#!/usr/bin/env python3

# Removes boolean operator from:
#   - "set service dhcp-server shared-network-name <xyz> subnet 172.31.0.0/24 ip-forwarding enable (true|false)"
#   - "set service dhcp-server shared-network-name <xyz> authoritative (true|false)"
#   - "set service dhcp-server disabled (true|false)"

import sys

from vyos.configtree import ConfigTree

if len(sys.argv) < 2:
    print("Must specify file name!")
    sys.exit(1)

file_name = sys.argv[1]

with open(file_name, 'r') as f:
    config_file = f.read()

config = ConfigTree(config_file)

if not config.exists(['service', 'dhcp-server']):
    # Nothing to do
    sys.exit(0)
else:
    base = ['service', 'dhcp-server']
    # Make node "set service dhcp-server dynamic-dns-update enable (true|false)" valueless
    if config.exists(base + ['dynamic-dns-update']):
        bool_val = config.return_value(base + ['dynamic-dns-update', 'enable'])

        # Delete the node with the old syntax
        config.delete(base + ['dynamic-dns-update'])
        if str(bool_val) == 'true':
            # Enable dynamic-dns-update with new syntax
            config.set(base + ['dynamic-dns-update'], value=None)

    # Make node "set service dhcp-server disabled (true|false)" valueless
    if config.exists(base + ['disabled']):
        bool_val = config.return_value(base + ['disabled'])

        # Delete the node with the old syntax
        config.delete(base + ['disabled'])
        if str(bool_val) == 'true':
            # Now disable DHCP server with the new syntax
            config.set(base + ['disable'], value=None)

    # Make node "set service dhcp-server hostfile-update (enable|disable) valueless
    if config.exists(base + ['hostfile-update']):
        bool_val = config.return_value(base + ['hostfile-update'])

        # Delete the node with the old syntax incl. all subnodes
        config.delete(base + ['hostfile-update'])
        if str(bool_val) == 'enable':
            # Enable hostfile update with new syntax
            config.set(base + ['hostfile-update'], value=None)

    # Run this for every instance if 'shared-network-name'
    for network in config.list_nodes(base + ['shared-network-name']):
        base_network = base + ['shared-network-name', network]
        # format as tag node to avoid loading problems
        config.set_tag(base + ['shared-network-name'])

        # Run this for every specified 'subnet'
        for subnet in config.list_nodes(base_network + ['subnet']):
            base_subnet = base_network + ['subnet', subnet]
            # format as tag node to avoid loading problems
            config.set_tag(base_network + ['subnet'])

            # Make node "set service dhcp-server shared-network-name <xyz> subnet 172.31.0.0/24 ip-forwarding enable" valueless
            if config.exists(base_subnet + ['ip-forwarding', 'enable']):
                bool_val = config.return_value(base_subnet + ['ip-forwarding', 'enable'])
                # Delete the node with the old syntax
                config.delete(base_subnet + ['ip-forwarding'])
                if str(bool_val) == 'true':
                    # Recreate node with new syntax
                    config.set(base_subnet + ['ip-forwarding'], value=None)

            # Rename node "set service dhcp-server shared-network-name <xyz> subnet 172.31.0.0/24 start <172.16.0.4> stop <172.16.0.9>
            if config.exists(base_subnet + ['start']):
                # This is the new "range" id for DHCP lease ranges
                r_id = 0
                for range in config.list_nodes(base_subnet + ['start']):
                    range_start = range
                    range_stop = config.return_value(base_subnet + ['start', range_start, 'stop'])

                    # Delete the node with the old syntax
                    config.delete(base_subnet + ['start', range_start])

                    # Create the node for the new syntax
                    # Note: range is a tag node, counter is its child, not a value
                    config.set(base_subnet + ['range', r_id])
                    config.set(base_subnet + ['range', r_id, 'start'], value=range_start)
                    config.set(base_subnet + ['range', r_id, 'stop'], value=range_stop)

                    # format as tag node to avoid loading problems
                    config.set_tag(base_subnet + ['range'])

                    # increment range id for possible next range definition
                    r_id += 1

                # Delete the node with the old syntax
                config.delete(['service', 'dhcp-server', 'shared-network-name', network, 'subnet', subnet, 'start'])


        # Make node "set service dhcp-server shared-network-name <xyz> authoritative" valueless
        if config.exists(['service', 'dhcp-server', 'shared-network-name', network, 'authoritative']):
            authoritative = config.return_value(['service', 'dhcp-server', 'shared-network-name', network, 'authoritative'])

            # Delete the node with the old syntax
            config.delete(['service', 'dhcp-server', 'shared-network-name', network, 'authoritative'])

            # Recreate node with new syntax - if required
            if authoritative == "enable":
                config.set(['service', 'dhcp-server', 'shared-network-name', network, 'authoritative'])

    try:
        with open(file_name, 'w') as f:
            f.write(config.to_string())
    except OSError as e:
        print("Failed to save the modified config: {}".format(e))
        sys.exit(1)