<?php

class QRmask
{
    public $runLength = array();
    public function __construct()
    {
        $this->runLength = array_fill(0, QRSPEC_WIDTH_MAX + 1, 0);
    }
    public function writeFormatInformation($width, &$frame, $mask, $level)
    {
        $blacks = 0;
        $format = QRspec::getFormatInfo($mask, $level);
        for ($i = 0; $i < 8; $i++) {
            if ($format & 1) {
                $blacks += 2;
                $v = 133;
            } else {
                $v = 132;
            }
            $frame[8][$width - 1 - $i] = chr($v);
            if ($i < 6) {
                $frame[$i][8] = chr($v);
            } else {
                $frame[$i + 1][8] = chr($v);
            }
            $format = $format >> 1;
        }
        for ($i = 0; $i < 7; $i++) {
            if ($format & 1) {
                $blacks += 2;
                $v = 133;
            } else {
                $v = 132;
            }
            $frame[$width - 7 + $i][8] = chr($v);
            if ($i == 0) {
                $frame[8][7] = chr($v);
            } else {
                $frame[8][6 - $i] = chr($v);
            }
            $format = $format >> 1;
        }
        return $blacks;
    }
    public function mask0($x, $y)
    {
        return $x + $y & 1;
    }
    public function mask1($x, $y)
    {
        return $y & 1;
    }
    public function mask2($x, $y)
    {
        return $x % 3;
    }
    public function mask3($x, $y)
    {
        return ($x + $y) % 3;
    }
    public function mask4($x, $y)
    {
        return (int) $y / 2 + (int) $x / 3 & 1;
    }
    public function mask5($x, $y)
    {
        return ($x * $y & 1) + $x * $y % 3;
    }
    public function mask6($x, $y)
    {
        return ($x * $y & 1) + $x * $y % 3 & 1;
    }
    public function mask7($x, $y)
    {
        return $x * $y % 3 + ($x + $y & 1) & 1;
    }
    private function generateMaskNo($maskNo, $width, $frame)
    {
        $bitMask = array_fill(0, $width, array_fill(0, $width, 0));
        for ($y = 0; $y < $width; $y++) {
            for ($x = 0; $x < $width; $x++) {
                if (ord($frame[$y][$x]) & 128) {
                    $bitMask[$y][$x] = 0;
                } else {
                    $maskFunc = call_user_func(array($this, 'mask' . $maskNo), $x, $y);
                    $bitMask[$y][$x] = $maskFunc == 0 ? 1 : 0;
                }
            }
        }
        return $bitMask;
    }
    public static function serial($bitFrame)
    {
        $codeArr = array();
        foreach ($bitFrame as $line) {
            $codeArr[] = join('', $line);
        }
        return gzcompress(join("\n", $codeArr), 9);
    }
    public static function unserial($code)
    {
        $codeArr = array();
        $codeLines = explode("\n", gzuncompress($code));
        foreach ($codeLines as $line) {
            $codeArr[] = str_split($line);
        }
        return $codeArr;
    }
    public function makeMaskNo($maskNo, $width, $s, &$d, $maskGenOnly = false)
    {
        $b = 0;
        $bitMask = array();
        $fileName = QR_CACHE_DIR . 'mask_' . $maskNo . DIRECTORY_SEPARATOR . 'mask_' . $width . '_' . $maskNo . '.dat';
        if (QR_CACHEABLE) {
            if (file_exists($fileName)) {
                $bitMask = self::unserial(file_get_contents($fileName));
            } else {
                $bitMask = $this->generateMaskNo($maskNo, $width, $s, $d);
                if (!file_exists(QR_CACHE_DIR . 'mask_' . $maskNo)) {
                    mkdir(QR_CACHE_DIR . 'mask_' . $maskNo);
                }
                file_put_contents($fileName, self::serial($bitMask));
            }
        } else {
            $bitMask = $this->generateMaskNo($maskNo, $width, $s, $d);
        }
        if ($maskGenOnly) {
            return NULL;
        }
        $d = $s;
        for ($y = 0; $y < $width; $y++) {
            for ($x = 0; $x < $width; $x++) {
                if ($bitMask[$y][$x] == 1) {
                    $d[$y][$x] = chr(ord($s[$y][$x]) ^ (int) $bitMask[$y][$x]);
                }
                $b += (int) ord($d[$y][$x]) & 1;
            }
        }
        return $b;
    }
    public function makeMask($width, $frame, $maskNo, $level)
    {
        $masked = array_fill(0, $width, str_repeat('' . "\0" . '', $width));
        $this->makeMaskNo($maskNo, $width, $frame, $masked);
        $this->writeFormatInformation($width, $masked, $maskNo, $level);
        return $masked;
    }
    public function calcN1N3($length)
    {
        $demerit = 0;
        for ($i = 0; $i < $length; $i++) {
