use 5.008001;
use strict;
use warnings;

package Log::Any::Adapter::Syslog;

# ABSTRACT: Send Log::Any logs to syslog
our $VERSION = '1.718';

use Log::Any::Adapter::Util qw{make_method};
use base qw{Log::Any::Adapter::Base};

use Sys::Syslog qw( :DEFAULT setlogsock );
use File::Basename ();

my $log_params;


# Build log level priorities
my @logging_methods = Log::Any->logging_methods;
our %logging_levels;
for my $i (0..@logging_methods-1) {
    $logging_levels{$logging_methods[$i]} = $i;
}
# some common typos
$logging_levels{warn} = $logging_levels{warning};
$logging_levels{inform} = $logging_levels{info};
$logging_levels{err} = $logging_levels{error};

sub _min_level {
    my $self = shift;

    return $ENV{LOG_LEVEL}
        if $ENV{LOG_LEVEL} && defined $logging_levels{$ENV{LOG_LEVEL}};
    return 'trace' if $ENV{TRACE};
    return 'debug' if $ENV{DEBUG};
    return 'info'  if $ENV{VERBOSE};
    return 'error' if $ENV{QUIET};
    return 'trace';
}

# When initialized we connect to syslog.
sub init {
    my ($self) = @_;

    $self->{name}     ||= File::Basename::basename($0) || 'perl';
    $self->{options}  ||= "pid";
    $self->{facility} ||= "local7";
    $self->{log_level} ||= $self->{min_level} || $self->_min_level;

    if ( $self->{options} !~ /\D/ ) {
        # This is a backwards-compatibility shim from previous versions
        # of Log::Any::Adapter::Syslog that relied on Unix::Syslog.
        # Unix::Syslog only allowed setting options based on the numeric
        # macros exported by Unix::Syslog. These macros are not exported
        # by Sys::Syslog (and Sys::Syslog does not accept them). So, we
        # map the Unix::Syslog macros onto the equivalent Sys::Syslog
        # strings.
        eval { require Unix::Syslog; } or die "Unix::Syslog is required to use numeric options";
        my $num_opt = $self->{options};
        my %opt_map = (
            pid => Unix::Syslog::LOG_PID(),
            cons => Unix::Syslog::LOG_CONS(),
            odelay => Unix::Syslog::LOG_ODELAY(),
            ndelay => Unix::Syslog::LOG_NDELAY(),
            nowait => Unix::Syslog::LOG_NOWAIT(),
            perror => Unix::Syslog::LOG_PERROR(),
        );
        $self->{options} = join ",", grep { $num_opt & $opt_map{ $_ } } keys %opt_map;
    }

    # We want to avoid re-opening the syslog unnecessarily, so only do it if
    # the parameters have changed or if we don't think Sys::Syslog has
    # opened a log yet.
    my $new_params = $self->_log_params;
    if ((not defined $log_params) or ($log_params ne $new_params) or (not $Sys::Syslog::facility)) {

        $log_params = $new_params;
        openlog($self->{name}, $self->{options}, $self->{facility});
    }

    return $self;
}

sub _log_params {
    my ($self) = @_;
    return sprintf('%s;%s;%s',
        $self->{options}, $self->{facility}, $self->{name});
}

# Create logging methods: debug, info, etc.
foreach my $method (Log::Any->logging_methods()) {
    my $priority = {
        trace     => "debug",
        debug     => "debug",
        info      => "info",
        inform    => "info",
        notice    => "notice",
        warning   => "warning",
        warn      => "warning",
        error     => "err",
        err       => "err",
        critical  => "crit",
        crit      => "crit",
        fatal     => "crit",
        alert     => "alert",
        emergency => "emerg",
    }->{$method};
    defined($priority) or $priority = "error"; # unknown, take a guess.

    make_method($method, sub {
        my $self = shift;
        return if $logging_levels{$method} <
                $logging_levels{$self->{log_level}};

        # Bad libraries may call Sys::Syslog::closelog() out from under
        # us. If so, we should re-open the log with our desired
        # parameters. We likely cannot protect against someone calling
        # closelog() from outside Perl, but we could include an adaptor
        # flag that calls openlog()/closelog() with every message if the
        # program deems it necessary...
        if (( not defined $Sys::Syslog::facility ) or ( $Sys::Syslog::facility ne $self->{facility} )) {
          openlog($self->{name}, $self->{options}, $self->{facility});
        }
        syslog($priority, join('', @_))
    });
}

# Create detection methods: is_debug, is_info, etc.
foreach my $method (Log::Any->detection_methods()) {
    my $level = $method; $level =~ s/^is_//;
    make_method($method, sub {
        my $self = shift;
        return $logging_levels{$level} >= $logging_levels{$self->{log_level}};
    });

}


1;

__END__

=pod

=encoding UTF-8

=head1 NAME

Log::Any::Adapter::Syslog - Send Log::Any logs to syslog

=head1 VERSION

version 1.718

=head1 SYNOPSIS

    use Log::Any::Adapter 'Syslog';
    # ... or ...
    use Log::Any::Adapter;
    Log::Any::Adapter->set('Syslog');

    # You can override defaults:
    Log::Any::Adapter->set(
        'Syslog',
        # name defaults to basename($0)
        name     => 'my-name',
        # options default to "pid"
        options  => "pid,ndelay",
        # facility defaults to "local7"
        facility => "mail"
    );

=head1 DESCRIPTION

L<Log::Any> is a generic adapter for writing logging into Perl modules; this
adapter use the L<Sys::Syslog> module to direct that output into the OS's
logging system (even on Windows).

=head1 CONFIGURATION

C<Log::Any::Adapter::Syslog> is designed to work out of the box with no
configuration required; the defaults should be reasonably sensible.

You can override the default configuration by passing extra arguments to the
C<Log::Any::Adapter> method:

=over

=item name

The I<name> argument defaults to the basename of C<$0> if not supplied, and is
inserted into each line sent to syslog to identify the source.

=item options

The I<options> configure the behaviour of syslog; see L<Sys::Syslog> for
details.

The default is C<"pid">, which includes the PID of the current process after
the process name:

    example-process[2345]: something amazing!

The most likely addition to that is C<perror> (non-POSIX) which causes
syslog to also send a copy of all log messages to the controlling
terminal of the process.

=item facility

The I<facility> determines where syslog sends your messages.  The default is
C<local7>, which is not the most useful value ever, but is less bad than
assuming the fixed facilities.

See L<Sys::Syslog> and L<syslog(3)> for details on the available facilities.

=item log_level

Minimum log level. All messages below the selected level will be silently
discarded. Default is debug.

If LOG_LEVEL environment variable is set, it will be used instead. If TRACE
environment variable is set to true, level will be set to 'trace'. If DEBUG
environment variable is set to true, level will be set to 'debug'. If VERBOSE
environment variable is set to true, level will be set to 'info'.If QUIET
environment variable is set to true, level will be set to 'error'.

=back

=head1 AUTHORS

=over 4

=item *

Jonathan Swartz <swartz@pobox.com>

=item *

David Golden <dagolden@cpan.org>

=item *

Doug Bell <preaction@cpan.org>

=item *

Daniel Pittman <daniel@rimspace.net>

=item *

Stephen Thirlwall <sdt@cpan.org>

=back

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2017 by Jonathan Swartz, David Golden, and Doug Bell.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut
