Migrate SMF 2.0 Like Posts mod to SMF 2.1 Likes

migrate_likes.php

<?php
/* migrate likes from "Like Posts" mod to SMF 2.1 format
 *
 * 20220227 jimt
 *
 * The database schema used by the Like Posts mod for SMF 2.0
 * (https://custom.simplemachines.org/index.php?mod=3708) and
 * the new built-in functionality of SMF 2.1 are different.
 * This is a quick way to migrate old likes to the new system.
 *
 * Put this script in the same directory as your Settings.php
 * file and run:
 *   php migrate_likes.php
 */

require_once 'Settings.php';

function connect(string $type, string $host, string $db, string $user, string $password): PDO {
        try {
                $dsn = "$type:host=$host;dbname=$db;";

                return new PDO(
                        $dsn,
                        $user,
                        $password,
                        [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]
                );
        } catch (PDOException $e) {
                die($e->getMessage());
        }
}

$db = connect($db_type, $db_server, $db_name, $db_user, $db_passwd);

// find duplicates in old like table
echo "Prune duplicates from likes\n";
$sql = "SELECT id_like, id_msg, COUNT(id_msg), id_member_gave, COUNT(id_member_gave) FROM smf_like_post GROUP BY id_msg, id_member_gave  HAVING COUNT(id_msg) >1 AND COUNT(id_member_gave) > 1";
$stmt = $db->prepare("DELETE FROM smf_like_post WHERE id_like = (SELECT id_like FROM smf_like_post WHERE id_msg=:id_msg AND id_member_gave=:id_member_gave ORDER BY liked_timestamp LIMIT 100000 OFFSET 1)");
$stmt->bindParam(':id_msg', $id_msg);
$stmt->bindParam(':id_member_gave', $id_member_gave);
foreach ($db->query($sql) as $row) {
        print $row['id_msg'] . "\t";
        print $row['id_member_gave'] . "\n";
        $id_msg = $row['id_msg'];
        $id_member_gave = $row['id_member_gave'];
        $stmt->execute();
}

// migrate total likes per message
echo "Migrate total likes per message\n";
$sql = 'SELECT id_msg,count(*) AS likes FROM smf_like_post GROUP BY id_msg ORDER BY id_msg';
$stmt = $db->prepare("UPDATE smf_messages SET likes = likes + :newlikes WHERE id_msg = :id_msg");
$stmt->bindParam(':newlikes', $likes);
$stmt->bindParam(':id_msg', $id_msg);
foreach ($db->query($sql) as $row) {
        $id_msg = $row['id_msg'];
        $likes = $row['likes'];
        $stmt->execute();
}

// migrate who liked what
echo "Migrate who liked what\n";
$sql = 'SELECT id_member_gave, id_msg, liked_timestamp FROM smf_like_post ORDER BY liked_timestamp';
$stmt = $db->prepare("INSERT INTO smf_user_likes (id_member, content_type, content_id, like_time) VALUES (:id_member, 'msg', :content_id, :like_time)");
$stmt->bindParam(':id_member', $member);
$stmt->bindParam(':content_id', $msg);
$stmt->bindParam(':like_time', $timest);
foreach ($db->query($sql) as $row) {
        $member = $row['id_member_gave'];
        $msg = $row['id_msg'];
        $timest = $row['liked_timestamp'];
        $stmt->execute();
}