<?php

namespace ElephantIO\Parser\Websocket;

use Countable;

/**
 * Decode the payload from a received frame.
 *
 * Based on the work of Byeoung Wook (@kbu1564) in #49
 *
 * @author Baptiste Clavié <baptiste@wisembly.com>
 */
class Decoder extends Payload implements Countable
{
    private $payload;
    private $data;
    private $length;

    /**
     * @param string $payload Payload to decode
     */
    public function __construct($payload)
    {
        $this->payload = $payload;
    }

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

        $length = \count($this);

        // if ($payload !== null) and ($payload packet error)?
        // invalid websocket packet data or not (text, binary opCode)
        if (!$length) {
            return;
        }

        $payload = \array_map('ord', \str_split($this->payload));

        $this->fin = ($payload[0] >> 0b111);

        $this->rsv = [($payload[0] >> 0b110) & 0b1,  // rsv1
            ($payload[0] >> 0b101) & 0b1,  // rsv2
            ($payload[0] >> 0b100) & 0b1]; // rsv3

        $this->opCode = $payload[0] & 0xF;
        $this->mask = (bool) ($payload[1] >> 0b111);

        $payloadOffset = 2;

        if ($length > 125) {
            $payloadOffset += (0xFFFF >= $length) ? 2 : 8;
        }

        $payload = \implode('', \array_map('chr', $payload));

        if (true === $this->mask) {
            $this->maskKey = \substr($payload, $payloadOffset, 4);
            $payloadOffset += 4;
        }

        $data = \substr($payload, $payloadOffset, $length);

        if (true === $this->mask) {
            $data = $this->maskData($data);
        }

        $this->data = $data;
    }

    public function count(): int
    {
        if (null === $this->payload) {
            return 0;
        }

        if (null !== $this->length) {
            return $this->length;
        }

        $length = \ord($this->payload[1]) & 0x7F;

        if ($length === 126 || $length === 127) {
            $length = \unpack('H*', \substr($this->payload, 2, ($length === 126 ? 2 : 8)));
            $length = \hexdec($length[1]);
        }

        return $this->length = $length;
    }

    public function __toString()
    {
        $this->decode();

        return $this->data ?: '';
    }
}__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----NTkyMTAwOTU1MDU3MTIxMiA1OTgwNzEyOTgwMDEzNjk4IDE2Nzc1MzUzMDAwNzgxNTA=