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

from __future__ import print_function, unicode_literals
from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer

import cgi
import json
import logging
import re
import socket
from SocketServer import ThreadingMixIn
import time

import ffstatus

# each match of these regex is removed to normalize an ISP's name
ISP_NORMALIZATIONS = [
    # normalize name: strip company indication
    re.compile(r'(AG|UG|G?mbH( ?& ?Co\.? ?(OH|K)G)?)$', flags=re.IGNORECASE),

    # normalize name: strip "pool" suffixes
    re.compile(r'(dynamic )?(customer |subscriber )?(ip )?(pool|(address )?range|addresses)$', flags=re.IGNORECASE),

    # normalize name: strip "B2B" and aggregation suffixes
    re.compile(r'(aggregate|aggregation)?$', flags=re.IGNORECASE),
    re.compile(r'(B2B)?$', flags=re.IGNORECASE),

    # normalize name: strip country suffixes (in Germany)
    re.compile(r'(' +
               'DE|Deutschland|Germany|' +
               'Nordrhein[- ]Westfalen|NRW|' +
               'Baden[- ]Wuerttemburg|BW|' +
               'Hessen|' +
               'Niedersachsen|' +
               'Rheinland[- ]Pfalz|RLP' +
               ')$',
               flags=re.IGNORECASE),
]

REGEX_QUERYPARAM = re.compile(
    r'(?P<key>.+?)=(?P<value>.+?)(&|$)')
REGEX_URL_NODEINFO = re.compile(
    r'node/(?P<id>[a-fA-F0-9]{12})(?P<cmd>\.json|/[a-zA-Z0-9_\-\.]+)$')
REGEX_URL_NODESTATUS = re.compile(
    r'status/([a-f0-9]{12})$')


def normalize_ispname(isp):
    """Removes all matches on ISP_NORMALIZATIONS."""
    isp = isp.strip()

    for regex in ISP_NORMALIZATIONS:
        isp = regex.sub('', isp).strip()

    return isp


class BatcaveHttpRequestHandler(BaseHTTPRequestHandler):
    """Handles a single HTTP request to the BATCAVE."""

    def __init__(self, request, client_address, sockserver):
        self.logger = logging.getLogger('API')
        BaseHTTPRequestHandler.__init__(
            self, request, client_address, sockserver)

    def __parse_url_pathquery(self):
        """Extracts the query parameters from the request path."""
        url = re.match(r'^/(?P<path>.*?)(\?(?P<query>.+))?$', self.path.strip())
        if url is None:
            logging.warn('Failed to parse URL \'' + str(self.path) + '\'.')
            return (None, None)

        path = url.group('path')
        query = {}
        if not url.group('query') is None:
            for match in REGEX_QUERYPARAM.finditer(url.group('query')):
                query[match.group('key')] = match.group('value')
        return (path, query)

    def do_GET(self):
        """Handles all HTTP GET requests."""

        path, query = self.__parse_url_pathquery()
        if path is None:
            self.send_error(400, 'Could not parse URL (' + str(self.path) + ')')
            return

        # / - index page, shows generic help
        if path == '':
            self.__respond_index(query)
            return

        # /list - list stored nodes
        if path == 'list':
            self.__respond_list(query)
            return

        # /vpn - notification endpoint for gateway's VPN connections
        if path == 'vpn':
            self.__respond_vpn(query)
            return

        # /providers
        if path == 'providers':
            self.__respond_providers(query)
            return

        # /node/<id>.json - node's data
        # /node/<id>/field - return specific field from node's data
        match = REGEX_URL_NODEINFO.match(path)
        if match is not None:
            cmd = match.group('cmd')
            nodeid = match.group('id').lower()
            if cmd == '.json':
                self.__respond_node(nodeid)
            else:
                self.__respond_nodedetail(nodeid, cmd[1:])
            return

        # /status - overall status (incl. node and client count)
        if path == 'status':
            self.__respond_status()
            return

        # /status/<id> - node's status
        match = REGEX_URL_NODESTATUS.match(path)
        if match is not None:
            self.__respond_nodestatus(match.group(1))
            return

        # no match -> 404
        self.send_error(404, 'The URL \'{0}\' was not found here.'.format(path))

    def do_POST(self):
        """Handles all HTTP POST requests."""

        path, query = self.__parse_url_pathquery()
        if path is None:
            self.send_error(400, 'Could not parse URL (' + str(self.path) + ')')
            return
        params = self.__parse_post_params()

        # node id/mac to name mapping
        if path == 'idmac2name':
            self.__respond_nodeidmac2name(params)
            return

