<?php

require_once './src/D2Functions.php';
require_once './src/D2BitReader.php';

/**
 *
 */
class D2ByteReader {

    /**
     * @var string
     */
    private string $data = '';
    /**
     * @var int
     */
    private int $offset = 0;

    /**
     * @param string $data
     */
    public function __construct(string $data) {
        if (!$data)
            return false;
        $this->data = $data;
    }

    /**
     * @param int $numBytes
     * @return bool
     */
    public function skip(int $numBytes): bool {
        if ($numBytes < 0 || $numBytes > strlen($this->data))
            return false;
        $this->offset += $numBytes;
        return $true;
    }

    /**
     * @param int $pos
     * @return bool
     */
    public function seek(int $pos): bool {
        if ($pos < 0 || $pos > strlen($this->data))
            return false;
        $this->offset = $pos;
        return true;
    }

    /**
     * @param int $offset
     * @param int $numBytes
     * @param bool $str
     * @return string
     */
    public function read(int $offset, int $numBytes) {
        $this->seek($offset);
        $bytes = null;
        for ($i = $this->offset; $i < $this->offset + $numBytes; $i++) {
            $bytes .= $this->data[$i];
        }
        return $bytes;
    }
    
    /**
     * @param int $offset
     * @param int $numBytes
     * @param bool $str
     * @return string
     */
    public function readh(int $offset, int $numBytes, bool $str = true) {
        $this->seek($offset);
        $bytes = null;
        for ($i = $this->offset; $i < $this->offset + $numBytes; $i++) {
            $str ? $bytes .= $this->data[$i] : $bytes[] = $this->data[$i];
        }
        return unpack('H*', $bytes)[1];
    }
    
    /**
     * @param int $offset
     * @param int $numBytes
     * @param bool $str
     * @return array
     */
    public function readc(int $offset, int $numBytes, bool $str = true) {
        $this->seek($offset);
        $bytes = null;
        for ($i = $this->offset; $i < $this->offset + $numBytes; $i++) {
            $str ? $bytes .= $this->data[$i] : $bytes[] = $this->data[$i];
        }
        return unpack('C*', $bytes);
    }

    /**
     * @return bool
     */
    public function rewind(): bool {
        $this->offset = 0;
        return true;
    }

    /**
     * @param int $offset
     * @param int $byte
     * @return void
     */
    public function writeByte(int $offset, int $byte) {
        $this->data[$offset] = pack('C', $byte);
    }

    /**
     * @param int $offset
     * @param string $bytes
     * @return false|void
     */
    public function writeBytes(int $offset, string $bytes) {
        if ($offset < 0 || $offset > strlen($this->data) || $bytes == '')
            return false;
        $_bytes = str_split($bytes, 2);
        foreach ($_bytes as $k => $byte) {
            $pos = $offset + $k;
            $this->data[$pos] = pack('H*', $byte);
        }
    }

    /**
     * @param int $offset
     * @param string $bytes
     * @return false|void
     */
    public function insertBytes(int $offset, string $bytes) {
        if ($offset < 0 || $offset > strlen($this->data) || $bytes == '')
            return false;
        $data = bin2hex($this->data); // convert to hex bytes string
        $newData = substr_replace($data, $bytes, $offset, 0);
        $this->data = hex2bin($newData);
    }

    /**
     * @return false|string
     */
    public function getData() {
        return $this->data ? $this->data : false;
    }

    /**
     * @param $data
     * @return void
     */
    public function setData($data){
        $this->data = $data;
    }

    /**
     * @return int
     */
    public function getOffset(): int {
        return $this->offset;
    }

    /**
     * @param string $str
     * @return bool
     */
    public function isHexString(string $str): bool {
        if (strlen($str) % 2 == 0 && (ctype_xdigit($str))) {
            return true;
        }
        return false;
    }

    /**
     * @param $input
     * @return string
     */
    public function toBits($input): string {
        $output = '';
        if ($this->isHexString($input)) {
            foreach (str_split($input, 2) as $byte) {
                $output .= (strrev(str_pad(decbin(hexdec($byte)), 8, 0, STR_PAD_LEFT)));
            }
            return $output;
        } else if (is_string($input)) {
            foreach (str_split($input) as $i) {
                $output .= strrev(str_pad(decbin(ord($i)), 8, 0, STR_PAD_LEFT));
            }
            return $output;
        } else if (is_int($input)) {
            return strrev(str_pad(decbin($input), 8, 0, STR_PAD_LEFT));
        } else if (is_array($input)) {
            foreach ($input as $i) {
                $output .= $this->tobits($i);
            }
            return $output;
        }
    }

    /**
     * @param string $bits
     * @return string
     */
    public function toBytesR(string $bits) : string {
        $bytes = '';
        foreach (str_split($bits, 8) as $byteString) {
            $bytes .= strtoupper(str_pad(dechex(bindec(($byteString))), 2, 0, STR_PAD_LEFT));
        }
        return $bytes;
    }

    /**
     * @param string $bits
     * @return string
     */
    public function toBytes(string $bits) : string {
        foreach (str_split($bits, 8) as $byteString) {
            $bytes .= strtoupper(str_pad(dechex(bindec(strrev($byteString))), 2, 0, STR_PAD_LEFT));
        }
        return $bytes;
    }

    /**
     * @param string $bits
     * @return string
     */
    public function bitsToHexString(string $bits): string {
        $bytes = '';
        foreach (str_split($bits, 8) as $byte) {
            $bytes .= (str_pad(dechex((bindec(strrev($byte)))), 2, 0, STR_PAD_LEFT));
        }
        return $bytes;
    }

    /**
     * @param string $bits
     * @return array
     */
    public function bitsToHexArray(string $bits): array {
        $bytes = [];
        foreach (str_split($bits, 8) as $byte) {
            $bytes[] = (str_pad(dechex((bindec(strrev($byte)))), 2, 0, STR_PAD_LEFT));
        }
        return $bytes;
    }

    /**
     * @param string $bits
     * @return array
     */
    public function bitsToIntArray(string $bits): array {
        $bytes = [];
        foreach (str_split($bits, 8) as $byte) {
            $bytes[] = (int) (str_pad(dechex((bindec(strrev($byte)))), 2, 0, STR_PAD_LEFT));
        }
        return $bytes;
    }

    /**
     * @param int $byte
     * @param int $pos
     * @param bool $bit
     * @return int
     */
    public function setBit(int $byte, int $pos, bool $bit) {
        return ($bit ? ($byte | (1 << $pos)) : ($byte & ~(1 << $pos)) );
    }

    /**
     * @param int $byte
     * @param int $pos
     * @return int
     */
    public function getBit(int $byte, int $pos): int {
        return intval(($byte & (1 << $pos)) != 0);
    }

}