#!/usr/pkg/bin/python3.12
"""A utility to create and manage party keyrings."""

# vim:tw=80:ai:tabstop=4:expandtab:shiftwidth=4

#
# Copyright (c) 2011 - present Phil Dibowitz (phil@ipom.com)
#
#   This program is free software; you can redistribute it and/or
#   modify it under the terms of the GNU General Public License as
#   published by the Free Software Foundation, version 2.
#

import email
import mailbox
import optparse
import os
import re
import shutil
import subprocess
import sys

from libpius.util import PiusUtil as util
from libpius.util import MyOption as piusopt
from libpius import mailer as pmailer
from libpius.constants import (
    VERSION,
    GPG_BASE_OPTS,
    GPG_QUIET_OPTS,
    GPG_FD_OPTS,
)

BADKEYS_RE = re.compile(r"00000000|12345678|no pgp key")
LIST_SEP_RE = re.compile(r"\s*,\s*")
DEFAULT_KEYSERVERS = [
    "pool.sks-keyservers.net",
    "pgp.mit.edu",
    "keys.gnupg.net",
]
DEFAULT_GPG_PATH = "/usr/pkg/bin/gpg"
DEFAULT_CSV_DELIMITER = ","
DEFAULT_CSV_NAME_FIELD = 2
DEFAULT_CSV_EMAIL_FIELD = 3
DEFAULT_CSV_FP_FIELD = 4
DEFAULT_TMP_DIR = "/tmp/pius_keyring_mgr_tmp"

DEFAULT_EMAIL_TEXT = """Dear %(name)s,

You signed up for the %(party)sPGP Keysigning Party with the following key:
  %(fp)s

However, I have not been able to find your key. I have tried the following
keyservers:
%(keyservers)s

Please upload your key to one of the aforementioned keyservers. You can do
this simply with:

  gpg --keyserver %(keyserver)s --send-key KEYID

Where 'KEYID' is the keyid of your PGP key. For more information see this site:
  http://www.phildev.net/pgp/

Your key will be searched for again in 24-48 hours and if your key is not there,
you will receive another email.

You do not need to contact me if you upload your key. If you have questions you
may email %(from)s.

Generated by PIUS Keyring Manager (http://www.phildev.net/pius/).
"""


def print_default_email():
    """Print the default email that is sent out."""
    interpolation_dict = {
        "name": "<name>",
        "email": "<email>",
        "from": "<your_email>",
        "party": "<party_name> ",
        "keyserver": "<example_keyserver>",
        "keyservers": "<keyserver_list>",
        "fp": "<fingerprint>",
    }
    print("DEFAULT EMAIL TEXT:\n")
    print(DEFAULT_EMAIL_TEXT % interpolation_dict)


def keyid_from_fp(fp):
    """Given a fingerprint without whitespace, returns keyid."""
    return fp[24:40]


class PiusParser:
    @classmethod
    def parse_csv(
        self,
        filename,
        sep,
        name_field,
        email_field,
        fp_field,
        ignore_emails,
        ignore_fps,
    ):
        """Parse a CSV for name, email, fingerprint, and generate keyid."""
        fp_field = fp_field - 1
        name_field = name_field - 1
        email_field = email_field - 1

        ignore_email_list = LIST_SEP_RE.split(ignore_emails)
        ignore_fp_list = LIST_SEP_RE.split(ignore_fps)
        report = open(filename, "r")
        keys = []
        for line in report:
            line = line.strip()
            # skip empty lines
            if not line:
                continue
            parts = line.split(sep)
            if BADKEYS_RE.search(parts[fp_field]):
                continue
            fp = parts[fp_field].replace(" ", "")
            if (
                parts[fp_field] in ignore_fp_list
                or parts[email_field] in ignore_email_list
            ):
                util.debug('Ignoring "%s" at user request' % line)
                continue
            keyid = keyid_from_fp(fp)
            keys.append(
                {
                    "name": parts[name_field],
                    "email": parts[email_field],
                    "keyid": keyid,
                    "fingerprint": fp,
                }
            )
        print("Found %s keys in file." % len(keys))
        return keys

    @classmethod
    def parse_flatfile(self, filename):
        with open(filename, "r") as fd:
            contents = fd.read()
        matches = self.FP_RE.findall(contents)
        keys = []
        for match in matches:
            flatfp = self.FIXFP_RE.sub("", match)
            keyid = flatfp[-8:]
            keys.append(
                {
                    "keyid": keyid,
                    "fingerprint": flatfp,
                    "name": None,
                    "email": None,
                }
            )
        print("Found %s keys in file." % len(keys))
        return keys

    @classmethod
    def parse_mbox(self, filename):
        """Parse an mbox for name, email, fingerprints and keys.