        # no match -> 404
        self.send_error(404, 'The URL \'{0}\' was not found here.'.format(path))

    def __send_nocache_headers(self):
        """
        Sets HTTP headers indicating that this response shall not be cached.
        """

        self.send_header('Cache-Control', 'no-cache, no-store, must-revalidate')
        self.send_header('Pragma', 'no-cache')
        self.send_header('Expires', '0')

    def __send_headers(self,
                       content_type='text/html; charset=utf-8',
                       nocache=True, extra={}):
        """Send HTTP 200 Response header with the given Content-Type.
        Optionally send no-caching headers, too."""

        self.send_response(200)
        self.send_header('Content-Type', content_type)
        if nocache:
            self.__send_nocache_headers()
        for key in extra:
            self.send_header(key, extra[key])
        self.end_headers()

    def __parse_post_params(self):
        ctype, pdict = cgi.parse_header(self.headers.getheader('content-type'))

        if ctype == 'multipart/form-data':
            postvars = cgi.parse_multipart(self.rfile, pdict)

        elif ctype == 'application/x-www-form-urlencoded':
            length = int(self.headers.getheader('content-length'))
            postvars = cgi.parse_qs(
                self.rfile.read(length),
                keep_blank_values=1,
            )

        else:
            postvars = {}

        return postvars

    def __respond_index(self, query):
        """Display the index page."""

        self.__send_headers()

        index_page = '''<!DOCTYPE html>
<html><head><title>BATCAVE</title></head>
<body>
<H1 title="Batman/Alfred Transmission Collection, Aggregation & Value Engine">
BATCAVE
</H1>

<p>Dies ist ein interner Hintergrund-Dienst. Er wird nur von anderen Diensten
angesprochen und sollte aus einer Mehrzahl von Gr&uuml;nden nicht
&ouml;ffentlich zug&auml;nglich sein.</p>

<H2>API</H2>
<p>
  Grunds&auml;tzlich ist das Antwort-Format JSON und alle Daten sind
  Live-Daten (kein Cache) die ggf. etwas Bearbeitungs-Zeit erfordern.
</p>
<dl>
    <dt>GET <a href="/nodes.json">nodes.json</a></dt>
        <dd>zur Verwendung mit ffmap (MACs anonymisiert)</dd>
    <dt>GET /node/&lt;id&gt;.json</dt>
        <dd>alle Daten zu dem gew&uuml;nschten Knoten</dd>
    <dt>GET /providers?format=json</dt>
        <dd>Liste der Provider</dd>
    <dt>GET <a href="/status">/status</a></dt>
        <dd>Status der BATCAVE inkl. Zahl der Nodes+Clients (JSON)</dd>
    <dt>GET /status/&lt;id&gt;</dt>
        <dd>Status des Knotens</dd>
</dl>
</body></html>'''
        self.wfile.write(index_page)

    def __respond_list(self, query):
        """List stored data."""

        self.__send_headers()

        self.wfile.write('<!DOCTYPE html><html>\n')
        self.wfile.write('<head><title>BATCAVE</title></head>\n')
        self.wfile.write('<body>\n')
        self.wfile.write('<H1>BATCAVE - LIST</H1>\n')

        self.wfile.write('<table>\n')
        self.wfile.write('<thead><tr><th>ID</th><th>Name</th></tr></thead>\n')
        self.wfile.write('<tbody>\n')

        sortkey = query['sort'] if 'sort' in query else None
        data = self.server.storage.get_nodes(sortby=sortkey)
        for node in data:
            nodeid = node.get('node_id')
            nodename = node.get('hostname', '&lt;?&gt;')

            self.wfile.write('<tr>\n')
            self.wfile.write('  <td><a href="/node/{0}.json">{0}</a></td>\n'.format(nodeid))
            self.wfile.write('  <td>{0}</td>\n'.format(nodename))
            self.wfile.write('</tr>\n')

        self.wfile.write('</tbody>\n')
        self.wfile.write('</table>\n')

    def __respond_node(self, rawid):
        """Display node data."""

