<?php declare(strict_types=1);
/**
 * Test stand-in for safePHP/hc_metrics_db_connect.php.
 *
 * Defines the DB_* constants and a fake mysqli that performs the checks the
 * real server would reject a statement for — INSERT column/value counts, and
 * bind_param type/variable/placeholder counts — then records each executed
 * statement to $HCM_TEST_DIR/db.log (one JSON object per line) instead of
 * touching a database.
 *
 * The number of rows the "session exists?" SELECT reports is read from
 * $HCM_TEST_DIR/select_rows.txt (default 0).
 *
 * The test runner loads PHP with -n, so the real mysqli extension is absent
 * and these class names are free.
 */

define('DB_HOST', 'fake');
define('DB_USER', 'fake');
define('DB_PASSWORD', 'fake');
define('DB_NAME', 'fake');

define('HCM_TEST_DIR', __DIR__ . '/..');

class mysqli_sql_exception extends RuntimeException {}

class mysqli
{
    public ?string $connect_error = null;
    public array $error_list = [];

    public function __construct(string $host, string $user, string $pass, string $db) {}

    public function prepare(string $sql): mysqli_stmt
    {
        // MySQL rejects an INSERT whose column list and VALUES list differ in length.
        if (preg_match('/^\s*INSERT\s+INTO\s+\S+\s*\(([^)]*)\)\s*VALUES\s*\((.*)\)\s*$/is', $sql, $m)) {
            $columns = count(array_map('trim', explode(',', $m[1])));
            $values  = count(array_map('trim', explode(',', $m[2])));
            if ($columns !== $values) {
                throw new mysqli_sql_exception("Column count doesn't match value count at row 1");
            }
        }
        return new mysqli_stmt($sql);
    }

    public function close(): bool { return true; }
}

class mysqli_stmt
{
    public int $num_rows = 0;
    private string $sql;
    private array $vars = [];

    public function __construct(string $sql) { $this->sql = $sql; }

    public function bind_param(string $types, mixed &...$vars): bool
    {
        if (strlen($types) !== count($vars)) {
            throw new ArgumentCountError('The number of elements in the type definition string must match the number of bind variables');
        }
        if (count($vars) !== substr_count($this->sql, '?')) {
            throw new ArgumentCountError('The number of variables must match the number of parameters in the prepared statement');
        }
        $this->vars = &$vars; // real mysqli reads the bound variables at execute time
        return true;
    }

    public function execute(): bool
    {
        $params = [];
        foreach ($this->vars as $v) {
            $params[] = $v;
        }
        file_put_contents(HCM_TEST_DIR . '/db.log',
            json_encode(['sql' => $this->sql, 'params' => $params]) . "\n", FILE_APPEND | LOCK_EX);
        return true;
    }

    public function store_result(): bool
    {
        $f = HCM_TEST_DIR . '/select_rows.txt';
        $this->num_rows = is_file($f) ? (int)trim((string)file_get_contents($f)) : 0;
        return true;
    }

    public function close(): bool { return true; }
}