#!/usr/bin/env python3
# Licensed under GPLv3
#
# Simple http server to allow user control of n2n edge nodes
#
# Currently only for demonstration
# - needs nicer looking html written
# - needs more json interfaces in edge
#
# Try it out with
#   http://localhost:8080/
#   http://localhost:8080/edge/edges
#   http://localhost:8080/edge/supernodes

import argparse
import socket
import json
import socketserver
import http.server
import signal
import functools
import base64

from http import HTTPStatus


class JsonUDP():
    """encapsulate communication with the edge"""

    def __init__(self, port):
        self.address = "127.0.0.1"
        self.port = port
        self.tag = 0
        self.key = None
        self.debug = False
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

    def _next_tag(self):
        tagstr = str(self.tag)
        self.tag = (self.tag + 1) % 1000
        return tagstr

    def _cmdstr(self, msgtype, cmdline):
        """Create the full command string to send"""
        tagstr = self._next_tag()

        options = [tagstr]
        if self.key is not None:
            options += ['1']  # Flags set for auth key field
            options += [self.key]
        optionsstr = ':'.join(options)

        return tagstr, ' '.join((msgtype, optionsstr, cmdline))

    def _rx(self, tagstr):
        """Wait for rx packets"""

        # TODO: there are no timeouts with any of the recv calls
        data, _ = self.sock.recvfrom(1024)
        data = json.loads(data.decode('utf8'))

        # TODO: We assume the first packet we get will be tagged for us
        # and be either an "error" or a "begin"
        assert(data['_tag'] == tagstr)

        if data['_type'] == 'error':
            raise ValueError('Error: {}'.format(data['error']))

        assert(data['_type'] == 'begin')

        # Ideally, we would confirm that this is our "begin", but that
        # would need the cmd passed into this method, and that would
        # probably require parsing the cmdline passed to us :-(
        # assert(data['cmd'] == cmd)

        result = list()
        error = None

        while True:
            data, _ = self.sock.recvfrom(1024)
            data = json.loads(data.decode('utf8'))

            if data['_tag'] != tagstr:
                # this packet is not for us, ignore it
                continue

            if data['_type'] == 'error':
                # we still expect an end packet, so save the error
                error = ValueError('Error: {}'.format(data['error']))
                continue

            if data['_type'] == 'end':
                if error:
                    raise error
                return result

            if data['_type'] != 'row':
                raise ValueError('Unknown data type {} from '
                                 'edge'.format(data['_type']))

            # remove our boring metadata
            del data['_tag']
            del data['_type']

            if self.debug:
                print(data)

            result.append(data)

    def _call(self, msgtype, cmdline):
        """Perform a rpc call"""
        tagstr, msgstr = self._cmdstr(msgtype, cmdline)
        self.sock.sendto(msgstr.encode('utf8'), (self.address, self.port))
        return self._rx(tagstr)

    def read(self, cmdline):
        return self._call('r', cmdline)

    def write(self, cmdline):
        return self._call('w', cmdline)


pages = {
    "/script.js": {
        "content_type": "text/javascript",
        "content": """
var verbose=-1;

function rows2verbose(id, unused, data) {
    row0 = data[0]
    verbose = row0['traceLevel']

    let div = document.getElementById(id);
    div.innerHTML=verbose
}

function rows2keyvalue(id, keys, data) {
    let s = "<table border=1 cellspacing=0>"
    data.forEach((row) => {
        keys.forEach((key) => {
            if (key in row) {
                s += "<tr><th>" + key + "<td>" + row[key];
            }
        });
    });

    s += "</table>"
    let div = document.getElementById(id);
    div.innerHTML=s
}

function rows2keyvalueall(id, unused, data) {
    let s = "<table border=1 cellspacing=0>"
    data.forEach((row) => {
        Object.keys(row).forEach((key) => {
            s += "<tr><th>" + key + "<td>" + row[key];
        });
    });

    s += "</table>"
    let div = document.getElementById(id);
    div.innerHTML=s
}

function rows2table(id, columns, data) {
    let s = "<table border=1 cellspacing=0>"
    s += "<tr>"
    columns.forEach((col) => {
        s += "<th>" + col
    });
    data.forEach((row) => {
        s += "<tr>"
        columns.forEach((col) => {
            val = row[col]
            if (typeof val === "undefined") {
                val = ''
            }
            s += "<td>" + val
        });
    });

    s += "</table>"
    let div = document.getElementById(id);
    div.innerHTML=s
}

function do_get(url, id, handler, handler_param) {
    fetch(url)
      .then(function (response) {
        return response.json();
      })
      .then(function (data) {
        handler(id,handler_param,data);

