#!/usr/bin/env python
# vim: set fileencoding=utf-8:
'''
warcprox/main.py - entrypoint for warcprox executable, parses command line
arguments, initializes components, starts controller, handles signals

Copyright (C) 2013-2018 Internet Archive

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; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
USA.
'''

from __future__ import absolute_import

try:
    import queue
except ImportError:
    import Queue as queue

import logging
import sys
import hashlib
import argparse
import os
import socket
import traceback
import signal
import threading
import certauth.certauth
import warcprox
import doublethink
import cryptography.hazmat.backends.openssl

class BetterArgumentDefaultsHelpFormatter(
                argparse.ArgumentDefaultsHelpFormatter,
                argparse.RawDescriptionHelpFormatter):
    '''
    HelpFormatter with these properties:

    - formats option help like argparse.ArgumentDefaultsHelpFormatter except
      that it omits the default value for arguments with action='store_const'
    - like argparse.RawDescriptionHelpFormatter, does not reformat description
      string
    '''
    def _get_help_string(self, action):
        if isinstance(action, argparse._StoreConstAction):
            return action.help
        else:
            return argparse.ArgumentDefaultsHelpFormatter._get_help_string(self, action)

def _build_arg_parser(prog='warcprox'):
    arg_parser = argparse.ArgumentParser(prog=prog,
            description='warcprox - WARC writing MITM HTTP/S proxy',
            formatter_class=BetterArgumentDefaultsHelpFormatter)
    arg_parser.add_argument('-p', '--port', dest='port', default='8000',
            type=int, help='port to listen on')
    arg_parser.add_argument('-b', '--address', dest='address',
            default='localhost', help='address to listen on')
    arg_parser.add_argument('-c', '--cacert', dest='cacert',
            default='./{0}-warcprox-ca.pem'.format(socket.gethostname()),
            help='CA certificate file; if file does not exist, it will be created')
    arg_parser.add_argument('--certs-dir', dest='certs_dir',
            default='./{0}-warcprox-ca'.format(socket.gethostname()),
            help='where to store and load generated certificates')
    arg_parser.add_argument('-d', '--dir', dest='directory',
            default='./warcs', help='where to write warcs')
    arg_parser.add_argument('--warc-filename', dest='warc_filename',
            default='{prefix}-{timestamp17}-{serialno}-{randomtoken}',
            help='define custom WARC filename with variables {prefix}, {timestamp14}, {timestamp17}, {serialno}, {randomtoken}, {hostname}, {shorthostname}')
    arg_parser.add_argument('-z', '--gzip', dest='gzip', action='store_true',
            help='write gzip-compressed warc records')
    arg_parser.add_argument('--no-warc-open-suffix', dest='no_warc_open_suffix',
            default=False, action='store_true', help=argparse.SUPPRESS)
    # not mentioned in --help: special value for '-' for --prefix means don't
    # archive the capture, unless prefix set in warcprox-meta header
    arg_parser.add_argument(
            '-n', '--prefix', dest='prefix', default='WARCPROX',
            help='default WARC filename prefix')
    arg_parser.add_argument(
            '-s', '--size', dest='rollover_size', default=1000*1000*1000,
            type=int, help='WARC file rollover size threshold in bytes')
    arg_parser.add_argument('--rollover-idle-time',
            dest='rollover_idle_time', default=None, type=int,
            help="WARC file rollover idle time threshold in seconds (so that Friday's last open WARC doesn't sit there all weekend waiting for more data)")
    try:
        hash_algos = hashlib.algorithms_guaranteed
    except AttributeError:
        hash_algos = hashlib.algorithms
    arg_parser.add_argument('-g', '--digest-algorithm', dest='digest_algorithm',
            default='sha1', help='digest algorithm, one of {}'.format(', '.join(hash_algos)))
    arg_parser.add_argument('--base32', dest='base32', action='store_true',
            default=False, help='write digests in Base32 instead of hex')
    arg_parser.add_argument('--method-filter', metavar='HTTP_METHOD',
                            action='append', help='only record requests with the given http method(s) (can be used more than once)')

    group = arg_parser.add_mutually_exclusive_group()
    group.add_argument(
            '--stats-db-file', dest='stats_db_file',
            default='./warcprox.sqlite', help=(
                'persistent statistics database file; empty string or '
                '/dev/null disables statistics tracking'))
    group.add_argument(
            '--rethinkdb-stats-url', dest='rethinkdb_stats_url', help=(
                'rethinkdb stats table url, e.g. rethinkdb://db0.foo.org,'
                'db1.foo.org:38015/my_warcprox_db/my_stats_table'))

