Autobarcode: Another cruddy Reddit bot

autobarcode.php

<?php
/**
 * Another dirty, dirty Reddit bot: autobarcode
 */

include_once 'reddit.php';

class RedditUser {
    const USERNAME = 'autobarcode';
    const PASSWORD = '***';
    const CLIENTID = '***';
    const SECRET   = '***';
}

class Autobarcode {
    const DB_HOST = 'localhost';
    const DB_NAME = '***';
    const DB_USER = '***';
    const DB_PASS = '***';

    const FORWARD_USER = '***';

    private static $subs_to_check = array(
        'Bitcoin',
    );
    private static $ignored_pm_authors = array(
    );

    private static $dbc;
    public static $subreddit;

    public static function parse_new_images() {
        self::_ensure_connection();

        foreach (self::$subs_to_check as $sub) {
            self::$subreddit = $sub;
            $threads = Reddit::fetch_threadlist($sub);
            if (isset(
                $threads['body'],
                $threads['body']['data'],
                $threads['body']['data']['children']
            )) {
                foreach ($threads['body']['data']['children'] as $thread) {
                    if (isset(
                        $thread['data'],
                        $thread['data']['preview'],
                        $thread['data']['preview']['images'],
                        $thread['data']['preview']['images'][0],
                        $thread['data']['preview']['images'][0]['source'],
                        $thread['data']['preview']['images'][0]['source']['url']
                    )) {
                        $id = Reddit::_from_id($thread['data']['id']);
                        $url = $thread['data']['preview']['images'][0]['source']['url'];

                        if (!self::_is_thread_seen($id)) {
                            $barcodes = self::parse_image($id, $url);
                            self::_add_thread($id, $barcodes);

                            if (count($barcodes)) {
                                self::post($id, $barcodes);
                            }
                        }
                    }
                }
            }
        }
    }

    private static function parse_image($id, $url) {
        $thread = '/r/'.self::$subreddit.'/comments/'.Reddit::_to_id($id);

        $img_parts = parse_url($url);
        $img_name = basename($img_parts['path']);
        $img_file = '/tmp/autobarcode/'.$img_name;
        file_put_contents($img_file, file_get_contents($url));
        $output = shell_exec("zbarimg {$img_file} 2>&1");
        $output = explode("\n", $output);
        $barcodes = array();

        if (strpos($output[0], 'scanned 0 barcode symbols') === 0) {
            // No barcodes in this image
            self::_log("{$thread}: No barcodes");
        } else {
            foreach ($output as $line) {
                if (preg_match('#^scanned \d+ barcode symbols#', $line)) {
                    break;
                } else {
                    $new_barcode = array(
                        'type' => substr($line, 0, strpos($line, ':')),
                        'value' => substr($line, strpos($line, ':') + 1)
                    );
                    if ($new_barcode['type'] !== 'ERROR') {
                        $barcodes[] = $new_barcode;
                    }
                }
            }
            self::_log("{$thread}: ".json_encode($barcodes));
        }
        unlink($img_file);
        return $barcodes;
    }

    private static function post($id, $barcodes) {
        $text[] = "Barcodes found in this image post:";
        $text[] = '';
        foreach ($barcodes as $barcode) {
            $text[] = "- `{$barcode['value']}` ({$barcode['type']})";
        }
        $text[] = '';
        $text[] = '----------------';
        $text[] = "[^\[Contact\]](https://reddit.com/message/compose?to=OrangeredStilton&subject=Hey,+your+barcode+bot+sucks)";// [^\[Source ^code\]](https://gist.github.com/Two9A/1d976f9b7441694162c8)";

        self::_log('Writing comment for thread '.Reddit::_to_id($id));
        Reddit::comment($id, join("\n", $text));
    }

    public static function forward_inbox($to = null) {
        if (!$to) {
            $to = self::FORWARD_USER;
        }

        $inbox = Reddit::inbox();
        if (isset(
            $inbox['body'],
            $inbox['body']['data'],
            $inbox['body']['data']['children']
        )) {
            foreach ($inbox['body']['data']['children'] as $msg) {
                $data = $msg['data'];
                Reddit::mark_read($data['name']);

                if (!in_array($data['author'], self::$ignored_pm_authors)) {
                    self::_log('Forwarding inbox message from '.$data['author']);
                    Reddit::send_message(
                        $to,
                        'Forwarded from '.__CLASS__,
                        join("  \n", array(
                            'From: '.$data['author'],
                            'Date: '.date('Y-m-d H:i:s', $data['created_utc']),
                            'Subject: '.$data['subject'],
                            'Context: '.$data['context'],
                            '',
                            $data['body']
                        ))
                    );
                }
            }
        }
    }

    private static function _is_thread_seen($thread_id) {
        $st = self::$dbc->prepare('SELECT COUNT(*) AS cnt FROM threads WHERE thread_id=:thread AND subreddit_name=:subreddit');
        $st->bindValue(':thread', $thread_id);
        $st->bindValue(':subreddit', self::$subreddit);
        $st->execute();
        $row = $st->fetch();
        
        return ($row['cnt'] > 0);
    }

    private static function _add_thread($thread_id, $barcodes) {
        $st = self::$dbc->prepare('INSERT INTO threads(thread_id, subreddit_name, barcode_data) VALUES(:thread, :subreddit, :barcodes)');
        $st->bindValue(':thread', $thread_id);
        $st->bindValue(':subreddit', self::$subreddit);
        $st->bindValue(':barcodes', json_encode($barcodes));
        $st->execute();
    }

    private static function _ensure_connection() {
        if (!self::$dbc) {
            self::$dbc = new PDO(
                sprintf('mysql:host=%s;dbname=%s', self::DB_HOST, self::DB_NAME),
                self::DB_USER,
                self::DB_PASS
            );
            self::$dbc->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            self::$dbc->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
        }
    }

    private static function _log($str) {
        $fp = fopen('/tmp/autobarcode.log', 'a');
        fprintf($fp, "[%s] [%s] %s\n", date('YmdHis'), self::$subreddit, $str);
        fclose($fp);
    }
}

Autobarcode::forward_inbox();
Autobarcode::parse_new_images();