#!/usr/bin/perl

######################################
# Thomas Schwery <thomas@schwery.me> #
######################################

use strict;
use IO::Socket;
use POSIX;
use threads;
use Switch;
use DBI;

$/ ="\r\n";
my $dbfile = "ircbot.db";

my ($server, $port, $channel, $nick) = @ARGV;

print "Server is " . $server . ":" . $port . "\n";
print "Channel is " . $channel . "\n";
print "Nickname is " . $nick . "\n";
print "\n";
print "Opening database " . $dbfile . "...\n";

our $db = DBI->connect("dbi:SQLite:dbname=" . $dbfile,"","");
our %users;

$db->do("CREATE TABLE IF NOT EXISTS users (id TEXT PRIMARY KEY, last INTEGER DEFAULT 0, time INTEGER DEFAULT 0)");

$SIG{INT} = \&signal_handler_interrupt;

our $socket = new IO::Socket::INET(  PeerAddr => $server,
                                    PeerPort => $port, 
                                    Proto => 'tcp'
                                );
                                
die "Unable to open port: $! \n" unless $socket;

print $socket "USER " . $nick . " " . $nick . " " . $nick . " :lacbot\n";
print $socket "NICK " . $nick . "\r\n";
print $socket "JOIN " . $channel . "\r\n";

while(<$socket>) {
    chomp;
    if (m/:(.+?)!.*?\sPRIVMSG\s(.*?)\s:(.*)/) {
        my $user = $1;
        my $channel = $2;
        my $message = $3;
        
        # we need to check for private conversations ...
        # if the command was sent privately, we respond privately
        if ($channel eq $nick) {
            $channel = $user;
        }
        
        if ($message =~ m/^!(\w+)(\s.+)?\s*/){
            processMessage($user, $channel, $1, $2);
        }
        
    } elsif (m/^PING\s+:(.*)/) {
        print $socket "PONG :" . $1 . "\r\n";
    } elsif (m/:(.+?)!(.+)@.*?\sPART\s(.*)/) {
        processLeave($1, $2, $3);
    } elsif (m/:(.+?)!(.+)@.*?\sJOIN\s:(.*)/) {
        processJoin($1, $2, $3);
    } else {
        print "Not matched: " . $_ . "\n";
    }
}

sub processStats {
    my ($channel) = @_;
    
    my $stmt = $db->prepare("SELECT * FROM users ORDER BY time DESC;");
    $stmt->execute or die "Couldn't execute statement: " . $stmt->errstr;
    
    my $stats_string = "User\tTime connected\n";
    
    while (my @data = $stmt->fetchrow_array()) {
        my $user = $data[0];
        my $last_time = $data[1];
        my $total_time = $data[2];
        $stats_string .= $user . "\t" . special_format($total_time) . "\n";
    }
    
    sendMessage($channel, $stats_string);
    
    $stmt->finish;
}

sub processLeave {
    my ($user_nick, $user, $channel) = @_;
    
    my $date_string = strftime("%s", localtime);
    my $date_arrival = $users{$user};
    my $elapsed_time = $date_string - $date_arrival;
    
    sendMessage($channel, $user_nick . " is leaving us after " . special_format($elapsed_time) . " ... How sad");
    
    my $stmt_insert = $db->prepare("INSERT OR IGNORE INTO users ('id') VALUES ( ? )");
    my $stmt_update = $db->prepare("UPDATE users SET time = time + ?, last = ? WHERE id = ?");
    $stmt_insert->execute($user);
    $stmt_update->execute($elapsed_time, $date_string, $user);
    
    $stmt_insert->finish;
    $stmt_update->finish;
}

sub processJoin {
    my ($user_nick, $user, $channel) = @_;
    if ($user_nick eq $nick) {
        return;
    }
    
    my $date_now = strftime("%s", localtime);
    $users{$user} = $date_now;
    
    my $stmt = $db->prepare("SELECT last FROM users WHERE id = ?;");
    $stmt->execute($user) or die "Couldn't execute statement: " . $stmt->errstr;
    
    my @date = $stmt->fetchrow_array();
    
    if ($stmt->rows == 0) {
        sendMessage($channel, "A new user has entered this channel ... How strange ...");
        return;
    }
    
    $stmt->finish;
    
    my $date_string = @date[0];
    
    my $seconds_elapsed = $date_now - $date_string;
    sendMessage($channel, "Hourra, our saviour, the great " . $user_nick . 
                " is returned after " . special_format($seconds_elapsed) . " of absence!");
    
}

sub special_format {
    my ($seconds) = @_;
    my $format_string = "";
    if ($seconds > 3600 * 24) {
        $format_string .= int($seconds/(3600*24)) . " days ";
        $seconds %= (3600*24);
    }
    if ($seconds > 3600) {
        $format_string .= int($seconds/3600) . " hours ";
        $seconds %= 3600;
    }
    
    if ($seconds > 60) {
        $format_string .= int($seconds/60) . " minutes ";
        $seconds %= 60;
    }
    
    if (length($format_string) > 0) {
        $format_string .= "and ";
    }
    
    return $format_string . $seconds . " seconds";
}

sub processMessage {
    my ($user, $chan, $command, $parameters) = @_;
    chomp $parameters;
    
    switch ($command) {
        case "echo"         { sendMessage($chan, $parameters); }
        case "private"      { sendMessage($user, $parameters); }
        case "fish"         { 
            if (length $parameters > 0) {
                $parameters =~ s/^\s+//;
                $parameters =~ s/\s+.*$//;
                if ($parameters eq $nick) {
                    $parameters = $user;
                }
                sendAction($chan, "slaps " . $parameters . " with a wet sloppy tuna fish.");
                sleep 2;
                sendMessage($chan, "take that bitch");
            }
            }
        case "sandwich"     { sendAction($chan, "prepares a yummi sandwich for " . $user); }
        case "help"         {
            sendMessage($chan, "I cannot help you with your pathetic, meaningless life ...");
            sendMessage($chan, "All I can do is repeat (!echo), make a sandwich (!sandwich), slap someone (!fish) and listen patiently.");
            }
        case "stats"        { processStats($chan); }
    }
    return 0;
}

sub sendAction {
    my ($channel, $message) = @_;
    print $socket "PRIVMSG " . $channel ." :\x01ACTION " . $message . "\x01\r\n";
    print "PRIVMSG " . $channel ." :\x01ACTION " . $message . "\x01\r\n";
}

sub sendMessage {
    my ($channel, $message) = @_;
    print $socket "PRIVMSG " . $channel . " :" . $message . "\n";
    print "PRIVMSG " . $channel . " :" . $message . "\n";
}

sub signal_handler_interrupt {
    print "ctrl-c, exiting...\n";
    
    print $socket "PRIVMSG " . $channel . " :I loved chatting with you but I " . 
                            "really have to go !\r\n";
    
    print $socket "QUIT " . $channel . "\n";
    $socket->shutdown(2);
    $socket->close();
    exit 0;
}