#!/usr/bin/env python3

# network.py - PVC client function library, Network fuctions
# Part of the Parallel Virtual Cluster (PVC) system
#
#    Copyright (C) 2018  Joshua M. Boniface <joshua@boniface.me>
#
#    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 3 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, see <https://www.gnu.org/licenses/>.
#
###############################################################################

import os
import socket
import time
import uuid
import re
import tempfile
import subprocess
import difflib
import colorama
import click
import lxml.objectify
import configparser
import kazoo.client

import client_lib.ansiiprint as ansiiprint
import client_lib.zkhandler as zkhandler
import client_lib.common as common

#
# Cluster search functions
#
def getClusterNetworkList(zk_conn):
    # Get a list of VNIs by listing the children of /networks
    vni_list = zk_conn.get_children('/networks')
    description_list = []
    # For each VNI, get the corresponding description from the data
    for vni in vni_list:
        description_list.append(zk_conn.get('/networks/{}'.format(vni))[0].decode('ascii'))
    return vni_list, description_list

def searchClusterByVNI(zk_conn, vni):
    try:
        # Get the lists
        vni_list, description_list = getClusterNetworkList(zk_conn)
        # We're looking for UUID, so find that element ID
        index = vni_list.index(vni)
        # Get the name_list element at that index
        description = description_list[index]
    except ValueError:
        # We didn't find anything
        return None

    return description

def searchClusterByDescription(zk_conn, description):
    try:
        # Get the lists
        vni_list, description_list = getClusterNetworkList(zk_conn)
        # We're looking for name, so find that element ID
        index = description_list.index(description)
        # Get the uuid_list element at that index
        vni = vni_list[index]
    except ValueError:
        # We didn't find anything
        return None

    return vni

def getNetworkVNI(zk_conn, network):
    # Validate and obtain alternate passed value
    if network.isdigit():
        net_description = searchClusterByVNI(zk_conn, network)
        net_vni = searchClusterByDescription(zk_conn, net_description)
    else:
        net_vni = searchClusterByDescription(zk_conn, network)
        net_description = searchClusterByVNI(zk_conn, net_vni)

    return net_vni

def getNetworkDescription(zk_conn, network):
    # Validate and obtain alternate passed value
    if network.isdigit():
        net_description = searchClusterByVNI(zk_conn, network)
        net_vni = searchClusterByDescription(zk_conn, net_description)
    else:
        net_vni = searchClusterByDescription(zk_conn, network)
        net_description = searchClusterByVNI(zk_conn, net_vni)

    return net_description

def getNetworkDHCPLeases(zk_conn, vni):
    # Get a list of DHCP leases by listing the children of /networks/<vni>/dhcp_leases
    dhcp_leases = zk_conn.get_children('/networks/{}/dhcp_leases'.format(vni))
    return sorted(dhcp_leases)

def getNetworkDHCPReservations(zk_conn, vni):
    # Get a list of VNIs by listing the children of /networks/<vni>/dhcp_leases
    dhcp_reservations = []
    dhcp_leases = getNetworkDHCPLeases(zk_conn, vni)
    for lease in dhcp_leases:
        timestamp = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_leases/{}'.format (vni, lease))
        if timestamp == 'static':
            dhcp_reservations.append(lease)
    return sorted(dhcp_reservations)

def getNetworkFirewallRules(zk_conn, vni):
    firewall_rules = zk_conn.get_children('/networks/{}/firewall_rules'.format(vni))
    return None

def getNetworkInformation(zk_conn, vni):
    description = zkhandler.readdata(zk_conn, '/networks/{}'.format(vni))
    domain = zkhandler.readdata(zk_conn, '/networks/{}/domain'.format(vni))
    ip_network = zkhandler.readdata(zk_conn, '/networks/{}/ip_network'.format(vni))
    ip_gateway = zkhandler.readdata(zk_conn, '/networks/{}/ip_gateway'.format(vni))
    dhcp_flag = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_flag'.format(vni))
    dhcp_start = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_start'.format(vni))
    dhcp_end = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_end'.format(vni))
    return description, domain, ip_network, ip_gateway, dhcp_flag, dhcp_start, dhcp_end

