<?php
// Usage: place this script next to users.txt and run: php import_users.php
// It will create users_with_passwords.txt with "login:password" lines.

require_once __DIR__ . '/config/db.php';

$inputFile = __DIR__ . '/users.txt';
$outputFile = __DIR__ . '/users_with_passwords.txt';

if (!file_exists($inputFile)) {
    fwrite(STDERR, "Input file not found: {$inputFile}\n");
    exit(1);
}

$lines = file($inputFile, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
if ($lines === false) {
    fwrite(STDERR, "Failed to read input file.\n");
    exit(1);
}

$charset = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
$charsetLen = strlen($charset);

function generatePassword(string $charset, int $charsetLen, int $length = 6): string
{
    $password = '';
    for ($i = 0; $i < $length; $i++) {
        $password .= $charset[random_int(0, $charsetLen - 1)];
    }
    return $password;
}

$pdo->beginTransaction();
try {
    $selectStmt = $pdo->prepare("SELECT id FROM users WHERE username = ?");
    $insertStmt = $pdo->prepare("INSERT INTO users (username, password_hash) VALUES (?, ?)");
    $updateStmt = $pdo->prepare("UPDATE users SET password_hash = ? WHERE id = ?");

    $out = fopen($outputFile, 'w');
    if ($out === false) {
        throw new RuntimeException('Failed to open output file for writing.');
    }

    $seen = [];
    foreach ($lines as $line) {
        $username = trim($line);
        if ($username === '' || isset($seen[$username])) {
            continue;
        }
        $seen[$username] = true;

        $password = generatePassword($charset, $charsetLen, 6);
        $hash = password_hash($password, PASSWORD_BCRYPT);

        $selectStmt->execute([$username]);
        $user = $selectStmt->fetch(PDO::FETCH_ASSOC);
        if ($user) {
            $updateStmt->execute([$hash, $user['id']]);
        } else {
            $insertStmt->execute([$username, $hash]);
        }

        fwrite($out, $username . ':' . $password . PHP_EOL);
    }

    fclose($out);
    $pdo->commit();
    echo "Done. Output: {$outputFile}\n";
} catch (Throwable $e) {
    $pdo->rollBack();
    fwrite(STDERR, "Error: " . $e->getMessage() . "\n");
    exit(1);
}
?>