct? [Y/n/q]')
    while True:
        choice = getch()
        if choice == 'q':
            print('Quit')
            exit(0)
        if choice in valid:
            return valid[choice]
        print('Please respond with "yes", "no" or "quit" (or "y", "n" or "q")')


def choose_package_class(old_package_class):
    """
    If there has not been a package class chosen on command line prompt
    the user to choose one
    """
    valid = {'s': PackageClass.single, 'i': PackageClass.indep,
             'l': PackageClass.library, 'p': PackageClass.python}
    while True:
        print('Type of package: (single, indep, library, python)\n'
              '[s/i/l/p]?')
        if old_package_class is not None:
            print('Hit enter for default: {}'.
                  format(old_package_class.name))
        choice = getch()
        if choice == '\n' and old_package_class is not None:
            return old_package_class
        if choice in valid:
            return valid[choice]
        print('Please respond with one of the following: s,i,l,p')


def parse_args():
    """
    Parse the arguments given to us by the user on the command line
    """
    args = parser.parse_args()

    if args.overlay is not None:
        args.addmissing = True
        args.defaultless = True
        args.templates = args.overlay

    # Sanity checking
    if not os.path.isdir('debian'):
        if args.overlay:
            print('--overlay flag used but cannot find debian subdirectory.')
            exit(1)
        if args.addmissing:
            print('--addmissing flag used but cannot find debian subdirectory')
            exit(1)

    args.package_class = PackageClass.from_args(args)
    args.license = License.from_args(args)
    return args


def check_origtar(source_file, create_orig, package_name, package_version):
    """
    Check for the orig.tar.* file, this can be satisfied by:
      specified with --file and found
      finding it in the .. directory
      created with --createorig

    Create the *.orig.tar.* file, if required
    """
    orig_suffixes = ('gz', 'bz2', 'lzma', 'xz')

    # Does the file specified by user exist?
    if source_file is not None:
        if os.path.exists(source_file):
            source_ext = os.path.splitext(source_file)[1][1:]
            if source_ext not in orig_suffixes:
                print('Source file {} has an unknown suffix "{}"'.
                      format(source_file, source_ext))
                exit(1)
            dest_file = '../{}_{}.orig.tar.{}'.\
                format(package_name, package_version, source_ext)
            copy2(source_file, dest_file)
            return
        else:
            print('Source archive you specified ( {} ) was not found!'.
                  format(source_file))
            exit(1)

    # Try to find the file in the .. directory
    for suff in orig_suffixes:
        filename = '../{}_{}.orig.tar.{}'.format(
                package_name, package_version, suff)
        if os.path.exists(filename):
            print('Skipping creating {} because it already exists'.
                  format(filename))
            return

    # Can we create the file?
    if create_orig:
        os.system('tar cfJ ../{}_{}.orig.tar.xz .'.
                  format(package_name, package_version))
        return

    # We failed :(
    print('''
Could not find {}_{}.orig.tar.xz
Either specify an alternate file to use with -f,
or add --createorig to create one.'''.
          format(package_name, package_version))
    exit(1)


def setup_python(subs):
    '''
    Setup a python package
    '''
    subs['RULES_START_TEXT'] = 'export PYBUILD_NAME={}\n'.format(
        subs['PACKAGE'])
    subs['RULES_END_TEXT'] = '''
# If you need to rebuild the Sphinx documentation
# Add sphinxdoc to the dh --with line
#
# And uncomment the following lines
#override_dh_auto_build: export http_proxy=127.0.0.1:9
#override_dh_auto_build: export https_proxy=127.0.0.1:9
#override_dh_auto_build:
#\tdh_auto_build
#\tPYTHONPATH=. python3 -m sphinx -N -bhtml \\
#\tdocs/ build/html # HTML generator
#\tPYTHONPATH=. python3 -m sphinx -N -bman \\
#\tdocs/ build/man # Manpage generator'''
    subs['DH_ADDON'] += ' --with python3'\
        ' --buildsystem=pybuild'
    subs['BUILD_DEPS'].extend([
        'dh-python',
        'python3-setuptools',
        'python3-all',
    ])


def setup_autotools(subs):
    '''
    Setup a package that uses autotools
    '''
    subs['BUILD_DEPS'].append('autotools-dev')


def setup_cmake(subs):
    '''
    Setup a package that uses cmake
    '''
    subs['BUILD_DEPS'].append('cmake')


def setup_make():
    '''
    Setup package that uses a makefile
    '''
    if not os.path.isfile('Makefile') and \
            not os.path.isfile('makefile') and \
            not os.path.isfile('GNUmakefile'):
        print('Currently there is not top level Makefile. This may '
              'require additional tuning')


