<?php
// GenericStream.php
// Created: 2021-04-30
// Updated: 2023-07-17

namespace Index\IO;

use InvalidArgumentException;

class GenericStream extends Stream {
    public const READABLE = [
        'r',  'rb',  'r+', 'r+b', 'w+', 'w+b',
        'a+', 'a+b', 'x+', 'x+b', 'c+', 'c+b',
    ];
    public const WRITEABLE = [
        'r+', 'r+b', 'w',  'wb',  'w+', 'w+b',
        'a',  'ab',  'a+', 'a+b', 'x',  'xb',
        'x+', 'x+b', 'c',  'cb',  'c+', 'c+b',
    ];

    protected $stream; // resource

    private bool $canRead;
    private bool $canWrite;
    private bool $canSeek;

    public function __construct($stream) {
        if(!is_resource($stream) || get_resource_type($stream) !== 'stream')
            throw new InvalidArgumentException('$stream is not a valid stream resource.');
        $this->stream = $stream;

        $metaData = $this->metaData();
        $this->canRead = in_array($metaData['mode'], self::READABLE);
        $this->canWrite = in_array($metaData['mode'], self::WRITEABLE);
        $this->canSeek = $metaData['seekable'];
    }

    public function getResource() {
        return $this->stream;
    }

    private function stat(): array {
        return fstat($this->stream);
    }

    public function getPosition(): int {
        return ftell($this->stream);
    }

    public function getLength(): int {
        if(!$this->canSeek())
            return -1;
        return $this->stat()['size'];
    }
    public function setLength(int $length): void {
        ftruncate($this->stream, $length);
    }

    private function metaData(): array {
        return stream_get_meta_data($this->stream);
    }
    public function canRead(): bool {
        return $this->canRead;
    }
    public function canWrite(): bool {
        return $this->canWrite;
    }
    public function canSeek(): bool {
        return $this->canSeek;
    }
    public function hasTimedOut(): bool {
        return $this->metaData()['timed_out'];
    }
    public function isBlocking(): bool {
        return $this->metaData()['blocked'];
    }

    public function isEnded(): bool {
        return feof($this->stream);
    }

    public function readChar(): ?string {
        $char = fgetc($this->stream);
        if($char === false)
            return null;
        return $char;
    }

    public function readLine(): ?string {
        return ($line = fgets($this->stream)) === false
            ? null : $line;
    }

    public function read(int $length): ?string {
        $buffer = fread($this->stream, $length);
        if($buffer === false)
            return null;
        return $buffer;
    }

    public function seek(int $offset, int $origin = Stream::START): int {
        return fseek($this->stream, $offset, $origin);
    }

    public function write(string $buffer, int $length = -1): void {
        if($length >= 0)
            fwrite($this->stream, $buffer, $length);
        else
            fwrite($this->stream, $buffer);
    }

    public function writeChar(string $char): void {
        fwrite($this->stream, $char, 1);
    }

    public function flush(): void {
        fflush($this->stream);
    }

    public function close(): void {
        try {
            fclose($this->stream);
        } catch(\Error $ex) {}
    }

    public function copyTo(Stream $other): void {
        if($other instanceof GenericStream) {
            stream_copy_to_stream($this->stream, $other->stream);
        } else parent::copyTo($other);
    }

    public function __toString(): string {
        return stream_get_contents($this->stream);
    }
}