def getDHCPLeaseInformation(zk_conn, vni, mac_address):
    hostname = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_leases/{}/hostname'.format(vni, mac_address))
    ip_address = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_leases/{}/ipaddr'.format(vni, mac_address))
    timestamp = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_leases/{}'.format(vni, mac_address))
    return hostname, ip_address, mac_address, timestamp

def formatNetworkInformation(zk_conn, vni, long_output):
    description, domain, ip_network, ip_gateway, dhcp_flag, dhcp_start, dhcp_end = getNetworkInformation(zk_conn, vni)

    if dhcp_flag == "True":
        dhcp_flag_colour = ansiiprint.green()
    else:
        dhcp_flag_colour = ansiiprint.blue()
    colour_off = ansiiprint.end()

    # Format a nice output: do this line-by-line then concat the elements at the end
    ainformation = []
    ainformation.append('{}Virtual network information:{}'.format(ansiiprint.bold(), ansiiprint.end()))
    ainformation.append('')
    # Basic information
    ainformation.append('{}VNI:{}           {}'.format(ansiiprint.purple(), ansiiprint.end(), vni))
    ainformation.append('{}Description:{}   {}'.format(ansiiprint.purple(), ansiiprint.end(), description))
    ainformation.append('{}Domain:{}        {}'.format(ansiiprint.purple(), ansiiprint.end(), domain))
    ainformation.append('{}IP network:{}    {}'.format(ansiiprint.purple(), ansiiprint.end(), ip_network))
    ainformation.append('{}IP gateway:{}    {}'.format(ansiiprint.purple(), ansiiprint.end(), ip_gateway))
    ainformation.append('{}DHCP enabled:{}  {}{}{}'.format(ansiiprint.purple(), ansiiprint.end(), dhcp_flag_colour, dhcp_flag, colour_off))
    if dhcp_flag == "True":
        ainformation.append('{}DHCP range:{}    {} - {}'.format(ansiiprint.purple(), ansiiprint.end(), dhcp_start, dhcp_end))

    if long_output:
        dhcp_reservations_list = getNetworkDHCPReservations(zk_conn, vni)
        if dhcp_reservations_list:
            ainformation.append('')
            ainformation.append('{}Client DHCP reservations:{}'.format(ansiiprint.bold(), ansiiprint.end()))
            ainformation.append('')
            # Only show static reservations in the detailed information
            dhcp_reservations_string = formatDHCPLeaseList(zk_conn, vni, dhcp_reservations_list)
            for line in dhcp_reservations_string.split('\n'):
                ainformation.append(line)

        firewall_rules = zk_conn.get_children('/networks/{}/firewall_rules'.format(vni))
        if firewall_rules:
            ainformation.append('')
            ainformation.append('{}Network firewall rules:{}'.format(ansiiprint.bold(), ansiiprint.end()))
            ainformation.append('')
            formatted_firewall_rules = get_list_firewall_rules(zk_conn, vni)

    # Join it all together
    information = '\n'.join(ainformation)
    return information

def formatNetworkList(zk_conn, net_list):
    net_list_output = []
    description = {}
    domain = {}
    ip_network = {}
    ip_gateway = {}
    dhcp_flag = {}
    dhcp_flag_colour = {}
    dhcp_start = {}
    dhcp_end = {}
    dhcp_range = {}
    colour_off = ansiiprint.end()

    # Gather information for printing
    for net in net_list:
        # get info
        description[net], domain[net], ip_network[net], ip_gateway[net], dhcp_flag[net], dhcp_start[net], dhcp_end[net] = getNetworkInformation(zk_conn, net)

        if dhcp_flag[net] == "True":
            dhcp_flag_colour[net] = ansiiprint.green()
            dhcp_range[net] = '{} - {}'.format(dhcp_start[net], dhcp_end[net])
        else:
            dhcp_flag_colour[net] = ansiiprint.blue()
            dhcp_range[net] = 'N/A'