        // update the timestamp on success
        let now = Math.round(new Date().getTime() / 1000);
        let time = document.getElementById('time');
        time.innerHTML=now;
      })
      .catch(function (err) {
        console.log('error: ' + err);
      });
}

function do_post(url, body, id, handler, handler_param) {
    fetch(url, {method:'POST', body: body})
      .then(function (response) {
        return response.json();
      })
      .then(function (data) {
        handler(id,handler_param,data);
      })
      .catch(function (err) {
        console.log('error: ' + err);
      });
}

function do_stop(tracelevel) {
    // FIXME: uses global in script library
    fetch(nodetype + '/stop', {method:'POST'})
}

function setverbose(tracelevel) {
    if (tracelevel < 0) {
        tracelevel = 0;
    }
    // FIXME: uses global in script library
    do_post(
        nodetype + '/verbose', tracelevel, 'verbose',
        rows2verbose, null
    );
}

function refresh_setup(interval) {
    var timer = setInterval(refresh_job, interval);
}
""",
    },
    "/": {
        "content_type": "text/html; charset=utf-8",
        "content": """
<html>
<head>
 <title>n2n edge management</title>
</head>
<body>
 <table>
    <tr>
        <td>Last Updated:
        <td><div id="time"></div>
        <td><button onclick=refresh_job()>update</button>
        <td><button onclick=do_stop()>stop edge</button>
    <tr>
        <td>Logging Verbosity:
        <td>
            <div id="verbose"></div>
        <td>
            <button onclick=setverbose(verbose+1)>+</button>
            <button onclick=setverbose(verbose-1)>-</button>
 </table>
 <br>
 <div id="communities"></div>
 <br>
 Edges/Peers:
 <div id="edges"></div>
 <br>
 Supernodes:
 <div id="supernodes"></div>
 <br>
 <div id="timestamps"></div>
 <br>
 <div id="packetstats"></div>

 <script src="script.js"></script>
 <script>
// FIXME: hacky global
var nodetype="edge";

function refresh_job() {
    do_get(
        nodetype + '/verbose', 'verbose',
        rows2verbose, null
    );
    do_get(
        nodetype + '/communities', 'communities',
        rows2keyvalue, ['community']
    );
    do_get(
        nodetype + '/supernodes', 'supernodes',
        rows2table, ['version','current','macaddr','sockaddr','uptime']
    );
    do_get(
        nodetype + '/edges', 'edges',
        rows2table, ['mode','ip4addr','macaddr','sockaddr','desc']
    );
    do_get(
        nodetype + '/timestamps', 'timestamps',
        rows2keyvalueall, null
    );
    do_get(
        nodetype + '/packetstats', 'packetstats',
        rows2table, ['type','tx_pkt','rx_pkt']
    );
}

refresh_setup(10000);
refresh_job();
 </script>
</body>
</html>
""",
    },
    "/supernode.html": {
        "content_type": "text/html; charset=utf-8",
        "content": """
<html>
<head>
 <title>n2n supernode management</title>
</head>
<body>
 <table>
    <tr>
        <td>Last Updated:
        <td><div id="time"></div>
        <td><button onclick=refresh_job()>update</button>
        <td><button onclick=do_stop()>stop supernode</button>
    <tr>
        <td>Logging Verbosity:
        <td>
            <div id="verbose"></div>
        <td>
            <button onclick=setverbose(verbose+1)>+</button>
            <button onclick=setverbose(verbose-1)>-</button>
        <td><button onclick=do_reload()>reload communities</button>
 </table>
 <br>
 Communities:
 <div id="communities"></div>
 <br>
 Edges/Peers:
 <div id="edges"></div>
 <br>
 <div id="timestamps"></div>
 <br>
 <div id="packetstats"></div>

 <script src="script.js"></script>
 <script>
// FIXME: hacky global
var nodetype="supernode";

function do_reload() {
    fetch(nodetype + '/reload_communities', {method:'POST'})
}

function refresh_job() {
    do_get(
        nodetype + '/verbose', 'verbose',
        rows2verbose, null
    );
    do_get(
        nodetype + '/communities', 'communities',
        rows2table, ['community','ip4addr','is_federation','purgeable']
    );
    do_get(
        nodetype + '/edges', 'edges',
        rows2table,
        ['community','ip4addr','macaddr','sockaddr','proto','desc']
    );
    do_get(
        nodetype + '/timestamps', 'timestamps',
        rows2keyvalueall, null
    );
    do_get(
        nodetype + '/packetstats', 'packetstats',
        rows2table, ['type','tx_pkt','rx_pkt']
    );
}

