<?php
namespace app\common\library\gif;
class Encoder
{
    public $GIF = "GIF89a"; /* GIF header 6 bytes    */
    public $VER = "GIFEncoder V2.05"; /* Encoder version        */
    public $BUF = [];
    public $LOP = 0;
    public $DIS = 2;
    public $COL = -1;
    public $IMG = -1;
    public $ERR = [
        'ERR00' => "Does not supported function for only one image!",
        'ERR01' => "Source is not a GIF image!",
        'ERR02' => "Unintelligible flag ",
        'ERR03' => "Does not make animation from animated GIF source",
    ];

    /*
    :::::::::::::::::::::::::::::::::::::::::::::::::::
    ::
    ::    GIFEncoder...
    ::
     */
    public function __construct(
        $GIF_src, $GIF_dly, $GIF_lop, $GIF_dis,
        $GIF_red, $GIF_grn, $GIF_blu, $GIF_mod
    )
    {
        if (!is_array($GIF_src)) {
            printf("%s: %s", $this->VER, $this->ERR['ERR00']);
            exit(0);
        }
        $this->LOP = ($GIF_lop > -1) ? $GIF_lop : 0;
        $this->DIS = ($GIF_dis > -1) ? (($GIF_dis < 3) ? $GIF_dis : 3) : 2;
        $this->COL = ($GIF_red > -1 && $GIF_grn > -1 && $GIF_blu > -1) ?
            ($GIF_red | ($GIF_grn << 8) | ($GIF_blu << 16)) : -1;
        for ($i = 0; $i < count($GIF_src); $i++) {
            if (strtolower($GIF_mod) == "url") {
                $this->BUF[] = fread(fopen($GIF_src[$i], "rb"), filesize($GIF_src[$i]));
            } else if (strtolower($GIF_mod) == "bin") {
                $this->BUF[] = $GIF_src[$i];
            } else {
                printf("%s: %s ( %s )!", $this->VER, $this->ERR['ERR02'], $GIF_mod);
                exit(0);
            }
            if (substr($this->BUF[$i], 0, 6) != "GIF87a" && substr($this->BUF[$i], 0, 6) != "GIF89a") {
                printf("%s: %d %s", $this->VER, $i, $this->ERR['ERR01']);
                exit(0);
            }
            for ($j = (13 + 3 * (2 << (ord($this->BUF[$i][10]) & 0x07))), $k = true; $k; $j++) {
                switch ($this->BUF[$i][$j]) {
                    case "!":
                        if ((substr($this->BUF[$i], ($j + 3), 8)) == "NETSCAPE") {
                            printf("%s: %s ( %s source )!", $this->VER, $this->ERR['ERR03'], ($i + 1));
                            exit(0);
                        }
                        break;
                    case ";":
                        $k = false;
                        break;
                }
            }
        }
        $this->addHeader();
        for ($i = 0; $i < count($this->BUF); $i++) {
            $this->addFrames($i, $GIF_dly[$i]);
        }
        $this->addFooter();
    }

    /*
    :::::::::::::::::::::::::::::::::::::::::::::::::::
    ::
    ::    GIFAddHeader...
    ::
     */
    public function addHeader()
    {
        if (ord($this->BUF[0][10]) & 0x80) {
            $cmap = 3 * (2 << (ord($this->BUF[0][10]) & 0x07));
            $this->GIF .= substr($this->BUF[0], 6, 7);
            $this->GIF .= substr($this->BUF[0], 13, $cmap);
            $this->GIF .= "!\377\13NETSCAPE2.0\3\1" . $this->word($this->LOP) . "\0";
        }
    }

