#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys
import argparse
import yaml
import os
import pkg_resources
from dns import resolver, reversename

from typing import Optional

OWN_DIRECTORY = os.path.dirname(os.path.abspath(os.path.realpath(__file__)))
LIB = os.path.join(OWN_DIRECTORY, '..')
if os.path.exists(os.path.join(LIB, 'hostinfo')):
    sys.path = [LIB] + sys.path

from hostinfo import printer
from hostinfo import utils


def _get_data(path):
    stream = open(path, 'r')
    return yaml.safe_load(stream)


def _match_key(data, keys):
    if data is None:
        return None

    if len(keys) == 0:
        return data

    key = keys[0]
    rest = keys[1:]

    if key == 'addresses' and 'addresses' in data:
        return _match_key(utils.group_by(data['addresses'], 'interface'), rest)

    if key == 'ports' and 'ports' in data:
        return _match_key(utils.group_by(data['ports'], 'process', 'UNKNOWN'), rest)

    if isinstance(data, dict):
        if key in data:
            return _match_key(data[key], rest)
        return None

    if isinstance(data, list):
        for elem in data:
            result = _match_key(elem, keys)
            if result is not None:
                return result
        return None

    if data == key:
        return data

    return None


def _match(host, search_key, search_value, negate):
    search_keys = search_key.split('.')

    result = _match_key(host, search_keys)
    if search_value is None:
        if negate:
            if result is not None:
                return (search_key, None)
            return (None, True)
        return (search_key, result)
    else:
        if result is None and negate:
            return (search_key, True)
        if result is not None:
            if (search_value in str(result)) != negate:
                return (search_key, result)
        return (search_key, None)


def _parse_search(search):
    if search[0] != '?':
        sys.stderr.write("Invalid search string.")
        sys.exit(1)
    search = search[1:]

    negate = False
    if search[0] == '~':
        search = search[1:]
        negate = True

    value = None
    if '=' in search:
        search_parts = search.split('=', 2)
        search = search_parts[0]
        value = search_parts[1]

    return (search, value, negate)


def print_search(basepath: str, flags: argparse.Namespace,
                 search: str, filter_key: Optional[str] = None):
    def _get_label(host):
        if flags.short:
            return host.replace('.spline.inf.fu-berlin.de',
                                '')
        return host

    metadata = os.path.join(basepath, 'metadata', 'hosts')
    if not os.path.exists(metadata):
        sys.stderr.write("Invalid hostinfo data. "
                         "'metadata/hosts' not found!\n")
        sys.exit(1)

    hosts = _get_data(metadata)
    length = [len(_get_label(host)) for host in hosts['hosts']]
    search_key, search_value, negate = _parse_search(search)
    for host in hosts['hosts']:
        data = _get_data(os.path.join(basepath, host))
        key, result = _match(data, search_key, search_value, negate)
        if result is not None:
            if flags.only_names:
                print((_get_label(host)))
                continue

            p = printer.Printer(data, flags)
            if filter_key is not None or flags.details:
                p.info(filter_key, label=_get_label(host),
                       maxlength=max(length), force=True)
            else:
                if key is None:
                    print((_get_label(host)))
                else:
                    p.info(key, label=_get_label(host),
                           maxlength=max(length), force=True)


def print_info(path, flags, key=None):
    data = _get_data(path)
    p = printer.Printer(data, flags)
    p.info(key)


def print_keys(path):
    def _print_keys(data, prefix = ''):
        if isinstance(data, str):
            return

        for key in list(data.keys()):
            print("%s%s" % (prefix, key))

            if key == 'addresses':
                for k in list(utils.group_by(data[key], 'interface').keys()):
                    print("%s%s.%s" % (prefix, key, k))
            elif key == 'ports':
                for k in list(utils.group_by(data[key], 'process', 'UNKNOWN').keys()):
                    print("%s%s.%s" % (prefix, key, k))
            elif isinstance(data[key], dict):
                _print_keys(data[key], "%s%s." % (prefix, key))
            elif isinstance(data[key], list):
                for value in data[key]:
                    _print_keys(value, "%s%s." % (prefix, key))

