package PVE::Network::SDN::Frr;

use strict;
use warnings;

=head1 NAME

C<PVE::Network::SDN::Frr> - Helper module for FRR

=head1 DESCRIPTION

This module contains helpers for handling the various intermediate FRR
configuration formats.

We currently mainly use two different intermediate formats throughout the SDN
module:

=head2 frr config

An frr config represented as a perl hash. The controller plugins generate their
frr configuration in this format. This format is also used for merging the local
FRR config (a user-defined configuration file) with the controller-generated
configuration.

=head2 raw config

This is generated from the frr config. It is an array where every entry is a
string that is a FRR configuration line.

=cut

use PVE::RESTEnvironment qw(log_warn);
use PVE::Tools qw(file_get_contents file_set_contents run_command);

=head3 read_local_frr_config

Returns the contents of `/etc/frr/frr.conf.local` as a string if it exists, otherwise undef.

=cut

sub read_local_frr_config {
    if (-e "/etc/frr/frr.conf.local") {
        return file_get_contents("/etc/frr/frr.conf.local");
    }
}

=head3 to_raw_config(\%frr_config)

Converts a given C<\%frr_config> to the raw config format.

=cut

sub to_raw_config {
    my ($frr_config) = @_;

    my $raw_config = [];

    generate_frr_vrf($raw_config, $frr_config->{frr}->{vrf});
    generate_frr_interfaces($raw_config, $frr_config->{frr_interfaces});
    generate_frr_recurse($raw_config, $frr_config->{frr}, undef, 0);
    generate_frr_list($raw_config, $frr_config->{frr_access_list}, "access-list");
    generate_frr_list($raw_config, $frr_config->{frr_prefix_list}, "ip prefix-list");
    generate_frr_list($raw_config, $frr_config->{frr_prefix_list_v6}, "ipv6 prefix-list");
    generate_frr_simple_list($raw_config, $frr_config->{frr_bgp_community_list});
    generate_frr_routemap($raw_config, $frr_config->{frr_routemap});
    generate_frr_simple_list($raw_config, $frr_config->{frr_ip_protocol});

    return $raw_config;
}

=head3 raw_config_to_string(\@raw_config)

Converts a given C<\@raw_config> to a string representing a complete frr
configuration, ready to be written to /etc/frr/frr.conf. If raw_config is empty,
returns only the FRR config skeleton.

=cut

sub raw_config_to_string {
    my ($raw_config) = @_;

    my $nodename = PVE::INotify::nodename();

    my @final_config = (
        "frr version 8.5.2",
        "frr defaults datacenter",
        "hostname $nodename",
        "log syslog informational",
        "service integrated-vtysh-config",
        "!",
    );

    push @final_config, @$raw_config;

    push @final_config, (
        "!", "line vty", "!",
    );

    return join("\n", @final_config);
}

=head3 raw_config_to_string(\@raw_config)

Writes a given C<\@raw_config> to /etc/frr/frr.conf.

=cut

sub write_raw_config {
    my ($raw_config) = @_;

    return if !-d "/etc/frr";
    return if !$raw_config;

    file_set_contents("/etc/frr/frr.conf", raw_config_to_string($raw_config));

}

=head3 append_local_config(\%frr_config, $local_config)

Takes an existing C<\%frr_config> and C<$local_config> (as a string). It parses
the local configuration and appends the values to the existing C<\%frr_config>
in-place.

=cut

sub append_local_config {
    my ($frr_config, $local_config) = @_;

    $local_config = read_local_frr_config() if !$local_config;
    return if !$local_config;

    my $section = \$frr_config->{""};
    my $router = undef;
    my $routemap = undef;
    my $routemap_config = ();
    my $routemap_action = undef;

    while ($local_config =~ /^\s*(.+?)\s*$/gm) {
        my $line = $1;
        $line =~ s/^\s+|\s+$//g;