    # Determine optimal column widths
    # Dynamic columns: node_name, hypervisor, migrated
    net_vni_length = 5
    net_description_length = 13
    net_domain_length = 8
    net_ip_network_length = 12
    net_ip_gateway_length = 9
    net_dhcp_range_length = 12
    for net in net_list:
        # vni column
        _net_vni_length = len(net) + 1
        if _net_vni_length > net_vni_length:
            net_vni_length = _net_vni_length
        # description column
        _net_description_length = len(description[net]) + 1
        if _net_description_length > net_description_length:
            net_description_length = _net_description_length
        # domain column
        _net_domain_length = len(domain[net]) + 1
        if _net_domain_length > net_domain_length:
            net_domain_length = _net_domain_length
        # ip_network column
        _net_ip_network_length = len(ip_network[net]) + 1
        if _net_ip_network_length > net_ip_network_length:
            net_ip_network_length = _net_ip_network_length
        # ip_gateway column
        _net_ip_gateway_length = len(ip_gateway[net]) + 1
        if _net_ip_gateway_length > net_ip_gateway_length:
            net_ip_gateway_length = _net_ip_gateway_length
        # dhcp_range column
        _net_dhcp_range_length = len(dhcp_range[net]) + 1
        if _net_dhcp_range_length > net_dhcp_range_length:
            net_dhcp_range_length = _net_dhcp_range_length

    # Format the string (header)
    net_list_output_header = '{bold}\
{net_vni: <{net_vni_length}} \
{net_description: <{net_description_length}} \
{net_domain: <{net_domain_length}} \
{net_ip_network: <{net_ip_network_length}} \
{net_ip_gateway: <{net_ip_gateway_length}} \
{net_dhcp_flag: <6} \
{net_dhcp_range: <{net_dhcp_range_length}} \
{end_bold}'.format(
        bold=ansiiprint.bold(),
        end_bold=ansiiprint.end(),
        net_vni_length=net_vni_length,
        net_description_length=net_description_length,
        net_domain_length=net_domain_length,
        net_ip_network_length=net_ip_network_length,
        net_ip_gateway_length=net_ip_gateway_length,
        net_dhcp_range_length=net_dhcp_range_length,
        net_vni='VNI',
        net_description='Description',
        net_domain='Domain',
        net_ip_network='Network',
        net_ip_gateway='Gateway',
        net_dhcp_flag='DHCP',
        net_dhcp_range='Range',
    )

    for net in net_list:
        net_list_output.append(
            '{bold}\
{net_vni: <{net_vni_length}} \
{net_description: <{net_description_length}} \
{net_domain: <{net_domain_length}} \
{net_ip_network: <{net_ip_network_length}} \
{net_ip_gateway: <{net_ip_gateway_length}} \
{dhcp_flag_colour}{net_dhcp_flag: <6}{colour_off} \
{net_dhcp_range: <{net_dhcp_range_length}} \
{end_bold}'.format(
                bold='',
                end_bold='',
                net_vni_length=net_vni_length,
                net_description_length=net_description_length,
                net_domain_length=net_domain_length,
                net_ip_network_length=net_ip_network_length,
                net_ip_gateway_length=net_ip_gateway_length,
                net_dhcp_range_length=net_dhcp_range_length,
                net_vni=net,
                net_description=description[net],
                net_domain=domain[net],
                net_ip_network=ip_network[net],
                net_ip_gateway=ip_gateway[net],
                net_dhcp_flag=dhcp_flag[net],
                net_dhcp_range=dhcp_range[net],
                dhcp_flag_colour=dhcp_flag_colour[net],
                colour_off=colour_off
            )
        )

    output_string = net_list_output_header + '\n' + '\n'.join(sorted(net_list_output))
    return output_string

def formatDHCPLeaseList(zk_conn, vni, dhcp_leases_list):
    dhcp_lease_list_output = []
    hostname = {}
    ip_address = {}
    mac_address = {}
    timestamp = {}