    data = _get_data(path)
    _print_keys(data)


def print_hosts(path: str, short: bool):
    metadata = os.path.join(path, 'metadata', 'hosts')
    if os.path.exists(metadata):
        hosts = yaml.safe_load(open(metadata, 'r'))
        if 'hosts' in hosts:
            for host in hosts['hosts']:
                if short:
                    print((host.replace('.spline.inf.fu-berlin.de','')))
                else:
                    print(host)
            return True

    sys.stderr.write("'%s' not found!\n" % metadata)
    return False


def find_host(basepath: str, host: str):
    path = os.path.join(basepath, host)
    if os.path.exists(path):
        return path

    # try to build the fqdn
    path = os.path.join(basepath, "%s.spline.inf.fu-berlin.de" %
                        host.replace('.spline.de', ''))
    if os.path.exists(path):
        return path

    try:
        # try to use reverse dns
        addr = reversename.from_address(host)
        hostname = str(resolver.query(addr,"PTR")[0])
        path = os.path.join(basepath, hostname[0:-1])
    except:
        pass

    if os.path.exists(path):
        return path

    return None


def print_version_and_exit():
    ver = None
    try:
        import version
        ver = version.get_git_version()
    except:
        ver = pkg_resources.require("hostinfo-tools")[0].version

    if ver is None:
        sys.stderr.write('Unable to identify the version information.')
        sys.exit(1)
    print(("hostinfo-tools %s" % ver))
    sys.exit(0)


def main() -> None:
    basepath = '/usr/local/share/hostinfo'
    if 'HOSTINFO_PATH' in os.environ and os.environ['HOSTINFO_PATH'] != '':
        basepath = os.environ['HOSTINFO_PATH']

    parser = argparse.ArgumentParser()
    parser.add_argument("name", nargs="?")
    parser.add_argument("filter", nargs="?")
    parser.add_argument("-o", "--oneline", action="store_true",
                        help="each line is a complete record")
    parser.add_argument("-f", "--file", action="store_true",
                        help="print the path of the file the "
                             "information is read from")
    parser.add_argument("-k", "--keys", action="store_true",
                        help="print only the available keys "
                             "(used for bash completion)")
    parser.add_argument("-v", "--verbose", action="store_true",
                        help="increase output verbosity")
    parser.add_argument("-n", "--nospaces", action="store_true",
                        help="remove unnecessary spaces from output")
    parser.add_argument("-p", "--path", default=basepath,
                        help="set the basepath to the hostinfo data")
    parser.add_argument("-l", "--hosts", action="store_true",
                        help="lists all available hosts")
    parser.add_argument("-s", "--short", action="store_true",
                        help="remove the domain from the output")
    parser.add_argument("--only-names", action="store_true",
                        help="only print the hostname of the matching entries")
    parser.add_argument("-d", "--details", action="store_true",
                        help="print details about matching hosts")
    parser.add_argument("-V", "--version", action="store_true",
                        help="only print the version number and exit")
    args = parser.parse_args()

    if args.version:
        print_version_and_exit()

    if args.path:
        basepath = args.path

    if args.hosts:
        if not print_hosts(basepath, args.short):
            sys.exit(1)
        sys.exit(0)

    if args.name is None:
        parser.print_help()
        sys.exit(1)

    if args.name.startswith('?'):
        # search
        print_search(basepath, search=args.name, filter_key=args.filter,
                     flags=args)
    else:
        # info
        path = find_host(basepath, args.name)
        if path is None:
            sys.stderr.write("Host '%s' could not be found!\n" % args.name)
            sys.exit(1)

        if args.file:
            print(path)
        elif args.keys:
            print_keys(path)
        else:
            print_info(path, key=args.filter, flags=args)

    sys.exit(0)


if __name__ == '__main__':
    main()