        if ($line =~ m/^router (.+)$/) {
            $router = $1;
            $section = \$frr_config->{'frr'}->{'router'}->{$router}->{""};
            next;
        } elsif ($line =~ m/^vrf (.+)$/) {
            $section = \$frr_config->{'frr'}->{'vrf'}->{$1};
            next;
        } elsif ($line =~ m/^interface (.+)$/) {
            $section = \$frr_config->{'frr_interfaces'}->{$1};
            next;
        } elsif ($line =~ m/^bgp community-list (.+)$/) {
            push(@{ $frr_config->{'frr_bgp_community_list'} }, $line);
            next;
        } elsif ($line =~ m/address-family (.+)$/) {
            $section = \$frr_config->{'frr'}->{'router'}->{$router}->{'address-family'}->{$1};
            next;
        } elsif ($line =~ m/^route-map (.+) (permit|deny) (\d+)/) {
            $routemap = $1;
            $routemap_config = ();
            $routemap_action = $2;
            $section = \$frr_config->{'frr_routemap'}->{$routemap};
            next;
        } elsif ($line =~ m/^access-list (.+) seq (\d+) (.+)$/) {
            $frr_config->{'frr_access_list'}->{$1}->{$2} = $3;
            next;
        } elsif ($line =~ m/^ip prefix-list (.+) seq (\d+) (.*)$/) {
            $frr_config->{'frr_prefix_list'}->{$1}->{$2} = $3;
            next;
        } elsif ($line =~ m/^ipv6 prefix-list (.+) seq (\d+) (.*)$/) {
            $frr_config->{'frr_prefix_list_v6'}->{$1}->{$2} = $3;
            next;
        } elsif ($line =~ m/^exit-address-family$/) {
            next;
        } elsif ($line =~ m/^exit$/) {
            if ($router) {
                $section = \$frr_config->{''};
                $router = undef;
            } elsif ($routemap) {
                push(@{$$section}, { rule => $routemap_config, action => $routemap_action });
                $section = \$frr_config->{''};
                $routemap = undef;
                $routemap_action = undef;
                $routemap_config = ();
            }
            next;
        } elsif ($line =~ m/!/) {
            next;
        }

        next if !$section;
        if ($routemap) {
            push(@{$routemap_config}, $line);
        } else {
            push(@{$$section}, $line);
        }
    }
}

sub generate_frr_recurse {
    my ($final_config, $content, $parentkey, $level) = @_;

    my $keylist = {};
    $keylist->{'address-family'} = 1;
    $keylist->{router} = 1;

    my $exitkeylist = {};
    $exitkeylist->{'address-family'} = 1;

    my $simple_exitkeylist = {};
    $simple_exitkeylist->{router} = 1;

    # FIXME: make this generic
    my $paddinglevel = undef;
    if ($level == 1 || $level == 2) {
        $paddinglevel = $level - 1;
    } elsif ($level == 3 || $level == 4) {
        $paddinglevel = $level - 2;
    }

    my $padding = "";
    $padding = ' ' x ($paddinglevel) if $paddinglevel;

    if (ref $content eq 'HASH') {
        foreach my $key (sort keys %$content) {
            next if $key eq 'vrf';
            if ($parentkey && defined($keylist->{$parentkey})) {
                push @{$final_config}, $padding . "!";
                push @{$final_config}, $padding . "$parentkey $key";
            } elsif ($key ne '' && !defined($keylist->{$key})) {
                push @{$final_config}, $padding . "$key";
            }

            my $option = $content->{$key};
            generate_frr_recurse($final_config, $option, $key, $level + 1);

            push @{$final_config}, $padding . "exit-$parentkey"
                if $parentkey && defined($exitkeylist->{$parentkey});
            push @{$final_config}, $padding . "exit"
                if $parentkey && defined($simple_exitkeylist->{$parentkey});
        }
    }

    if (ref $content eq 'ARRAY') {
        push @{$final_config}, map { $padding . "$_" } @$content;
    }
}

sub generate_frr_vrf {
    my ($final_config, $vrfs) = @_;

    return if !$vrfs;

    my @config = ();

    foreach my $id (sort keys %$vrfs) {
        my $vrf = $vrfs->{$id};
        push @config, "!";
        push @config, "vrf $id";
        foreach my $rule (@$vrf) {
            push @config, " $rule";

        }
        push @config, "exit-vrf";
    }

    push @{$final_config}, @config;
}

sub generate_frr_simple_list {
    my ($final_config, $rules) = @_;

    return if !$rules;

    my @config = ();
    push @{$final_config}, "!";
    foreach my $rule (sort @$rules) {
        push @{$final_config}, $rule;
    }
}

sub generate_frr_list {
    my ($final_config, $lists, $type) = @_;

    my $config = [];

    for my $id (sort keys %$lists) {
        my $list = $lists->{$id};

        for my $seq (sort keys %$list) {
            my $rule = $list->{$seq};
            push @$config, "$type $id seq $seq $rule";
        }
    }

    if (@$config > 0) {
        push @{$final_config}, "!", @$config;
    }
}

sub generate_frr_interfaces {
    my ($final_config, $interfaces) = @_;

    foreach my $k (sort keys %$interfaces) {
        my $iface = $interfaces->{$k};
        push @{$final_config}, "!";
        push @{$final_config}, "interface $k";
        foreach my $rule (sort @$iface) {
            push @{$final_config}, " $rule";
        }
    }
}

sub generate_frr_routemap {
    my ($final_config, $routemaps) = @_;

    foreach my $id (sort keys %$routemaps) {

        my $routemap = $routemaps->{$id};
        my $order = 0;
        foreach my $seq (@$routemap) {
            $order++;
            next if !defined($seq->{action});
            my @config = ();
            push @config, "!";
            push @config, "route-map $id $seq->{action} $order";
            my $rule = $seq->{rule};
            push @config, map { " $_" } @$rule;
            push @{$final_config}, @config;
            push @{$final_config}, "exit";
        }
    }
}

1;