    arg_parser.add_argument('-P', '--playback-port', dest='playback_port',
            type=int, default=None, help='port to listen on for instant playback')
    # arg_parser.add_argument('--playback-index-db-file', dest='playback_index_db_file',
    #         default='./warcprox-playback-index.db',
    #         help='playback index database file (only used if --playback-port is specified)')
    group = arg_parser.add_mutually_exclusive_group()
    group.add_argument('-j', '--dedup-db-file', dest='dedup_db_file',
            default='./warcprox.sqlite', help='persistent deduplication database file; empty string or /dev/null disables deduplication')
    group.add_argument(
            '--rethinkdb-dedup-url', dest='rethinkdb_dedup_url', help=(
                'rethinkdb dedup url, e.g. rethinkdb://db0.foo.org,'
                'db1.foo.org:38015/my_warcprox_db/my_dedup_table'))
    group.add_argument(
            '--rethinkdb-big-table-url', dest='rethinkdb_big_table_url', help=(
                'rethinkdb big table url (table will be populated with '
                'various capture information and is suitable for use as '
                'index for playback), e.g. rethinkdb://db0.foo.org,'
                'db1.foo.org:38015/my_warcprox_db/captures'))
    group.add_argument(
            '--rethinkdb-trough-db-url', dest='rethinkdb_trough_db_url', help=(
                '🐷   url pointing to trough configuration rethinkdb database, '
                'e.g. rethinkdb://db0.foo.org,db1.foo.org:38015'
                '/trough_configuration'))
    group.add_argument('--cdxserver-dedup', dest='cdxserver_dedup',
            help='use a CDX Server URL for deduplication; e.g. https://web.archive.org/cdx/search')
    arg_parser.add_argument(
            '--rethinkdb-services-url', dest='rethinkdb_services_url', help=(
                'rethinkdb service registry table url; if provided, warcprox '
                'will create and heartbeat entry for itself'))
    # optional cookie values to pass to CDX Server; e.g. "cookie1=val1;cookie2=val2"
    arg_parser.add_argument('--cdxserver-dedup-cookies', dest='cdxserver_dedup_cookies',
            help=argparse.SUPPRESS)
    arg_parser.add_argument('--queue-size', dest='queue_size', type=int,
            default=500, help=argparse.SUPPRESS)
    arg_parser.add_argument('--max-threads', dest='max_threads', type=int,
            help=argparse.SUPPRESS)
    arg_parser.add_argument('--profile', action='store_true', default=False,
            help=argparse.SUPPRESS)
    arg_parser.add_argument(
            '--writer-threads', dest='writer_threads', type=int, default=None,
            help=argparse.SUPPRESS)
    arg_parser.add_argument(
            '--onion-tor-socks-proxy', dest='onion_tor_socks_proxy',
            default=None, help=(
                'host:port of tor socks proxy, used only to connect to '
                '.onion sites'))
    # Configurable connection socket timeout, default is 60 sec.
    arg_parser.add_argument(
            '--socket-timeout', dest='socket_timeout', type=float,
            default=None, help=argparse.SUPPRESS)
    # Increasing this value increases memory usage but reduces /tmp disk I/O.
    arg_parser.add_argument(
            '--tmp-file-max-memory-size', dest='tmp_file_max_memory_size',
            type=int, default=512*1024, help=argparse.SUPPRESS)
    arg_parser.add_argument(
            '--max-resource-size', dest='max_resource_size', type=int,
            default=None, help='maximum resource size limit in bytes')
    arg_parser.add_argument(
            '--crawl-log-dir', dest='crawl_log_dir', default=None, help=(
                'if specified, write crawl log files in the specified '
                'directory; one crawl log is written per warc filename '
                'prefix; crawl log format mimics heritrix'))
    arg_parser.add_argument(
            '--plugin', metavar='PLUGIN_CLASS', dest='plugins',
            action='append', help=(
                'Qualified name of plugin class, e.g. "mypkg.mymod.MyClass". '
                'May be used multiple times to register multiple plugins. '
                'See README.rst for more information.'))
    arg_parser.add_argument('--version', action='version',
            version="warcprox {}".format(warcprox.__version__))
    arg_parser.add_argument('-v', '--verbose', dest='verbose', action='store_true')
    arg_parser.add_argument('--trace', dest='trace', action='store_true')
    arg_parser.add_argument('-q', '--quiet', dest='quiet', action='store_true')

    return arg_parser

def dump_state(signum=None, frame=None):
    '''
    Signal handler, logs stack traces of active threads.
    '''
    state_strs = []

    for th in threading.enumerate():
        try:
            state_strs.append(str(th))
            stack = traceback.format_stack(sys._current_frames()[th.ident])
            state_strs.append(''.join(stack))
        except Exception as e:
            state_strs.append('<n/a:%r>' % e)

    logging.warn(
            'dumping state (caught signal %s)\n%s',
            signum, '\n'.join(state_strs))

def parse_args(argv):
    '''
    Parses command line arguments with argparse.
    '''
    arg_parser = _build_arg_parser(prog=os.path.basename(argv[0]))
    args = arg_parser.parse_args(args=argv[1:])

    try:
        hashlib.new(args.digest_algorithm)
    except Exception as e:
        logging.fatal(e)
        exit(1)

    return args

def main(argv=None):
    '''
    Main method, entry point of warcprox command.
    '''
    args = parse_args(argv or sys.argv)

    if args.trace:
        loglevel = warcprox.TRACE
    elif args.verbose:
        loglevel = logging.DEBUG
    elif args.quiet:
        loglevel = logging.WARNING
    else:
        loglevel = logging.INFO

    logging.basicConfig(
            stream=sys.stdout, level=loglevel, format=(
                '%(asctime)s %(process)d %(levelname)s %(threadName)s '
                '%(name)s.%(funcName)s(%(filename)s:%(lineno)d) %(message)s'))

