<?php
require_once 'config.php';

try {
    $dsn = "mysql:host=" . DB_HOST . ";dbname=" . DB_NAME . ";charset=utf8mb4";
    $options = [
        PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        PDO::ATTR_EMULATE_PREPARES   => false,
    ];

    $pdo = new PDO($dsn, DB_USER, DB_PASS, $options);
    ensureOptionalSchema($pdo);
} catch (\PDOException $e) {
    throw new \PDOException($e->getMessage(), (int)$e->getCode());
}

function ensureOptionalSchema(PDO $pdo) {
    static $done = false;

    if ($done || DB_PREFIX === '') {
        return;
    }

    $done = true;
    $usersTable = DB_PREFIX . "users";

    try {
        $columns = $pdo->query("SHOW COLUMNS FROM {$usersTable}")->fetchAll(PDO::FETCH_COLUMN, 0);
        $indexes = $pdo->query("SHOW INDEX FROM {$usersTable}")->fetchAll(PDO::FETCH_ASSOC);
    } catch (\PDOException $e) {
        error_log($e->getMessage());
        return;
    }

    $indexNames = array_column($indexes, 'Key_name');
    $statements = [];

    if (!in_array('email', $columns, true)) {
        $statements[] = "ALTER TABLE {$usersTable} ADD COLUMN email varchar(255) DEFAULT NULL AFTER username";
    }
    if (!in_array('display_name', $columns, true)) {
        $statements[] = "ALTER TABLE {$usersTable} ADD COLUMN display_name varchar(255) DEFAULT NULL AFTER email";
    }
    if (!in_array('oauth_provider', $columns, true)) {
        $statements[] = "ALTER TABLE {$usersTable} ADD COLUMN oauth_provider varchar(50) DEFAULT NULL AFTER role";
    }
    if (!in_array('oauth_subject', $columns, true)) {
        $statements[] = "ALTER TABLE {$usersTable} ADD COLUMN oauth_subject varchar(191) DEFAULT NULL AFTER oauth_provider";
    }
    if (!in_array('oauth_tenant_id', $columns, true)) {
        $statements[] = "ALTER TABLE {$usersTable} ADD COLUMN oauth_tenant_id varchar(64) DEFAULT NULL AFTER oauth_subject";
    }
    if (!in_array('last_login_at', $columns, true)) {
        $statements[] = "ALTER TABLE {$usersTable} ADD COLUMN last_login_at datetime DEFAULT NULL AFTER oauth_tenant_id";
    }
    if (!in_array('uniq_users_email', $indexNames, true)) {
        $statements[] = "ALTER TABLE {$usersTable} ADD UNIQUE KEY uniq_users_email (email)";
    }
    if (!in_array('idx_users_oauth_identity', $indexNames, true)) {
        $statements[] = "ALTER TABLE {$usersTable} ADD KEY idx_users_oauth_identity (oauth_provider, oauth_subject, oauth_tenant_id)";
    }

    foreach ($statements as $statement) {
        try {
            $pdo->exec($statement);
        } catch (\PDOException $e) {
            error_log($e->getMessage());
        }
    }
}
?>