#!/usr/bin/perl
use strict;
use warnings;
use Socket;

# Disable buffering for STDOUT
$| = 1;

# Configuration
my $mail_dir = '/var/mails';
my $log_file = '/var/log/smtp';

# Create directory to store emails
mkdir $mail_dir unless -d $mail_dir;

# Open log file for appending
open(my $log_fh, '>>', $log_file) or die "Could not open log file: $!";

# Log function
sub log_message {
    my ($message) = @_;
    my $timestamp = localtime;
    print $log_fh "[$timestamp] $message\n";
}

# Get client IP address
my $client_ip = get_client_ip();
log_message("Server started. Client IP: $client_ip");

# SMTP protocol handling
print "220 morena.rip Perl SMTP Server\r\n";

my ($sender, $recipient, $data);
while (<STDIN>) {
    chomp;
    my $line = $_;

    if ($line =~ /^HELO\s+(.+)/i) {
        print "250 Hello $1, pleased to meet you hero\r\n";
        log_message("HELO received from $1 (Client IP: $client_ip)");
    }
    elsif ($line =~ /^EHLO\s+(.+)/i) {
        # If EHLO is not implemented
        print "502 Command not implemented\r\n";
        log_message("EHLO received but not implemented (Client IP: $client_ip)");
    }
    elsif ($line =~ /^MAIL FROM:\s*(<)?(.+?)(>)?\s*$/i) {
        $sender = $2;
        print "250 Sender $sender OK\r\n";
        log_message("MAIL FROM received: $sender (Client IP: $client_ip)");
    }
    elsif ($line =~ /^RCPT TO:\s*(<)?(.+?)(>)?\s*$/i) {
        my $recipient_email = $2;  # Extract the email address
        if ($recipient_email =~ /\@morena\.rip$/i) {
            $recipient = $recipient_email;
            print "250 Recipient $recipient OK\r\n";
            log_message("RCPT TO received: $recipient (Client IP: $client_ip)");
        } else {
            print "550 Error: Recipient must be from the domain morena.rip\r\n";
            log_message("RCPT TO rejected: Invalid domain for $recipient_email (Client IP: $client_ip)");
        }
    }
    elsif ($line =~ /^DATA/i) {
        # Check if sender and recipient are defined
        if (!defined $sender || !defined $recipient) {
            print "550 Error: Missing sender or recipient\r\n";
            log_message("DATA command rejected: Missing sender or recipient (Client IP: $client_ip)");
            next;  # Skip processing DATA
        }

        print "354 Enter mail, end with . on a line by itself\r\n";
        log_message("DATA command received (Client IP: $client_ip)");
        $data = '';
        while (<STDIN>) {
            last if /^\.\r?\n/;
            $data .= $_;
        }
        print "250 Message accepted for delivery\r\n";
        log_message("Email data received (Client IP: $client_ip)");

        # Normalize line endings (remove \r)
        $data =~ s/\r\n/\n/g;

        # Save the email to a file
        my $filename = "$mail_dir/mail_" . time() . ".eml";
        open(my $fh, '>', $filename) or do {
            log_message("Error: Could not open file $filename: $! (Client IP: $client_ip)");
            next;
        };
        print $fh "From: $sender\nTo: $recipient\n$data";
        close($fh);
        log_message("Email saved to $filename (Client IP: $client_ip)");

        # Reset state for the next email
        $sender = undef;
        $recipient = undef;
        $data = undef;
    }
    elsif ($line =~ /^QUIT/i) {
        print "221 Bye\r\n";
        log_message("QUIT command received (Client IP: $client_ip)");
        last;
    }
    else {
        print "500 Command not recognized\r\n";
        log_message("Unknown command received: $line (Client IP: $client_ip)");
    }
}

# Close log file
close($log_fh);

# Function to get client IP address
sub get_client_ip {
    # Get the peer address from STDIN
    my $peeraddr = getpeername(STDIN) or return 'unknown';
    my ($port, $ip) = sockaddr_in($peeraddr);
    return inet_ntoa($ip);
}