    /*
    :::::::::::::::::::::::::::::::::::::::::::::::::::
    ::
    ::    GIFAddFrames...
    ::
     */
    public function addFrames($i, $d)
    {
        $Locals_img = '';
        $Locals_str = 13 + 3 * (2 << (ord($this->BUF[$i][10]) & 0x07));
        $Locals_end = strlen($this->BUF[$i]) - $Locals_str - 1;
        $Locals_tmp = substr($this->BUF[$i], $Locals_str, $Locals_end);
        $Global_len = 2 << (ord($this->BUF[0][10]) & 0x07);
        $Locals_len = 2 << (ord($this->BUF[$i][10]) & 0x07);
        $Global_rgb = substr($this->BUF[0], 13,
            3 * (2 << (ord($this->BUF[0][10]) & 0x07)));
        $Locals_rgb = substr($this->BUF[$i], 13,
            3 * (2 << (ord($this->BUF[$i][10]) & 0x07)));
        $Locals_ext = "!\xF9\x04" . chr(($this->DIS << 2) + 0) .
            chr(($d >> 0) & 0xFF) . chr(($d >> 8) & 0xFF) . "\x0\x0";
        if ($this->COL > -1 && ord($this->BUF[$i][10]) & 0x80) {
            for ($j = 0; $j < (2 << (ord($this->BUF[$i][10]) & 0x07)); $j++) {
                if (
                    ord($Locals_rgb[3 * $j + 0]) == (($this->COL >> 16) & 0xFF) &&
                    ord($Locals_rgb[3 * $j + 1]) == (($this->COL >> 8) & 0xFF) &&
                    ord($Locals_rgb[3 * $j + 2]) == (($this->COL >> 0) & 0xFF)
                ) {
                    $Locals_ext = "!\xF9\x04" . chr(($this->DIS << 2) + 1) .
                        chr(($d >> 0) & 0xFF) . chr(($d >> 8) & 0xFF) . chr($j) . "\x0";
                    break;
                }
            }
        }
        switch ($Locals_tmp[0]) {
            case "!":
                /**
                 * @var string $Locals_img ;
                 */
                $Locals_img = substr($Locals_tmp, 8, 10);
                $Locals_tmp = substr($Locals_tmp, 18, strlen($Locals_tmp) - 18);
                break;
            case ",":
                $Locals_img = substr($Locals_tmp, 0, 10);
                $Locals_tmp = substr($Locals_tmp, 10, strlen($Locals_tmp) - 10);
                break;
        }
        if (ord($this->BUF[$i][10]) & 0x80 && $this->IMG > -1) {
            if ($Global_len == $Locals_len) {
                if ($this->blockCompare($Global_rgb, $Locals_rgb, $Global_len)) {
                    $this->GIF .= ($Locals_ext . $Locals_img . $Locals_tmp);
                } else {
                    $byte = ord($Locals_img[9]);
                    $byte |= 0x80;
                    $byte &= 0xF8;
                    $byte |= (ord($this->BUF[0][10]) & 0x07);
                    $Locals_img[9] = chr($byte);
                    $this->GIF .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp);
                }
            } else {
                $byte = ord($Locals_img[9]);
                $byte |= 0x80;
                $byte &= 0xF8;
                $byte |= (ord($this->BUF[$i][10]) & 0x07);
                $Locals_img[9] = chr($byte);
                $this->GIF .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp);
            }
        } else {
            $this->GIF .= ($Locals_ext . $Locals_img . $Locals_tmp);
        }
        $this->IMG = 1;
    }

    /*
    :::::::::::::::::::::::::::::::::::::::::::::::::::
    ::
    ::    GIFAddFooter...
    ::
     */
    public function addFooter()
    {
        $this->GIF .= ";";
    }

    /*
    :::::::::::::::::::::::::::::::::::::::::::::::::::
    ::
    ::    GIFBlockCompare...
    ::
     */
    public function blockCompare($GlobalBlock, $LocalBlock, $Len)
    {
        for ($i = 0; $i < $Len; $i++) {
            if (
                $GlobalBlock[3 * $i + 0] != $LocalBlock[3 * $i + 0] ||
                $GlobalBlock[3 * $i + 1] != $LocalBlock[3 * $i + 1] ||
                $GlobalBlock[3 * $i + 2] != $LocalBlock[3 * $i + 2]
            ) {
                return (0);
            }
        }
        return (1);
    }

    /*
    :::::::::::::::::::::::::::::::::::::::::::::::::::
    ::
    ::    GIFWord...
    ::
     */
    public function word($int)
    {
        return (chr($int & 0xFF) . chr(($int >> 8) & 0xFF));
    }

    /*
    :::::::::::::::::::::::::::::::::::::::::::::::::::
    ::
    ::    GetAnimation...
    ::
     */
    public function getAnimation()
    {
        return ($this->GIF);
    }
}