    Note that in the even of a fingerprint, keyid is generated, otherwise
    just the ASCII-armored key is stored."""
        box = mailbox.mbox(filename)
        keys = []
        num_fps = num_keys = 0
        for msg in box:
            m = email.parser.Parser()
            p = m.parsestr(msg.as_string())
            uid = p.get("From")
            name = None
            mail = None
            if uid:
                match = self.UID_RE.search(uid)
                if match:
                    name = match.group(1)
                    mail = match.group(2)
                    name = self.FIXNAME1_RE.sub("", name)
                    name = self.FIXNAME2_RE.sub("", name)
            for part in msg.walk():
                # if decoded returns None, we're in multipart messages, or other
                # non-convertable-to-text data, so we can move on. If it's multipart
                # then we'll get to the sub-parts on further iterations of walk()
                decoded = part.get_payload(None, True)
                if not decoded:
                    util.debug("Skipping non-decodable part")
                    continue
                decoded = decoded.decode("utf8")
                data = {"name": name, "email": mail}
                matches = self.KEY_RE.findall(decoded)
                if matches:
                    for match in matches:
                        num_keys = num_keys + 1
                        tmp = data.copy()
                        tmp["key"] = match
                        keys.append(tmp)
                    continue
                matches = self.FP_RE.findall(decoded)
                if matches:
                    for match in matches:
                        num_fps = num_fps + 1
                        fp = self.FIXFP_RE.sub("", match)
                        keyid = keyid_from_fp(fp)
                        tmp = data.copy()
                        tmp.update({"fingerprint": fp, "keyid": keyid})
                        keys.append(tmp)
                        fp = "wonk"
        print(
            "Found %s keys in mbox: %s fingerprints and %s full keys"
            % (len(keys), num_fps, num_keys)
        )
        return keys


class KeyringBuilder:
    """A class for building and managing keyrings."""

    AUTO_OPTS = GPG_FD_OPTS + [
        "--command-fd", "0",
        "--status-fd", "1",
        "--no-options",
        "--with-colons",
    ]

    def __init__(self, gpg_path, keyring, keyservers, tmp_dir):
        self.gpg = gpg_path
        if os.path.exists(keyring):
            self.keyring = keyring
            self.exported_keyring = None
        else:
            keyring_dir, keyring_file = os.path.split(keyring)
            self.keyring = os.path.join(keyring_dir, ".pius." + keyring_file)
            self.exported_keyring = keyring
        self.found = []
        self.notfound = []
        self.keyservers = keyservers
        self.tmp_dir = tmp_dir
        self.party = ""
        self.basecmd = [self.gpg] + GPG_BASE_OPTS + ["--keyring", self.keyring]

    def num_not_found(self):
        return len(self.notfound)

    #
    # BEGIN INTERNAL FUNCTIONS
    #
    def _tmpfile_path(self, tfile):
        """Internal function to take a filename and put it in self.tmp_dir."""
        return "%s/%s" % (self.tmp_dir, tfile)

    def _remove_file(self, tfile):
        if os.path.exists(tfile):
            os.unlink(tfile)

    def _printable_fingerprint(self, fp):
        """Given a whitespace-collapsed FP, print it in friendly format."""
        return "%s %s %s %s %s  %s %s %s %s %s" % (
            fp[0:4],
            fp[4:8],
            fp[8:12],
            fp[12:16],
            fp[16:20],
            fp[20:24],
            fp[24:28],
            fp[28:32],
            fp[32:36],
            fp[36:40],
        )