    # Gather information for printing
    for dhcp_lease in dhcp_leases_list:
        # get info
        hostname[dhcp_lease], ip_address[dhcp_lease], mac_address[dhcp_lease], timestamp[dhcp_lease] = getDHCPLeaseInformation(zk_conn, vni, dhcp_lease)
       

    # Determine optimal column widths
    lease_hostname_length = 13
    lease_ip_address_length = 11
    lease_mac_address_length = 13
    for dhcp_lease in dhcp_leases_list:
        # hostname column
        _lease_hostname_length = len(hostname[dhcp_lease]) + 1
        if _lease_hostname_length > lease_hostname_length:
            lease_hostname_length = _lease_hostname_length
        # ip_network column
        _lease_ip_address_length = len(ip_address[dhcp_lease]) + 1
        if _lease_ip_address_length > lease_ip_address_length:
            lease_ip_address_length = _lease_ip_address_length
        # ip_gateway column
        _lease_mac_address_length = len(mac_address[dhcp_lease]) + 1
        if _lease_mac_address_length > lease_mac_address_length:
            lease_mac_address_length = _lease_mac_address_length

    # Format the string (header)
    dhcp_lease_list_output_header = '{bold}\
{lease_hostname: <{lease_hostname_length}} \
{lease_ip_address: <{lease_ip_address_length}} \
{lease_mac_address: <{lease_mac_address_length}} \
{lease_timestamp: <{lease_timestamp_length}} \
{end_bold}'.format(
        bold=ansiiprint.bold(),
        end_bold=ansiiprint.end(),
        lease_hostname_length=lease_hostname_length,
        lease_ip_address_length=lease_ip_address_length,
        lease_mac_address_length=lease_mac_address_length,
        lease_timestamp_length=12,
        lease_hostname='Hostname',
        lease_ip_address='IP Address',
        lease_mac_address='MAC Address',
        lease_timestamp='Timestamp'
    )

    for dhcp_lease in dhcp_leases_list:
        dhcp_lease_list_output.append('{bold}\
{lease_hostname: <{lease_hostname_length}} \
{lease_ip_address: <{lease_ip_address_length}} \
{lease_mac_address: <{lease_mac_address_length}} \
{lease_timestamp: <{lease_timestamp_length}} \
{end_bold}'.format(
                bold='',
                end_bold='',
                lease_hostname_length=lease_hostname_length,
                lease_ip_address_length=lease_ip_address_length,
                lease_mac_address_length=lease_mac_address_length,
                lease_timestamp_length=12,
                lease_hostname=hostname[dhcp_lease],
                lease_ip_address=ip_address[dhcp_lease],
                lease_mac_address=mac_address[dhcp_lease],
                lease_timestamp=timestamp[dhcp_lease]
            )
        )

    output_string = dhcp_lease_list_output_header + '\n' + '\n'.join(sorted(dhcp_lease_list_output))
    return output_string

def isValidMAC(macaddr):
    allowed = re.compile(r"""
                         (
                            ^([0-9A-F]{2}[:]){5}([0-9A-F]{2})$
                         )
                         """,
                         re.VERBOSE|re.IGNORECASE)

    if allowed.match(macaddr) is None:
        return False
    else:
        return True

def isValidIP(ipaddr):
    ip_blocks = str(ipaddr).split(".")
    if len(ip_blocks) == 4:
        for block in ip_blocks:
            # Check if number is digit, if not checked before calling this function
            if not block.isdigit():
                 return False
            tmp = int(block)
            if 0 > tmp > 255:
                 return False
        return True
    return False

#
# Direct functions
#
def add_network(zk_conn, vni, description, domain, ip_network, ip_gateway, dhcp_flag, dhcp_start, dhcp_end):
    if description == '':
        description = vni

    if dhcp_flag and ( not dhcp_start or not dhcp_end ):
        return False, 'ERROR: DHCP start and end addresses are required for a DHCP-enabled network.'

