package App::ImapNotify;
use v5.24;
use strict;
use warnings;

our $VERSION = "0.01";

use App::ImapNotify::ImapClient;
use App::ImapNotify::Notifier;

use Carp;
use Encode qw(encode decode);
use Function::Parameters;
use Log::Any qw($log);
use Syntax::Keyword::Try;

=encoding utf-8

=head1 NAME

App::ImapNotify - It's new $module

=head1 SYNOPSIS

    use App::ImapNotify;

=head1 DESCRIPTION

App::ImapNotify is a simple notification script using IMAP NOTIFY. Note that it is very simple and
implements a custom IMAP client with very limited features. Mostly a proof of
concept and personal script.

=head1 LICENSE

Copyright (C) Florian Pritz.

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

=head1 AUTHOR

Florian Pritz E<lt>bluewind@xinu.atE<gt>

=cut

method new($class: $config, $deps = {}) {
	$deps->{imap_client} //= App::ImapNotify::ImapClient->new({$config->%{qw(host port log_id username password keepalive_timeout)}});
	$deps->{notifier} //= App::ImapNotify::Notifier->new();
	return $class->new_no_defaults($config, $deps);
}

method new_no_defaults($class: $config, $deps = {}) {
	my $self = {};
	bless $self, $class;
	$self->{config} = $config;
	$self->{deps} = $deps;
	return $self;
}

=head3 loop_reconnect

 $app->loop_reconnect();

Same as loop(), but automatcally calls loop() again if the connection is lost.

=cut

method loop_reconnect() {
	my $holdoff_time = 10;
	my $holdoff_repeat = 0;
	my $holdoff_limit = 300;

	while (1) {
		my $last_time = time;
		try {
			$self->loop();
		} catch {
			die $@ unless $@ =~ m/^Lost connection while .*/;
		}
		$holdoff_repeat = 0 if (time - $last_time) > $holdoff_limit;
		sleep($holdoff_time * $holdoff_repeat++);
	}
}

=head3 loop

 $app->loop();

Open a connection and wait for NOTIFY notifications. When a NOTIFY notification
arrives, show a notification to the user.

This method throws an exception when the connection to the server is lost. If
you want to continue waiting for new notifications, you may call this method
again. Also look at loop_reconnect().

=cut

method loop() {
	my $imap = $self->{deps}->{imap_client};
	$imap->reconnect();
	$imap->select($self->{config}->{mailboxes}->@[0]);

	$imap->send_command("notify set (selected (MessageExpunge MessageNew (uid body.peek[header.fields (from to subject)]))) (mailboxes (".join(' ', $self->{config}->{mailboxes}->@*).") (MessageNew MessageExpunge MailboxName))");

	$log->info("Waiting for notify events");
	while (my $line = $imap->readline_timeout()) {
		$log->tracef("Got line: '%s'", $line =~ s/\r\n$//r);
		if ($line =~ m/^\* .* FETCH /) {
			my $message = $imap->handle_fetch($line);
			$self->_notify($message);
			next;
		}
		if ($line =~ m/^\* STATUS (?<mailbox>[^ ]+) \(MESSAGES \d+ UIDNEXT (?<uidnext>\d+) UNSEEN \d+\)/) {
			my $mailbox = $+{mailbox};
			my $uid = $+{uidnext} - 1;
			$log->debugf("Got status change: '%s'", $line =~ s/\r\n$//r);
			$imap->select($mailbox);
			my $message = $imap->send_command("uid fetch $uid (body.peek[header.fields (from to subject)])");
			pop @{$message};
			$self->_notify($message);
			next;
		}

		next if $line =~ /\* \d+ RECENT/;
		next if $line =~ /\* \d+ EXISTS/;
		next if $line =~ /\* \d+ EXPUNGE/;

		confess(sprintf("Got unexpected line: '%s'", $line));
	}
}

method _notify($message) {
	$log->debugf("Got data for notification: %s", $message);
	my $fields = {};
	my $current_field;

	return if $message->@* == 0;

	for my $line ($message->@*) {
		if ($line =~ m/^(?<label>[^\s:]+): (?<value>.*)\r\n$/) {
			$current_field = lc($+{label});
			$fields->{$current_field} = decode('MIME-Header', $+{value});
			next;
		}

		if ($line =~ m/^\s+(.*)$/) {
			$fields->{$current_field} .= $1;
		}
	}

	$log->debugf("Sending notification with data: %s", $fields);
	my $notify_heading = sprintf("From: %s", $fields->%*->@{qw(from)});
	my $notify_body = sprintf("Subject: %s", $fields->%*->@{qw(subject)});
	$self->{deps}->{notifier}->notify($notify_heading, $notify_body);
}



1;
__END__