    def _import_key_file(self, kfile):
        """Given a keyfile, import it into our keyring."""
        extra_opts = GPG_QUIET_OPTS + self.AUTO_OPTS
        cmd = self.basecmd + extra_opts + ["--import", kfile]
        util.logcmd(cmd)
        gpg = subprocess.Popen(
            cmd,
            shell=False,
            stdin=None,
            close_fds=True,
            text=True,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
        )
        for line in gpg.stdout:
            parts = line.strip().split(" ")
            if parts[1] == "IMPORTED":
                print(
                    "Importing %s (%s)" % (parts[2][8:16], " ".join(parts[3:]))
                )

        gpg.wait()
        retval = gpg.returncode
        if retval != 0:
            return False
        return True

    def _write_and_import_key(self, key):
        """Write out key to a file and call _import_key_file() on it."""
        # FIXME
        filename = self._tmpfile_path("pius_keyring_mgr.tmp.txt")
        fh = open(filename, "w")
        fh.write(key["key"])
        fh.close()
        self._import_key_file(filename)
        self._remove_file(filename)

    def _print_list(self, keylist):
        """Helper function for print_report."""
        for key in keylist:
            print(
                "  %s <%s>\n    %s"
                % (
                    key["name"],
                    key["email"],
                    self._printable_fingerprint(key["fingerprint"]),
                )
            )

    def _get_email_body(self, keyinfo, mailer):
        kstext = "  " + "\n  ".join(self.keyservers)
        interp = {
            "name": keyinfo["name"],
            "email": keyinfo["email"],
            "from": mailer.from_addr,
            "fp": self._printable_fingerprint(keyinfo["fingerprint"]),
            "party": self.party,
            "keyservers": kstext,
            "keyserver": self.keyservers[0],
        }
        to = """%(name)s <%(email)s>""" % interp
        subject = (
            """%(party)sPGP Keysignign Party: Can't find your key!""" % interp
        )
        body = ""
        if mailer.mail_text():
            body = open(mailer.mail_text(), "r").read() % interp
        else:
            body = DEFAULT_EMAIL_TEXT % interp
        return (to, subject, body)

    def _send_email(self, mailer, keyinfo):
        to, subject, body = self._get_email_body(keyinfo, mailer)
        print("Sending mail to %s" % to)
        mailer.send_mail(to, subject, body)

    #
    # BEGIN PUBLIC FUNCTIONS
    #
    def have_key(self, key):
        cmd = self.basecmd + GPG_QUIET_OPTS + ["--fingerprint", key]
        gpg = subprocess.Popen(
            cmd,
            shell=False,
            stdin=None,
            close_fds=True,
            text=True,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
        )
        gpg.wait()
        retval = gpg.returncode
        if retval == 0:
            print("Already have %s" % key)
            return True
        return False

    def get_key(self, key):
        """Try to get key from any keyservers we know about."""
        basecmd = (
            self.basecmd + GPG_QUIET_OPTS + ["--keyserver-options", "timeout=2"]
        )

        found = False
        for ks in self.keyservers:
            cmd = basecmd + ["--keyserver", ks, "--recv-key", key]
            util.logcmd(cmd)
            gpg = subprocess.Popen(
                cmd,
                shell=False,
                stdin=None,
                close_fds=True,
                text=True,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
            )
            gpg.wait()
            retval = gpg.returncode
            if retval == 0:
                found = True
                print("Found %s (%s)" % (key, ks))
                break
        if not found:
            print("NOT Found %s" % key)

        return found

    def get_all_keys(self, keys):
        """Wrapper to call get_key() on all keys."""
        attempted_keyids = []
        for key in keys:
            if "keyid" in key:
                if key["keyid"] == "":
                    print(
                        "%s has an old-style key (%s)"
                        % (key["email"], key["fingerprint"])
                    )
                    continue
                if key["keyid"] in attempted_keyids:
                    util.debug("Skipping %s, already processed" % key["keyid"])
                    continue
                attempted_keyids.append(key["keyid"])
                # So as not to beat up the keyservers, check if we
                # already have a key
                if self.have_key(key["keyid"]):
                    continue
                if self.get_key(key["keyid"]):
                    self.found.append(key)
                else:
                    self.notfound.append(key)
            elif "key" in key:
                self._write_and_import_key(key)

    def print_report(self):
        """Print small report about what was and was not found."""
        print("KEYS FOUND:")
        self._print_list(self.found)
        print("KEYS NOT FOUND:")
        self._print_list(self.notfound)

    def send_emails(self, mailer, party):
        self.party = ""
        if party:
            self.party = "%s " % party
        for k in self.notfound:
            self._send_email(mailer, k)

    def _backup_keyring(self):
        return shutil.copy(self.keyring, "%s-pius-backup" % self.keyring)

    # stolen from pius
    def get_all_keyids(self, sort_keyring):
        """Given a keyring, get all the KeyIDs from it."""
        util.debug("extracting all keyids from keyring")
        extra_opts = GPG_QUIET_OPTS + self.AUTO_OPTS + ["--fixed-list-mode"]
        cmd = self.basecmd + extra_opts + ["--fingerprint"]
        util.logcmd(cmd)
        gpg = subprocess.Popen(
            cmd,
            shell=False,
            text=True,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
        )
        # We use 'pub' instead of 'fpr' to support old crufty keys too...
        pub_re = re.compile("^pub:")
        uid_re = re.compile("^uid:")
        key_tuples = []
        name = keyid = None
        for line in gpg.stdout.readlines():
            if pub_re.match(line):
                lineparts = line.split(":")
                keyid = lineparts[4][8:16]
            elif keyid and uid_re.match(line):
                lineparts = line.split(":")
                name = lineparts[9]
                util.debug("Got id %s for %s" % (keyid, name))
                key_tuples.append((name, keyid))
                name = keyid = None

        # sort the list
        if sort_keyring:
            return [i[1] for i in sorted(key_tuples)]
        return [i[1] for i in key_tuples]

    def export_keyring(self):
        """
        If we created a new keyring, it may not be in a suitable format for
        sharing.  So we go ahead and export it to the real filename which will
        force a shareable format. Once it exists, we'll continue to use it.
        """
        if self.exported_keyring is None:
            util.debug("Not exporting keyring, exported_keyring is None")
            return
        cmd = (
            self.basecmd
            + GPG_QUIET_OPTS
            + ["--export", "--output", self.exported_keyring]
        )
        util.logcmd(cmd)
        subprocess.call(cmd)
        # Remove the temp file
        os.remove(self.keyring)
        # And GPG's backup
        backup = self.keyring + "~"
        if os.path.exists(backup):
            os.remove(backup)

    def prune(self, sort_keyring):
        self._backup_keyring()
        keyids = self.get_all_keyids(sort_keyring)

        basecmd = self.basecmd + ["--fingerprint"]
        basedelcmd = (
            self.basecmd
            + GPG_QUIET_OPTS
            + self.AUTO_OPTS
            + ["--yes", "--delete-key"]
        )
        for fp in keyids:
            cmd = basecmd + [fp]
            gpg = subprocess.Popen(
                cmd, text=True, shell=False, stdout=subprocess.PIPE
            )
            for line in gpg.stdout:
                print(line.strip())
            ans = input(
                "Delete this key? ('yes' to delete, 'q' to quit"
                " anything to skip) "
            )
            if ans in ("q", "Q"):
                print("Dying at user request")
                sys.exit(1)
            if ans in ("yes", "y"):
                print("Deleting key ...")
                cmd = basedelcmd + [fp]
                util.logcmd(cmd)
                subprocess.call(cmd)
            print()

        backup = "%s-pius-backup" % self.keyring
        print("A backup file is in %s" % backup)

    def raw(self, args):
        cmd = self.basecmd + args
        util.logcmd(cmd)
        ret = subprocess.call(cmd, shell=False)


# END class KeyringBuilder


def check_options(parser, mode, options):
    """Check options for user error."""
    if mode == "help":
        parser.print_help()
        sys.exit(0)

    if not mode or mode not in ("build", "prune", "raw"):
        parser.error("Invalid or missing mode: %s" % mode)

    if options.debug:
        util.DEBUG_ON = True

    if not options.keyring:
        parser.error("Must specify a keyring")

    if mode == "build":
        if (
            not options.csv_file
            and not options.mbox_file
            and not options.flat_file
        ):
            parser.error("Build mode needs one of --csv-file or --mbox-file")

