<?php

/**
 * Class BitBuffer
 *
 * @created      25.11.2015
 * @author       Smiley <smiley@chillerlan.net>
 * @copyright    2015 Smiley
 * @license      MIT
 */
namespace WCPOS\Vendor\chillerlan\QRCode\Common;

use WCPOS\Vendor\chillerlan\QRCode\QRCodeException;
use function count, floor, min;
/**
 * Holds the raw binary data
 */
final class BitBuffer
{
    /**
     * The buffer content
     *
     * @var int[]
     */
    private array $buffer;
    /**
     * Length of the content (bits)
     */
    private int $length;
    /**
     * Read count (bytes)
     */
    private int $bytesRead = 0;
    /**
     * Read count (bits)
     */
    private int $bitsRead = 0;
    /**
     * BitBuffer constructor.
     *
     * @param int[] $bytes
     */
    public function __construct(array $bytes = [])
    {
        $this->buffer = $bytes;
        $this->length = count($this->buffer);
    }
    /**
     * appends a sequence of bits
     */
    public function put(int $bits, int $length) : self
    {
        for ($i = 0; $i < $length; $i++) {
            $this->putBit(($bits >> $length - $i - 1 & 1) === 1);
        }
        return $this;
    }
    /**
     * appends a single bit
     */
    public function putBit(bool $bit) : self
    {
        $bufIndex = (int) floor($this->length / 8);
        if (count($this->buffer) <= $bufIndex) {
            $this->buffer[] = 0;
        }
        if ($bit === \true) {
            $this->buffer[$bufIndex] |= 0x80 >> $this->length % 8;
        }
        $this->length++;
        return $this;
    }
    /**
     * returns the current buffer length
     */
    public function getLength() : int
    {
        return $this->length;
    }
    /**
     * returns the buffer content
     *
     * to debug: array_map(fn($v) => sprintf('%08b', $v), $bitBuffer->getBuffer())
     */
    public function getBuffer() : array
    {
        return $this->buffer;
    }
    /**
     * @return int number of bits that can be read successfully
     */
    public function available() : int
    {
        return 8 * ($this->length - $this->bytesRead) - $this->bitsRead;
    }
    /**
     * @author Sean Owen, ZXing
     *
     * @param int $numBits number of bits to read
     *
     * @return int representing the bits read. The bits will appear as the least-significant bits of the int
     * @throws \chillerlan\QRCode\QRCodeException if numBits isn't in [1,32] or more than is available
     */
    public function read(int $numBits) : int
    {
        if ($numBits < 1 || $numBits > $this->available()) {
            throw new QRCodeException('invalid $numBits: ' . $numBits);
        }
        $result = 0;
        // First, read remainder from current byte
        if ($this->bitsRead > 0) {
            $bitsLeft = 8 - $this->bitsRead;
            $toRead = min($numBits, $bitsLeft);
            $bitsToNotRead = $bitsLeft - $toRead;
            $mask = 0xff >> 8 - $toRead << $bitsToNotRead;
            $result = ($this->buffer[$this->bytesRead] & $mask) >> $bitsToNotRead;
            $numBits -= $toRead;
            $this->bitsRead += $toRead;
            if ($this->bitsRead === 8) {
                $this->bitsRead = 0;
                $this->bytesRead++;
            }
        }
        // Next read whole bytes
        if ($numBits > 0) {
            while ($numBits >= 8) {
                $result = $result << 8 | $this->buffer[$this->bytesRead] & 0xff;
                $this->bytesRead++;
                $numBits -= 8;
            }
            // Finally read a partial byte
            if ($numBits > 0) {
                $bitsToNotRead = 8 - $numBits;
                $mask = 0xff >> $bitsToNotRead << $bitsToNotRead;
                $result = $result << $numBits | ($this->buffer[$this->bytesRead] & $mask) >> $bitsToNotRead;
                $this->bitsRead += $numBits;
            }
        }
        return $result;
    }
    /**
     * Clears the buffer and resets the stats
     */
    public function clear() : self
    {
        $this->buffer = [];
        $this->length = 0;
        return $this->rewind();
    }
    /**
     * Resets the read-counters
     */
    public function rewind() : self
    {
        $this->bytesRead = 0;
        $this->bitsRead = 0;
        return $this;
    }
}