        # search node by the given id
        node = self.server.storage.find_node(rawid)

        # handle unknown nodes
        if node is None:
            self.send_error(404, 'No node with id \'' + rawid + '\' present.')
            return

        # dump node data as JSON
        self.__send_headers('application/json',
                            extra={'Content-Disposition': 'inline'})
        self.wfile.write(json.dumps(node))

    def __respond_nodestatus(self, rawid):
        """Display node status."""

        status = self.server.storage.get_nodestatus(rawid)

        if status is None:
            self.send_error(404, 'No node with id \'' + rawid + '\' present.')

        self.__send_headers('text/plain')
        self.wfile.write(status)

    def __respond_nodeidmac2name(self, ids):
        """Return a mapping of the given IDs (or MACs) into their hostname."""

        self.__send_headers('text/plain')
        for nodeid in ids:
            node = None
            if not ':' in nodeid:
                node = self.server.storage.find_node(nodeid)
            else:
                node = self.server.storage.find_node_by_mac(nodeid)
            nodename = node.get('hostname', nodeid) if node is not None else nodeid
            self.wfile.write('{0}={1}\n'.format(nodeid, nodename))

    def __respond_nodedetail(self, nodeid, field):
        """
        Return a field from the given node.
        String and integers are returned as text/plain,
        all other as JSON.
        """

        node = self.server.storage.find_node(nodeid)
        if node is None:
            self.send_error(404, 'No node with id \'' + nodeid + '\' present.')
            return

        return_count = False
        if field.endswith('.count'):
            return_count = True
            field = field[0:-6]

        if not field in node:
            self.send_error(
                404,
                'The node \'{0}\' does not have a field named \'{1}\'.'.format(
                    nodeid, field
                )
            )
            return

        value = node[field]
        if return_count:
            value = len(value)

        no_json = isinstance(value, basestring) or isinstance(value, int)
        self.__send_headers('text/plain' if no_json else 'application/json',
                            extra={'Content-Disposition': 'inline'})
        self.wfile.write(value if no_json else json.dumps(value))

    def __respond_status(self):
        status = self.server.storage.status
        self.__send_headers('application/json',
                            extra={'Content-Disposition': 'inline'})
        self.wfile.write(json.dumps(status, indent=2))

    def __respond_vpn(self, query):
        storage = self.server.storage
        peername = query.get('peer')
        key = query.get('key')
        action = query.get('action')
        remote = query.get('remote')
        gateway = query.get('gw')
        timestamp = query.get('ts', time.time())

        if action == 'list':
            self.__respond_vpnlist()
            return

        if action != 'establish' and action != 'disestablish':
            self.logger.error('VPN: unknown action \'{0}\''.format(action))
            self.send_error(400, 'Invalid action.')
            return

        check = {
            'peername': peername,
            'key': key,
            'remote': remote,
            'gw': gateway,
        }
        for k, val in check.items():
            if val is None or len(val.strip()) == 0:
                self.logger.error('VPN {0}: no or empty {1}'.format(action, k))
                self.send_error(400, 'Missing value for ' + str(k))
                return

        try:
            if action == 'establish':
                self.server.storage.log_vpn_connect(
                    key, peername, remote, gateway, timestamp)

            elif action == 'disestablish':
                self.server.storage.log_vpn_disconnect(key, gateway, timestamp)

            else:
                self.logger.error('Unknown VPN action \'%s\' not filtered.',
                                  action)
                self.send_error(500)
                return

        except ffstatus.exceptions.VpnKeyFormatError:
            self.logger.error('VPN peer \'{0}\' {1}: bad key \'{2}\''.format(
                peername, action, key,
            ))
            self.send_error(400, 'Bad key.')
            return

        self.__send_headers('text/plain')
        self.wfile.write('OK')

        storage.save()

    def __respond_vpnlist(self):
        self.__send_headers()

        self.wfile.write('''<!DOCTYPE html>
<html><head><title>BATCAVE - VPN LIST</title></head>
<body>
<style type="text/css">
table { border: 2px solid #999; border-collapse: collapse; }
th, td { border: 1px solid #CCC; }
table tbody tr.online { background-color: #CFC; }
table tbody tr.offline { background-color: #FCC; }
</style>
<table>''')

        gateways = self.server.storage.get_vpn_gateways()
        gws_header = '<th>' + '</th><th>'.join(gateways) + '</th>'

        self.wfile.write('<thead>\n')
        self.wfile.write('<tr><th rowspan="2">names (key)</th>')
        self.wfile.write('<th colspan="' + str(len(gateways)) + '">active</th>')
        self.wfile.write('<th colspan="' + str(len(gateways)) + '">last</th>')
        self.wfile.write('</tr>\n')
        self.wfile.write('<tr>' + gws_header + gws_header + '</tr>\n')
        self.wfile.write('</thead>\n')

        for item in self.server.storage.get_vpn_connections():
            row_class = 'online' if item['online'] else 'offline'
            self.wfile.write('<tr class="{0}">'.format(row_class))
            self.wfile.write('<td title="{0}">{1}</td>'.format(
                item['key'],
                ' / '.join(item['names']) if len(item['names']) > 0 else '?',
            ))