    # Check if a network with this VNI already exists
    if zk_conn.exists('/networks/{}'.format(vni)):
        return False, 'ERROR: A network with VNI {} already exists!'.format(vni)

    # Add the new network to Zookeeper
    zkhandler.writedata(zk_conn, {
        '/networks/{}'.format(vni): description,
        '/networks/{}/domain'.format(vni): domain,
        '/networks/{}/ip_network'.format(vni): ip_network,
        '/networks/{}/ip_gateway'.format(vni): ip_gateway,
        '/networks/{}/dhcp_flag'.format(vni): str(dhcp_flag),
        '/networks/{}/dhcp_start'.format(vni): dhcp_start,
        '/networks/{}/dhcp_end'.format(vni): dhcp_end,
        '/networks/{}/dhcp_leases'.format(vni): '',
        '/networks/{}/firewall_rules'.format(vni): ''
    })

    return True, 'Network "{}" added successfully!'.format(description)

def modify_network(zk_conn, vni, **parameters):
    # Add the new network to Zookeeper
    transaction = zk_conn.transaction()
    zk_data = {}
    if parameters['description'] != None:
        zk_data.update({'/networks/{}'.format(vni): parameters['description']})
    if parameters['ip_network'] != None:
        zk_data.update({'/networks/{}/ip_network'.format(vni): parameters['ip_network']})
    if parameters['ip_gateway'] != None:
        zk_data.update({'/networks/{}/ip_gateway'.format(vni): parameters['ip_gateway']})
    if parameters['dhcp_flag'] != None:
        zk_data.update({'/networks/{}/dhcp_flag'.format(vni): str(parameters['dhcp_flag'])})

    zkhandler.writedata(zk_conn, zk_data)
    
    return True, 'Network "{}" modified successfully!'.format(vni)

def remove_network(zk_conn, network):
    # Validate and obtain alternate passed value
    vni = getNetworkVNI(zk_conn, network)
    description = getNetworkDescription(zk_conn, network)
    if not vni:
        return False, 'ERROR: Could not find network "{}" in the cluster!'.format(network)

    # Delete the configuration
    try:
        zk_conn.delete('/networks/{}'.format(vni), recursive=True)
    except:
        pass

    return True, 'Network "{}" removed successfully!'.format(description)


def add_dhcp_reservation(zk_conn, network, ipaddress, macaddress, hostname):
    # Validate and obtain standard passed value
    net_vni = getNetworkVNI(zk_conn, network)
    if net_vni == None:
        return False, 'ERROR: Could not find network "{}" in the cluster!'.format(network)

    # Use uppercase MAC format exclusively
    macaddress = macaddress.upper()

    if not isValidMAC(macaddress):
        return False, 'ERROR: MAC address "{}" is not valid! Always use ":" as a separator.'.format(macaddress)

    if not isValidIP(ipaddress):
        return False, 'ERROR: IP address "{}" is not valid!'.format(macaddress)

    if zk_conn.exists('/networks/{}/dhcp_leases/{}'.format(net_vni, macaddress)):
        return False, 'ERROR: A reservation with MAC "{}" already exists!'.format(macaddress)

    # Add the new static lease to ZK
    try:
        zkhandler.writedata(zk_conn, {
            '/networks/{}/dhcp_leases/{}'.format(net_vni, macaddress): 'static',
            '/networks/{}/dhcp_leases/{}/hostname'.format(net_vni, macaddress): hostname,
            '/networks/{}/dhcp_leases/{}/ipaddr'.format(net_vni, macaddress): ipaddress
        })
    except Exception as e:
        return False, 'ERROR: Failed to write to Zookeeper! Exception: "{}".'.format(e)

    return True, 'DHCP reservation "{}" added successfully!'.format(macaddress)

def remove_dhcp_lease(zk_conn, network, lease):
    # Validate and obtain standard passed value
    net_vni = getNetworkVNI(zk_conn, network)
    if net_vni == None:
        return False, 'ERROR: Could not find network "{}" in the cluster!'.format(network)

    match_description = ''

