<?php

namespace Zxing;

/**
 * This class is used to help decode images from files which arrive as GD Resource
 * It does not support rotation.
 */
final class IMagickLuminanceSource extends LuminanceSource
{
    public $luminances;
    private $dataWidth;
    private $dataHeight;
    private $left;
    private $top;
    private $image;

    public function __construct(
        \Imagick $image,
        $dataWidth,
        $dataHeight,
        $left = null,
        $top = null,
        $width = null,
        $height = null
    ) {
        if (!$left && !$top && !$width && !$height) {
            $this->_IMagickLuminanceSource($image, $dataWidth, $dataHeight);

            return;
        }
        parent::__construct($width, $height);
        if ($left + $width > $dataWidth || $top + $height > $dataHeight) {
            throw new \InvalidArgumentException("Crop rectangle does not fit within image data.");
        }
        $this->luminances = $image;
        $this->dataWidth  = $dataWidth;
        $this->dataHeight = $dataHeight;
        $this->left       = $left;
        $this->top        = $top;
    }

    public function _IMagickLuminanceSource(\Imagick $image, $width, $height)
    {
        parent::__construct($width, $height);

        $this->dataWidth  = $width;
        $this->dataHeight = $height;
        $this->left       = 0;
        $this->top        = 0;
        $this->image      = $image;


// In order to measure pure decoding speed, we convert the entire image to a greyscale array
// up front, which is the same as the Y channel of the YUVLuminanceSource in the real app.
        $this->luminances = [];

        $image->setImageColorspace(\Imagick::COLORSPACE_GRAY);
        // $image->newPseudoImage(0, 0, "magick:rose");
        $pixels = $image->exportImagePixels(1, 1, $width, $height, "RGB", \Imagick::PIXEL_CHAR);

        $array = [];
        $rgb   = [];

        $countPixels = count($pixels);
        for ($i = 0; $i < $countPixels; $i += 3) {
            $r = $pixels[$i] & 0xff;
            $g = $pixels[$i + 1] & 0xff;
            $b = $pixels[$i + 2] & 0xff;
            if ($r == $g && $g == $b) {
// Image is already greyscale, so pick any channel.

                $this->luminances[] = $r;//(($r + 128) % 256) - 128;
            } else {
// Calculate luminance cheaply, favoring green.
                $this->luminances[] = ($r + 2 * $g + $b) / 4;//(((($r + 2 * $g + $b) / 4) + 128) % 256) - 128;
            }
        }
    }

//@Override
    public function getRow($y, $row = null)
    {
        if ($y < 0 || $y >= $this->getHeight()) {
            throw new \InvalidArgumentException('Requested row is outside the image: ' . $y);
        }
        $width = $this->getWidth();
        if ($row == null || count($row) < $width) {
            $row = [];
        }
        $offset = ($y + $this->top) * $this->dataWidth + $this->left;
        $row    = arraycopy($this->luminances, $offset, $row, 0, $width);

        return $row;
    }

//@Override
    public function getMatrix()
    {
        $width  = $this->getWidth();
        $height = $this->getHeight();

// If the caller asks for the entire underlying image, save the copy and give them the
// original data. The docs specifically warn that result.length must be ignored.
        if ($width == $this->dataWidth && $height == $this->dataHeight) {
            return $this->luminances;
        }

        $area        = $width * $height;
        $matrix      = [];
        $inputOffset = $this->top * $this->dataWidth + $this->left;

// If the width matches the full width of the underlying data, perform a single copy.
        if ($width == $this->dataWidth) {
            $matrix = arraycopy($this->luminances, $inputOffset, $matrix, 0, $area);

            return $matrix;
        }

// Otherwise copy one cropped row at a time.
        $rgb = $this->luminances;
        for ($y = 0; $y < $height; $y++) {
            $outputOffset = $y * $width;
            $matrix       = arraycopy($rgb, $inputOffset, $matrix, $outputOffset, $width);
            $inputOffset  += $this->dataWidth;
        }

        return $matrix;
    }

//@Override
    public function isCropSupported()
    {
        return true;
    }

//@Override
    public function crop($left, $top, $width, $height)
    {
        return $this->luminances->cropImage($width, $height, $left, $top);

        return new GDLuminanceSource($this->luminances,
            $this->dataWidth,
            $this->dataHeight,
            $this->left + $left,
            $this->top + $top,
            $width,
            $height);
    }
}