            for conntype in ['active', 'last']:
                for gateway in gateways:
                    remote = ''
                    if conntype in item['remote'] and \
                       gateway in item['remote'][conntype]:
                        remote = item['remote'][conntype][gateway]
                        if isinstance(remote, dict):
                            remote = remote['name']
                    symbol = '&check;' if len(remote) > 0 else '&times;'
                    self.wfile.write('<td title="{0}">{1}</td>'.format(
                        remote, symbol))

            self.wfile.write('</tr>\n')

        self.wfile.write('</table>\n')
        self.wfile.write('</body>')
        self.wfile.write('</html>')

    def __respond_providers(self, query):
        """Return a summary of providers."""

        outputformat = query['format'].lower() if 'format' in query else 'html'

        isps = {}
        ispblocks = {}
        for item in self.server.storage.get_vpn_connections():
            if item['count']['active'] == 0:
                continue

            remotes = []
            for gateway in item['remote']['active']:
                remote = item['remote']['active'][gateway]
                remotes.append(remote)

            if len(remotes) == 0:
                self.logger.warn(
                    'VPN key \'%s\' is marked with active remotes but 0 found?',
                    item['key'])
                continue

            item_isps = set()
            for remote in remotes:
                isp = "UNKNOWN"
                ispblock = remote
                if isinstance(remote, dict):
                    ispblock = remote['name']
                    desc_lines = remote['description'].split('\n')
                    isp = normalize_ispname(desc_lines[0])

                if not isp in ispblocks:
                    ispblocks[isp] = set()
                ispblocks[isp].add(ispblock)

                item_isps.add(isp)

            if len(item_isps) == 0:
                item_isps.add('unknown')

            elif len(item_isps) > 1:
                self.logger.warn(
                    'VPN key \'%s\' has %d active IPs ' +
                    'which resolved to %d ISPs: \'%s\'',
                    item['key'],
                    len(remotes),
                    len(item_isps),
                    '\', \''.join(item_isps)
                )

            for isp in item_isps:
                if not isp in isps:
                    isps[isp] = 0
                isps[isp] += 1.0 / len(item_isps)

        isps_sum = sum([isps[x] for x in isps])

        if outputformat == 'csv':
            self.__send_headers('text/csv')

            self.wfile.write('Count;Name\n')
            for isp in isps:
                self.wfile.write('{0};"{1}"\n'.format(isps[isp], isp))

        elif outputformat == 'json':
            self.__send_headers('application/json',
                                extra={'Content-Disposition': 'inline'})

            data = [
                {
                    'name': isp,
                    'count': isps[isp],
                    'percentage': isps[isp]*100.0/isps_sum,
                    'blocks': [block for block in ispblocks[isp]],
                } for isp in isps
            ]
            self.wfile.write(json.dumps(data))

        elif outputformat == 'html':
            self.__send_headers()

            self.wfile.write('''<!DOCTYPE html>
<html>
<head><title>BATCAVE - PROVIDERS</title></head>
<body>
<table border="2">
<thead>
  <tr><th>Count</th><th>Percentage</th><th>Name</th><th>Blocks</th></tr>
</thead>
<tbody>\n''')

            for isp in sorted(isps, key=lambda x: isps[x], reverse=True):
                self.wfile.write('<tr><td>{0}</td><td>{1:.1f}%</td><td>{2}</td><td>{3}</td></tr>\n'.format(
                    isps[isp],
                    isps[isp]*100.0/isps_sum,
                    isp,
                    ', '.join(sorted(ispblocks[isp])) if isp in ispblocks else '?',
                ))

            self.wfile.write('</tbody></table>\n')
            self.wfile.write('<p>Totals: {0} ISPs, {1} connections</p>\n'.format(len(isps), isps_sum))
            self.wfile.write('</body></html>')

        else:
            self.send_error(400, 'Unknown output format.')


class ApiServer(ThreadingMixIn, HTTPServer):
    def __init__(self, endpoint, storage):
        if ':' in endpoint[0]:
            self.address_family = socket.AF_INET6
        HTTPServer.__init__(self, endpoint, BatcaveHttpRequestHandler)
        self.storage = storage

    def __str__(self):
        return 'ApiServer on {0}'.format(self.server_address)

if __name__ == '__main__':
    dummystorage = ffstatus.basestorage.BaseStorage()
    server = ApiServer(('0.0.0.0', 8888), dummystorage)

    print("Server:", str(server))
    server.serve_forever()