refresh_setup(10000);
refresh_job();
 </script>
</body>
</html>
""",
    },
}


class SimpleHandler(http.server.BaseHTTPRequestHandler):

    def __init__(self, rpc, snrpc, *args, **kwargs):
        self.rpc = rpc
        self.snrpc = snrpc
        super().__init__(*args, **kwargs)

    def log_request(self, code='-', size='-'):
        # Dont spam the output
        pass

    def _simplereply(self, number, message):
        self.send_response(number)
        self.end_headers()
        self.wfile.write(message.encode('utf8'))

    def _replyjson(self, data):
        self.send_response(HTTPStatus.OK)
        self.send_header('Content-type', 'application/json')
        self.end_headers()
        self.wfile.write(json.dumps(data).encode('utf8'))

    def _replyunauth(self):
        self.send_response(HTTPStatus.UNAUTHORIZED)
        self.send_header('WWW-Authenticate', 'Basic realm="n2n"')
        self.end_headers()

    def _extractauth(self, rpc):
        # Avoid caching the key inside the object for all clients
        rpc.key = None

        header = self.headers.get('Authorization')
        if header is not None:
            authtype, encoded = header.split(' ')
            if authtype == 'Basic':
                user, key = base64.b64decode(encoded).decode('utf8').split(':')
                rpc.key = key

        if rpc.key is None:
            rpc.key = rpc.defaultkey

    def _rpc(self, method, cmdline):
        try:
            data = method(cmdline)
        except ValueError as e:
            if str(e) == "Error: badauth":
                self._replyunauth()
                return

            self._simplereply(HTTPStatus.BAD_REQUEST, 'Bad Command')
            return

        self._replyjson(data)
        return

    def _rpc_read(self, rpc):
        self._extractauth(rpc)
        tail = self.path.split('/')
        cmd = tail[2]
        # if reads ever need args, could use more of the tail

        self._rpc(rpc.read, cmd)

    def _rpc_write(self, rpc):
        self._extractauth(rpc)
        content_length = int(self.headers['Content-Length'])
        post_data = self.rfile.read(content_length).decode('utf8')

        tail = self.path.split('/')
        cmd = tail[2]
        cmdline = cmd + ' ' + post_data

        self._rpc(rpc.write, cmdline)

    def do_GET(self):
        if self.path.startswith("/edge/"):
            self._rpc_read(self.rpc)
            return

        if self.path.startswith("/supernode/"):
            self._rpc_read(self.snrpc)
            return

        if self.path in pages:
            page = pages[self.path]

            self.send_response(HTTPStatus.OK)
            self.send_header('Content-type', page['content_type'])
            self.end_headers()
            self.wfile.write(page['content'].encode('utf8'))
            return

        self._simplereply(HTTPStatus.NOT_FOUND, 'Not Found')
        return

    def do_POST(self):
        if self.path.startswith("/edge/"):
            self._rpc_write(self.rpc)
            return

        if self.path.startswith("/supernode/"):
            self._rpc_write(self.snrpc)
            return


def main():
    ap = argparse.ArgumentParser(
            description='Control the running local n2n edge via http')
    ap.add_argument('-t', '--mgmtport', action='store', default=5644,
                    help='Management Port (default=5644)', type=int)
    ap.add_argument('--snmgmtport', action='store', default=5645,
                    help='Supernode Management Port (default=5645)', type=int)
    ap.add_argument('-k', '--key', action='store',
                    help='Password for mgmt commands')
    ap.add_argument('-d', '--debug', action='store_true',
                    help='Also show raw internal data')
    ap.add_argument('port', action='store',
                    default=8080, type=int, nargs='?',
                    help='Serve requests on TCP port (default 8080)')

    args = ap.parse_args()

    rpc = JsonUDP(args.mgmtport)
    rpc.debug = args.debug
    rpc.defaultkey = args.key

    snrpc = JsonUDP(args.snmgmtport)
    snrpc.debug = args.debug
    snrpc.defaultkey = args.key

    signal.signal(signal.SIGPIPE, signal.SIG_DFL)

    socketserver.TCPServer.allow_reuse_address = True
    handler = functools.partial(SimpleHandler, rpc, snrpc)
    with socketserver.TCPServer(("", args.port), handler) as httpd:
        try:
            httpd.serve_forever()
        except KeyboardInterrupt:
            return


if __name__ == '__main__':
    main()