    if os.path.exists(options.tmp_dir) and not os.path.isdir(options.tmp_dir):
        parser.error(
            "%s exists but isn't a directory. It must not exist or be\n"
            "a directory." % options.tmp_dir
        )
    if not os.path.exists(options.tmp_dir):
        try:
            os.mkdir(options.tmp_dir, 0o700)
        except OSError as msg:
            parser.error(
                "%s was doesn't exist, and was unable to be created: %s"
                % (options.tmp_dir, msg)
            )


def main():
    usage = "%prog <mode> [options]"
    intro = """
%prog has several modes to help you manage keyrings. It is primarily designed
to help manage keysigning party rings, but can be used to manage any PGP
keyring. A mode must be the first argument. The options below are grouped by
their mode, and an explanation of modes is at the bottom.
"""

    outro = (
        """
Example: %s build --csv-file /tmp/report --mbox-file /tmp/mbox --mail
you@company.com
"""
        % sys.argv[0]
    )

    parser = optparse.OptionParser(
        usage=usage,
        description=intro,
        epilog=outro,
        version="%%prog %s" % VERSION,
        option_class=piusopt,
    )
    parser.set_defaults(
        delimiter=DEFAULT_CSV_DELIMITER,
        name_field=DEFAULT_CSV_NAME_FIELD,
        email_field=DEFAULT_CSV_EMAIL_FIELD,
        fp_field=DEFAULT_CSV_FP_FIELD,
        gpg_path=DEFAULT_GPG_PATH,
        party="",
        ignore_emails="",
        ignore_fps="",
        tmp_dir=DEFAULT_TMP_DIR,
    )

    common = optparse.OptionGroup(parser, "Options common to all modes")
    common.add_option(
        "-d", "--debug", dest="debug", action="store_true", help="Debug output"
    )
    common.add_option(
        "-g",
        "--gpg-path",
        dest="gpg_path",
        metavar="PATH",
        help="Path to gpg binary. [default; %default]",
    )
    common.add_option(
        "-r",
        "--keyring",
        dest="keyring",
        metavar="KEYRING",
        nargs=1,
        help="Keyring file.",
    )
    common.add_option(
        "-v",
        "--verbose",
        dest="verbose",
        action="store_true",
        help="Print summaries",
    )
    parser.add_option_group(common)

    build_intro = """
The "build" mode is the most common mode. It's primary functionality is parsing
a CSV file, attempting to find all the keys, and then emailing anyone whose key
could not be found. For completness sake, it can also import keys from a file.
  Options for 'build' mode"""

    build = optparse.OptionGroup(parser, build_intro)
    build.add_option(
        "-b",
        "--mbox-file",
        dest="mbox_file",
        metavar="FILE",
        help="Parse mbox FILE, examining each message for"
        " fingerprints or ascii-armored keys. Tries to be as"
        " intelligent as possible here, including decoding"
        " messages as necessary.",
    )
    build.add_option(
        "-c",
        "--csv-file",
        dest="csv_file",
        metavar="FILE",
        help="Parse FILE as a CSV and import keys. You will almost"
        " want -D, -E, -F, and -N to control CSV parsing.",
    )
    build.add_option(
        "--delimiter",
        dest="delimiter",
        metavar="DELIMITER",
        help="Only meaningful with -c. Field delimiter to use when"
        " parsing the CSV. [default: %default]",
    )
    build.add_option(
        "-E",
        "--email-field",
        dest="email_field",
        metavar="FIELD",
        type="int",
        help="Only meaningful with -c. The field number of the CSV"
        " where the email is. [default: %default]",
    )
    build.add_option(
        "-f",
        "--flat-file",
        dest="flat_file",
        metavar="FILE",
        help="Parse flat file FILE for fingerprints.",
    )
    build.add_option(
        "-F",
        "--fp-field",
        dest="fp_field",
        metavar="FIELD",
        type="int",
        help="Only meaningful with -c. The field number of the CSV"
        " where the fingerprint is. [default: %default]",
    )
    build.add_option(
        "-m",
        "--mail",
        dest="mail",
        metavar="EMAIL",
        help="Email people whos keys were not found, using EMAIL",
    )
    build.add_option(
        "-N",
        "--name-field",
        dest="name_field",
        metavar="FIELD",
        type="int",
        help="Only meaningful with -c. The field number of the CSV"
        " where the name is. [default: %default]",
    )
    build.add_option(
        "-p",
        "--party",
        dest="party",
        metavar="NAME",
        nargs=1,
        help="The name of the party. This will be printed in the"
        " emails sent out. Only useful with -m.",
    )
    build.add_option(
        "-s",
        "--keyservers",
        dest="keyservers",
        metavar="KEYSERVER",
        action="append",
        help=(
            "Keyservers to try. Specify this option once for each"
            "server (-s foo -s bar). [default: %s]"
            % ", ".join(DEFAULT_KEYSERVERS)
        ),
    )
    build.add_option(
        "-t",
        "--tmp-dir",
        dest="tmp_dir",
        help="Directory to put temporary stuff in. [default:" " %default]",
    )
    build.add_option(
        "-T",
        "--print-default-email",
        dest="print_default_email",
        action="store_true",
        help="Print the default email.",
    )
    build.add_option(
        "--ignore-emails",
        dest="ignore_emails",
        help="Comma-separated list of emails to ignore.",
    )
    build.add_option(
        "--ignore-fingerprints",
        dest="ignore_fps",
        help="Comma-separated list of fingerprints to ignore - no" " spaces.",
    )
    pmailer.PiusMailer.add_options(parser, build)
    parser.add_option_group(build)

