<?php

namespace AWS\CRT;

use AWS\CRT\Internal\Extension;
use AWS\CRT\Internal\FFI;

use \RuntimeException;

/**
 * Wrapper for the interface to the CRT. There only ever needs to be one of these, but
 * additional instances won't cost anything other than their memory.
 * Creating an instance of any NativeResource will activate the CRT binding. User code
 * should only need to create one of these if they are only accessing CRT:: static functions.
 */
final class CRT {

    private static $impl = null;
    private static $refcount = 0;

    function __construct() {
        if (is_null(self::$impl)) {
            try {
                self::$impl = new Extension();
            } catch (RuntimeException $rex) {
                try {
                    self::$impl = new FFI();
                } catch (RuntimeException $frex) {
                    throw new RuntimeException('Unable to initialize AWS CRT via extension or FFI', -1, $frex);
                }
            }
        }
        ++self::$refcount;
    }

    function __destruct() {
        if (--self::$refcount == 0) {
            self::$impl = null;
        }
    }

    /**
     * @return integer last error code reported within the CRT
     */
    public static function last_error() {
        return self::$impl->aws_crt_last_error();
    }

    /**
     * @param integer $error Error code from the CRT, usually delivered via callback or {@see last_error}
     * @return string Human-readable description of the provided error code
     */
    public static function error_str($error) {
        return self::$impl->aws_crt_error_str((int) $error);
    }

    /**
     * @param integer $error Error code from the CRT, usually delivered via callback or {@see last_error}
     * @return string Name/enum identifier for the provided error code
     */
    public static function error_name($error) {
        return self::$impl->aws_crt_error_name((int) $error);
    }

    function event_loop_group_new($num_threads) {
        return self::$impl->aws_crt_event_loop_group_new($num_threads);
    }

    function event_loop_group_release($elg) {
        return self::$impl->aws_crt_event_loop_group_release($elg);
    }
}