<?php

namespace Mpdf\PsrHttpMessageShim;

/**
 * @link nyholm/psr7
 */
class Stream implements \Psr\Http\Message\StreamInterface {
    /**
     * A resource reference.
     *
     * @var resource
     */
    private $stream;

    /**
     * @var bool
     */
    private $seekable;

    /**
     * @var bool
     */
    private $readable;

    /**
     * @var bool
     */
    private $writable;

    /**
     * @var array|mixed|null|void
     */
    private $uri;

    /**
     * @var int
     */
    private $size;

    /** @var array Hash of readable and writable stream types */
    private static $readWriteHash = [
        'read' => [
            'r' => true, 'w+' => true, 'r+' => true, 'x+' => true, 'c+' => true,
            'rb' => true, 'w+b' => true, 'r+b' => true, 'x+b' => true,
            'c+b' => true, 'rt' => true, 'w+t' => true, 'r+t' => true,
            'x+t' => true, 'c+t' => true, 'a+' => true,
        ],
        'write' => [
            'w' => true, 'w+' => true, 'rw' => true, 'r+' => true, 'x+' => true,
            'c+' => true, 'wb' => true, 'w+b' => true, 'r+b' => true,
            'x+b' => true, 'c+b' => true, 'w+t' => true, 'r+t' => true,
            'x+t' => true, 'c+t' => true, 'a' => true, 'a+' => true,
        ],
    ];

    private function __construct() {
    }

    /**
     * @param resource $resource
     *
     * @return Stream
     */
    public static function createFromResource($resource) {
        if (!is_resource($resource)) {
            throw new \InvalidArgumentException('Stream must be a resource');
        }

        $obj = new self();
        $obj->stream = $resource;
        $meta = stream_get_meta_data($obj->stream);
        $obj->seekable = $meta['seekable'];
        $obj->readable = isset(self::$readWriteHash['read'][$meta['mode']]);
        $obj->writable = isset(self::$readWriteHash['write'][$meta['mode']]);
        $obj->uri = $obj->getMetadata('uri');

        return $obj;
    }

    /**
     * @param string $content
     *
     * @return Stream
     */
    public static function create($content) {
        $resource = fopen('php://temp', 'rwb+');
        $stream = self::createFromResource($resource);
        $stream->write($content);
        $stream->seek(0);

        return $stream;
    }

    /**
     * Closes the stream when the destructed.
     */
    public function __destruct() {
        $this->close();
    }

    public function __toString() {
        try {
            if ($this->isSeekable()) {
                $this->seek(0);
            }

            return $this->getContents();
        } catch (\Exception $e) {
            return '';
        }
    }

    public function close() {
        if (isset($this->stream)) {
            if (is_resource($this->stream)) {
                fclose($this->stream);
            }
            $this->detach();
        }
    }

    public function detach() {
        if (!isset($this->stream)) {
            return;
        }

        $result = $this->stream;
        unset($this->stream);
        $this->size = $this->uri = null;
        $this->readable = $this->writable = $this->seekable = false;

        return $result;
    }

    public function getSize() {
        if ($this->size !== null) {
            return $this->size;
        }

        if (!isset($this->stream)) {
            return;
        }

        // Clear the stat cache if the stream has a URI
        if ($this->uri) {
            clearstatcache(true, $this->uri);
        }

        $stats = fstat($this->stream);
        if (isset($stats['size'])) {
            $this->size = $stats['size'];

            return $this->size;
        }
    }

    public function tell() {
        $result = ftell($this->stream);

        if ($result === false) {
            throw new \RuntimeException('Unable to determine stream position');
        }

        return $result;
    }

    public function eof() {
        return !$this->stream || feof($this->stream);
    }

    public function isSeekable() {
        return $this->seekable;
    }

    public function seek($offset, $whence = SEEK_SET) {
        if (!$this->seekable) {
            throw new \RuntimeException('Stream is not seekable');
        }

        if (fseek($this->stream, $offset, $whence) === -1) {
            throw new \RuntimeException('Unable to seek to stream position ' . $offset . ' with whence ' . var_export($whence, true));
        }
    }

    public function rewind() {
        $this->seek(0);
    }

    public function isWritable() {
        return $this->writable;
    }

    public function write($string) {
        if (!$this->writable) {
            throw new \RuntimeException('Cannot write to a non-writable stream');
        }

        // We can't know the size after writing anything
        $this->size = null;
        $result = fwrite($this->stream, $string);

        if ($result === false) {
            throw new \RuntimeException('Unable to write to stream');
        }

        return $result;
    }

    public function isReadable() {
        return $this->readable;
    }

    public function read($length) {
        if (!$this->readable) {
            throw new \RuntimeException('Cannot read from non-readable stream');
        }

        return fread($this->stream, $length);
    }

    public function getContents() {
        if (!isset($this->stream)) {
            throw new \RuntimeException('Unable to read stream contents');
        }

        $contents = stream_get_contents($this->stream);

        if ($contents === false) {
            throw new \RuntimeException('Unable to read stream contents');
        }

        return $contents;
    }

    public function getMetadata($key = null) {
        if (!isset($this->stream)) {
            return $key ? null : [];
        }

        if ($key === null) {
            return stream_get_meta_data($this->stream);
        }

        $meta = stream_get_meta_data($this->stream);

        return isset($meta[$key]) ? $meta[$key] : null;
    }

}