def output_source_format(args):
    '''
    Write the debian/source/format file
    '''
    outfile = 'source/format'

    if args.overlay is None and not args.addmissing and \
            os.path.isfile(outfile):
        print('File {} exists, skipping\n'.format(outfile))
        return

    if not os.path.isdir('source'):
        try:
            os.mkdir('source', 0o755)
        except OSError as e:
            print('Unable to make debian/source subdirectory: {}'.
                  format(e.strerror))
            exit(1)

    try:
        with open(outfile, 'w') as f:
            if args.native:
                f.write('3.0 (native)\n')
            else:
                f.write('3.0 (quilt)\n')
    except Exception as e:
        print('Unable to write source file {} for writing: {}'.
              format(outfile, e.strerror))
        exit(1)


def do_debianize(args, subs):
    """
    Actually make a Debian package out of the source files
    """
    if not args.native:
        check_origtar(args.file, args.createorig,
                      subs['PACKAGE'], subs['VERSION'])

    if args.package_class == PackageClass.python:
        print('pth')
        setup_python(subs)
    else:
        subs['RULES_START_TEXT'] = '''
# see FEATURE AREAS in dpkg-buildflags(1)
#export DEB_BUILD_MAINT_OPTIONS = hardening=+all

# see ENVIRONMENT in dpkg-buildflags(1)
# package maintainers to append CFLAGS
#export DEB_CFLAGS_MAINT_APPEND  = -Wall -pedantic
# package maintainers to append LDFLAGS
#export DEB_LDFLAGS_MAINT_APPEND = -Wl,--as-needed

'''
        subs['RULES_END_TEXT'] = '''
# dh_make generated override targets
# This is example for Cmake (See https://bugs.debian.org/641051 )
#override_dh_auto_configure:
#\tdh_auto_configure -- \\
#\t-DCMAKE_LIBRARY_PATH=$(DEB_HOST_MULTIARCH)'''
        if os.path.isfile('./configure') and os.access('./configure', os.X_OK):
            setup_autotools(subs)
        elif os.path.isfile('CmakeLists.txt'):
            setup_cmake(subs)
        else:
            setup_make()

    # Create debian directory
    if args.addmissing is False:
        if os.path.isdir('debian'):
            print('You already have a debian/ subdirectory in the source'
                  'tree.\ndh_make will not try to overwrite anything.')
            exit(1)
        try:
            os.mkdir('debian', 0o755)
        except OSError as e:
            print('Unable to make debian subdirectory: {}\n'.format(
                e.strerror))
            exit(1)
    try:
        os.chdir('debian')
    except OSError as e:
        print('Unable to change to debian subdirectory: {}\n'.format(
            e.strerror))
        exit(1)

    # Translate the lists to strings
    subs['BUILD_DEPS'] = ', '.join(subs['BUILD_DEPS'])
    subs_func = make_subs_func(subs)

    if not args.defaultless:
        output_source_format(args)

        process_dhlib(args, subs_func, 'debian')
        process_copyright(args, subs_func)

        # native packages don't have a watch file #806672
        if args.native:
            os.unlink('watch.ex')

        # Files specific to package classes
        process_dhlib(args, subs_func, 'debian' + args.package_class.value)

        if args.with_emacs:
            process_dhlib(args, subs_func, 'emacs')

        if args.native:
            process_dhlib(args, subs_func, 'native')

    # Custom templates
    if args.templates is not None:
        if not os.path.isdir(args.templates):
            print('Cannot find customization directory, {}'.
                  format(args.templates))
            exit(1)
        process_dir(args, subs_func, args.templates)

    process_docs(args.python, args.docs, subs['PACKAGE'])
    process_infos(args.python, args.docs, subs['PACKAGE'])

    rename_package_files(subs['PACKAGE'])

    if os.path.exists('rules'):
        os.chmod('rules', 0o755)

    print('Done. Please edit the files in the debian/ subdirectory now.\n')
    if args.package_class == PackageClass.library:
        print('''
Make sure you edit debian/control and change the Package: lines from
{0}BROKEN to something else, such as {0}1\n'''.format(subs['PACKAGE']))


def main():
    """
    Main function of the script
    """

    check_dhlib_path()
    args = parse_args()
    subs = get_subs(args)
    get_package(args, subs)

    # Create line of dashes
    first = True
    while True:
        if not args.defaultless and \
                (not first or args.package_class is None):
            args.package_class = choose_package_class(args.package_class)

        if confirm_fields(args, subs):
            do_debianize(args, subs)
            break
        first = False


if __name__ == '__main__':
    main()