    # Check if the reservation matches a description, a mac, or an IP address currently in the database
    dhcp_leases_list = zk_conn.get_children('/networks/{}/dhcp_leases'.format(net_vni))
    for macaddr in dhcp_leases_list:
        hostname = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_leases/{}/hostname'.format(net_vni, macaddr))
        ipaddress = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_leases/{}/ipaddr'.format(net_vni, macaddr))
        if lease == macaddr or lease == hostname or lease == ipaddress:
            match_description = macaddr
    
    if not match_description:
        return False, 'ERROR: No DHCP lease exists matching "{}"!'.format(reservation)

    # Remove the entry from zookeeper
    try:
        zk_conn.delete('/networks/{}/dhcp_leases/{}'.format(net_vni, match_description), recursive=True)
    except:
        return False, 'ERROR: Failed to write to Zookeeper!'

    return True, 'DHCP lease "{}" removed successfully!'.format(match_description)

def get_info(zk_conn, network, long_output):
    # Validate and obtain alternate passed value
    net_vni = getNetworkVNI(zk_conn, network)
    if net_vni == None:
        return False, 'ERROR: Could not find network "{}" in the cluster!'.format(network)

    information = formatNetworkInformation(zk_conn, net_vni, long_output)
    click.echo(information)
    click.echo('')

    return True, ''

def get_list(zk_conn, limit):
    net_list = []
    full_net_list = zk_conn.get_children('/networks')

    for net in full_net_list:
        description = zkhandler.readdata(zk_conn, '/networks/{}'.format(net))
        if limit != None:
            try:
                # Implcitly assume fuzzy limits
                if re.match('\^.*', limit) == None:
                    limit = '.*' + limit
                if re.match('.*\$', limit) == None:
                    limit = limit + '.*'

                if re.match(limit, net) != None:
                    net_list.append(net)
                if re.match(limit, description) != None:
                    net_list.append(net)
            except Exception as e:
                return False, 'Regex Error: {}'.format(e)
        else:
            net_list.append(net)

    output_string = formatNetworkList(zk_conn, net_list)
    click.echo(output_string)

    return True, ''

def get_list_dhcp_leases(zk_conn, network, limit, only_static=False):
    # Validate and obtain alternate passed value
    net_vni = getNetworkVNI(zk_conn, network)
    if net_vni == None:
        return False, 'ERROR: Could not find network "{}" in the cluster!'.format(network)

    dhcp_leases_list = []
    full_dhcp_leases_list = getNetworkDHCPLeases(zk_conn, net_vni)

    if limit:
        try:
            # Implcitly assume fuzzy limits
            if re.match('\^.*', limit) == None:
                limit = '.*' + limit
            if re.match('.*\$', limit) == None:
                limit = limit + '.*'
        except Exception as e:
            return False, 'Regex Error: {}'.format(e)
        

    for lease in full_dhcp_leases_list:
        valid_lease = False
        if only_static:
            lease_timestamp = zkhandler.readdata(zk_conn, '/networks/{}/dhcp_leases/{}'.format(net_vni, lease))
            if lease_timestamp == 'static':
                if limit:
                    if re.match(limit, lease) != None:
                        valid_lease = True
                    if re.match(limit, lease) != None:
                        valid_lease = True
                else:
                    valid_lease = True
        else:
            if limit:
                if re.match(limit, lease) != None:
                    valid_lease = True
                if re.match(limit, lease) != None:
                    valid_lease = True
            else:
                valid_lease = True

        if valid_lease:
            dhcp_leases_list.append(lease)

    output_string = formatDHCPLeaseList(zk_conn, net_vni, dhcp_leases_list)
    click.echo(output_string)

    return True, ''

def get_list_firewall_rules(zk_conn, network):
    # Validate and obtain alternate passed value
    net_vni = getNetworkVNI(zk_conn, network)
    if net_vni == None:
        return False, 'ERROR: Could not find network "{}" in the cluster!'.format(network)

    firewall_rules = getNetworkFirewallRules(zk_conn, net_vni)
    return firewall_rules