            if (5 <= $this->runLength[$i]) {
                $demerit += N1 + ($this->runLength[$i] - 5);
            }
            if ($i & 1) {
                if (3 <= $i && $i < $length - 2 && $this->runLength[$i] % 3 == 0) {
                    $fact = (int) $this->runLength[$i] / 3;
                    if ($this->runLength[$i - 2] == $fact && $this->runLength[$i - 1] == $fact && $this->runLength[$i + 1] == $fact && $this->runLength[$i + 2] == $fact) {
                        if ($this->runLength[$i - 3] < 0 || 4 * $fact <= $this->runLength[$i - 3]) {
                            $demerit += N3;
                        } else {
                            if ($length <= $i + 3 || 4 * $fact <= $this->runLength[$i + 3]) {
                                $demerit += N3;
                            }
                        }
                    }
                }
            }
        }
        return $demerit;
    }
    public function evaluateSymbol($width, $frame)
    {
        $head = 0;
        $demerit = 0;
        for ($y = 0; $y < $width; $y++) {
            $head = 0;
            $this->runLength[0] = 1;
            $frameY = $frame[$y];
            if (0 < $y) {
                $frameYM = $frame[$y - 1];
            }
            for ($x = 0; $x < $width; $x++) {
                if (0 < $x && 0 < $y) {
                    $b22 = ord($frameY[$x]) & ord($frameY[$x - 1]) & ord($frameYM[$x]) & ord($frameYM[$x - 1]);
                    $w22 = ord($frameY[$x]) | ord($frameY[$x - 1]) | ord($frameYM[$x]) | ord($frameYM[$x - 1]);
                    if (($b22 | $w22 ^ 1) & 1) {
                        $demerit += N2;
                    }
                }
                if ($x == 0 && ord($frameY[$x]) & 1) {
                    $this->runLength[0] = -1;
                    $head = 1;
                    $this->runLength[$head] = 1;
                } else {
                    if (0 < $x) {
                        if ((ord($frameY[$x]) ^ ord($frameY[$x - 1])) & 1) {
                            $head++;
                            $this->runLength[$head] = 1;
                        } else {
                            $this->runLength[$head]++;
                        }
                    }
                }
            }
            $demerit += $this->calcN1N3($head + 1);
        }
        for ($x = 0; $x < $width; $x++) {
            $head = 0;
            $this->runLength[0] = 1;
            for ($y = 0; $y < $width; $y++) {
                if ($y == 0 && ord($frame[$y][$x]) & 1) {
                    $this->runLength[0] = -1;
                    $head = 1;
                    $this->runLength[$head] = 1;
                } else {
                    if (0 < $y) {
                        if ((ord($frame[$y][$x]) ^ ord($frame[$y - 1][$x])) & 1) {
                            $head++;
                            $this->runLength[$head] = 1;
                        } else {
                            $this->runLength[$head]++;
                        }
                    }
                }
            }
            $demerit += $this->calcN1N3($head + 1);
        }
        return $demerit;
    }
    public function mask($width, $frame, $level)
    {
        $minDemerit = PHP_INT_MAX;
        $bestMaskNum = 0;
        $bestMask = array();
        $checked_masks = array(0, 1, 2, 3, 4, 5, 6, 7);
        if (QR_FIND_FROM_RANDOM !== false) {
            $howManuOut = 8 - QR_FIND_FROM_RANDOM % 9;
            for ($i = 0; $i < $howManuOut; $i++) {
                $remPos = rand(0, count($checked_masks) - 1);
                unset($checked_masks[$remPos]);
                $checked_masks = array_values($checked_masks);
            }
        }
        $bestMask = $frame;
        foreach ($checked_masks as $i) {
            $mask = array_fill(0, $width, str_repeat('' . "\0" . '', $width));
            $demerit = 0;
            $blacks = 0;
            $blacks = $this->makeMaskNo($i, $width, $frame, $mask);
            $blacks += $this->writeFormatInformation($width, $mask, $i, $level);
            $blacks = (int) (100 * $blacks) / ($width * $width);
            $demerit = (int) (int) abs($blacks - 50) / 5 * N4;
            $demerit += $this->evaluateSymbol($width, $mask);
            if ($demerit < $minDemerit) {
                $minDemerit = $demerit;
                $bestMask = $mask;
                $bestMaskNum = $i;
            }
        }
        return $bestMask;
    }
}
define('N1', 3);
define('N2', 3);
define('N3', 40);
define('N4', 10);