#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;
use OpenSRF::System;
use OpenSRF::AppSession;
use OpenSRF::EX qw(:try);

# Sane-ish default
my $opt_osrf_config = '/openils/conf/opensrf_core.xml';

# For storing the list of supposedly active services
my @services;
# For storing our list of routers to check
my @routers;

GetOptions(
    'osrf-config=s' => \$opt_osrf_config,
);

# If we can't bootstrap then something is horribly wrong!
# Probably "ejabberd isn't running"
try {
    OpenSRF::System->bootstrap_client(config_file => $opt_osrf_config);
} otherwise {
    print "Bootstrap failed\n";
    exit 2;
};

# This gets the list of supposedly active services
sub prep_service_list {
    # Using settings directly, as I don't know how to ask with pre-existing classes
    my $session = OpenSRF::AppSession->create('opensrf.settings');
    try {
        $session->connect;
    } otherwise {
        print "Settings Connect Failed\n";
        exit 2;
    };
    # This xpath is "Find every instace of an appname node under an activeapps node, anywhere"
    # It should grab every app configured to run on any drone
    # If your config contains apps that are not run on real drones you will get errors ;)
    my $req = $session->request('opensrf.settings.xpath.get', '//activeapps/appname');
    my $list = $req->recv;

    if(UNIVERSAL::isa($list,"Error")) {
        print "Active Apps List Failed\n";
        exit 2;
    }

    $req->finish;
    # Quick and dirty de-dupe
    my %u_list = map { ($_ => 1) } @{$list->content};
    # And save for later
    @services = keys(%u_list);

    $session->finish;
    $session->disconnect;
}

# This gets the list of supposedly active routers
# This relies on the bootstrap being accurate in that regard
sub prep_routers_list {
    # First, we grab our (hopefully) cached config
    my $config = OpenSRF::Utils::Config->current;
    # Loop over it quick
    foreach(@{$config->bootstrap->routers}) {
        # And make entries for each router
        my $router = {};
        $router->{name} = $_->{name};
        $router->{domain} = $_->{domain};
        # If we don't have a services list assume all active ones (aka, private router)
        $router->{services} = \@services unless $_->{services};
        # Otherwise, make note of what we are supposed to be running (aka, public router)
        $router->{services} = $_->{services}->{service} if $_->{services};
        # And tack it onto the list
        push @routers, $router;
    }
}

# This does the actual checking of routers/services
sub check_routers {
    # Shortcut
    my $conf = OpenSRF::Utils::Config->current;
    foreach my $router (@routers) {
        # HACK WARNING - This changes the router we will be querying
        # This basically edits the cached bootstrap file. This is not guaranteed to keep working.
        # This does NOT change what domain we are querying from
        $conf->bootstrap->router_name($router->{name});
        $conf->bootstrap->domain($router->{domain});
        # Assume things failed unless they didn't.
        my $failed = 1;
        # First, check the router to see what it claims to have active services-wise
        my $session = OpenSRF::AppSession->create('router');
        try {
            $failed = 0 if $session->connect;
        } otherwise {
            $failed = 1;
        };
        if($session->state != $session->CONNECTED || $failed) {
            $router->{online} = 0;
            next;
        }
        # Yay router commands! This should give us all services with at least one listener
        my $req = $session->request('opensrf.router.info.class.list');
        my $class_list = $req->recv;
        $req->finish;

        if(UNIVERSAL::isa($class_list,"Error")) {
            $session->finish;
            $session->disconnect;
            $router->{online} = 0;
            next;
        }

        # If we got an answer then this router is online!
        $router->{online} = 1;
        # Counters and storage for services checks
        $router->{checked} = 0;
        $router->{pass} = 0;
        $router->{failed} = [];
        # Quick reference of what the router told us it has
        my %online_services = map { ($_ => 1) } @{$class_list->content};
        foreach my $service (@{$router->{services}}) {
            # This skips services not in the active list. Mainly for routers with explicit lists (aka, public routers) that not all may be configured to run.
            next unless grep { $service eq $_ } @services;
            # Assume we did not pass until proven otherwise
            my $passed = 0;
            $router->{checked} += 1;
            if($online_services{$service}) {
                # Check the service, even if a listener is registered it may be dead
                my $session2 = OpenSRF::AppSession->create($service);
                try {
                    $session2->connect;
                };
                if($session2->state == $session2->CONNECTED) {
                    # To my knowledge, EVERY service should have atomic echo available
                    my $req2 = $session2->request('opensrf.system.echo.atomic','Test');
                    my $testresult = $req2->recv;
                    if(!UNIVERSAL::isa($testresult,"Error")) {
                        # If we got back what we passed in the service is working! Ish. Not a flawless test.
                        $passed = 1 if @{$testresult->content}[0] eq 'Test';
                    }
                    $req2->finish;
                    $session2->finish;
                    $session2->disconnect;
                }
            }
            if($passed) {
                # Looks like it works, make note!
                $router->{pass} += 1;
            } else {
                # Doesn't work! Save for later reporting.
                push @{$router->{failed}}, $service;
            }
        }
        $session->finish;
        $session->disconnect;        
    }
}

# This outputs the result for Nagios
sub output_result {
    # Counters/storage
    my $checked_services = 0;
    my $up_services = 0;
    my @down_services;
    my @down_routers;
    # Assume all is good until proven otherwise
    my $retcode = 0;
    foreach my $router (@routers) {
        # If the router isn't online then we don't need to look at services - We didn't check any!
        if(!$router->{online}) {
            push @down_routers, $router->{domain};
            next;
        }
        # Otherwise increment our counters as needed
        $checked_services += $router->{checked};
        $up_services += $router->{pass};
        foreach (@{$router->{failed}}) {
            # Keep track of any down services for reporting in a minute
            push @down_services, $router->{domain} . ':' . $_;
        }
    }
    if(@down_routers) {
        # Down routers are really bad. Chances are there will only ever be one here (public), but join with commas anyway.
        print "Router(s) Offline: " . join(', ', @down_routers) . "\n";
        $retcode = 2;
    } elsif ($checked_services != $up_services) {
        # Non-responsive services are also really bad
        print "Service(s) not responding\n";
        $retcode = 2;
    } else {
        # But if we have nothing then things are good!
        print "Routers/Services OK\n";
    }
    # If there are down services then spit them out as additional information.
    print "$_\n" foreach (@down_services);
    # And return our response code
    exit $retcode;
}

# CHEAT - We need SettingsClient to have cached stuff
try {
    OpenSRF::Utils::SettingsClient->new()->config_value('none');
} otherwise {
    print "Settings Fetch Failed\n";
    exit 2;
};
# And run all of the above functions
prep_service_list();
prep_routers_list();
check_routers();
output_result();

# This code should NEVER run, as the only way out of output_result is an exit statement
print "What? I shouldn't have reached here.";
exit 3;