<?php



declare(strict_types=1);



namespace GuzzleHttp\Psr7;



use Psr\Http\Message\StreamInterface;



/**

 * Compose stream implementations based on a hash of functions.

 *

 * Allows for easy testing and extension of a provided stream without needing

 * to create a concrete class for a simple extension point.

 */

#[\AllowDynamicProperties]

final class FnStream implements StreamInterface

{

    private const SLOTS = [

        '__toString', 'close', 'detach', 'rewind',

        'getSize', 'tell', 'eof', 'isSeekable', 'seek', 'isWritable', 'write',

        'isReadable', 'read', 'getContents', 'getMetadata'

    ];



    /** @var array<string, callable> */

    private $methods;



    /**

     * @param array<string, callable> $methods Hash of method name to a callable.

     */

    public function __construct(array $methods)

    {

        $this->methods = $methods;



        // Create the functions on the class

        foreach ($methods as $name => $fn) {

            $this->{'_fn_' . $name} = $fn;

        }

    }



    /**

     * Lazily determine which methods are not implemented.

     *

     * @throws \BadMethodCallException

     */

    public function __get(string $name): void

    {

        throw new \BadMethodCallException(str_replace('_fn_', '', $name)

            . '() is not implemented in the FnStream');

    }



    /**

     * The close method is called on the underlying stream only if possible.

     */

    public function __destruct()

    {

        if (isset($this->_fn_close)) {

            call_user_func($this->_fn_close);

        }

    }



    /**

     * An unserialize would allow the __destruct to run when the unserialized value goes out of scope.

     *

     * @throws \LogicException

     */

    public function __wakeup(): void

    {

        throw new \LogicException('FnStream should never be unserialized');

    }



    /**

     * Adds custom functionality to an underlying stream by intercepting

     * specific method calls.

     *

     * @param StreamInterface         $stream  Stream to decorate

     * @param array<string, callable> $methods Hash of method name to a closure

     *

     * @return FnStream

     */

    public static function decorate(StreamInterface $stream, array $methods)

    {

        // If any of the required methods were not provided, then simply

        // proxy to the decorated stream.

        foreach (array_diff(self::SLOTS, array_keys($methods)) as $diff) {

            /** @var callable $callable */

            $callable = [$stream, $diff];

            $methods[$diff] = $callable;

        }



        return new self($methods);

    }



    public function __toString(): string

    {

        try {

            return call_user_func($this->_fn___toString);

        } catch (\Throwable $e) {

            if (\PHP_VERSION_ID >= 70400) {

                throw $e;

            }

            trigger_error(sprintf('%s::__toString exception: %s', self::class, (string) $e), E_USER_ERROR);

            return '';

        }

    }



    public function close(): void

    {

        call_user_func($this->_fn_close);

    }



    public function detach()

    {

        return call_user_func($this->_fn_detach);

    }



    public function getSize(): ?int

    {

        return call_user_func($this->_fn_getSize);

    }



    public function tell(): int

    {

        return call_user_func($this->_fn_tell);

    }



    public function eof(): bool

    {

        return call_user_func($this->_fn_eof);

    }



    public function isSeekable(): bool

    {

        return call_user_func($this->_fn_isSeekable);

    }



    public function rewind(): void

    {

        call_user_func($this->_fn_rewind);

    }



    public function seek($offset, $whence = SEEK_SET): void

    {

        call_user_func($this->_fn_seek, $offset, $whence);

    }



    public function isWritable(): bool

    {

        return call_user_func($this->_fn_isWritable);

    }



    public function write($string): int

    {

        return call_user_func($this->_fn_write, $string);

    }



    public function isReadable(): bool

    {

        return call_user_func($this->_fn_isReadable);

    }



    public function read($length): string

    {

        return call_user_func($this->_fn_read, $length);

    }



    public function getContents(): string

    {

        return call_user_func($this->_fn_getContents);

    }



    /**

     * {@inheritdoc}

     *

     * @return mixed

     */

    public function getMetadata($key = null)

    {

        return call_user_func($this->_fn_getMetadata, $key);

    }

}

