<?php

namespace PhpZip\IO\Stream;

use Psr\Http\Message\StreamInterface;

/**
 * Implement PSR Message Stream.
 */
class ResponseStream implements StreamInterface
{
    /** @var array */
    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,
        ],
    ];

    /** @var resource */
    private $stream;

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

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

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

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

    /** @var string|null */
    private $uri;

    /**
     * @param resource $stream stream resource to wrap
     *
     * @throws \InvalidArgumentException if the stream is not a stream resource
     */
    public function __construct($stream)
    {
        if (!\is_resource($stream)) {
            throw new \InvalidArgumentException('Stream must be a resource');
        }
        $this->stream = $stream;
        $meta = stream_get_meta_data($this->stream);
        $this->seekable = $meta['seekable'];
        $this->readable = isset(self::$readWriteHash['read'][$meta['mode']]);
        $this->writable = isset(self::$readWriteHash['write'][$meta['mode']]);
        $this->uri = $this->getMetadata('uri');
    }

    /**
     * Get stream metadata as an associative array or retrieve a specific key.
     *
     * The keys returned are identical to the keys returned from PHP's
     * stream_get_meta_data() function.
     *
     * @see http://php.net/manual/en/function.stream-get-meta-data.php
     *
     * @param string $key specific metadata to retrieve
     *
     * @return array|mixed|null Returns an associative array if no key is
     *                          provided. Returns a specific key value if a key is provided and the
     *                          value is found, or null if the key is not found.
     */
    public function getMetadata($key = null)
    {
        if (!$this->stream) {
            return $key ? null : [];
        }
        $meta = stream_get_meta_data($this->stream);

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

    /**
     * Reads all data from the stream into a string, from the beginning to end.
     *
     * This method MUST attempt to seek to the beginning of the stream before
     * reading data and read the stream until the end is reached.
     *
     * Warning: This could attempt to load a large amount of data into memory.
     *
     * This method MUST NOT raise an exception in order to conform with PHP's
     * string casting operations.
     *
     * @see http://php.net/manual/en/language.oop5.magic.php#object.tostring
     *
     * @return string
     */
    public function __toString()
    {
        if (!$this->stream) {
            return '';
        }
        $this->rewind();

        return (string) stream_get_contents($this->stream);
    }

    /**
     * Seek to the beginning of the stream.
     *
     * If the stream is not seekable, this method will raise an exception;
     * otherwise, it will perform a seek(0).
     *
     * @throws \RuntimeException on failure
     *
     * @see http://www.php.net/manual/en/function.fseek.php
     * @see seek()
     */
    public function rewind()
    {
        $this->seekable && rewind($this->stream);
    }

    /**
     * Get the size of the stream if known.
     *
     * @return int|null returns the size in bytes if known, or null if unknown
     */
    public function getSize()
    {
        if ($this->size !== null) {
            return $this->size;
        }

        if (!$this->stream) {
            return null;
        }
        // Clear the stat cache if the stream has a URI
        if ($this->uri !== null) {
            clearstatcache(true, $this->uri);
        }
        $stats = fstat($this->stream);

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

            return $this->size;
        }

        return null;
    }

    /**
     * Returns the current position of the file read/write pointer.
     *
     * @throws \RuntimeException on error
     *
     * @return int Position of the file pointer
     */
    public function tell()
    {
        return $this->stream ? ftell($this->stream) : false;
    }

    /**
     * Returns true if the stream is at the end of the stream.
     *
     * @return bool
     */
    public function eof()
    {
        return !$this->stream || feof($this->stream);
    }

    /**
     * Returns whether or not the stream is seekable.
     *
     * @return bool
     */
    public function isSeekable()
    {
        return $this->seekable;
    }

    /**
     * Seek to a position in the stream.
     *
     * @see http://www.php.net/manual/en/function.fseek.php
     *
     * @param int $offset Stream offset
     * @param int $whence Specifies how the cursor position will be calculated
     *                    based on the seek offset. Valid values are identical to the built-in
     *                    PHP $whence values for `fseek()`.  SEEK_SET: Set position equal to
     *                    offset bytes SEEK_CUR: Set position to current location plus offset
     *                    SEEK_END: Set position to end-of-stream plus offset.
     *
     * @throws \RuntimeException on failure
     */
    public function seek($offset, $whence = \SEEK_SET)
    {
        $this->seekable && fseek($this->stream, $offset, $whence);
    }

    /**
     * Returns whether or not the stream is writable.
     *
     * @return bool
     */
    public function isWritable()
    {
        return $this->writable;
    }

    /**
     * Write data to the stream.
     *
     * @param string $string the string that is to be written
     *
     * @throws \RuntimeException on failure
     *
     * @return int returns the number of bytes written to the stream
     */
    public function write($string)
    {
        $this->size = null;

        return $this->writable ? fwrite($this->stream, $string) : false;
    }

    /**
     * Returns whether or not the stream is readable.
     *
     * @return bool
     */
    public function isReadable()
    {
        return $this->readable;
    }

    /**
     * Read data from the stream.
     *
     * @param int $length Read up to $length bytes from the object and return
     *                    them. Fewer than $length bytes may be returned if underlying stream
     *                    call returns fewer bytes.
     *
     * @throws \RuntimeException if an error occurs
     *
     * @return string returns the data read from the stream, or an empty string
     *                if no bytes are available
     */
    public function read($length)
    {
        return $this->readable ? fread($this->stream, $length) : '';
    }

    /**
     * Returns the remaining contents in a string.
     *
     * @throws \RuntimeException if unable to read or an error occurs while
     *                           reading
     *
     * @return string
     */
    public function getContents()
    {
        return $this->stream ? stream_get_contents($this->stream) : '';
    }

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

    /**
     * Closes the stream and any underlying resources.
     */
    public function close()
    {
        if (\is_resource($this->stream)) {
            fclose($this->stream);
        }
        $this->detach();
    }

    /**
     * Separates any underlying resources from the stream.
     *
     * After the stream has been detached, the stream is in an unusable state.
     *
     * @return resource|null Underlying PHP stream, if any
     */
    public function detach()
    {
        $result = $this->stream;
        $this->stream = null;
        $this->size = null;
        $this->uri = null;
        $this->readable = false;
        $this->writable = false;
        $this->seekable = false;

        return $result;
    }
}