    # see https://github.com/pyca/cryptography/issues/2911
    cryptography.hazmat.backends.openssl.backend.activate_builtin_random()

    options = warcprox.Options(**vars(args))
    controller = warcprox.controller.WarcproxController(options)

    signal.signal(signal.SIGTERM, lambda a,b: controller.stop.set())
    signal.signal(signal.SIGINT, lambda a,b: controller.stop.set())
    try:
        signal.signal(signal.SIGQUIT, dump_state)
    except AttributeError:
        # SIGQUIT does not exist on some platforms (windows)
        pass

    controller.run_until_shutdown()

def ensure_rethinkdb_tables(argv=None):
    '''
    Creates rethinkdb tables if they don't already exist. Warcprox normally
    creates the tables it needs on demand at startup, but if multiple instances
    are starting up at the same time, you can end up with duplicate broken
    tables. So it's a good idea to use this utility at an early step when
    spinning up a cluster.
    '''
    argv = argv or sys.argv
    arg_parser = argparse.ArgumentParser(
            prog=os.path.basename(argv[0]),
            formatter_class=BetterArgumentDefaultsHelpFormatter)
    arg_parser.add_argument(
            '--rethinkdb-stats-url', dest='rethinkdb_stats_url', help=(
                'rethinkdb stats table url, e.g. rethinkdb://db0.foo.org,'
                'db1.foo.org:38015/my_warcprox_db/my_stats_table'))
    group = arg_parser.add_mutually_exclusive_group()
    group.add_argument(
            '--rethinkdb-dedup-url', dest='rethinkdb_dedup_url', help=(
                'rethinkdb dedup url, e.g. rethinkdb://db0.foo.org,'
                'db1.foo.org:38015/my_warcprox_db/my_dedup_table'))
    group.add_argument(
            '--rethinkdb-big-table-url', dest='rethinkdb_big_table_url', help=(
                'rethinkdb big table url (table will be populated with '
                'various capture information and is suitable for use as '
                'index for playback), e.g. rethinkdb://db0.foo.org,'
                'db1.foo.org:38015/my_warcprox_db/captures'))
    group.add_argument(
            '--rethinkdb-trough-db-url', dest='rethinkdb_trough_db_url', help=(
                '🐷   url pointing to trough configuration rethinkdb database, '
                'e.g. rethinkdb://db0.foo.org,db1.foo.org:38015'
                '/trough_configuration'))
    arg_parser.add_argument(
            '--rethinkdb-services-url', dest='rethinkdb_services_url', help=(
                'rethinkdb service registry table url; if provided, warcprox '
                'will create and heartbeat entry for itself'))
    arg_parser.add_argument(
            '-q', '--quiet', dest='log_level',
            action='store_const', default=logging.INFO, const=logging.WARN)
    arg_parser.add_argument(
            '-v', '--verbose', dest='log_level',
            action='store_const', default=logging.INFO, const=logging.DEBUG)
    args = arg_parser.parse_args(args=argv[1:])

    logging.basicConfig(
            stream=sys.stdout, level=args.log_level, format=(
                '%(asctime)s %(levelname)s %(name)s.%(funcName)s'
                '(%(filename)s:%(lineno)d) %(message)s'))

    options = warcprox.Options(**vars(args))

    did_something = False
    if args.rethinkdb_services_url:
        parsed = doublethink.parse_rethinkdb_url(
                options.rethinkdb_services_url)
        rr = doublethink.Rethinker(servers=parsed.hosts, db=parsed.database)
        svcreg = doublethink.ServiceRegistry(rr, table=parsed.table)
        did_something = True
    if args.rethinkdb_stats_url:
        stats_db = warcprox.stats.RethinkStatsProcessor(options=options)
        stats_db._ensure_db_table()
        did_something = True
    if args.rethinkdb_dedup_url:
        dedup_db = warcprox.dedup.RethinkDedupDb(options=options)
        did_something = True
    if args.rethinkdb_big_table_url:
        dedup_db = warcprox.bigtable.RethinkCapturesDedup(options=options)
        did_something = True
    if args.rethinkdb_trough_db_url:
        dedup_db = warcprox.dedup.TroughDedupDb(options)
        logging.warn(
                'trough is responsible for creating most of the rethinkdb '
                'tables that it uses')
        did_something = True

    if not did_something:
        logging.error('nothing to do, no --rethinkdb-* options supplied')

if __name__ == '__main__':
    main()