    prune_intro = """
The "prune" mode asks about each key on a keyring and removes one you specify.
This is useful for trimming a keyring of people who didn't show after a party
before distributing they keyring.
  Options for 'prune' mode"""
    prune = optparse.OptionGroup(parser, prune_intro)
    prune.add_option(
        "--no-sort-keyring",
        dest="sort_keyring",
        action="store_false",
        help="Do not sort the keyring by name.",
    )
    parser.add_option_group(prune)

    raw_intro = """
The "raw" mode allows you pass gpg options which will be run for you. The
options will be added to the options necessary to operate on the keyring safely
(to load only the party keyring, not your keyring). This is primary useful for
adding keys manually. All such options should be passed after a '--' to prevent
pius-keyring-manager interpreting them as options to itself. Example:

  pius-keyring-manager raw -r path/to/keyring.gpg -- --recv-key <keyid>

There are no options"""
    raw = optparse.OptionGroup(parser, raw_intro)
    parser.add_option_group(raw)

    all_opts = util.parse_dotfile(parser)
    all_opts.extend(sys.argv[1:])
    (options, args) = parser.parse_args(all_opts)
    mode = None
    if args:
        mode = args.pop(0)

    if options.print_default_email:
        print_default_email()
        sys.exit(0)

    check_options(parser, mode, options)

    # We can't set this as a default above because 'append' will not allow
    # users to completely override the list
    if not options.keyservers:
        options.keyservers = DEFAULT_KEYSERVERS

    kb = KeyringBuilder(
        options.gpg_path, options.keyring, options.keyservers, options.tmp_dir
    )

    if mode == "prune":
        kb.prune(options.sort_keyring)
    elif mode == "raw":
        kb.raw(args)
    elif mode == "build":
        keys = []
        if options.mbox_file:
            keys = PiusParser.parse_mbox(options.mbox_file)

        if options.csv_file:
            keys.extend(
                PiusParser.parse_csv(
                    options.csv_file,
                    options.delimiter,
                    options.name_field,
                    options.email_field,
                    options.fp_field,
                    options.ignore_emails,
                    options.ignore_fps,
                )
            )

        if options.flat_file:
            keys.extend(PiusParser.parse_flatfile(options.flat_file))

        if not keys:
            print("No keys IDs extract from CSV/mbox")
            sys.exit(0)

        if keys:
            kb.get_all_keys(keys)
            if options.verbose:
                kb.print_report()
            if options.mail and kb.num_not_found() > 0:
                print(
                    "Preparing to send out emails to those whose keys were not found"
                )
                mailer = pmailer.PiusMailer(
                    options.mail,
                    options.display_name,
                    options.mail_host,
                    options.mail_port,
                    options.mail_user,
                    options.mail_tls,
                    options.mail_no_pgp_mime,
                    options.mail_override,
                    options.mail_text,
                    options.tmp_dir,
                )
                kb.send_emails(mailer, options.party)
    else:
        print("Unrecognized mode %s" % mode)
        sys.exit(1)

    # No matter what, we need to export into a common format
    kb.export_keyring()


if __name__ == "__main__":
    main()
